Monday 3rd April
Tuesday 4th April
Wednesday 5th April
Thursday 6th April
Monday 3rd April
UMMER HABITAT SUITABILITY OF THREE TEUTHOPHAGOUS ODONTOCETES IN THE NORTH WESTERN MEDITERRANEAN SEA.
PRACA, E. (1,3), GANNIER, A. (2) AND DAS, K. (3)
(1) Centre de Recherche sur les Cétacés - Marineland, 306 avenue Mozart, 06600 Antibes, France; (2) Groupe de Recherche sur les Cétacés, BP715, 06633 Antibes cedex, France; Laboratoire d'Océanologie B6c, Université de Li?ge, Allée de la Chimie 3, Li?ge 4000, Belgique
The prediction of habitat suitability of a species provides information about the relation between its distribution and environmental factors and forecasts its potential presence. It's therefore an important tool for species conservation and management of protected zones. In the northwestern Mediterranean, sperm whales (Physeter macrocephalus), pilot whales (Globicephala melas) and Risso's dolphins (Grampus griseus), all teuthophageous, may be in competition for the resource. Modelling their distribution allowed us to evaluate their possible competition for the habitat. The Ecological-Niche Factor Analysis (ENFA) is a recent multi-factorial analysis based on presence-only data. It gives an ecological mean to the resultant axes, representing the marginality (M, difference between the species habitat and the mean conditions available) and the specialization (S, difference between variance of the species observed habitat and variance of the study area) of the species. Data sampled in summer 1998 to 2005 (N=191 for sperm whale, 22 for pilot whale and 17 for Risso's dolphin) were compiled with topography, temperature and concentrations in chlorophyll factors. Sperm and pilot whales seemed to have close habitat suitability. Marginality (M=1.13 and 1.48 respectively) indicated their preference for colder and more productive waters than the mean of the study area. The pilot whale was more specialized than sperm whale (S=19.54 vs. 2.46) and principally influenced by the presence of thermal fronts in spring. Distribution of sperm whale was either related to fronts and to the slope. The principal habitat area for those species were then the central Ligurian-Provençal Basin, the more productive part of the northwestern Mediterranean, but more restricted for the pilot whale. The Risso's dolphin's model was less powerful, probably reflecting the migratory behaviour of this species. Nevertheless, the marginality (M=0.64) highlighted an important relation to waters closest to the shore, contrary to the previous species.
Day: Monday 3 April ; Time: 8:40; Eligible for Student Award: Postgraduate
TEMPORAL AND SPATIAL HABITAT PARTITIONING BETWEEN HARBOUR PORPOISES AND BOTTLENOSE DOLPHINS.
SIMON, M. (1,3), REYES ZAMUDIO, M. M. (2), NUUTTILA, H. (3) AND EVANS, P. G. (3)
(1) Greenland Institute of Natural Resources, Nuuk, Groenland; (2) School of Biological Sciences, University of Wales, Bangor, UK; (3) Sea Watch Foundation, Oxford, UK
During recent years, the frequency of porpoise deaths attributed to bottlenose dolphin kills in Cardigan Bay has increased markedly. The cause of this remains uncertain, but one hypothesis is that numbers and distribution of one or both species has changed so that the two species compete for some resource, such as space or prey. Analyses were undertaken of spatio-temporal patterns of stranded porpoises killed by dolphins, and generalised additive modelling was conducted on sightings data, to identify areas where the two species are concentrated, and from this to predict potential areas of competition and possible habitat partitioning. All of these analyses showed seasonal variations: dolphins being scarce or absent in the winter and abundant in the summer but no pronounced seasonal variation in presence of harbour porpoises. However, no clear patterns in spatio-temporal habitat partitioning were found. Passive acoustic monitoring using T-PODs can provide information of the presence of bottlenose dolphins and harbour porpoise at strategic locations over long periods of time, throughout 24-hours, and independent of sea state. We calibrated ten T-PODs in pool and field conditions, in order to ensure inter T-POD data comparability, and we deployed the ten T-PODs in Cardigan Bay SAC from March to December 2005. In order to gain insight to the behavioural context of the T-POD detections and the relationship between rate and intensity of detections, group size and behaviour, theodolite tracking was carried out for comparison of acoustic detections with visual observations. The T-POD data confirmed the seasonal variations but in addition revealed clear spatial-temporal habitat partitioning between the two species in some parts of the SAC. This might be a result of the aggressive behaviour of dolphins towards porpoises in the area. Further investigations, such as examination of dietary preferences, are needed to identify the factors promoting this unusual behaviour.
Day: Monday 3 April ; Time: 9:00; Eligible for Student Award: No
SPATIOTEMPORAL PREDICTION OF FIN WHALE DISTRIBUTION IN THE MEDITERRANEAN SEA.
LARAN, S.(1) AND GANNIER, A.(2)
(1) Centre de Recherche sur les Cétacés, 306 avenue Mozart, 06600 Antibes, France; (2) Groupe de Recherche sur les Cétacés, BP 715, 06633 Antibes cedex, France
Prediction models were developed for fin whale (Balaenoptera physalus) in the Ligurian Sea. An effort of 2,745 km distributed on twelve dedicated surveys was carried out between mainland and Corsica from 2001 to 2003. Surveys were conducted on a monthly basis, using the same platform and the same protocol. Using multiple logistic regression, presence of fin whales was related to predictor variables as topographic variables (Depth, Contour Index, distance to the shore) and oceanographic parameters from remote sensing (Sea Surface Temperature, Chlorophyll and Net primary production) on 8-day periods.
Simultaneous primary production, water temperature and distance to the coast were selected by stepwise procedure as influent on whale distribution. Model predicted correctly 62.5% of the sampled cells. The model predicted successfully the fin whale spreading between June and August and spatial shift of whale distribution from a year to the next. Cross validation of the predicted distribution was done with external data set from 1998 to 2002 (on 8,240 km). The selected model predicted correctly 74% of the external data set (73.8% of the presence and 74.1% of the absence). Reliable prediction were obtained for fin whale, providing promising results for the development of future applications. This project will contribute to understand fin whale distribution and links with environmental parameters in an area or whales are well known to concentrate each summer to feed. Prediction of weekly distribution of fin whale in relation to environmental parameters represent a very useful conservation tool to prevent collisions with ship or as conservation tool in the Marine Protected Area.
Day: Monday 3 April ; Time: 9:20; Eligible for Student Award: No
SPATIO-TEMPORAL VARIATIONS IN HABITAT PREFERENCES OF HARBOUR PORPOISES IN THE WATERS NORTHWEST OF SCOTLAND.
BANNON, S.M., MACLEOD, C.D. AND PIERCE, G.J.
School of Biological Sciences (Zoology), University of Aberdeen, Tillydrone Avenue, Aberdeen, AB24 2TN, United Kingdom
The relationships between eco-geographic variables (EGVs) and harbour porpoise (Phocoena phocoena) occurrence in the waters around the Scottish northwest coast were investigated. Data were collected throughout May to September of 2001 to 2004 via regular surveys conducted from a network of passenger ferries. A geographical information system (GIS) was constructed to process the field data and to allow integration of the eco-geographic variables. Generalised additive modelling (GAM) and generalised linear modelling (GLM) was used to identify relationships between the EGVs (seabed gradient, seabed aspect, water depth and distance to coast) and harbour porpoise occurrence. A single model covering the whole study area and all survey months explained only a small amount of the variation in harbour porpoise occurrence (10.9%). However, when the study area was sub-divided and data were examined for monthly differences, the performance of the models generally increased. For example, a model restricted to the Sea of Hebrides and the month of May explained 29.7% of variation in porpoise occurrence. In addition, different EGVs were significantly related to porpoise occurrence in different areas and months. This suggests that habitat preferences of harbour porpoises vary both spatially and temporally in the waters of northwest Scotland. Similarly, the accuracy of the models spatial predictive abilities improved when monthly variations were examined within each geographic sub-division. The physical EGVs may be influencing the spatial and temporal occurrence of harbour porpoises by affecting the biological productivity of an area which will in turn, effect the distribution, abundance and availability of prey.
Day: Monday 3 April ; Time: 9:40; Eligible for Student Award: Postgraduate
AN UNEXPECTED EFFECT OF GLOBAL WARMING: INCREASED RISK OF HARBOUR PORPOISE ICE ENTRAPMENT.
BJORGE, A. (1) AND GRANER, F. (2)
(1) Institute of Marine Research, c/o University of Oslo, Department of Biology, P.O. Box 1066 Blindern, N-0316 Oslo, Norway; (2) Sealife Productions, 226 Walnut Street, Pacific Grove, CA 93950 USA
The fjords of Norway penetrate up to 200 km from the open coast into the mountain areas. Several fjords host resident stocks of sprat and herring, and they are important harbour porpoise foraging habitats. Historically, inner parts of the fjords froze during winter and ice entrapments of porpoises were known to occur. As autumn progressed the temperature dropped and the precipitation came as snow. The ground froze and the river water flow became strongly reduced. Winds caused vertical mixing of the fjord waters, and lower air temperatures only gradually cooled the surface water with subsequent gradual formation of ice. Frozen fjords often remained ice-covered until spring. We provide information on local climate change and formation of fjord ice during the 20th century. We give some recent examples of ice entrapment of porpoises, and we hypothesise that the increased winter temperatures in combination with passages of strong Atlantic low-pressure systems increase the risk of porpoise ice entrapment. In recent years the average winter temperature increased between 1o and 2oC and the fjords remain free of ice during large parts of the winter. Throughout the winter, passages of strong Atlantic low-pressure systems provide periods of mild westerly winds and rainfall, even at some altitude in the mountains. River floods form shallow fresh water surface layer in the fjords. After low-pressure passages, the clouds brake up, winds calm and temperatures drop to well below freezing. The thin fresh water surface layer freezes rapidly and ice expands over large fjord areas in matter of few hours causing frequent entrapment of porpoises. The salt water below the fresh surface layer might still hold temperatures well above freezing, and the ice might be broken by the next low-pressure passage, followed by new temperature drops and subsequent rapid re-freezing and new possibilities for entrapment of harbour porpoises.
Day: Monday 3 April ; Time: 11:40; Eligible for Student Award: No
SEASONAL HAULOUT PATTERNS OF THE SOUTHERN MOST COLONY OF EUROPEAN GREY SEALS: COMBINING INDIVIDUAL AND POPULATION-BASED STUDIES.
VINCENT, C. (1), GÉRONDEAU, M. (1), BARBRAUD, C. (2), MCCONNELL, B.J. (3), FEDAK, M.A. (3) AND RIDOUX, V. (1)
(1) Laboratoire de Biologie et Environnements Marins, UMR 6217, CNRS/Université de La Rochelle, Avenue Michel Crépeau, 17 042 La Rochelle cedex, France; (2) Centre d'Etudes Biologiques de Chizé, CNRS UPR 1934, Villiers-en-bois, 79 360 Beauvoir sur Niort, France; (3) NERC Sea Mammal Research Unit, Gatty Marine Laboratory, School of Environmental and Evolutionary Biology, University of Saint-Andrews, Fife KY16 8LB, Scotland, UK
We studied year-round haulout site use by grey seals in the Mol?ne archipelago, France, by combining individual and population-based approaches. We investigated how population patterns emerged from individual movements in a colony at the limit of the species' range. Monthly censuses (n=49) showed that the number of seals hauled-out in the archipelago peaked during the moult, and was at a minimum during reproduction. The sex ratio was highly biased towards males during the moult, but less so the rest of the year. Photo-identification indicated high inter-annual fidelity for the Mol?ne archipelago for both sexes (70-95%). Multistate mark-recapture analysis showed that female fidelity was low from summer to breeding (34-43%) but higher from breeding to moult and then to summer (60-85%). However, all females observed during breeding were already photographed during summer. Males showed constant rates of fidelity/movements from one season to the next (56% and 44% respectively). Individual movements were assessed by fitting 16 seals with Satellite Relay Data Loggers (SMRU) during May-November in 1999, 2002 and 2003 (mean tracking duration: 104 days). While 56.8% of their tracking time was spent within the Mol?ne archipelago, fourteen seals also hauled out in Northern Brittany, the Isles of Scilly, Cornwall, Wales, and the Channel Islands up to 400 km away. On average, we recorded 0.6 long-distance trip/seal/month before summer, 0.3 during summer and 1.2 before breeding. We suggest that male and female grey seals use the haulout site of the Mol?ne archipelago during summer in the vicinity of their foraging grounds in order to replenish their fat reserves for breeding. However, most of them then breed elsewhere while a significant proportion of males return for moulting. A smaller proportion of male and female seals may remain in the archipelago during breeding and moulting, but almost all known individuals come back during summer.
Day: Monday 3 April ; Time: 12:00; Eligible for Student Award: No
FLOOD EVENTS AND THEIR IMPACT ON BOTTLENOSE DOLPHINS (TURSIOPS ADUNCUS) HABITAT USE IN TWO ESTUARIES IN AUSTRALIA.
FURY, C.A. (1), ROSS, G. (2) AND HARRISON, P. (1)
(1) Southern Cross University Whale Research Centre, P.O. Box 157, Lismore, New South Wales, Australia, 2480; (2) 21 Pudney Street, Farrer, Canberra, 2607, Australia
Habitat use of Bottlenose dolphins (Tursiops aduncus) were investigated in two estuaries in New South Wales, Australia. The study tested whether a flood event had any affect on dolphin habitat use within two estuaries. 118 boat-based surveys were undertaken in the Clarence River (CR) and Richmond River (RR) over 2 years comprising 618 hours (CR 290; RR 328) with 305 (CR) and 128 (RR) dolphins observed. The Clarence River has an estimated dolphin population of 58 SE 1.2 (58-73 95% CI) and the Richmond River 24 SE 0.9 (24-30 95% CI). Feeding was the major behaviour exhibited by the dolphins in both estuaries occurring 57% (CR) and 74% (RR) of their total time in the estuaries. A determining factor of the dolphins habitat use in the estuaries was 3 flood events that occurred during the 2 years of the study. The Clarence River dolphin abundance were estimated in non-flood periods at 1.13 per hour and in flood 0.29 per hour, additionally, in the Richmond River in non-flood periods 0.49 per hour and in flood 0.04 per hour making the difference statistically significant in both cases (Chi square CR 4.750, p = 0.029; RR 6.494, p = 0.011). These results indicate that during a flood event dolphins move out of the estuary. Water quality at this time is adversely affected by lowering pH, dissolved oxygen, turbidity, conductivity, water temperature and salinity. These changes also cause fish species to migrate out of the estuary and the dolphins movements are strongly related to the movements of their prey. This study demonstrates that flood events cause changes in Bottlenose dolphin habitat use in two Australian estuaries by leaving the estuary at times of flood. Management of agricultural practices in the catchments could improve water quality and would benefit estuarine fauna in times of flood.
Day: Monday 3 April ; Time: 12:20; Eligible for Student Award: Postgraduate
NOISE DURING OFFSHORE WIND TURBINE CONSTRUCTION AND IT'S EFFECTS ON HARBOUR PORPOISES (PHOCOENA PHOCOENA).
THOMSEN, F. (1,2), BETKE, K. (3), SCHULTZ-VON GLAHN, M.(2) AND PIPER, W. (1)
(1) Biologisch-landschaftsökologische Arbeitsgemeinschaft, Gotenstraße 4, D-20097 Hamburg, Germany; (2) Biozentrum Grindel, Universität Hamburg, Martin-Luther-King-Platz 3, D-20146 Hamburg, Germany; (3) Institut für technische und angewandte Physik, Marie-Curie-Straße 8, D-26129 Oldenburg, Germany
The extensive plans for installation of offshore wind farms in European waters have raised concerns about possible impacts on one of the most common cetacean species in the area, the harbour porpoise (Phocoena phocoena). Especially the noise generated during construction of wind turbines is potentially harmful for the species. However, detailed information on sound pressure levels in frequencies relevant to the hearing abilities of harbour porpoises are rarely provided and impact assessments are therefore difficult to conduct. We measured peak sound pressure levels (Lpeak) and sound exposure levels (LE) in 1/3 octave bands (frequency range = 20 Hz - 20 kHz) during ramming of a jacket-pile construction in the German Bight in summer 2003 (distance = 400 m from the source). We then calculated sound pressure levels at various distances and assessed zones of noise influence based on published data. The broadband Lpeak at 400 m was 189 dB re 1µPa (LE = 166 dB re 1µPa), resulting in a peak broadband source level of 228 dB re 1 µPa @ 1m (LE = 206 dB re 1 µPa @ 1m). The 1/3 octave SPL was highest at the 315 center frequency (Lpeak = 218 dB re 1 µPa @ 1m) with considerable pressures above 2 kHz. We predict that the measured noise is loud enough to be audible for porpoises in distances beyound 80 km, can mask communication in the range of 30 - 40 km and might induce behavioural reactions at distances of 10 - 20 km. TTS is expected within 1 km around the source, with frequencies above 2 kHz most harmful. We conclude that noise during construction of offshore windfarms has the potential to affect porpoise behaviour and physiology at considerable distances and that mitigation should focuss on damping of the higher frequency part of the ramming noise.
Day: Monday 3 April ; Time: 14:20; Eligible for Student Award: No
KILLER WHALE RESPONSES TO BOATS VARIES WITH BOAT NUMBER: IMPLICATIONS FOR EXPERIMENTAL DESIGN OF VESSEL IMPACT ASSESSMENTS.
ASHE, E.(1) AND WILLIAMS R. ( 2, 3)
(1) 2104 N 54th St. Seattle, WA 98103 USA; (2) Raincoast Conservation Society, Pearse Island, Box 193 Alert Bay BC V0N 1A0 Canada; (3) Sea Mammal Research Unit, Gatty Marine Laboratory, University of St Andrews, St Andrews, Scotland KY16 8LB UK
Vessel traffic has been implicated as a potential contributing factor to the at-risk status of two killer whale populations in western Canada and the US. Relevant guidelines can be informed by conducting experimental impact assessments that allow animal response to guide vessel management. Two published experimental studies documented stereotyped avoidance responses. Opportunistic observations from these studies suggested a shift in avoidance behavior when approximately 3 boats approached within 1000m. Our experiment was designed to test whether whales responded differently to approach by few (1-3) versus many (>3) vessels. Data were collected in summer 2004, in Johnstone Strait, British Columbia using a theodolite to track positions of boats and individually identifiable whales. Experimental trials included 20-minute "no boat" and 20-minute "boat" phases with local whalewatching vessels during which data were collected continuously on the focal whale. Responses of the 16 adult male killer whales tracked differed significantly between treatment levels (Wilcoxon's test P =0.0148). Swimming path became less direct when approached by few boats, and whales increased path directness when approached by many boats. Consistent with previous experiments, inter-breath interval, swimming speed, angle between successive dives, and rates of surface behavior did not differ significantly. The distinction between "few" and "many" boats was supported by opportunistic observations on 26 whales from the population of 216. Pooling both treatments would have masked these significant responses with strong statistical confidence (Wilcoxon's test P > 0.999), falsely suggesting that boat presence had no effect. Generalized Additive Models were used to control for effects of potentially confounding variables, and confirmed a non-linear relationship between approach within 1000m and a whales' swimming path directness with an inflection point around 3 boats. Interpreting biological significance of null findings from impact asessments is problematic and therefore statistical power, experimental design, and appropriateness of response variables must be considered.
Day: Monday 3 April ; Time: 14:40; Eligible for Student Award: No
SHIP COLLISIONS WITH NORTH ATLANTIC RIGHT WHALES: MODELLING ENCOUNTER PROBABILITIES FOR CONSERVATION MANAGEMENT.
FIRESTONE, J. (1), CORBETT, J.J. (1), TAGGART, C.T. (2), WANG, C.F. (1), LYONS, S.B.(1) AND VANDERLAAN, A.S.M. (2)
(1) Graduate College of Marine Studies, University of Delaware, Robinson Hall, Newark, Delaware, 19716, USA; (2) Department of Oceanography, Dalhousie University, Room 4664 LSC, Halifax, Nova Scotia, B3H 4J1, Canada
The risk of an interaction between the critically endangered north Atlantic right whale (Eubalaena glacialis) and a ship is asymmetric; the small population of right whales (300-345) and large number of ships makes the risk several orders of magnitude greater for a whale than a ship. Researchers have dedicated significant effort to understanding right whale distribution in breeding, feeding and calving areas; much less is known regarding both right whale migration among these areas and vessel traffic throughout the right whale's range. These are critical gaps given that ship strikes are the leading anthropogenic cause of right whale mortality. We have engaged in cross-border collaboration bringing together engineering, legal, statistical, oceanographic, and policy analytic expertise to develop statistical and GIS models to quantify the interaction probability of right whales and vessels along the North American Atlantic coast spatially, temporally, and by vessel characteristics (type, speed, tonnage). This work builds on the Canadian collaborator's work in the Bay of Fundy that led to the movement of shipping lanes. We employ data from the Right Whale Consortium database and ship position data (ICOADs, AMVER, ECAREG) for commercial and fishing vessels, port entrance and clearance data, and Lloyds shipping data. The model establishes an empirical commercial ship traffic network from twenty years of historical ship observations, incorporates large fishing vessels based on three years of data, and employs fractional polynomial regression to estimate right whale distribution in migratory pathways. By overlaying whale and ship activities layers, we estimate the risk of an encounter between ships and whales spatially and temporally. This information can be used by decision-makers who are presently considering regulation or are parties to litigation (e.g., NOAA and the US Coast Guard) to create practical vessel management solutions that reduce the likelihood of ship strikes.
Day: Monday 3 April ; Time: 15:00; Eligible for Student Award: No
APPLICATION OF SHIP SPEED AND MASS CHARACTERISTICS TO DESCRIBE POTENTIAL SEVERITY OF RISK-BASED SHIP COLLISIONS WITH WHALES.
CORBETT, J.J. (1), FIRESTONE, J. (1), TAGGART, C.T. (2), WANG, C.F. (1), VANDERLAAN, A.S.M. (2), AND LYONS, S.B. (1)
(1) Graduate College of Marine Studies, University of Delaware, Robinson Hall, Newark, Delaware, 19716, USA; (2) Department of Oceanography, Dalhousie University, Room 4664 LSC, Halifax, Nova Scotia, B3H 4J1, Canada
The consequences of ship-strikes to the critically endangered north Atlantic right whale (Eubalaena glacialis) are understood mainly in terms of observed mortality and injury through a limited set of observations resulting from opportunistic and survey data for the small population of right whales (300-345). This work presents analysis of data from the Right Whale Consortium database, demonstrating that ship speed and mass are important predictors of whale lethality from a ship-strike. We then illustrate the geographic nature of these potential consequences using an empirical commercial ship traffic network from twenty years of historical ship position data (ICOADs, AMVER, ECAREG) for commercial vessels. By overlaying this consequence layer onto a GIS projection of the risk of an encounter between ships and whales, we are able to evaluate potential whale-recovery benefits such as modification of ship speed behaviour, route location, or other measures in terms of spatially and temporally varying whale habitat. This information can be used by decision-makers who are presently considering regulation or are parties to litigation (e.g., NOAA and the US Coast Guard) to create practical vessel management solutions that reduce the likelihood of ship strikes.
Day: Monday 3 April ; Time: 15:20; Eligible for Student Award: No
PASSIVE ACOUSTIC MONITORING: A TOOL TO INVESTIGATE THE RESPONSE OF BOTTLENOSE DOLPHINS TO PINGERS.
ROGAN, E AND PHILPOTT, E.
Dept. Zoology, Ecology and Plant Science, University College Cork, Lee Maltings, Prospect Row, Cork, Ireland
The acoustic response of bottlenose dolphins to two types of pinger (Dukane NetMark™ 1000 and AQUAmark 200) was examined in the Shannon Estuary, Ireland from 7th August-3rd October 2005. Three pingers spaced 100m apart, and a T-POD were moored in an array below the observation site. Control (non active) intervals separated the active pinger trials. The closest observed dolphin group was tracked using a theodolite. Data from the T-POD was downloaded every month and echolocation encounter rate, duration and minimum interclick interval were analysed. An encounter was defined as a series of click trains separated by no more than ten minutes (after Carlstrom 2005). A significant difference was found in echolocation encounter rate between the four trials (Kruskal Wallis p 0.001) with a much lower echolocation encounter rate during both active pinger trials compared with the control trials (Mann Whitney, p<0.05). No significant difference in encounter rate per day was found between pinger types (Mann-Whitney, p>0.5) (i.e. similar encounter rates for both active pingers). There was no difference in encounter duration between the trials (Kruskal Wallis, p>0.05) but there was a significant difference in the length of time between encounters (Kruskal Wallis, p<0.005), with longer time between encounters during active pingers trials. No significant difference was found in minimum interclick interval between control and both active pinger trials. During both active pinger trials, there was a difference in echolocation encounter rate among the diel phases (morning, day, evening and night) (Kruskal Wallis p<0.05) but not during the control trials (Kruskal Wallis p>0.5). There was a significant difference in encounter rate during both active pinger trials (Dukane p<0.001, AQUAmark p<0.05) with higher encounter rates recorded at night in both instances. Examination of echolocation behaviour suggests that bottlenose dolphins either echolocate less or are displaced from the area when pingers are active.
Day: Monday 3 April ; Time: 16:10; Eligible for Student Award: No
PASSIVE ACOUSTIC MONITORING AS A TOOL FOR MONITORING HARBOUR PORPOISE POPULATIONS: PRELIMINARY RESULTS FROM THE SCANS II SURVEYS.
SWIFT, R. J. (1), GILLESPIE, D. M. (1), CAILLAT, M. (1), MACLEOD, K. (1) AND HAMMOND, P. S. (1)
(1) Sea Mammal Research Unit, Gatty Marine Laboratory, University of St. Andrews, Fife, KY16 8LB Scotland
The SCANS-II project (LIFE04 NAT/GB/000245) aims to recommend best practice for monitoring cetacean populations in shelf waters of the European Atlantic. Passive acoustic monitoring is an established method for monitoring harbour porpoise relative abundance and, as such, was a core component of the July 2005 SCANS II survey. A hydrophone array, high frequency recording equipment and software designed to detect harbour porpoise clicks in real time were operated on each vessel taking part in the survey. Data were collected continuously on each vessel while it was on track, and candidate clicks from porpoises and other species archived for later analysis. Usable acoustic data were obtained from all seven survey ships and an eighth ship operating in the Baltic; 28,917km were surveyed 'on effort'. Acoustic data analysis was carried out independently of the visual survey data. Bearings to clicks were calculated using time of arrival differences on two hydrophones. Individual porpoise clicks were identified by using the peak frequency in the click spectrum and the ratio of the energy in the porpoise frequency band (100 - 150 kHz) and a lower control frequency band (40 - 90kHz). Clicks were then grouped into events (or click trains) by hand. Where a clear track could be seen as an animal passed astern, a location was calculated using target motion analysis. 432 multi-click porpoise events were detected, and 285 of these (66%) could be reliably tracked. Fitted detection functions indicated that porpoise can reliably be detected out to distances of 200-300m, and occasionally out to 600m, whist suggesting avoidance close (<50m) to the vessel. Noise levels were measured for each ship and the effects of noise levels in the porpoise band (100-150kHz), and of 'avoidance' in response to underway vessel noise were investigated. These results are discussed in terms of current and future monitoring programmes.
Day: Monday 3 April ; Time: 16:30; Eligible for Student Award: No
T-POD DETECTION AND ACOUSTIC BEHAVIOUR OF BOTTLENOSE DOLPHINS IN CARDIGAN BAY SAC: A COMPARISON BETWEEN T-POD RECORDINGS AND VISUAL OBSERVATIONS
REYES ZAMUDIO, M.M., (1,3), SIMON, M. (2,3), EVANS, P.G.H. (3) AND GOOLD, J. (1)
(1) School of Biological Sciences, University of Wales, Bangor, UK; (2) Greenland Institute of Natural Resources, Nuuk, Groenland; (3) Sea Watch Foundation, Wales, UK
T-PODs are acoustic data loggers that detect echolocation clicks from harbour porpoise (Phocoena phocoena) and bottlenose dolphin (Tursiops truncatus). T-POD research has focused mainly on harbour porpoises. This study aimed to investigate T-POD performance when studying bottlenose dolphins by: measuring the detection range, detection probability in the presence of dolphins and investigating the possibility of identifying dolphin behaviour from T-POD data. Two T-PODs were deployed for a period of six weeks (27th June - 8th August, 2005), at two different locations (Mwnt and New Quay, Cardigan Bay Special Area for Conservation, West Wales). Visual surveys using theodolites to calculate the distance between T-POD and dolphins, and observing the animal behaviour, were carried out at each location. . Comparison between data obtained with T-PODs and simultaneous visual surveys showed that the maximum T-POD detection range of bottlenose dolphin clicks was 650m. When the dolphins were present within this range, the T-PODs only detected them 11 percent of the time and there was a significant negative correlation between the distance and the T-POD detection probability. In addition, the detection probability varied with dolphin behaviour so that dolphins that were feeding had a significantly higher probability of being detected by the T-POD than dolphins that were travelling. T-POD data showed that dolphins that were feeding emitted click trains with significantly higher numbers of clicks, and had significantly lower inter click intervals than travelling dolphins, suggesting that click trains with high numbers of clicks (< 30) and low minimum inter click intervals (< 350 µs) identify feeding behaviour in T-POD data. This could be a first step to use T-PODs for abundance estimates.
Day: Monday 3 April ; Time: 16:50; Eligible for Student Award: No
EFFECTS OF WHALE WATCHING ACTIVITIES ON RISSO'S DOLPHIN RESTING BEHAVIOUR AT THE AZORES
VISSER, F. (1, 2) HARTMAN, K.L. (1) ROOD, E.J.J. (1) HENDRIKS, A.J.E. (1)
(1) Nova Atlantis Foundation. Rua dr. A. Freitas Pimentel 11, 9930-309 Santa Cruz das Ribeiras, Pico, Azores, Portugal. (2) Netherlands Organisation for Applied Scientific Research, TNO. Oude Waalsdorperweg 63, 2597 AK Den Haag, the Netherlands
Whale watching activities at the Azores have been growing exponentially over the last decade, posing a high disturbance potential for the cetacean species present. In this study, we investigated Risso's dolphin (Grampus griseus) behavioural response to the presence of whale watching activities by comparison of the resting rate in the presence and absence of whale watching vessels. At the Azores, due to the species' daily presence in inshore waters, we have the exceptional opportunity to study Risso's dolphin behaviour from land. Land observations have the strong advantage that observers do not have an impact on the animals of focus, enabling comparisons of behaviour in undisturbed environment, with behaviour in the presence of vessels. Daily, binocular-aided focal follows of Risso's dolphin groups were conducted from a permanent observation platform on the south coast of Pico, Azores. Behavioural budget was determined per month and per 1-hour intervals over the day. Overall resting rate decreased from 25% to 21% in the presence of whale watching vessels. Risso's dolphin natural resting behaviour showed a clear, daily pattern, with distinct peaks in the morning and afternoon. During the high pressure months of whale watching (July-August; average daily vessel presence: 5), this pattern shifted completely towards a single peak around 1 PM, during the low pressure hours of whale watching activity (0-2 vessels present). As resting rate was shown to be negatively correlated to vessel abundance, this can not merely be a seasonal pattern. Apparently, Risso's dolphins adjust their patterns of resting behaviour to vessel abundance. The alteration of their natural resting pattern implies that the dolphins have to adapt to an alternative and probably less favourable situation, especially as their resting behaviour shows a clear pattern. Adaptation to a less favourable situation can be directly translated to a less efficient time management of the dolphins and consequently to a negative impact on the population.
Day: Monday 3 April ; Time: 17:10; Eligible for Student Award: No
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Tuesday 4th April
SELECTING SPECIAL AREAS OF CONSERVATION FOR HARBOUR PORPOISES (PHOCOENA PHOCOENA) IN DENMARK.
SVEEGAARD, S. (1), JOERGENSEN, P.B. (2), BECH, N.I. (3), TEILMANN, J. (4),
JOHNSEN, I.(5), RYE, J.H. (6)
(1,2,3,4) National Environmental Research Institute (NERI), Department of Arctic
Environment, Frederiksborgvej 399, 4000 Roskilde,
Denmark; (5) University of Copenhagen, Institute of
Biology, Øster Farimagsgade 2D, 1353 Copenhagen K,
Denmark; (6) Research- and Technology Centre Westcoast (FTZ), Hafentörn, D-25761 Büsum, Germany
The Habitats Directive (92/43/EEC) categorises the harbour porpoise as a species in need of strict protection and whose conservation requires the designation of Special Areas of Conservation. Hence, all EU countries are legally obligated to protect harbour porpoises in its natural habitat by selecting protected areas. However, the method to make this selection is still unspecified and no official guidelines have been published. The purpose of this study is to examine and evaluate biological methods used for studying harbour porpoises and suggest guidelines for future selection of important habitats. From 1997 to 2005, 57 harbour porpoises were tagged with satellite transmitters in Denmark. Data shows that two subpopulations exist; with a border in the northern Kattegat. Thus, protected areas should be selected for both populations. The southern population shows a preference of gathering in the southern waters around Flensborg Fjord. Consequently, Flensborg Fjord was selected as a candidate for harbour porpoise habitat protection. Two stationary acoustic loggers (T-PODs) were deployed in Flensborg Fjord during August-November 2005. Recordings by T-PODs can provide a continuous monitoring of relative abundance. In Flensborg Fjord an average of 8.6 encounters per day was detected. In comparison harbour porpoises were acoustically recorded on an average of 17.7 encounters per day in Jammerland Bay in the Great Belt and an average of 8.5 encounters per day at Gedser in the western Baltic. These results are consistent with the telemetry data and show the potential of using T-PODs for comparing seasonal importance between areas. Special Areas of Conservation for harbour porpoises may be localised by tracking harbour porpoises with satellite telemetry. The detailed use of the areas should be monitored using several methods like T-PODs, tagging and surveys to evaluate the relative importance of the area in relation to other areas.
Day: Tuesday 4 April ; Time: 8:30; Eligible for Student Award: Postgraduate
MODELLING HABITAT PREFERENCES FOR FIN WHALES AND STRIPED DOLPHINS IN THE PELAGOS SANCTUARY (WESTERN MEDITERRANEAN SEA).
PANIGADA, S. (1,2), ZANARDELLI, M. (1), MACKENZIE, M. (3), DONOVAN, C. (3), MÉLIN, F. (4) AND HAMMOND, P.S. (2)
(1) Tethys Research Institute, c/o Acquario Civico, Viale G.B. Gadio 2, 20121 Milano, Italy; (2) Sea Mammal Research Unit, Gatty Marine Lab, University of St. Andrews. St. Andrews, Fife, KY16 8LB, U.K; (3) CREEM, The Observatory, Buchanan Gardens, University of St Andrews. St Andrews, Fife, KY169LZ, UK; (4) Joint Research Centre of the E.C. Institute for Environment and Sustainability,T.P. 272 I-21020 Ispra (VA), Italy
One of the needs of the Pelagos Sanctuary for the Conservation of Mediterranean Marine Mammals is information on critical habitats for cetaceans. This study modelled habitat use and preferences of fin whales and striped dolphins (the two most abundant species in the area) with the aim of providing this information. The study area was divided into a 2' latitude by 2' longitude grid. The explanatory variables considered in the models were physiographic variables (mean, range and standard deviation of depth and slope, and distance from the nearest coastline) and remotely sensed data (sea surface temperature and chlorophyll a concentration). The former were calculated for each cell using GIS tools, while the latter were obtained by AVHRR and SeaWiFS sensors. Generalized Additive Models (GAMs) with multidimensional smoothers were used to model the distribution of fin whales and striped dolphins in relation to these variables, and classification and regression trees (CART) were used for habitat characterization. The search effort, expressed kilometres surveyed in each grid cell under favourable conditions, was treated as an offset. To justify the complexity of the models, CART and GAMs were compared with a more conventional, more restrictive approach (Generalized Linear Models, GLMs). Chlorophyll, SST, depth and slope were found to be important predictors of habitat use, and substantial gains in predictive ability were made when CART and GAMs were used. The techniques applied to this dataset proved to be valuable tools to describe habitat use and preferences of cetaceans, and the use of the remotely sensed data substantially improved the predictions. The results of this study will be used for assessing critical habitats within the Pelagos Sanctuary and will provide information for conservation and management in the Sanctuary.
Day: Tuesday 4 April ; Time: 8:50; Eligible for Student Award: No
ARE COMMON DOLPHINS IN THE NORTH-EAST ATLANTIC CLOSE TO THEIR CARRYING CAPACITY?.
MURPHY, S. (1), NORTHRIDGE, S. P. (1), JEPSON, P. D. (2), DEAVILLE, R. (2) AND REID, R. J. (3).
(1) Sea Mammal Research Unit, Gatty Marine Laboratory, University of St Andrews, St Andrews, Fife, KY16 8LB, U.K.; (2) Institute of Zoology, Zoological Society of London, Regent's Park, London, NW1 4RY, UK; (3) Wildlife Unit, SAC Veterinary Services, Drummondhill, Stratherrick Road, Inverness, IV2 4JZ, Scotland
Concerns have been raised that incidental captures of common dolphins in fishing gear may be leading to a population level decline in common dolphins numbers in the Western Channel, Celtic Sea and Bay of Biscay area. Incidental captures are known to be at least in the hundreds of animals per year, but are only partially known at present, and have been ongoing for at least 15 years. In the absence of sequential abundance estimates, a population level decline may be observable in density dependent changes in population parameters. Specifically, substantial population declines would be expected to be accompanied by any or all of the following changes in population parameters: increased individual growth rates, decreased calving intervals, an increase in the pregnancy rate, or lowering in the age at sexual maturity. Samples obtained from the UK strandings and observer bycatch programmes, between 1990 and 2004 were analysed in order to examine some of these population parameters. In the sample, 87 females were identified as mature individuals, and of these 24 were pregnant. The annual pregnancy rate (APR) was calculated at 28.8%, and the inter-calving interval was estimated at 42 months/3.5 years. Excluding individuals that died during the mating period May to September, an APR of 31.6% was calculated. Similar results were found in a study examining the pregnancy rate and calving interval in common dolphin's inhabiting waters off the Irish coast. Age at sexual maturity in Irish samples was estimated at 9-10 years. Taken together, and when compared with populations elsewhere that are able to reproduce every two years, these data all suggest that common dolphins in the North-east Atlantic may in fact be close to their carrying capacity. However, it remains possible that low pregnancy rates could also be a result of high contaminant burdens causing reduced fertility in females.
Day: Tuesday 4 April ; Time: 9:10; Eligible for Student Award: No
TOWARDS CONSERVATION OF THE SHORT-BEAKED COMMON DOLPHIN (DELPHINUS DELPHIS) OFF THE SOUTHERN COAST OF SPAIN.
CANADAS, A. (1) AND HAMMOND, P.S. (2)
(1) ALNITAK and SEC, Nalón 16. E-28240 Hoyo de Manzanares, Madrid, Spain; (2) Sea Mammal Research Unit, Gatty Marine Laboratory, University of St. Andrews, St. Andrews, Fife KY16 8LB, UK
The short-beaked common dolphin is believed to have suffered a steep decline in the Mediterranean in recent years. ACCOBAMS (Agreement for the Conservation of Cetaceans in the Black Sea, Mediterranean Sea and contiguous Atlantic waters) is developing a Conservation Plan for this species. Effective conservation will depend critically on our understanding and ability to predict the relationship between the population and its habitats. The Alborán Sea is the most important remaining habitat for this species in the basin and constitutes, therefore, a vital source of information on its ecology, essential for the development of conservation measures.
Spatial modelling using GAMs was used to provide information on distribution and abundance of common dolphins in the area. In total, 37,385 km of non-systematic line transects conducted from 1992 to 2004, generating 738 sightings in a 19,189 km2 study area, were analyzed. Analyses examined differences among sub-areas, years, seasons and 'intrinsic' factors (behaviour, calving, interespecies aggregations). Seasonal variation in abundance was detected, with higher average density in summer (1.0 animals/km2) than in winter (0.5 animals/km2). Geographical differences were also found, with higher density in the west (1.5 animals/km2) than in the east (0.4 animals/km2) during summer. No overall trend in abundance was observed in the whole area but a decline was observed in the eastern portion (Gulf of Vera) with a summer density of 0.34 in 1992-1995 and 0.11 in 1996-2004. With respect to depth, a bimodal distribution was predicted, with higher densities around the continental slope (100-400m) and in deeper waters (800-1200m). This can partially be explained by the difference in predicted habitat use depending on intrinsic factors: groups with calves, feeding groups and single species groups preferred shallower waters; socialising groups, groups with no calves and multi-species groups preferred deeper waters. These results will inform conservation efforts in the Mediterranean.
Day: Tuesday 4 April ; Time: 9:30; Eligible for Student Award: No
COASTAL POPULATIONS OF SMALL CETACEANS ARE LESS EXPOSED TO TOXIC METALS THAN OCEANIC ONES IN EUROPEAN WATERS.
LAHAYE, V. (1), BUSTAMANTE, P. (1), DABIN W. (2), DAS, K. (3), HOLSBEEK, L. (4), LAW, R.J. (5), ROGAN, E. (6), PIERCE, G.J. (7) AND CAURANT, F. (1)
(1) Laboratoire de Biologie et Environnement Marins, FRE 2727, Université de La Rochelle, Ave. Michel Crépeau, 17000 La Rochelle, France; (2) Centre de Recherche sur les Mammif?res Marins, Institut du Littoral et de l'Environnement, Port des Minimes, Ave. Lazaret, 17000 La Rochelle, France; (3) Laboratoire d'Océanologie, B6c, Université de Li?ge, Sart-Tilman, B-4000 Li?ge, Belgium; (4) Laboratory for Ecotoxicology and Polar Ecology, Free University of Brussels, Pleinlaan 2, B-1050 Brussels, Belgium; (5) The Centre for Environment, Fisheries and Aquaculture Science, Burnham Laboratory, Remembrance Avenue, Burnham-on-Crouch, Essex CM0 8HA, UK; (6) Aquaculture Development Centre, Department of Zoology, Ecology and Plant Science, University College, Lee Maltings, Prospect Row, Cork, Ireland; (7) Department of Zoology, University of Aberdeen, Tillydrone Av. ABZ4 2TZ, UK
Upper-level predators like small cetaceans can display particularly high concentrations of mercury (Hg) and cadmium (Cd) in their tissues. Given that exposure to these toxic elements may depend on metal bioavailability and feeding preferences, bioaccumulation in cetaceans may vary among species, habitat and geographical area. We focussed at the most abundant small cetaceans in European waters, i.e. harbour porpoises (n=102), common (n=230), striped (n=63) and bottlenose (n=15) dolphins. Most individuals were originated from stranding events along the coasts of France, Netherlands, Scotland, Ireland and Galicia, but sampling also included by-caught animals from Atlantic neritic and oceanic waters. Some prey were collected in order to infer about metal exposure. Hence, oceanic Atlantic prey displayed the highest concentrations of both Cd (Cranchid cephalopod) and Hg (Myctophid fish). High Hg levels were also encountered in Mediterranean prey (collected over the continental shelf), likely as a consequence of the natural Hg enrichment in this area. Regarding cetaceans, accumulation of renal Cd with age was the most important in the typically oceanic striped dolphin, but also in common dolphins by-caught in oceanic waters. With the two most representative species, increase of Cd concentrations also occurred with latitude. In addition, Hg accumulation in the liver was the most important in Mediterranean bottlenose and striped dolphins but also in Atlantic striped dolphins. The similar Hg levels in Atlantic and Mediterranean striped dolphins could be striking. However, regarding results from prey, offshore feeding in the Atlantic versus inshore feeding in the Mediterranean Sea could effectively lead to similar Hg exposure in these areas. Consequently, small cetacean populations that would be the most exposed to toxic metals would be those feeding in oceanic and northern ecosystems rather than coastal ones. Hence, in European waters, exposure to metals in cetaceans would be enhanced by natural processes rather than anthropogenic influence.
Day: Tuesday 4 April ; Time: 11:10; Eligible for Student Award: Postgraduate
SURVIVAL ESTIMATES OF BOTTLENOSE DOLPHINS (TURSIOPS TRUNCATUS) IN KVARNERIC (CROATIA).
FORTUNA (3), C.M., MACKELWORTH, P.C.(2), WIEMANN, A.(2) AND HAMMOND, P.S. (1)
(1) Sea Mammal Research Unit, Gatty Marine Laboratory, University of St Andrews, Fife KY16 8LB, UK (2) Blue World Institute for Marine Research & Conservation, Kaštel 24, HR-51551, Veli Lošinj, Croatia, (3) Tethys Research Institute, viale G.B. Gadio 2, I-20121 Milano, Italy
Survival estimates are of fundamental importance not only for a better understanding of the ecology of a population, but also to define effective conservation measures. Here we represent the first survival estimates for a Mediterranean population of bottlenose dolphins that inhabits Kvarneric waters (Croatia). , We used capture-recapture models applied to nine years of photo-identification data (1995-2003) to estimate adult and calf survival. During 625 dedicated surveys, we made 370 encounters allowing photo-identification of 110 naturally well-marked adult individuals. Pollock's robust design models that estimate temporary emigration rates were fitted to these data. Two subsets were also considered: one of all 42 known mature females and the other of 9 confirmed males and 50 unsexed individuals, both males and immature females. We assumed this group to be mostly males. A Cormack-Jolly-Seber model was fitted to data on 48 known-age calves, to estimate survival during their first 4 years of life. The apparent survival of adults was S=0.924 (95%CI=0.895-0.949), with a low temporary emigration rate 5.7% (95%CI=0.022-0.136) and a very high probability of remaining outside the study area once outside (?'=0.499, 95%CI=0.160-0.838). Calf survival rates ranged between 0.500 and 0.912, with a maximum at Age 2-3. The apparent survival of the mostly male group was lower (S=0.907; 95%CI 0.853-0.942) than female survival (S=0.946; 95%CI 0.908-0.968). The adult female emigration probability was extremely low (near to zero), but the probability of remaining outside the study area was 0.215. The mostly male group had a temporary emigration rate of about 0.08 and a probability of remaining outside of up to 0.58. These results give an important insight into the ecology of Adriatic bottlenose dolphins. They also indicate the need for a strong synergic regional and local approach to the conservation of this population, rather then relying only on very localised protection measures.
Day: Tuesday 4 April ; Time: 11:30; Eligible for Student Award: Postgraduate
BY-CAUGHT CETACEANS STRANDED ALONG THE BELGIAN AND NORTHERN FRANCE COASTLINE: ARE THEY A GOOD CONTROL POPULATION?.
JAUNIAUX, P.(1), BRENEZ, C. (1), DAS, K.(2), HAELTERS, J. (3) AND COIGNOUL, F.(1)
(1) Department of Pathology, University of Liege, Sart Tilman B.43, 4000 Liege, Belgium; (2) Laboratory of Oceanology, University of Liege, Sart Tilman B.6c, 4000 Liege, Belgium; (3) Management Unit of the North Sea Mathematical Models, Royal Belgian Institute of Natural Science, 3de en 23ste Linieregimentsplein, 8400 Oostende, Belgium
Since 1991, marine mammals stranded along Belgium and northern France coastline are necropsied and sampled using a standard protocol and a cause of death identified (MARIN project -Marine Animals Research & Intervention Network-). By-catch can be only diagnosed on stranded animals as fishermen release net-entrapped animals and such diagnosis is frequently based on external lesions. In addition, for comparison with sick animals, by-caught cetaceans are considered as being "control" animals for toxicological or biological studies, based on the assumption that they are healthy. The aim of the present study is to identify observations on stranded by-caught porpoises (Phocoena phocoena). From January 1995 to December 2005, 60 stranded porpoises out of 275 animals were diagnosed as being by-caught. Most of them were juvenile (90%), without sex predisposition. Observations related with net-entrapment were net marks (50%), amputation (10%), subcutaneous and muscular haemorrhages (30%), lung edema (63%), lung congestion (54%) and lung haemorrhage (10%). Surprisingly, lesions unrelated with net capture were observed in 50% of by-caught porpoises: mild to severely emaciation (42%), slight parasitism of airways and stomach (21%), severe parasitism with acute pneumonia (15%) or chronic gastritis (15%). The median blubber thickness was 16.2 mm and the gastro-intestinal tract was empty in 30%, without evidence of feeding. Some lesions were enough severe to be the cause of death if such animals were not by-caught. Our study showed that by-catch diagnosis can not be based on external observations only because such lesions are present in just half of the animals and that by-caught porpoises are not always healthy. Therefore, they should not be declared control animals by default without a detailed post-mortem examination. Such considerations should be taken into account in toxicological or biological investigations and confirm the rule of necropsies in multidisciplinary studies on the cause of death of marine mammals.
Day: Tuesday 4 April ; Time: 11:50; Eligible for Student Award: No
COMPARISON OF THE REACTION OF WILD HARBOUR PORPOISES EXPOSED TO AN ARRAY OF INTERACTIVE PINGERS AND AQUAMARK 100'S.
STENBACK, J. (1,2), AMUNDIN, M. (3), POULSEN, L. R. (1), DESPORTES, G. (1,4), LARSEN, F. (5), PETERSEN, N. K. (1), BJ?RGE, A. (6), BYLUND, K. (1), ESKESEN, I. (1), ERIKSEN, N. (1), INGVERSEN, S. (1), JEPSEN, T. B. (1), KINDT-LARSEN, L. (1) AND VANMAN, C. (3)
(1) Fjord & Baelt, Margrethesplads 1, 5300 Kerteminde, Denmark; (2) Department of Biology, IFM, Linköpings Universitet, SE-581 83 Linköping, Sweden; (3) Kolmarden Djurpark, 61892 Kolmarden, Sweden; (4) GDnatur, Stejlestr?de 9, 5300 Bregn?r, Denmark; (5) Danish Institute for Fisheries Research, Charlottenlund Castle, 2920 Charlottenlund, Denmark; (6) Institute of Marine Research, Department of Biology, Pb. 1066, Blindern, 0316 Oslo, Norway
Harbour porpoise (Phocoena phocoena) bycatch is of such a magnitude in European waters that EU regulations made it mandatory to use acoustic alarms (pingers) in many commercial fisheries. The pingers available emit displacement sounds continuously in regular or irregular intervals irrespective of the presence of porpoises. This excessive emission causes unnecessary disturbance of the marine life and may lead to habituation and thus reduced effectiveness. Thus, the effect of a more environmental and porpoise friendly interactive pinger, which only emits displacement sounds when triggered by porpoise sonar, was compared with the effect of an AQUAmark 100 (standard pinger). The study was conducted at Fyns Hoved, Denmark, in August-September 2005. Free-ranging porpoises were exposed to an array of four pingers in a simulated gillnet situation. Surface positions of the porpoises were obtained with a digital theodolite from a 20m high cliff, and combining subsequent surfacings formed tracks. Only data within a 400m range of the pingers were analysed (based on theoretical auditory detection range and tracking precision), and the interactive pingers and AQUAmark 100's were deployed for a day at a time, respectively. The results are based on 52 tracks/7days and 14 tracks/3days for the interactive pingers and AQUAmark 100's, respectively. The interactive pingers emitted on average less than 7 displacement sounds per hour, which is equivalent to 1-6% of the sound emissions from an AQUAmark 100. The median of the minimum approach distance was 29m for the interactive pinger and 44m for the AQUAmark 100 (not significantly different), and there was no significant difference in the usage of a 400m range around the pinger array. In conclusion, the porpoises reacted in the same manner to the interactive pinger and the AQUAmark 100. And with significantly less sound emissions the interactive pinger constitutes an interesting alternative to the standard pingers.
Day: Tuesday 4 April ; Time: 14:00; Eligible for Student Award: Undergraduate
ARE PINGERS EFFECTIVE AT REDUCING INTERACTIONS BETWEEN BOTTLENOSE DOLPHINS AND ARTISANAL FISHERIES AROUND THE BALEARIC ISLANDS?.
BROTONS, J.M. (1) MUNILLA, Z. (1) GRAU, A.M. (1) AND RENDELL, L.E. (2)
(1) Direcció General de Pesca, Govern de les Illes Balears, C/ Foners 10.07006, Palma de Mallorca, Balearic Islands, Spain; (2) Sea Mammal Research Unit, School of Biology, University of St Andrews, Fife, KY16 8LB, U.K.
Interactions between marine mammals and fisheries represent a serious and growing conservation issue. Around the Balearics Islands bottlenose dolphins regularly interact with coastal artisanal fisheries. We estimate that this interaction results in an economic cost of 6.5% of the total landed catch value (95% CI 1.6%-12.3%), and the interaction also results in dolphin mortality. Pingers are one possible mitigation measure. We tested the efficacy of three brands of commercially available pingers using both inactive (placebo condition) and active (treatment condition) pingers and nets with no pingers (control condition). Each vessel was equipped with 15 identical bottom-set gill nets for the study, 60m long, 1.25m high and with 50mm mesh. Nets were equipped with either one of three brands of pinger (SavewaveTM, AquamarkTM and NetmarkTM) or with no pingers. Pinger activation was carried out such that those reporting on the fishing were unaware of the condition. Catch data were recorded for each operation on board the vessel. Up to November 15th, 39 of 59 participating vessels have reported on 719 fishing operations over 112 different days since July 1, 2005. Of these operations, 413 were with active pingers, 190 with inactive pingers and 116 with no pingers. Depredation was evidenced either by direct observation of dolphins taking from nets or by the presence of characteristically damaged fish in the hauled net. Preliminary data show that the frequency of depredation on nets with no pingers was 0.0345 (95% CI 0.0095-0.0859). Across all pinger types, there was no reduction in the probability of depredation with activated pingers (control vs. treatment, Binomial test, p = 0.105). However, there were differences in depredation probability between brands. Surprisingly, there was a significant increase in the probability of depredation when nets carried inactive pingers (control vs. placebo, Binomial test, p = 0.004).
Day: Tuesday 4 April ; Time: 14:20; Eligible for Student Award: No
EVALUATING THE EFFECTS OF PELAGIC TRAWL PINGERS ON THE BEHAVIOUR OF BOTTLENOSE DOLPHINS TURSIOPS TRUNCATUS.
LEENEY, R.H. (1), BERROW, S. (2), MCGRATH, D. (3) AND COSGROVE, R. (4)
(1) Centre for Ecology and Comservation, University of Exeter in Cornwall, Tremough Campus, Penryn, Tr10 9EZ, Cornwall, UK; (2) Shannon Dolphin & Wildlife Foundation, Merchant's Quay, Kilrush, Co. Clare, Ireland; (3) Galway-Mayo Institute of Technology, Dublin Road, Galway, Ireland; (4) Bord Iascaigh Mhara, Dock Road, Galway, Ireland
Large numbers of dolphins and porpoises die in fishing gear worldwide, posing serious threats to several populations and species. Several mitigation measures, including acoustic deterrent devices or "pingers", have been used in attempts to reduce this bycatch. In order to reduce the number of common dolphins (Delphinus delphis) caught in pelagic trawls fishing for albacore tuna in Irish waters, two models of pinger are being tested. Standard "continuous pingers" (CP) produce a continuous, high intensity sound at 20-160 Hz. A new prototype "responsive" pinger (RP) produces an alarm activated by the reception of dolphin vocalisations, and also logs the dolphin clicks themselves. Prior to this study, both models had been tested in a controlled environment where they have been shown to alter dolphin behaviour, but had yet to be tested in the field. This study compared the responses of bottlenose dolphins (Tursiops truncatus) to both pinger models, in the Shannon estuary, southwest Ireland. This is the most reliable location in which to encounter dolphins in Irish waters. Pinger-T-POD pairs were individually deployed at, and alternated between, six sites for replicate 24-hour periods. Pingers were either active or inactive (control). T-PODs and the responsive pinger collected acoustic data on the vocalisation activity of dolphins within range. Behavioural sampling of dolphins in response to pingers was carried out during "observer-blind" boat-based trials. T-POD detection rates were significantly greater for inactive CPs than for active ones, whereas detection rates were similar for active and inactive RPs. Minimum inter-click intervals were lower for inactive CPs than for active ones. Observed responses of dolphins to active pingers differed significantly from responses to inactive pingers of both types. This study provides an important step towards the refinement of a dynamic tool for reducing bycatch levels in tuna trawl fisheries.
Day: Tuesday 4 April ; Time: 14:40; Eligible for Student Award: No
IMPACT OF FISHERIES LEGISLATION ON THE RESEARCH OF HARBOUR PORPOISE BYCATCH IN POLAND AS DEMONSTRATED BY EC BYCATCH REGULATION.
KUKLIK, I. AND SKÓRA, K.E.
Hel Marine Station, Institute of Oceanography, University of Gdansk, 84-150 Hel, P.O.Box 2, Poland
The harbour porpoise is considered a rare species in the Polish Baltic and in urgent need of well targeted conservation measures. Due to low abundance the collection of data is very difficult and would be impossible without voluntary involvement of the society, especially fishermen. Reports have been collected since 1990, initially limited to bycaught animals and delivered exclusively by fishermen. Later, additional reports on sighted and stranded porpoises were delivered by tourists and maritime administration. For the last five years data collected have been complemented by PODs registrations. The reporting system was largely based on cooperation with fishermen. In 16 years 92 reports were collected, of which 64 concerned bycaught animals. The majority were entangled in anchored nets in coastal waters, others in offshore set nets. In 2004, the European Union decided to ban drift net fishing in the Baltic Sea from 2008 onwards to help the harbour porpoise population recover. In the light of collected data, this ban was apparently not required and in fact inappropriate as a protective measure since so far no data have been collected to confirm the harmfulness of drift nets to porpoises in Polish Baltic waters. This decision has caused incomprehension and indignation among fishermen and a collapse of the voluntary reporting system on bycatch. Fishermen have qualified this regulation as incomprehensible and unjustified. It has also undermined the trust of fishermen in the use of research results. The number of reports has decreased. As a result of protests by fishermen the Polish government has officially asserted that harbour porpoises do not occur in the Polish Baltic. This demonstrates that taking generic decisions without bearing in mind the particularities of local problems can severely affect the process of creating a scientific and a socio-economic bases for sustainable co-existence of man and the marine environment.
Day: Tuesday 4 April ; Time: 15:00; Eligible for Student Award: No
BOWHEAD WHALE (BALAENA MYSTICETUS) MIGRATION AND CALLING BEHAVIOUR IN THE ALASKAN BEAUFORT SEA IN AUTUMN 2001-2004 SHOWN BY PASSIVE ACOUSTIC LOCALIZATION.
BLACKWELL, S.B. (1), GREENE, C.R. JR. (1) AND RICHARDSON, W.J. (2)
(1) Greeneridge Sciences Inc., 1411 Firestone Road, Goleta CA 93117, USA (2) LGL Ltd, environmental research associates, 22 Fisher St., POB 280, King City, Ont. L7B 1A6, Canada
The westward migration of bowhead whales was studied during autumn 2001-2004 as part of a larger study investigating possible effects of an oil production island on whale behaviour. An array of directional autonomous seafloor acoustic recorders (DASARs) was deployed northeast of the Northstar oil production island close to Prudhoe Bay, in the Alaskan Beaufort Sea. Sounds were recorded continuously for 24-35 days per year. More than 130 000 bowhead calls were detected, and the directional capability of DASARs allowed triangulation of the whale position for ~93 500 of those calls. This showed that the migration pathway was closer to shore in 2003-2004 than in 2001-2002. Calls were clumped in space and time, with call detection rates varying between 0 and >600 calls per hour. There was significantly more calling at night than during the daytime. Sixty-five to 82% of calls were simple FM calls, and the percentage of complex calls was positively related to the daily number of calls. No songs were detected, but in 2004 there were a number of call sequences consisting of repeated identical calls in series lasting up to 30 min and more. During these long sequences the calling whale(s) could be tracked. The DASAR methodology is independent of weather and time-of-day constraints and provides a continuous acoustic record over several weeks. It provides detailed information on the temporal and spatial distribution of calling whales and on characteristics of their acoustic repertoire. It therefore complements aerial surveys carried out over a much larger geographical area, but with low spatial and temporal resolution and a low sample size.
Day: Tuesday 4 April ; Time: 16:00; Eligible for Student Award: No
ANALYSIS OF SPERM WHALE ORIENTATION RESPONSE TO CONTROLLED EXPOSURE OF SONAR.
SHAPIRO, A.D. (1), TYACK, P.L. (1) AND SOLOW, A.R. (2)
(1) Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA; (2) Marine Policy Center, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
Controlled exposure experiments of mid-frequency sonar were conducted on three adult male sperm whales in the Ligurian Sea tens of kilometers offshore. A digital archival tag on each whale recorded the received level (RL) of pings emitted once every 15s and provided a 3D orientation and movement track of the animal throughout the exposure. The source vessel circled the animal and gradually increased the sonar source level from 160 dB RMS re 1 ?Pa to an intensity designed to reach a predetermined RL at the whale below 160 dB. A directional time series was computed from the paths of the animal and ship, providing an angular measure of the direction in which the whale was pointing relative to the vessel. We developed a regression model based upon the von Mises distribution for circular random variables to assess dependence of the angular response variable on ping RL that tested the null hypothesis of no effect of RL on orientation against the alternative effects of avoidance or attraction. Based on the null that whale orientation was independent of RL, a randomization test was conducted where the RLs were randomly distributed among the angular variable data. Using a log likelihood ratio test to assess significance, two sperm whales significantly (P<0.01) and the third weakly significantly (P=0.11) oriented more towards the source vessel with increasing RL. The value of the regression coefficient had the same sign and magnitude across experiments. These results suggest that the RL ramp up procedure often proposed for mitigation purposes may, in certain cases where animals orient towards and approach the source, expose them to higher levels than anticipated. The novel experimental design and statistical approach described here offer insight into developing future controlled exposure experiments exploring the behavioral responses of whales to anthropogenic noise sources.
Day: Tuesday 4 April ; Time: 16:20; Eligible for Student Award: Postgraduate
VOCAL DIALECTS AND POPULATION STRUCTURE IN KILLER WHALES OF EASTERN KAMCHATKA.
FILATOVA, O.A. (1), BURDIN, A.M. (2,3) AND HOYT, E. (4)
(1) Department of Vertebrate Zoology, Faculty of Biology, Moscow State University, Vorobiovy gory, 1/12, Moscow 119992, Russia; (2)Kamchatka Branch of Pacific Institute of Geography, Far East Division of Russian Academy of Sciences, Petropavlovsk-Kamchatsky, Russia; (3) Alaska Sealife Center, P.O.Box 1329, 301 Railway Ave., Seward, AK 99664, USA; (4)Whale and Dolphin Conservation Society, North Berwick, Scotland, UK
Investigations of killer whale (Orcinus orca) behaviour in the Eastern North Pacific showed the existence of two ecotypes of killer whales: fish-eating (resident) and mammal-eating (transient). Each resident pod has its own unique repertoire of discrete calls. Pods that share calls belong to the same acoustic clan. Resident and transient whales share no calls and differ greatly by vocal activity, as well as by ecology, social organization and genetics. Until recently, the vocal repertoire of Western North Pacific killer whales remained completely unstudied. We now present a description of vocal dialects of killer whales from Eastern Kamchatka (Far East Russia). Materials and data being used for this study were collected in 2000-2005 in Avacha Gulf. Whales were individually recognized through photographic identification. We classified 25 discrete call types and 24 more subtypes - a total of 49 calls. We identified individual group repertoires and measured the similarity of call repertoires between pods by calculating an index of the degree of call sharing. The index values were then used to calculate a dendrogram of the hierarchical structure of acoustic similarity. Most of the groups shared at least one call type with another group, which means that all are members of one clan. One group shared no calls with other groups, and their appearance and behaviour looked like mammal-eating (transient) killer whales from the Eastern North Pacific. These results enable us to demonstrate the existence of at least two sympatric populations of killer whales in the Western North Pacific. Through this work, we believe it will be possible to make important comparisons to the well-studied Eastern North Pacific killer whales, which will help to illuminate the function of vocal dialects and unlock the evolutionary mechanisms and the role of social learning or cultural transmission, in dialect formation and development.
Day: Tuesday 4 April ; Time: 16:40; Eligible for Student Award: No
ACOUSTIC DETECTION OF MARINE MAMMALS WITH DIFFERENT SONAR SYSTEMS.
LUDWIG, S. (1), CORSTEN, A. (2) AND KNOLL, M. (1)
(1) Forschungsanstalt der Bundeswehr fuer Wasserschall und Geophysik (FWG), Klausdorfer Weg 2-24, 24148 Kiel, Germany; (2) ATLAS Elektronik GmbH, Sebaldsbruecker Heerstr. 235, 28305 Bremen, Germany
We compared the passive detection abilities of different sonar systems used or planned to be used by the German Navy. This included hull-mounted sonar (HMS), Low Frequency Towed Active Sonar (LFTAS) and Intercept. The objective was to test if and how these sonar types can improve marine mammal risk mitigation by a timely detection of various marine mammal sounds in passive mode. Furthermore it was looked into how these sonar systems could be adapted and extended in the future to minimize the risk for marine mammals. In total sounds of 50 different marine mammal species were analyzed by generated MATLAB programs. Signals of 8 baleen whale species, 39 toothed whale species including 6 beaked whale species, 2 pinniped species and 1 sirenia species were available. 420 signals (e.g. whistles, chirps, clicks, bursts, grunts, moans) of marine mammals were used for the study. Signal signatures (source level, frequency, amplitude, duration of signal, sweep form, variance and repetition rate) were catalogued. The modification of the signals by the transmission channel of HMS, LFTAS and Intercept was simulated by signal processing and detection ranges were calculated. Best detection ranges for lower spectral source levels (SSL < 150 dB relµPa/Hz) of marine mammal signals were obtained by HMS. HMS and LFTAS showed detection ranges > 6 km in their frequency band when SSL ? 150 dB. In comparison, the detection range of the Intercept was much lower caused by the high medium absorption. The results showed that especially the use of HMS for detection of marine mammals would improve risk mitigation. Future sonar types could have adaptable spectrogram displays and a memory for transient signals. For the detection of higher frequent signals of beaked whales (> 20 kHz) which is the major risk group, the additional use of high frequency antennas would optimize detection.
Day: Tuesday 4 April ; Time: 17:00; Eligible for Student Award: No
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Wednesday 5th April
DIFFERENCES IN TIMING OF SEXUAL MATURITY IN DANISH AND GREENLANDIC HARBOUR PORPOISES (PHOCOENA PHOCOENA): VARYING LEVELS OF PAEDOMORPHOSIS?.
GALATIUS, A. (1) AND KINZE, C. C. (2)
(1) Dept. of Cell Biology and Comparative Zoology, Institute of Biology, University of Copenhagen, Universitetsparken 15, DK-2100 Copenhagen, Denmark; (2) Falkonér Allé 35 1. th, 2000 Frederiksberg, Denmark
Several characters of the skeletal morphology of the phocoenoids have been diagnosed as paedomorphic relative to their delphinid relatives. Phocoenids differ from delphinids in terms of life history: They have earlier onset of sexual maturity, higher pregnancy rate and shorter life span. This suggests that phocoenid paedomorphosis is caused by progenesis (onset of sexual maturity at a juvenile state of development). In order to elucidate this, we tested whether differences in timing of sexual maturity in porpoises were linked with the level of paedomorphosis. Differences in the timing of epiphyseal ankylosis and allometric growth and proportions of linear measurements of skeletal parts were investigated on 225 porpoise from the inner Danish waters and 101 from West Greenland and compared with life history data. Epiphyses in the postcranial skeleton matured later in males than females, despite earlier termination of growth and onset of sexual maturity in males. In fully-grown specimens, females had proportionally shorter skulls, while the vertebrae were relatively longer than in males. Since these characters show negative and positive allometry respectively and allometric growth patterns did not differ between the sexes, we suggest that males cease growing at an earlier stage of development than females, retaining more paedomorphic proportions. Porpoises from West Greenland attain smaller asymptotic sizes than their Danish conspecifics and data suggest that they have an earlier onset of sexual maturity. Compared to the Danish sample fully-grown West Greenland porpoises retained even more paedomorphic skeletal characters than their Danish peers. On the basis of these results, we suggest that phocoenid paedomorphosis is the result of progenesis and that differences in size and onset of sexual maturity between sexes and populations is the result of varying levels of paedomorphosis. Varying paedomorphosis may allow phocoenoids some flexibility in the specifics of life history.
Day: Wednesday 5 April ; Time: 8:30; Eligible for Student Award: Postgraduate
STRANDINGS AND SIGHTINGS OF DWARF SPERM WHALES, KOGIA SIMA, IN BAJA CALIFORNIA SUR, MEXICO.
GUERRERO-RUIZ, M. (1), JAUME-SCHINKEL, S. (1), AURIOLES-GAMBOA, D. (2) AND URBÁN-R., J. (1)
(1) Programa de Investigación de Mamíferos Marinos. Depto. de Biología Marina. Universidad Autónoma de Baja California Sur. Apdo. Post. 19-B. La Paz, B.C.S., 23081 México; (3) Laboratorio de Ecología de Mamíferos Marinos. Centro Interdisciplinario de Ciencias Marinas-IPN. Apdo. Post. 592. La Paz, B.C.S., 23090. México
The dwarf sperm whale (Kogia sima) is a very unknown species. Scarce information is available about its distribution and abundance, and most of the information about this species comes from strandings and few sightings. One of the difficulties to observe this species at sea is its evasive behavior and relatively small size. Strandings in some areas, however, indicate that the dwarf sperm whales are more common than previously suspected. A total of seventeen confirmed dwarf sperm whales strandings have been recorded in La Paz Bay, from February 1983 through February 2004. The size at which dwarf sperm whales attain sexual maturity is 2.1 m for both sexes. Eight of the stranded individuals were close to this size (mean length of 2.2 m), and five of them were females, whereas two were males and one was of unknown sex. On the other hand, more than 170 sightings have been recorded from 1991 to 2005 on the southwest portion of the Gulf of California year round. Group sizes have ranged from 1 to 10 dwarf sperm whales, with a mean group size of 2.1 individuals. The presence of pregnant females (March and October) mainly in Bahía de La Paz, and sightings of cow-calf pairs (June) suggest that the species breeds in the southern Gulf of California. The dwarf sperm whale is listed in the IUCN Red Data Book as "inssuficiently known" and is classified as a species under "special protection" in the Official Mexican Regulation NOM-059-SEMARNAT-2001. We suggest that more effort needs to be done in the area in order to know more about the current status and the importance of this area for the species.
Day: Wednesday 5 April ; Time: 8:50; Eligible for Student Award: No
POPULATION STRUCTURE AND PHYLOGENETIC PLACEMENT OF INDO-PACIFIC BOTTLENOSE DOLPHINS (TURSIOPS ADUNCUS) OFF ZANZIBAR, TANZANIA.
SÄRNBLAD, A. (1), DANBOLT, M. (1), DALÉN, L. (1), BERGGREN, P. (1) AND AMIR, O. (2)
(1) Department of Zoology, Stockholm University, S-106 91 Stockholm, Sweden; (2) I nstitute of Marine Sciences, University of Dar es Salaam, P.O. Box 668, Zanzibar, Tanzania
We examined the phylogenetic placement of bottlenose dolphins from Zanzibar, east Africa and the potential population differentiation between animals found off the southern and northern coasts of Zanzibar using variation in mtDNA control region sequences. Samples from animals incidentally caught in fishing gear and skin biopsies collected during boat surveys were used and comparisons made with published mtDNA sequences from populations of T. aduncus from southeast Australia, T. aduncus and T. truncatus off China and a proposed new species of Tursiops off South Africa. The phylogenetic analyses separated the haplotypes into three groups where Zanzibar and South African haplotypes grouped together in a lineage separated from both T. truncatus and Chinese and Australian T. aduncus haplotypes suggesting that the dolphins found off Zanzibar should be classified as T. aduncus, alongside the South African animals. This is based on the assumption that the animals in the western Pacific are given a new species name. Further, analyses of genetic differentiation showed a significant separation between the bottlenose dolphin populations off northern and southern Zanzibar indicating a limited exchange of reproducing females over this relatively short distance (approx. 80 km). No differentiation was found between southern Zanzibar and South Africa suggesting a more recent common evolutionary history for these populations than for the northern and southern Zanzibar populations.
Day: Wednesday 5 April ; Time: 9:10; Eligible for Student Award: Postgraduate
THE ROLE OF CULTURAL INNOVATION IN THE EVOLUTIONARY RADIATION OF CETACEANS.
BARRETT-LENNARD, L. (1) AND MATKIN, C. (2)
(1) Vancouver Aquarium Marine Science Center, PO Box 3232, Vancouver, B.C. V6B-3X8, Canada (1) Zoology Department, University of British Columbia, 6270 University Blvd, Vancouver, B.C. V7P-2E2, Canada (2) North Gulf Oceanic Society, 3430 Main St., Suite B1, Homer, Alaska, 99603, USA
A fundamental goal of evolutionary biology is to understand processes driving speciation. A critical prerequisite for speciation is the development of reproductive isolation, allowing populations to evolve genetic, morphological, and/or ecological differences. In the best understood situation, allopatric speciation, geographic separation prevents gene flow and allows separated populations to diverge. In contrast, relatively few plausible mechanisms have been proposed by which positive assortative mating could allow sympatric speciation. Since physical barriers to dispersal by large mobile species are more rare in the ocean than on land, the extensive evolutionary radiation of cetaceans demands explanation. Here, we advance the hypothesis that sympatric speciation in cetaceans is facilitated by culturally-transmitted behavioural innovations combined with social conformism. In support of the hypothesis, we present recent findings from our field work on killer whales in western Alaska which, combined with earlier findings from British Columbia and the eastern Gulf of Alaska, indicate that the number of sympatric and parapatric populations in the north eastern Pacific Ocean numbers at least eight. All but one of the populations are distributed within previously-described mammal-eating and fish-eating ecotypes, indicating that diversification is common to both. Fixed differences in mitochondrial DNA control region sequences and/or microsatellite allele frequency differences indicate that there is little if any gene flow between populations. We describe a recently-discovered group of killer whales in False Pass, Alaska that uses specialized behaviours for hunting and feeding on gray whale calves as an instance in which innovation appears to be driving population segregation. We argue that the tendency form behaviourally distinct, socially and reproductively isolated subgroups occurs in other odontocetes species as well as killer whales and is capable of restricting gene flow enough to allow sympatric speciation and, in the long term, evolutionary diversification.
Day: Wednesday 5 April ; Time: 9:30; Eligible for Student Award: No
TRENDS IN DIET OF HARBOUR PORPOISES (PHOCOENA PHOCOENA) IN THE EASTERN NORTH SEA.
SANTOS, M.B. (1,2), PIERCE, G.J. (1), IENO, E.N. (1,3), ADDINK, M. (4), SMEENK, C. (4), KINZE, C.C. (5), IVERSON, M. (6) AND LOCKYER, C. (7)
(1) School of Biological Sciences (Zoology), University of Aberdeen, Tillydrone Avenue, Aberdeen, AB24 2TZ, UK; (2) Instituto Espa?ol de Oceanografía, Centro Oceanográfico de Vigo, P.O. Box 1552, 36200, Vigo, Spain; (3) Highland Statistics Ltd., 6 Laverock road, Newburgh, Aberdeenshire, AB41 6FN, UK; (4) National Museum of Natural History, Darwinweg 22300 RA, Leiden, The Netherlands; (5) CCKonsult Falkoner Alle 35 1th, 2000 Frederiksberg, Denmark; (6) Danish Institute for Fisheries Research, Kavalerg?rden 6, DK-2920 Charlottenlund, Denmark; (7) Age Dynamics, Huldbergs Allé 42, DK2800 Kongens Lyngby, Denmark
Results are presented of the analyses of harbour porpoise stomach contents from animals stranded and by-caught in Denmark and he Netherlands. Around 130 stomach content samples from Denmark (1985-92 and 1996-2000) were analysed, along with around 100 non-empty stomachs from the Netherlands (1985-2003). Cod, whiting (Gadidae), sandeels (Ammodytidae) and gobies (Gobiidae) were the most important prey. Diet was found to vary in relation to area, year, season, size-class and sex. Interannual dietary trends were apparently not related to known changes in large-scale fish abundance estimates. It has been suggested that the recent increase in porpoise sightings and strandings off and in the Netherlands could be associated with increased herring abundance. This prediction will be tested once new stomach samples from the Netherlands for 2004-05 have been analysed.
Day: Wednesday 5 April ; Time: 11:10; Eligible for Student Award: No
FEEDING STRATEGY OF STRIPED DOLPHINS IN A NEAR SHORE AREA.
MEISSNER, A.M. (1,2) AND RIDOUX, V. (2)
(1) Centre de Recherche sur les Cétacés, Marineland, 306 avenue Mozart, 06600 Antibes, France; (2) Laboratoire de Biologie et Environnement Marins, Port des Minimes, 17000 La Rochelle, France
Since 2003, a coastal part of the northwestern mediterranean population of striped dolphins, Stenella coeruleoalba, has been studied off Antibes, France, to understand habitat use of this oceanic species in a near shore area. Here, we focus on feeding tactics to underline influence of local environment on foraging strategies. Forty seven survey sessions (totalling 17 hours) in the inshore area allowed us to describe eighteen bouts of foraging behaviours. Two different feeding tactics came out by comparing distance to shore (Kruskal-Wallis, p<0,01, N=210). The coastal tactics involves dolphins structured into widely spread subgroups of one to a few animals. Dolphins foraging from dusk to dawn (4h30 after sunrise in average, N=7) are known to feed during the night. They forage within 5 km from the shore (SD=2 km, N=176) over steep slope (µ =14%, N=176) above 550 m deep (SD=270 m, N=176). The offshore behaviour is characterized by entire schools foraging in coordination: animals move forward in a line formation. Dolphins momentary take advantage of preys present underneath the surface (feeding extends from 15 min to 1 hour during daylight hours) and then return to their previous activity. Feeding dolphins were observed within15 km from the shore (N=34) above 1200 m deep (SD=385 m, N=24). Both tactics are used alternately by the same individual during a daily loop pattern of habitat use, inshore at night and offshore during the day. The coastal tactics appears to be a predictable activity, the specific offshore-inshore diel movement having previously been described. The second tactics seems to be more opportunistic, depending on prey availability. Resightings of eighteen dolphins throughout this 3-years-study suggests site fidelity between January and June. Knowledge of local habitat and understanding of prey behaviour could lead to this feeding strategy, reflecting an adaptation of the species to a specific feeding ground.
Day: Wednesday 5 April ; Time: 11:30; Eligible for Student Award: Postgraduate
FORAGING BEHAVIOR OF MALE SPERM WHALES OFF NORTHERN NORWAY.
TELONI, V. (1), JONHSON, M.P. (2), MADSEN, P.T. (1) AND MILLER, P.J.O. (3)
(1) Dept. of Zoophysiology, Aarhus University, 8000 Aarhus C, Denmark; (2) Woods Hole Oceanographic Institution, MA 02543, USA; (3) Sea Mammal Research Unit, School of Biology, University of St. Andrews, St. Andrews KY16 8LB, UK
Male sperm whales are known to frequent the submarine canyon northwest of Andenes (69N/15E) during summer. To uncover the dynamics of this foraging activity, the diving and acoustic behavior of four male sperm whales off Andenes has been studied during the summer of 2005 by means of archival digital tags (Dtags). The Dtags recorded the whales' sound and movement patterns for 25, 26, 14 and 13 hours, during which the whales performed 35, 39, 17 and 11 dives, respectively. The diving depth ranged between 50 and 1860 m, where the same whale was foraging at depths as disparate as 100 and 1800 m. The acoustic repertoire was made of usual clicks, buzzes and slow clicks and the former two were consistent with hypotheses of use in echolocation of prey. In 30% of the dives, usual clicks were produced during ascent all the way up to the surface, whereas sperm whales are normally reported to stop clicking early during the ascent phase. Buzzes, which are considered indicators of the foraging phase in a dive, were emitted in both shallow and deep dives, during the bottom phase as well as the descent and ascent phases of the dives. The shallowest buzz was emitted at 20 m depth. The number of buzzes per dive (range 1-41) was higher during deep dives. It is concluded that male sperm whales in this habitat exploit a greater depth range than females and juveniles foraging at lower latitudes and employ a more dynamic foraging behavior.
Day: Wednesday 5 April ; Time: 11:50; Eligible for Student Award: Postgraduate
DIFFERENCE BETWEEN THE FEEDING HABITS OF FIN WHALE AND BRYDE'S WHALE IN THE GULF OF CALIFORNIA USING STABLE NITROGEN AND CARBON ISOTOPES.
JAUME-SCHINKEL, M.S. (1), GENDRON D. (2), URBÁN, J. (1) AND AGUÍ?IGA S. (2)
(1) UABCS. Carr. Al Sur km 5.5, La Paz, B.C.S. Mexico; (2) CICIMAR. Col Santa Rita. A.P. 592, La Paz, B.C.S. Mexico
In the Gulf of California two rorquals feed, the fin whale Balaenoptera physalus is a resident species meanwhile the Bryde's whale Balaenoptera edeni is frequently seen in the area. Confirmed by stable nitrogen and carbon isotopes we found that the fin whale presents a seasonal shift in their diet in the Gulf. They change their feeding on euphausiids during winter and spring (cold season) for higher trophic level preys such as juvenile sardines in summer-fall (warm season). In contrast the Bryde's whale is recognized as an ictiologist species and in the Gulf it has been associated to big schools of pelagic sardines. In this study we show differences in the feeding habits of this rorquals and that both present a seasonal shift in their diet in the Gulf of California. Monthly field trips were made between January 2001 and June 2002 in the southwestern Gulf. We collected 19 skin biopsies of fin whales and 6 form the Bryde's whales. An increment in d15N of fin whale skin samples of 1.5‰ is observed between the warm season (16.11±0.35‰) and the cold season (14.61±0.95‰). A similar increment of 1.28‰ is found between the skin samples of the Bryde's whale from the warm season (17.44±0.54‰) and the cold season (16.16±0.16‰). The differences in d15N between both rorquals and both seasons are significant (F=5.31: p<0.05: cold and F=13.35; p<0.05: warm). The results suggest that both species explode the same resource in different moments avoiding feeding competence.
Day: Wednesday 5 April ; Time: 12:10; Eligible for Student Award: No
TRANSFER OF FATTY ACIDS FROM MOTHER TO PUP IN GREY SEALS HALICHOERUS GRYPUS.
WALTON, M. AND POMEROY P.
Sea Mammal Research Unit, University of St Andrews, St Andrews, KY16 8LB, Scotland
Blubber fatty acids profiles (FAPs) are related to those found in the dietary prey but are not identical because individual fatty acids are subjected to differential metabolism, deposition, utilization etc. An understanding of these differences is important in the application of FAPs for quantitative dietary studies. One way to do this is to follow the transfer of fatty acids via milk from grey seal mothers to pups. After giving birth the mothers do not feed for about 3 weeks. Blubber triacylglycerols TAG are broken down and transported in the blood as free fatty acids FFA for conversion into milk or energy. The pups ingest the milk and the fatty acids are carried in the blood as TAG and stored as such in the blubber. Blubber, milk and blood samples were collected at early and late lactation from 25 mother/pup pairs. Blubber and milk lipids are predominantly TAG, but blood lipids were separated into TAG, FFA, sterolester and phospholipid fractions. The fatty acid profiles of all fractions were compared using multivariate statistical techniques.
Results indicated preferential release and retention of some fatty acids by blubber during lactation. The FAPs of the blood phospholipids and sterolesters were very different from the other fractions. Although not totally identical mother and pup blubber FAP were very similar and were more like milk FAP than to any of the blood fractions. Thus this similarity occurred despite differences seen in the milk and blood lipid fractions. Thus it was not due to the mother's profile being simply released and transported as an entity in the blood and milk to the pup. The exact mechanisms involved are unclear, at present, but would appear to involve the uptake and release mechanisms acting at the blood/blubber interface.
Day: Wednesday 5 April ; Time: 12:30; Eligible for Student Award: No
ACOUSTIC RELEASE OF GAS BUBBLES TO PREVENT CETACEAN ENTANGLEMENT IN FISHING NETS.
ANDRÉ, M. (1), COATANHAY, A. (2), GERVAISE, C. (2), GRACIA, J. (3), DELORY, E. (1) AND VAN DER SCHAAR, M. (1)
(1) Laboratory of Applied Bioacoustics (LAB), Technical University of Catalonia (UPC), Spain; (2) Laboratoire Extraction et Exploitation de l'Information en Environnements Incertains, ENSIETA, Brest, France; (3) Tecnología Marina Ximo S.L., MAREXI, Vigo, Spain
Cetacean entanglement in fishing nets has become a global conservation issue. Although acoustic deterrents appeared to be a promising solution to reduce bycatch, their general use in European waters may not be a definitive answer to the problem. The large scale introduction of these acoustic sources may also worsen the noise load in certain areas already heavily exposed to artificial sounds. We studied the properties of underwater sound backscattered from air bubbles to model their acoustic response to incident sonar waves from Tursiops truncatus and Phocoena phocoena (two of the most common cetacean species involved in fishing interactions). Depending on bubble size, incident angles and wave lengths, we defined the reflection coefficients and target strengths of single bubbles and bubble clouds in a dense and homogeneous medium. Modelling showed that the incident narrow-beam acoustic energy was backscattered nearly omnidirectionally, sending acoustic "flashes" back to the source. To experimentally test the model and the deterrent effect on cetaceans, we developed a depth sensitive passive device that releases a cloud of air bubbles when detecting cetacean sounds (piezo ceramic hydrophone with a hybrid integrated DSP allowing the processing of received sounds), through a micro-electrovalve able to generate different sizes of bubbles and control the release parameters. The device was presented under different scenarios (presence and absence of fish) to captive bottlenose dolphins that immediately showed escape behaviour after the bubble reflection. Real-time acoustic recording confirmed the results indicating the potential use of air bubbles to prevent cetacean bycatch in fishing nets.
Day: Wednesday 5 April ; Time: 14:30; Eligible for Student Award: No
A DYNAMIC HYDROPHONE ARRAY FOR STUDYING UNDERWATER VOCAL BEHAVIOUR.
RENDELL, L.E. (1), SCHULZ, T. (2) AND WHITEHEAD, H. (2)
(1) Sea Mammal Research Unit, Gatty Marine Laboratory, University of St Andrews, Fife, UK; (2) Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada
The difficulty of attributing sounds to individual marine mammals inhibits our understanding of how these animals use sound in social interactions. We have developed and trialed a dynamic hydrophone array system to overcome this difficulty at sea. The system is a simple extension of current fixed arrays whereby hydrophones are placed onboard small remote-operated (radio controlled) vessels which are launched from a main research vessel. Simple VHF transmitters broadcast acoustic signals back to the research vessel where they are received by handheld radios and simultaneously recorded by a digital multi-track recorder. GPS pseudo-range and phase data are received onboard the ROVs by OEM GPS boards, logged to flash memory cards and downloaded after recovery. The system can be stored, deployed and recharged onboard a small 40' sailing vessel. Once deployed, the vessels can be piloted to establish and maintain favourable array geometry, provided focal animals are not moving too rapidly. GPS error is a concern for localisation accuracy, however polynomial smoothing of GPS positions over time improves relative receiver positioning. Calibration trials with sound sources of a known separation distance have demonstrated accuracy in acoustic localisation of up to 0.5 metres. We have deployed the system several times at sea in the Northwest Atlantic and successfully localised social signals from sperm whales, showing the potential for this system in understanding social vocalisations. We present prelimary results on directionality in apparent inter-pulse intervals from coda clicks. We also show how the integration of inter-pulse-interval data provides extra information in unravelling vocal exchanges. Finally, recordings of northern bottlenose whales using this system show that its utility is not limited to sperm whales. However, improvements are possible in some aspects of the system including ROV mobility, reliability of the acoustic system and the robustness of GPS data-logging.
Day: Wednesday 5 April ; Time: 14:50; Eligible for Student Award: No
A SIMPLE METHOD TO EXTRACT ANIMAL'S PATHS FROM NOISY DATA (DEMONSTRATED ON GREY SEALS)..
LONERGAN, M. (1) AND MCCONNELL B. (2)
Sea Mammal Research Unit, Gatty Marine Laboratory, University of St Andrews, St Andrews KY16 8LB, UK
Electronic tags have been attached to large numbers of marine mammals and provided many insights into their behaviour over the last twenty years. However, there are practical and technological limitations to the amount and precision of the information they provide. There are particular problems with location, which is both obviously important and difficult to measure accurately. In the case of ARGOS, a widely used satellite based system, the nominal accuracy of individual estimates ranges from 150m to several kilometres in each direction, though a small proportion of results are clearly far worse. We demonstrate a simple , and reasonably quick, Bayesian approach to reducing error in locational data and estimating the remaining uncertainty. The underlying behavioural model is based on the results produced by a novel FASTLOC GPS tag attached to a free-living grey seal (Halichoerus grypus) at Abertay Sands in eastern Scotland . The model is fitted to ARGOS data from other novel hybrid ARGOS/FASTLOC GPS tags attached to similar individuals, and evaluated using the separate and parallel GPS data they produce. The results are consistent and indicate that the method removes the majority of the noise and produces plausible estimates of the remaining uncertainty. It is then applied to data from other seals and its limitations and potential for improving the understanding of the animals' movment, behaviour and usage of the marine environment are discussed along with the importance of this information in the management of such areas and populations.
Day: Wednesday 5 April ; Time: 15:10; Eligible for Student Award: No
WHO, WHERE, WHEN AND HOW - THE SPATIO-TEMPORAL DISTRIBUTION AND OCEANOGRAPHIC CORRELATIONS OF STRANDINGS IN A HOTSPOT REGION.
VANMAN, C. (1) BOGOMOLNI, A. (2), MOORE, M.J. (2) AND TOUHEY, K.(3)
(1) Fjord&B?lt, Margrethes Plads 1, Kerteminde, 5550, Denmark; (2) Woods Hole Oceanographic Institution, Biology Department, Redfield Building 2 - 44, Woods Hole, MA, USA; (3) Cape Cod Stranding Network, P.O box 287, Buzzards Bay, MA, 02532, USA
Cape Cod, located in the Gulf of Maine, US, has been named a stranding hotspot for several species, among them Atlantic white-sided dolphin (L. acutus) and Common dolphin (D. delphis), yet the reasons for their occurrence have remained under-scrutinised in scientific terms. We present the results of a spatio-temporal analysis of D. delphis and L. acutus strandings in Cape Cod between 1968 - 2003 and the environmental parameters surrounding those occurring during 1998 - 2003. The entire study period saw 55 mass- and 316 single strandings, of which 46 and 227, respectively, took place within Eastern Cape Cod Bay, particularly in the local area Wellfleet. Mass-strandings peaked in winter for D. delphis and in spring for L. acutus, mainly during storms, known as 'Nor'easters', with wind speeds of >72 m/s, while single strandings were linked to south westerly winds. An analysis in the statistical program PRIMER showed single strandings in Cape Cod Bay to be different from events in other areas and that they were defined by their similarities in wind direction and speed, sea surface temperature, state of tide and the time of year when they occurred. Single strandings elsewhere were more random in the environmental variables affecting them. Seasonal stranding peaks appeared to be an expression both of the seasonal peak abundance of the two species in the study region and the intensified weather conditions during winter and spring, while Wellfleets' highly complex bathymetry in tandem with certain meteorological settings make it a sub-region stranding hotspot. Local weather patterns, ecological conditions attracting cetaceans to Cape Cod waters and the movements of large water masses with which L. acutus and D. delphis are associated, are influenced by the North Atlantic Oscillation, strongly suggesting links between stranding trends and large-scale environmental variability in the Gulf of Maine.
Day: Wednesday 5 April ; Time: 16:10; Eligible for Student Award: No
DEVELOPMENT OF THE ZFX / ZFY 5?-EXONUCLEASE ASSAY, A NEW TOOL FOR SEX DETERMINATION IN CETACEANS AND ITS APPLICATION TO SPERM WHALES IN THE GULF OF CALIFORNIA..
RUBIO-CISNEROS N. (1), MORIN P. (2), MESNICK S. (2), GENDRON D. (4), NESTLER A. (2,4), ROBERTSON K. (2) AND JAQUET N. (5)
(1) Centro de Investigaciones Biológicas del Noroeste (CIBNOR), La Paz, B.C.S., México; (2) Southwest Fisheries Science Center (SWFSC), National Marine Fisheries Service (NMFS), 8604 La Jolla Shores Drive, La Jolla, CA, USA; (3) Centro Interdisciplinario de Ciencias Marinas, Instituto Politécnico Nacional, La Paz, B.C.S., México; (4) Current address: Applied Biosystems, 850 Lincoln Centre Dr., Foster City, CA 94404, USA; (5) Provincetown Center for Coastal Studies, Provincetown, Massachusetts, USA
Sex determination in cetaceans is essential for population studies, but is very difficult in the field because most species lack sexual dimorphism and have internal genitalia. Previous sexing methods have been limited to a subset of species and require sampling of high quality DNA. We developed a 5?-exonuclease fluorescent assay based on ZFX/ZFY gene orthologs. This method produces a small 105-bp PCR product. Using primers and sex-specific fluorescent probes designed from conserved regions of seven families, a rapid, highly sensitive, and unambiguous sex determination assay is available. We demonstrated sex specificity for 33 cetacean species in nine families. We found the ZFX/ZFY 5?-exonuclease assay method highly successful for sloughed skin of 66 samples of sperm whales from the Gulf of California taken during the field seasons of 1996-2004. This is important because sloughed skin usually bears low quality or low concentration of DNA. Of the 66 sperm whale samples, 16 had information form the dorsal fin callus. Ten animals bear the callus, of which nine were females of different age classes and one was a juvenile male. Three males and three females did not bear the callus. The high resolution of the ZFX/ZFY 5?-exonuclease assay in sloughed skin from sperm whales allows us to continue using a none invasive method for sampling tissue of free-living sperm whales in this region and enlarge our sample number of gendered samples with callus information. This will help to clarify whether the dorsal fin callus could be a sexual character useful for distinguishing male from female sperm whales at sea.
Day: Wednesday 5 April ; Time: 16:30; Eligible for Student Award: Postgraduate
PCR METHOD FOR IDENTIFICATION OF NEMATODES FROM SUPERFAMILY ASCARIDOIDEA.
ROKICKI J. (1), KIJEWSKA A.(2), KUKLIK I. (3) AND ŒWI¥TECKA A.(1)
(1) Department of Invertebrate Zoology, University of Gdañsk, Gdynia, Poland; (2) Institute of Oceanology, Polish Academy of Sciences, Gdynia, Poland; (3) Hel Marine Station, Hel, Poland
Nematodes belonging to the Ascaridoidea superfamily are worldwide-distributed parasites. The life cycle include many species of invertebrates and teleostean fish as intermediate or paratenic host and marine mammals or fish - eating birds as definitive hosts. Their sources of infection are several fish species. Traditional classification of Ascaridoidea species bases on various morphological and anatomical criteria. Recently, molecular techniques have been introduced as a tool for nematode systematic, and PCR quickly became the standard technique. The choice of this ribosomal DNA as a target sequence for identification of species was motivated by the presence of the conserved region (the gene coding 5.8S RNA) and the variable flanking fragments (internal transcribed sequences ITS-1 and ITS-2). Analysis of sequences of both fragments would permit the analysis including also sibling species form Anisakis simplex complex and Contracaecum osculatum complex. In this work, we present the analysis of ribosomal DNA (ITS 1-5.8S-ITS2) of the representatives of Anisakidae (Anisakis sp. and Contracaecum sp.) collected from 13 porpoises (Phocoena phocoena, L.) and 1 grey seal (Halioherchus grypus, L.) bycaught in the Southern Baltic. Fourteen ascaridoid species was detected with the method of PCR-RFLP. Two species from the sister complex Anisakis - parasites of porpoises, dolphins and whales and different morphologically Anisakis physeteris (parasite of Physeter catodon). Also were investigated Contracaecum osculatum C, C. radiatum, C. rudolphii (the parasites of pinnipeds and fish eating birds), Pseudoterranova decipiens (seal parasite) and from family Rapidascarididae Rapidascaris acus, Hysterothylacium bidentatum and H. aduncum (fish parasite). Super family Ascaridoidea is represented Porrocaecum ensicaudatum, P. angusticolle, P. depressum and P. crassum. For digestion were used endonuklease Taq I, Alu I, Bsu RI and Rsa I. This method is good for identification of nematods independent of the larval stage and geographical region.
Day: Wednesday 5 April ; Time: 16:50; Eligible for Student Award: No
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Thursday 6th April
TAKING STOCK OF EUROPEAN CETACEANS: THE SCANS-II SURVEYS..
MACLEOD, K. (1), SCHEIDAT, M. (2) AND HAMMOND, P. (1)
(1) Sea Mammal Research Unit, Gatty Marine Laboratory, University of St. Andrews, Fife, KY16 8LB, Scotland; (2) AG7 Oekologie der Voegel und Meeressaeuger, Forschungs- und Technologiezentrum Westkueste, Hafentoern, 25761 Buesum, Germany
In EU Atlantic waters, the harbour porpoise and common dolphin suffer bycatch mainly in bottom set gillnets and pelagic trawls, respectively. The Habitats Directive specifies that Member States should employ conservation measures to ensure that bycatch does not have a serious negative impact on cetacean populations. Information on abundance is fundamental to an assessment of population status and to inform conservation actions. In 1994, the SCANS survey provided the first robust estimates of abundance for small cetaceans in the North Sea and adjacent waters. In July 2005, the SCANS-II surveys were carried out to generate new estimates of cetacean abundance for the whole European Atlantic continental shelf. Seven ships and three aircraft surveyed the area. Double platform line transect surveys were carried out by all ships to allow analyses to account for the probability of detection on the transect line to be less than one and for responsive movement of animals to the ship. Shipboard transects covered 19 000 km in an area of 1 011 000 km2. The "racetrack" method used for aerial surveying also allows analyses to take account of animals missed on the transect line. Aircraft flew 15 220 km on effort in an area of 353 000 km2. Over 1 900 encounters with thirteen cetacean species were recorded. The harbour porpoise was most commonly encountered and was widely distributed but there were few sightings south of 47?N. Many more sightings were recorded in the southern North Sea than on the SCANS survey suggesting changes in distribution have occurred in this area. Common dolphin sightings were restricted to the west of the UK, Ireland, France and the Iberian Peninsula, where densities were highest. Abundance estimates will be calculated from these data and incorporated into the management framework being developed to allow safe bycatch limits to be recommended.
Day: Thursday 6 April ; Time: 9:00; Eligible for Student Award: No
VALIDATING THE USE OF SPATIAL MODELS TO ESTIMATE CETACEAN ABUNDANCE.
GOMEZ DE SEGURA, A. (1), HAMMOND, P.S. (2), CA?ADAS, A. (3) AND RAGA, J.A. (1)
(1) Instituto Cavanilles de Biodiversidad y Biología Evolutiva, Universidad de Valencia, P.O. Box 22085, E-46071, Valencia, Spain; (2) Sea Mammal Research Unit, Gatty Marine Laboratory, University of St Andrews, Fife KY16 8LB, St Andrews, UK; (3) ALNITAK, Nalón 16, E-28240 Hoyo de Manzanares, Madrid, Spain
Spatial modelling is increasingly being used as an alternative to conventional line transect methods to estimate cetacean abundance. This new method can have several advantages including: the ability to use data collected from "platforms of opportunity" that are cheaper but do not give equal coverage of the surveyed area; the ability to estimate abundance for any defined area within the study area; and the possibility for increased precision if covariates explain sufficient variability in the data. One study has been conducted to compare these model-based methods with conventional design-based methods, but the use of covariates in detection function estimation and stratification by school size have not previously been investigated. In this study, the density of striped dolphins was estimated in Western Mediterranean waters using distance sampling models and spatially applied Generalized Additive Models (GAMs). This estimate was compared with density previously estimated in the same area using conventional line transect methods. The densities estimated were almost the same: 0.494 animals.km-2 (CV= 0.16) using spatial models and 0.489 animals.km-2 (CV= 0.19) using conventional line transect methods. Densities were also similar when they were calculated in stratified areas defined during the original line transect study. The precision of the estimates from spatial modelling was higher than that of the estimates obtained from conventional line transect analysis, particularly in the smaller areas. The results confirm that spatial modeling is a good approach for estimating cetacean abundance, although there are some factors that must to be borne in mind when this method is used.
Day: Thursday 6 April ; Time: 9:20; Eligible for Student Award: Postgraduate
COUNTING THE INVISBLE. A COMPARISON BETWEEN ESTIMATES OF THE SIZE OF THE BALTIC GREY SEAL POPULATION DERIVED FROM TRADITIONAL COUNTS DURING MOULT AND PHOTO-IDENTIFICATION USING MARK RECAPTURE TECHNIQUE.
KARLSSON O. AND HELANDER B.
Contaminant Research Group, Swedish Museum of Natural History, Box 50007, 104 05 Stockholm, Sweden
Counts of grey seals during moult have been the basis for population monitoring in the Baltic since the mid 1970s. In recent years combined counts over the distribution range in the Baltic have been performed. Moult counts is a useful tool for monitoring population trends, but counted numbers just represent an index of population size, since the fraction of the population hauling out at any time is not known. It is therefore important to try to assess the proportion of the population at sea. A study of photo identification of individual seals was used to estimate the size of the summer population of grey seals in the Baltic Sea in year 2000 using mark-recapture. The point estimate was 15,631, with 95% confidence limits from 9,592 to 19,005. In 2000 the number of seals counted during moult was 9,700 representing 62% of the point estimate. Counted numbers varies between years, probably mainly due to differences in weather conditions during the census period that affect the probability for seals hauling out. We used the point estimate from the photo-identification study, increased with 7.49% per year (the mean annual growth rate estimated from the Swedish study), to compare with the results from the combined counts between 2000-2004 (table 1). The data suggests that an average 72% (SE 4.9) of the population is counted during moult census. The proportion varies widely between years (table 1), but moult counts at least give a rough lower estimate of population size.
Day: Thursday 6 April ; Time: 9:40; Eligible for Student Award: No
ABUNDANCE AND DISTRIBUTION OF HARBOUR PORPOISES (PHOCOENA PHOCOENA) IN THE CENTRAL GERMAN BIGHT DURING 2002-2004.
PIPER, W. (1), LACZNY, M. (1) AND THOMSEN, F. (1,2)
(1) Biologisch-landschaftsökologische Arbeitsgemeinschaft, Gotenstraße 4, D-20097 Hamburg, Germany; (2)) Biozentrum Grindel, Universität Hamburg, Martin-Luther-King-Platz 3, D-20146 Hamburg, Germany
The harbour porpoise (Phocoena phocoena) is widely distributed within the North Sea. Areas of highest population densities appear to be in the north- western North Sea and along the German and Danish west coast. During the first SCANS survey, in summer 1994, porpoises were also commonly encountered in offshore waters, for example in the central North Sea. However, precise information on year-round abundance and distribution of harbour porpoises in the central North-Sea is sparse. Between 2002 and 2004, we undertook 12 aerial line-transect surveys in a 2.500 km2 area in the central German Bight, 100 km north of the Island of Borkum (Eastern-Frisia). We also monitored porpoise activity with automated-porpoise-detectors (T-PODs) temporarily deployed from an anchorage in the study area. Data were analysed with distance-sampling and T-POD-software. A total of 303 harbour porpoises were sighted from the plane. Sighting rates peaked in July 2002, February, May and July 2003, and in January 2004. Absolute densities (g(0) corrected) ranged between < 0.4 and 1.22 animals / km2 (peak = February 2003). Calving rates varied between 3.2 and 9.6 %. The sightings were evenly distributed within the study area. The data from the T-PODs gave similar results, however, porpoise-positive-minutes were highest during April 2003. Our results show a rather irregular appearance of harbour porpoises in one part the central German Bight. They also indicate that the area is used as a transitory route with harbour porpoise moving in from regions of high density in summer (Northern-Frisia) and early spring (Eastern-Frisia).
Day: Thursday 6 April ; Time: 11:20; Eligible for Student Award: No
HARBOUR PORPOISES IN THE NORTH SEA: PEAK STRANDING NUMBERS IN THE SOUTH IN YEARS OF FOOD SHORTAGE IN THE NORTH - EVIDENCE OF OCCASIONAL MASS MIGRATION?.
ABT, K. (1) AND SIEBERT, U. (2)
(1) Wildlife Consulting, Samwerstr. 32, 24118 Kiel, Germany (2) Research and Technology Centre West Coast, University of Kiel, Hafentörn, 25761 Büsum, Germany
In spite of high scientific and public interest, little is yet known about harbour porpoise (Phocoena phocoena) population dynamics and migration patterns in the North Sea. As census data are still scarce, systematic stranding records remain a valuable source of information. Data collected in 1991-2004 in the northeastern German Bight were analysed for possible evidence of population change. The number of recorded dead strandings per year varied between 62 and 164, with no significant trend over time (P = 0.49). Year-to-year changes were generally moderate, remaining between -31% and +45% in 11 out of 13 cases. In 1998 and 2004, however, numbers increased by 132% and 125%, respectively. On a monthly basis, stranding numbers in both these years did not vary erratically, as may be expected if peaks were driven by weather or unusual mortalities through e.g. by-catch, infectious disease or sonar activity. Instead, numbers remained consistently above seasonal normal levels for 5 months (Apr-Aug) in 1998 and for 8 months (May-Dec) in 2004. Literature recherche revealed that in both these years there was a collapse of sandeel (Ammodytes spec.) stocks northeast of Scotland. Reported consequences included severe food shortage for seabirds, gadoid fishes, and larger cetaceans in Scotland, as well as unusual whiting (Merlangius merlangus) mass occurrence in the German Bight. Both sandeel and whiting are major prey species of harbour porpoise in Scotland. We suggest that the peak stranding numbers of porpoises at the German coast in 1998 and 2004 reflected temporarily increased population density due to immigration. Porpoises invading from Northeast Scotland may have been motivated by lack of one key prey and southward movement of another. Our results further suggest that systematic stranding records may be more useful in monitoring population changes of cetaceans than commonly thought.
Day: Thursday 6 April ; Time: 11:40; Eligible for Student Award: No
POPULATION ESTIMATION AND SURVIVAL RATE OF LONG-FINNED PILOT WHALES (GLOBICEPHALA MELAS) IN THE STRAIT OF GIBRALTAR AND INTERACTIONS WITH THE MARITIME TRAFFIC.
VERBORGH, P. (1), DE STEPHANIS, R. (1), PÉREZ, S. (1), SANCHEZ, A. (1) AND GUINET, C. (2)
(1) CIRCé Cabeza de Manzaneda 3, Pelayo, 11390 Algeciras, Cadiz, Spain; (2)CEBC-CNRS, 79360 Villiers-en-Bois, France
The distribution of long-finned pilot whales in the Strait of Gibraltar is analysed using GAMs (7521km sailed and 113 sightings) and the results shows that they are situated on the routes of 91009 cargos and ferries that crosses the Strait every year. They are then exposed to risks of collisions and probably also acoustic and physical disturbances. They are also the main target of the whale watching companies (13 boats). The aim of this study is to estimate the population and survival rate of long-finned pilot whales using photo-identification. Closed population models were applied using the program CAPTURE to estimate the population and the Cormack-Jolly-Seber model was used to estimate survival rate with the program MARK. A total of 8111 pictures representing 15 178 individual pilot whales were analysed. Between 1999 and 2005, 210 marked pilot whales have been identified in the catalogue. Corrected population estimations during summer for 1999 is 270 (95% CI:216-376), 2000 is 249 (95% CI:218-307), 2001 was not included for lack of data, 2002 is 259 (95% CI:202-380), 2003 is 270 (95% CI:206-415), 2004 is 267 (95% CI:238-330) and 2005 is 263 (95% CI:231-319). The survival rate of adults between 1999 and 2005 is estimated at 0.979 (95% CI:0.941-0.993) which is a life span of around 48 years. The same individuals have been observed all year round and from year to year which strongly suggests that there is a resident population of long-finned pilot whales in the Strait of Gibraltar. So far, the adult population does not seem to suffer great mortality. However, it is important to follow the population in the long term as a new important harbour is in construction on the Moroccan coast which will increase the passage of ferries and fast-ferries on the distribution area of the long-finned pilot whales.
Day: Thursday 6 April ; Time: 12:00; Eligible for Student Award: Postgraduate
TRENDS IN CAUSES OF MORTALITY IN HARBOUR PORPOISES (PHOCOENA PHOCOENA) STRANDED IN UK WATERS (1990-2004)..
DEAVILLE, R. (1), PATTERSON, T. (2), BAKER, J. (3), ROSS, H. (2), SIMPSON, V. (4), MONIES, B. (4), REID, B (2), PENROSE, R. (5), SABIN, R. (6), MUIR, A. (6), PERKINS, M. (1), TURK, S. (7), CUNNINGHAM, A. (1) AND JEPSON P. (1)
(1) Institute of Zoology, Regents Park, London, NW1 4RY, UK; (2) Scottish Agricultural College, Veterinary Services Division, Inverness, IV2 4JZ, UK; (3) Department of Veterinary Pathology, University of Liverpool, Neston, Wirral, CH61 7TE, UK; (4) Veterinary Investigation Unit Truro, Polwhele, Truro, Cornwall, TR4 9AD, UK; (5) Marine Environmental Monitoring, Penwalk, Llechryd, Cardigan, Ceredigion, SA43 2PS, UK; (6) The Natural History Museum, Cromwell Road, London, SW1 5BD, UK; (7) Cornwall Wildlife Trust, Allet, Truro, Cornwall, TR4 9DJ, UK
The most common UK-stranded cetacean species in 1990-2004 was the harbour porpoise (Phocoena phocoena) (n= 3005). No harbour porpoise mass mortality events were recorded during this period. The most common causes of mortality in 1310 necropsied UK-stranded harbour porpoises during this period were attack from bottlenose dolphins (Tursiops truncatus) (n=238), by-catch (n=225), pneumonias due to combinations of parasitic, bacterial and fungal infections (n=179), starvation (n=146), physical trauma (unknown origin) (n=55) and generalised bacterial infection (n=54). All porpoises fatally attacked by bottlenose dolphins stranded in northeast Scotland, west Wales or southwest England where porpoises share sympatric distributions with bottlenose dolphins. In Scotland, the spatial distribution of Tursiops-killed harbour porpoises occurred with increasing frequency outside the Moray Firth area consistent with a change in distribution of the Moray Firth bottlenose dolphin population. The number and proportion of stranded harbour porpoises killed by bottlenose dolphins has increased annually in West Wales between 1999 and 2004. The primary cause(s) of these violent inter-specific interactions remain inconclusive. The increasing number of harbour porpoise by-catches stranded in southwest England (Cornwall, Devon and Dorset) between December and April in recent years may reflect a genuine increase in (predominantly by-catch-related) mortality, although other factors such as changes in abundance and distribution of harbour porpoises and improved reporting of stranded carcasses in southwest England may also play a considerable role. Analyses of age and body-length data suggest that harbour porpoises stranding in southwest England (presumably from the Celtic Sea stock) are morphometrically distinct from porpoises in other UK regions. Cases of infectious disease mortality occurred more frequently in winter than summer months and have been linked to exposure to elevated blubber levels of polychlorinated biphenyls. Only 10 cases of fatal malignant tumours were recorded during this period consistent with low tissue levels of carcinogenic pollutants such as radionuclides and polycyclic aromatic hydrocarbons.
Day: Thursday 6 April ; Time: 13:50; Eligible for Student Award: No
ASSESSMENT OF HEALTH STATUS OF HARBOUR SEALS (PHOCA VITULINA) FROM GERMAN WATERS AROUND TWO PHOCINE DISTEMPER VIRUS MASS MORTALITIES.
SIEBERT, U. (1), WOHLSEIN, P. (2), FONFARA, S. (3), LEHNERT, K. (1), MÜLLER, G. (2), HASSELMEIER, I. (1) AND BAUMGÄRTNER, W. (2)
(1) Research and Technology Center Westcoast, Christian-Albrechts-Universität zu Kiel, Werftstr. 6, 25761 Buesum, Germany; (2) Institute of Pathology, Stiftung Tierärztliche Hochschule Hannover, Bünteweg 17, 30559 Hannover, Germany; (3) GKSS Research Center Geesthacht, Werftstr. 6, 25761 Buesum, Germany
The population of harbour seals (Phoca vitulina) in the Wadden Sea was decreasing until the mid of the seventies. The banning of hunting and the installation of national parks in German waters allowed the recovery of the population size. But in 1988/89 and 2002 two Phocine Distemper Virus Mass Mortalities killed 40-65% of the population. Because pathological investigations outside the seal die-offs were rare in Schleswig-Holstein a health monitoring was established to gain more insight into the development of the health status of harbour seals. Here we present findings from investigations between1996 to 2004. A post mortem examination was performed according to the ECS guidelines modified for seals. The carcasses were weighed and measured, and a caninus from the upper jaw was removed for age determination by counting the annual growth layers. Histology, microbiology, parasitology and immunohistochemistry were performed. With regard to all findings the cause of death was determined. The respiratory tract was the organ system with the majority of pathological findings. Parasitic bronchopneumonia was most often diagnosed in animals younger than one year. Other findings were parasites in the alimentary system, displacement or invagination of the intestine, hepatitis, hepatocellular lipidosis, wounds/scars, dermatitis/panniculitis/cellulitis, polyarthritis and lymphadenitis. The cause of death or principal morphological changes for euthanatised animals were bronchopneumonia, emaciation and septicemia caused by hemolytic streptococci and Escherichia coli, in rare cases Erysipelothrix rhusiopathiae and Brucella maris. Phocine Distemper Virus (PDV) as cause of death was only found in 2002 during the seal epizootic. Overall, the frequencies of different diagnoses clearly differed between years as well in spontaneously died as in euthanatised seals. Compared to the pathological findings described before the first seal die-off the health status of the seal population has improved probably due to an improved management in the National parks of the German waters.
Day: Thursday 6 April ; Time: 14:10; Eligible for Student Award: No
EPIDEMIOLOGIC AND PATHOLOGIC FINDINGS OF KILLER WHALES (ORCINUS ORCA) STRANDED 1944-2003.
RAVERTY, S., (1), GAYDOS, J., (2) AND HANSON, M.B. (3)
(1) Animal Health Center, British Columbia Ministry of Agriculture, Food and Fisheries, Abbotsford, BC, V3G 2M3; (2) SeaDoc Society, UC Davis Wildlife Health Center, Eastsound, Washington State, 98245, USA; (3) Northwest Fisheries Science Center, Seattle, Washington, USA
Within the northeastern Pacific Ocean, between 1996 and 2001, there was a significant decline in the population of southern resident killer whales (Orcinus orca) from 97 to 78. In order to put these mortalities in perspective, we solicited information globally from multiple electronic mailings lists including MARMAM, AAVLD, Marine Pathology, Australian Wildlife Health Network, as well as case records from the Armed Forces Institute of Pathology, Washington, DC and other diagnostic facilities. In response to these requests, over 60 individuals provided information and we compiled data from 198 killer whales that stranded and died between 1944 and 2003. Most (93%) strandings were reported from the last 3 decades and the majority of cases reported were from Brazil, Canada (British Columbia), Japan, Russia, United States (Washington and Alaska), and Western Europe. Complete necropsies were performed on 3% (6/198) of reported killer whale strandings and intermediate (select tissue sampling) examinations were conducted on 13% (26/198) of beach cast animals. A total of 309 tissues from 48 killer whales were evaluated. Histopathology of 309 tissues revealed abnormalities in 226 (73.1%) samples from 46 animals. Diagnostic interpretations were evaluated and diagnoses assigned according to relative significance: 70 (31%) diagnoses considered the proximate cause of death, 8 (3.5%) as secondary or contributory disease processes, and 17 (7.5%) as incidental findings. Primary disease processes included infectious and parasitic n=70 (33.6%), traumatic n=10 (4.4%), endocrine, metabolic and nutritional disorders n=7 (3.1%), neoplastic n=6 (2.7%), and was undetermined in 127 (56.2%) of the cases. Most commonly affected tissues included lung (50% of animals with abnormal tissues), lymph node (37%), liver (38%), skin/blubber (30%), and heart (26%). Each dead animal affords a valuable opportunity to further resolve the natural history and monitor for emergent and enzootic disease concerns which may impact this species.
Day: Thursday 6 April ; Time: 14:30; Eligible for Student Award: No
PATHOGENIC ROLE OF THE HOOKWORM UNCINARIA SPP IN NEW ZEALAND SEA LION (PHOCARCTOS HOOKERI) PUPS: EFFECT ON GROWTH AND BLOOD PARAMETERS.
CASTINEL, A. (1), DUIGNAN, P.J. (1), DONALD, J. (2), POMROY, W.E. (1), LOPEZ-VILLALOBOS, N. (1), CHILVERS, B.L. (3) AND WILKINSON, I.S. (3)
(1) New Zealand Wildlife Health Centre, IVABS, Massey University, Private Bag 11-222, Palmerston North, New Zealand (2) New Zealand Veterinary Pathology, PO Box 325, IVABS, Massey University, Private Bag 11-222, Palmerston North, New Zealand (3) Marine Conservation Unit, Department of Conservation, P.O. Box 10-420, Wellington, New Zealand
The New Zealand sea lion (Phocarctos hookeri) is an endangered species restricted to a limited breeding area concentrated on the Auckland Islands, New Zealand. A mortality survey at Sandy Bay breeding colony (Enderby Island) from 1999 to 2005 found that hookworm was the primary cause of death for 13% of pups but a survey of live pups for fecal eggs suggests that the prevalence of infection is much higher. In dead pups heavy hookworm burdens (> 2,000 per individual) were often associated with intestinal petechiae or with severe diffuse haemorrhagic enteritis. Pups with lower burdens may not die from infection but may suffer sub-lethal effects such as growth retardation and/or hematological changes. An experiment was conducted to test this hypothesis using the negative controls created by treating pups (n = 24) with the anthelminthic ivermectin and were matched with untreated pups of the same sex and age. Blood samples were regularly taken from 1 to 58 days-old. The main hematological parameters were measured: microhematocrit, total white blood cells (WBC) count, leucocytes formula and platelets counts. The growth rate was estimated with the daily weight gain for every pup. Microhematocrit in the control group was 35.0±1.3% with no significant difference compared to the non-treated group (36.0±1.5%) but the parameter was strongly negatively correlated with the pups' age in all pups (n=44, r=-0.754, p<0.001). There was no significant effect of treatment, sex or age on the WBC and platelets counts. Hookworm infection did not significantly affect pups' growth with regard to the daily weight gain to two months-old (n=258, p=0.111). This it would appear that low to moderate hookworm burdens are generally well tolerated by sea lion pups.
Day: Thursday 6 April ; Time: 15:30; Eligible for Student Award: Postgraduate
TRACE ELEMENTS, PCBS AND ORGANOCHLORINE PESTICIDES IN TISSUES OF COMMON DOLPHINS (DELPHINUS SP.) STRANDED IN THE HAURAKI GULF, NEW ZEALAND.
STOCKIN, K.A. (1), LAW, R.J. (2), DUIGNAN, P.J. (3), MEYNIER, L. (3), THOMPSON, E. (4) AND ORAMS, M.B. (1)
(1) Coastal-Marine Research Group, Institute of Natural Resources, Massey University, Private Bag 102 904, North Shore MSC, New Zealand; (2) The Centre for Environment, Fisheries and Aquaculture Science, Cefas Burnham Laboratory, Remembrance Avenue, Burnham on Crouch, Essex CM0 8HA, UK; (3) New Zealand Wildlife Centre, Institute of Veterinary, Animal and Biomedical Sciences, Massey University, Private Bag 111 222, Palmerston North, New Zealand; (4) AgriQuality Limited, PO Box 31 242, Lower Hutt, New Zealand
Apex marine predators such as cetaceans are particularly susceptible to persistent pollutants that may bio-accumulate thorough the food chain. Despite this, few studies have examined contaminant levels in New Zealand marine mammals. Here we report trace elements, polychlorinated biphenyls (PCBs) and organochlorine (OC) pesticide levels as determined in tissues collected from common dolphins (Delphinus sp) that stranded in the Hauraki Gulf, New Zealand. The concentration of Hg, Sn, Cr, Zn, Ni, Cd, Co, Mn, Fe, Cu, Ti, Pb, As and Ag was determined in liver, kidney, muscle and blubber tissue. PCBs (46 congeners) and a range of organochlorine pesticides concentrations including HCH, HCB, aldrin, dieldrin and DDE (plus derivatives) were determined from blubber tissue. Cr and Ni were not detected in any samples and concentrations of Co, Sn and Pb were generally low. Liver concentrations of Cu and Zn were within the normal ranges of homeostatic control (3-30 and 20-100 mg/kg wet weight, respectively). Concentrations of Hg ranged from 0.17 to 110 mg/kg wet weight, with the lowest concentrations in blubber and the highest in liver. The Hg:Se molar ratio varied from 0.02 to 1.11 reflecting the detoxification of MeHg. Of the organochlorines determined, HCB, dieldrin o,p'-DDT and p,p'-DDE were present at the highest concentrations in blubber. ?DDT concentrations ranged from 17 to 654 µg/kg wet weight, and ICES7CBs from 29 to 289 µg/kg wet weight. Comparably, levels of organochlorines found in New Zealand common dolphins were more than an order of magnitude lower than those reported from European seas.
Day: Thursday 6 April ; Time: 15:50; Eligible for Student Award: Postgraduate
MONITORING HEALTH AND STRESS INDICES IN HECTOR'S DOLPHINS CAPTURED FOR SATELLITE TELEMETRY IN NEW ZEALAND.
DUIGNAN, P.J. (1), GESCHKE, K (2), STONE, G, (3), TEILMANN, J.(4), HUTT A. (5), SUISTED R. (5), RUSSELL K. (6), JONES, G.W. (1), COCKREM J. (1) AND YOSHINAGA, A. (3)
(1) New Zealand Wildlife Health Centre, IVABS, Massey University, Palmerston North, New Zealand; (2) Wellington Zoo, New Zealand, (3) The New England Aquarium Boston, USA; (4) National Environmental Research Institute, Department for Arctic Environment, Denmark, (5) Dept. of Conservation, New Zealand, (6) Auckland University, New Zealand
Health and stress indices were measured in three Hector's dolphins (Cephalorhynchus hectori hectori) caught and released following attachment of lightweight satellite transmitters in New Zealand. The animals were an adult female and a juvenile of each sex. The trial was intended to evaluate the efficacy and safety of satellite tagging for potential application to the critically endangered Maui's dolphin (Cephalorhynchus hectori maui). The trial also provided the first baseline health data for this species to assess the physiological or behavioural effects of capture and handling on these animals. Body condition was assessed by standard measurements and ultrasound of blubber depth. Blood was collected for hematology, serum chemistry, serology (morbillivirus, calicivirus, influenza A, leptospirosis, and brucellosis), and endocrinology (cortisol, oestrogen, testosterone and progesterone). Expired breath and body orifice swabs were cultured for bacterial and fungal pathogens and viral culture was conducted on blood leukocytes. Heart rate and respiration rate were monitored and recorded throughout handling. No significant bacterial, viral, or fungal pathogens were isolated but one adult female was sero-positive for Brucella. Eosinophils were elevated in all dolphins suggesting endoparasitism. Cortisol levels were low (0.26 to 0.59 ug/dl) and similar to those of captive bottlenose dolphins. Breathing and heart rates remained constant throughout the handling period that ranged from 25 mins. to 29 mins. Progesterone was elevated in the adult female (30 ng/ml) suggesting early pregnancy. All dolphins were in good body condition and exhibited normal behaviour before and after release. The results indicate that capture and handling of Hectors dolphins can be conducted safely and with minimal stress on the dolphins for procedures such as satellite transmitter deployment.
Day: Thursday 6 April ; Time: 16:10; Eligible for Student Award: No
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