[MARMAM] Abstracts - Aquatic Mammals, Vol 33(3) - 2007

Dagmar Fertl dagmar_fertl at hotmail.com
Sun Jan 6 12:43:01 PST 2008


Apologies to those of you on both listserves, since you will receive cross-postings. The following are the contents and abstracts for the most recent issue of Aquatic Mammals. This journal was established by the European Association for Aquatic Mammals (EAAM) in 1974. The EAAM, Alliance of Marine Mammal Parks and Aquariums, and International Marine Animal Trainer's Association sponsor the journal. 
 
Aquatic Mammals accepts a wide variety of papers on the care, conservation, medicine, and science of marine mammals.  Dr. Jeanette Thomas of Western Illinois University is the editor and Dr. Kathleen Dudzinski of Mystic Aquarium is the co-editor. These abstracts are posted as a courtesy to the Marmam editors and the sponsoring societies, as well as the managing editor of Aquatic Mammals. For more information on the journal, please follow the link: http://www.aquaticmammalsjournal.org/
 
Please find below, the addresses (including email) of the authors to whom reprint requests and other inquiries should be directed. Thank you for your continued interest in these postings, as well as other publication postings to the listserves.
 
With regards,
 
Dagmar Fertl
dagmar_fertl at hotmail.com
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Bjørge, A., N. Øien, and K-A Fagerheim. 2007. Abundance of harbour seals (Phoca vitulina) in Norway based on aerial surveys and photographic documentation of hauled-out seals during the moulting season, 1996 to 1999. Aquatic Mammals 33(3):269-275.
Institute of Marine Research, P.O. Box 1870 Nordnes, N-5817 Bergen, Norway; email: Arne.Bjorge at imr.no
 
The first nationwide aerial survey to count harbour seals (Phoca vitulina) in Norway was conducted between 1996 and 1999. Haulout sites were surveyed during the early moult period of the seals in the second half of August, and most of the known haulout sites along the Norwegian coast (excluding Svalbard) were covered. The haulout sites were photographed, and the films were subsequently analysed at the Institute of Marine Research (IMR), Bergen. The number of seals hauled-out and documented during aerial surveys numbered 7,272. Some haulout sites in fjords of the alpine landscape of western Norway were difficult to cover by aerial surveys, so 193 hauled-out seals counted from boat surveys in these fjords were added, and the total counted population was 7,465. 
 
Applying a correction factor for estimating the total population from the number of hauled-out harbour seals in the adjacent Swedish Skagerrak, the total estimate was 13,000 seals in Norway. We assumed that this was possibly an overestimate of the true population, however, because the tidal amplitude and diurnal light variation differ significantly along the Norwegian coast and are reported to affect the haulout patterns of harbour seals. When correction factors based on regional studies in Norwegian Skagerrak, western Norway, and Finnmark in northern Norway of haulout behaviour in relation to tidal amplitude and diurnal light variation were applied, the total population was estimated at 10,000 harbour seals. Most sites were surveyed only once; consequently, there is no estimate of variance. 
 
Because survey methods have changed from previous questionnaire studies and boat-based surveys, the current estimate cannot be used to assess trends in population size. Harbour seals in Norway are currently intensively hunted, however, and they are subject to high by-catch levels. A decline in numbers is expected under the current management regime, and there is an urgent demand for a new abundance estimate and improved survey design and methodology to account for bias, as well as the appropriate measures of uncertainty involved.
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Iñíguez, M.A.* and V.P. Tossenberger. 2007. Commerson's dolphins (Cephalorhynchus commersonii) off Ría Deseado, Patagonia, Argentina. Aquatic Mammals 33(3):276-285.
 
*Fundación Cethus, Potosí 2087, Olivos, (1636), Provincia de Buenos Aires, Argentina; email: miguel.iniguez at cethus.org
 
Studies of the biology and ecology of Commerson's dolphins (Cephalorhynchus commersonii) in the Ría Deseado estuary (47º 46' S, 65º 58' W) were carried out during January-February 1986 to 1991 and 1994 to 1997, August 1987 and 1988, September 1995, and May 2003. Commerson's dolphins were consistently located along a 24-km stretch of the Ría Deseado. Twenty-six dolphins were identified using marks, scars, and differences in the black and white pigmentation of the head, back, and sides. Two adult dolphins with the typical grey colour pattern of the calves of this species have been observed since 1994. Behavioural observations were recorded and fell into four general categories: (1) traveling (51%), (2) resting (21%), (3) feeding (19%), or (4) socialising (9%). Feeding behaviours included dolphins feeding at the surface, near anchor lines, and around piers. Commerson's dolphins were directly observed feeding on silversides (Odontesthes). Calves were observed between mid-September and mid-March, which suggests that calves are born in the austral spring and early summer. Interactions between dolphins and seabirds/marine mammals were recorded. Killer whales (Orcinus orca) may prey on Commerson's dolphins in this area.
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Desportes, G.*, L. Buholzer, K. Anderson-Hansen, M-A Blanchet, M. Acquarone, G. Shephard, S. Brando, A. Vossen, and U. Siebert. 2007. Decrease stress; train your animals: The effect of handling methods on cortisol levels in harbour porpoises (Phocoena phocoena) under human care. Aquatic Mammals 33(3):286-292.
*Fjord and Bælt Centre, DK-5300 Kerteminde, Denmark; email: genevieve at gdnatur.dk
 
Circulating cortisol levels are accepted as a sensitive indicator of acute stress in marine mammals, particularly in relation with capture and handling. The present study provides the first long-term monitoring of cortisol levels in four harbour porpoises held in human care—an adult male and adult female and two juvenile females. It also compares levels in blood obtained after removing the animal from the water (OWR sampling) with levels in blood obtained at poolside under voluntary husbandry behaviours (VHB sampling). Cortisol levels differed significantly between the four porpoises, although they all exhibited quite high variations in cortisol levels, with averages of 64.9 and 70.5 μg/l in the adult male and female, respectively, and 90.7 and 51.4 μg/l in the juvenile females. OWR sampling induced significantly higher cortisol levels than VHB sampling, with a dramatic threefold decrease in circulating cortisol levels obtained under VHB sampling compared to levels obtained under OWR sampling (16.6 and 20.2 μg/l compared with 64.9 and 70.5 μg/l in the adult male and female respectively). Even if the porpoises showed some habituation to handling, regular and frequent handling over several years did not suppress a significant stress response in the porpoises when they were removed from the water, pointing to the advantage of using VHB for limiting stress in husbandry practices.
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Lockyer, C., A.A. Hohn, W.D. Doidge, M.P. Heide-Jørgensen, and R. Suydam. 2007. Age determination in belugas (Delphinapterus leucas): A quest for validation of dentinal layering. Aquatic Mammals 33(3):293-304.
*NAMMCO, Polar Environmental Centre, N-9296 Tromsø, Norway; email: christina.lockyer at nammco.no
 
A workshop for experts in age determination of beluga whales was convened to (1) determine the number of dentinal Growth Layer Groups (GLGs) in beluga teeth and the variation therein among readers; (2) assess the deposition rate of dentinal GLGs in beluga teeth, specifically on the question of one or two GLGs per year; (3) define the appearance of dentinal GLGs in order to standardize reading methods among readers of beluga teeth; and (4) provide a consensus report with specific conclusions on deposition rate and GLG definition. Tooth specimens from ten belugas, all originally from Churchill, Manitoba, Canada, with captive histories ranging from 4 to 30 y, were the focus of the investigation. Three of these animals had medication histories of tetracycline antibiotics which "time-mark" hard tissues. Results from the inter-reader GLG comparisons, GLG counts compared with captive history, and tetracycline mark placement indicated that despite considerable problems with the inter-reader count variability, using certain assumptions, there was evidence that two GLGs per year was not possible in six of the ten specimens; however, there were some specimens for which it was clear that two GLGs per year could be feasible, and yet others where the derived estimate of age at first capture did not appear to be compatible with the most likely age for that size of animal. The conclusions were that one GLG annual deposition rate in dentine was clearly upheld in some instances but that the results were equivocal for several specimens for a variety of reasons. In light of the fact that tooth GLGs are likely to continue being the predominant method for aging in this species, the workshop members agreed on a list of seven recommendations that included, as a priority, experimental approaches that could help to standardize and validate GLG counting in age determination.
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Hayes, V.J., and J.M. Terhune. 2007. Underwater call sequences of Weddell seals (Leptonychotes weddellii) at the Vestfold Hills, Antarctica. Aquatic Mammals 33(3):305-314.
 
Department of Biology, University of New Brunswick, P.O. Box 5050, Saint John, New Brunswick, Canada E2L 4L5; email: terhune at unbsj.ca
 
Repeated sequences of different call types have been reported in some recordings of underwater calls of Weddell seals (Leptonychotes weddellii) but not others. Recordings made during the breeding seasons of 1990 (1 site, n = 1,136 calls), 1991 and 1992 at three and seven sites, respectively (n < 210 calls per study site) at the Vestfold Hills, Antarctica, were examined. Calls were classified into 16 types, and series of calls were examined for two data sets (1990) and for all years. The low number of seals at these breeding sites resulted in a long series of calls with no overlap, thus facilitating the opportunity for sequence analyses. At most, but not all, study sites there was a three-call-sequence that occurred above chance levels. Thirty-five of 43 three-call-sequences were only detected in one year at one recording location; the other eight were heard at up to four study sites in the same year. Five sets of three-call-sequences occurred in the reverse order of other sequences. Pairs of calls were common, and most occurred in one order and not the reverse. During 3 h of observations of a male-female pair of Weddell seals lying quietly in a pool, there were no sequences of calls or dueting (n = 241 calls). Our findings support the hypothesis that some Weddell seals make nonrandom series of calls, but the functional significance of these patterns is uncertain. Because similar sequences occurred at several study sites, however, it is not likely that call sequences could be used as a natural acoustic tag to identify individual seals.
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Aurioles-Gamboa, D., and F.J. Camacho-Ríos. 2007. Diet and feeding overlap of two otariids, Zalophus californianus and Arctocephalus townsendi: Implications to survive environmental uncertainty. Aquatic Mammals 33(3):315-326.
Centro Interdisciplinario de Ciencias-Marinas – Instituto Politécnico Nacional, Departamento de Biología Marina y Pesquerías, Apdo. Postal 592, La Paz, Baja California Sur, México; email: dgamboa at ipn.mx
 
The San Benito Islands in Mexico host a population of about 7,000 California sea lions (Zalophus californianus) and have been recolonized by Guadalupe fur seals (Arctocephalus townsendi) since 1997. Due to similarities in natural history between the two species, we undertook a study to determine their feeding habits, measure diversity of their diets, examine trophic feeding level and overlap as indicators of competition, and estimate ability to adjust to changes in prey availability. During winter and summer 2001 and 2002, 289 sea lion scats and 218 fur seal scats were collected. To identify prey species, samples were sieved to recover otoliths and cephalopod beaks. A total of 1,495 structures were recovered from the sea lion scats: 83.8% otoliths and 16.2% cephalopod beaks. The most prevalent prey was in fish species (Argentina sialis, Merluccius angustimanus, andSebastes spp.) and the squid (Loligo opalescens). Of the 1,866 structures recovered from the Guadalupe fur seal scats, 95.6% were cephalopod beaks and 4.4% were otoliths, with L. opalescens as the most prevalent prey. The diversity of the trophic spectrum (H') of the sea lion was greater than the fur seal in every one of the samples, placing it as a "generalist predator" (Levins Index B = 4.65) in comparison to the fur seal (B = 1.53). The only significant trophic overlap (Morisita-Horn Index) occurred during the summer of 2001 (CH = 0.73). Both species consumed prey at similar trophic levels (sea lion = 4.42; fur seal = 4.22), which placed them as secondary-tertiary carnivores. The evidence suggests that the California sea lion forages in both benthic and pelagic habitats, resulting in a broader feeding spectrum and better adaptations to cope with changes in prey availability than the Guadalupe fur seal.
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Pires, R.*, H.C. Neves, and A.A. Karamanlidis. 2007. Activity patterns of the Mediterranean monk seal (Monachus monachus) in the Archipelago of Madeira. Aquatic Mammals 33(3):327-336. 
 
*Parque Natural da Madeira, Quinta do Bom Sucesso, Caminho do Meio, Funchal 9064-512, Portugal
Activity patterns of the critically endangered Mediterranean monk seal (Monachus monachus) were examined in the Desertas Islands Nature Reserve in the archipelago of Madeira. Activity of seals at sea was recorded from 25 lookout sites positioned along the reserve's coastline and correlated to site location, season, time of day, and state of tide. From 1994 to 2005, monk seal activity, related mainly to the reproductive behaviour of the species, was recorded primarily at the three pupping sites within the reserve. Activity was influenced by site location, season, and state of tide but not by the time of day. Activity was highest during the autumn and winter months and was related to the pupping and post-parturition necessities of the species, and during high tide, when the incoming action of the sea led monk seals to move out of coastal caves, which are used for resting and breeding. Differences in activity among the three sites monitored were attributed to the level of protection offered by these locations against wind and wave action. The findings of this study, the most extensive study of its kind, have enabled the identification of priority research, and conservation actions for the species in the area.
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Goldstein, T., C.A. Stephens, S.S. Jang, P.A. Conrad, C. Field, L.J. Dunn, and J.E. Mellish. 2007. Longitudinal health and disease monitoring in juvenile Steller sea lions (Eumetopias jubatus) in temporary captivity in Alaska compared with a free-ranging cohort. Aquatic Mammals 33(3):337-348. 
 
*current address: The Marine Mammal Center, 1065 Fort Cronkite, Sausalito, CA 94965, USA: email: goldsteint at tmmc.org 
 
From March 2003 to June 2006, 77 juvenile Steller sea lions (Eumetopias jubatus) from the endangered western stock were captured in Resurrection Bay and Prince William Sound, Alaska. Thirty-one were brought into temporary captivity (transient juveniles) for short-term research studies, and 46 were captured, sampled, and released for a control comparison. The groups of wild-caught sea lions were rotated through a quarantine facility. The objectives of this study were to measure exposure to marine and terrestrial mammalian pathogens in temporarily captive Steller sea lions over time, screen for commensal and pathogenic bacteria, and monitor changes in antimicrobial resistance in bacterial isolates. Antibodies to Toxoplasma gondii and Brucella marinus were detected in both free-ranging and transient juveniles. Although an increase in titers to Leptospira spp. and phocine herpesvirus-1 was detected in a small number of sea lions while housed in temporary captivity, none developed evidence of clinical disease. Additionally, exposure was also found to these potential pathogens in the free-ranging control Steller sea lions. There were no significant differences among the variety of bacterial types obtained from any culture site or animal groups, and antibiotic resistance did not occur in any transient juveniles while in captivity nor in isolates from the free-ranging controls. Results therefore indicated that free-ranging Steller sea lions were not placed at risk for disease following the release of the transient juveniles back into the marine environment.
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Finerty, S.E.*, G.R. Hillman, and R.W. Davis. 2007. Computer-matching of sea otter (Enhydra lutris) nose scars: A new method for tracking individual otters. Aquatic Mammals 33(3):349-358.
*Department of Wildlife and Fisheries, Texas A&M University, 5007 Avenue U, Galveston, TX 77551, USA; email: shannonfinerty at yahoo.com
 
The Sea Otter Nose Matching Program, or SONMaP, was developed to identify individual Alaskan sea otters using a blotch-pattern recognition algorithm based on the shape and location of lightly colored nose scars. The program ranks all the images in order of similarity, most similar first, with six images displayed at a time. The user then selects the final match. In this study, the performance of the SONMaP program was tested using images of otters that had been previously matched by visually comparing every otter in a catalog of 1,638 animals. After running the images through SONMaP, they were classified as BEST, AVERAGE, or WORST based on whether the correct match was within the first 10%, 11 to 50%, or 51 to 100% of images in the catalog, respectively. In 48.9% of the previously visually matched images, the program accurately selected the correct image in the first 10% of the catalog, which compares favorably with other computer-assisted photo-identification studies of marine mammals.
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McGuire, T.L.* and T. Henningsen. 2007. Movement patterns and site fidelity of river dolphins (Inia geoffrensis and Sotalia fluviatilis) in the Peruvian Amazon as determined by photo-identification. Aquatic Mammals 33(3):359-367.
*Marine Mammal Research Program, Texas A&M University, Galveston, TX 77551-5923, USA; tmcguire at lgl.com
 
Photo-identification was used to examine range, rate of movement, and site fidelity of the river dolphins (Inia geoffrensis and Sotalia fluviatilis) in Peru's Pacaya-Samiria Reserve from 1991 to 2000 (field work conducted all years and all seasons). Dolphins were identified by scars, cuts, nicks, pigmentation patterns, and abnormal beaks. Seventy-two Inia and 7 Sotalia were identified, and 25 Inia and one Sotalia were resighted. Sighting histories ranged from 1 d to 7.6 y. Maximum range of movement for Inia was 220 km, with a mean range of 60.8 km. Maximum range for Sotalia was 130 km. The greatest rates of movement observed were 120 km/2 d for Inia, and 56 km/9 h for Sotalia. The mean rate of movement was 14.5 km/d for Inia and 56 km/d for Sotalia. Identified dolphins were not observed to move between surveyed tributaries of the Marañón River but, instead, were always observed within the same tributary system. Ninety percent of all Inia resighted in one river system were seen in the same lake at least once, and 33% of dolphins resighted in the lake were never seen outside of the lake. Although photo-identification yielded new information about river dolphin movements and site fidelity, its utility was limited due to behavioral, morphological, and ecological characteristics of these cetacean species.
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Beasley, I.L.* and P.J.A. Davidson. 2007. Conservation status of marine mammals in Cambodian waters, including seven new cetacean records of occurrence. Aquatic Mammals 33(3):368-379.
*School of Tropical Environment Studies and Geography, James Cook University, Australia; email: isabel.beasley at jcu.edu.au
 
The first dedicated, boat-based marine mammal surveys in Cambodian coastal waters were conducted over seven discrete survey periods, spanning February to September 2001. These surveys covered the majority of Cambodian coastal waters, in addition to the main offshore islands. 
 
As a result of these surveys, ten marine mammal species have now been confirmed to occur in Cambodian waters. Six of these, the false killer whale, a long-beaked form of common dolphin, pantropical spotted dolphin, dwarf spinner dolphin, Indo-Pacific bottlenose dolphin, and Indo-Pacific humpback dolphin, constitute new country records for Cambodia. Additionally, a short-finned pilot whale was found live-stranded, constituting a further new country record. These initial results indicate that the current status of marine mammals in Cambodian waters is encouraging, both in terms of species diversity and abundance. Cambodian waters appear to support regionally, if not globally, significant populations of several of these species. The dugong is almost certainly the most highly threatened marine mammal in the region. 
 
Studies to date have provided important baseline knowledge regarding the status, distribution, and important areas of occurrence for marine mammals in Cambodia. It is now essential that conservation and management strategies are developed and implemented. Public education and awareness and community-based management programs, as well as stricter laws, regulations, and adequate enforcement will be essential to conserving the remaining marine mammal populations and ensuring their survival in Cambodian coastal waters.
 
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Highfill, L.E., and S.A. Kuczaj II. 2007. Do bottlenose dolphins (Tursiops truncatus) have distinct and stable personalities? Aquatic Mammals 33(3):380-389.
*Department of Psychology, University of Southern Mississippi, 118 College Drive #5025, Hattiesburg, MS 39406, USA; email: Lauren.Highfill at usm.edu
 
Psychologists have long been interested in the role of individual differences in the behavior of many species, particularly consistent differences that might reflect temperament or personality. Only recently has animal personality become an important and credible topic of research, however. In an effort to add to the literature on animal personality, the possibility of consistent personality characteristics was explored for a previously unstudied species, the bottlenose dolphin (Tursiops truncatus). Dolphin personality was assessed using a measure that evaluated possible personality characteristics. The measure consisted of a list of adjectives and descriptions commonly associated with dolphin behaviors (e.g., "curious: appears to be interested in new situations or objects"). Judges rated each animal on each description using a seven-point rating scale. The stability of individual dolphin personality characteristics was assessed by comparing results from judgments of individual dolphin personalities collected prior to Hurricane Katrina with those collected approximately 15 months later. In the interval between these two ratings, the dolphins' home at MarineLife Oceanarium was destroyed, and the dolphins were subsequently relocated to a facility in the Bahamas. The second set of judgments was made by individuals in the Bahamas who had no experience with the dolphins prior to Hurricane Katrina and no information about the results of the earlier dolphin personality assessments. The results support the notions that dolphins demonstrate different personalities and that these personalities are relatively stable over time and across situations.
 
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Book Reviews
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Simmonds, M. 2007. Book Review: Whales, Whaling and Ecosystems. Editors: J.A. Estes, D.P. DeMaster, D.F. Doak, T.M. Williams, and R. Brownell. Aquatic Mammals 33(3):390-391.
 

Email: mark.simmonds at wdcs.org
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Prothero, D.R. 2007. Book Review: Neptune’s Ark: From Ichthyosaurs to Orcas. Author: D. Rains Wallace. Aquatic Mammals 33(3):392-393.
 
No email provided; Donald R. Prothero, Department of Geology, Occidental College, Los Angeles, CA 90041, USA
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Thewissen, J.G.M. 2007. Book Review: Morphology of the Auditory and Vestibular Organs in Mammals, with Emphasis on Marine Mammals. Author: G.N. Solntseva. Aquatic Mammals 33(3):394-395.
 
No email provided; J.G.M. Thewissen, Department of Anatomy, Northeastern Ohio Universities College of Medicine, Rootstown, Ohio 44272, USA
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