[MARMAM] Abstracts - Aquatic Mammals, vol 35(2), 2009

Dagmar Fertl dagmar_fertl at hotmail.com
Thu Jul 9 15:55:14 PDT 2009



Dear Marmam and ECS-mail subscribers,
 
Apologies to those of you who will get duplicate emails due to cross-posting. The following are abstracts from the most recent issue of Aquatic Mammals, the scientific peer-reviewed journal of the European Association for Aquatic Mammals (EAAM).  Abstracts are presented as a courtesy to the EAAM and the journal editors – Drs. Jeanette Thomas (managing editor; aquaticmammals at gmail.com) and Kathleen Dudzinski (co-editor; kdudzinski at dolphincommunicationproject.org). The journal publishes papers dealing with all aspects of the care, conservation, medicine and science of aquatic mammals. The journal receives support of the Alliance of Marine Mammal Parks and Aquariums and the International Marine Animal Trainers' Association (IMATA). For more information on the journal, please go to: http://www.aquaticmammalsjournal.org/. Contact information is provided for the corresponding author for each article. Please do not contact the listserve editors or me for pdfs or copies of the articles.
 
Thank you for your continued interest in the journal and these postings. 
 
With regards,
 
Dagmar Fertl
Ziphius EcoServices
dfertl at gmail.com

http://www.ziphiusecoservices.com
 
Winter, A.,* R. J. Foy, & K. Wynne. 2009. Seasonal differences in prey availability around a Steller sea lion haulout and rookery in the Gulf of Alaska. Aquatic Mammals 35(2):145-162.
 
* E-mail: awinter at vt.edu
 
Abundance and distribution of fish biomass were surveyed around a Steller sea lion (Eumetopias jubatus) haulout (nonbreeding) and rookery (breeding) site in the Gulf of Alaska to test the hypothesis that seasonal occupation of either site was related to the availability of prey. The haulout and rookery are located 30 nmi (55.56 km) apart at Long Island and Marmot Island in the Central Gulf of Alaska region where the Steller sea lion population is slowly recovering from a severe decline. Surveys conducted in May and November of 2002 (just before and after the breeding season) showed significantly higher prey energy density (total fish biomass density × energy content; kJ nmi-2) around the Long Island haulout than around the Marmot Island rookery. A survey conducted in July of 2002 (during breeding season) showed prey energy densities that were not significantly different between Long Island and Marmot Island but that were more concentrated in a single area by Marmot Island. Major prey species groups in all surveys were arrowtooth flounder, walleye pol-lock, cod, and soles; all are known prey of Steller sea lions in this area. Steller sea lion counts at Long Island during nonbreeding seasons from 2000 to 2004 correlated significantly with midwater prey energy densities. Steller sea lion counts at Marmot Island over the same period did not correlate with midwater prey energy densities in either breeding or nonbreeding seasons. The results of the study indicate that prey availability may be an important factor in the choice of haulout sites by Steller sea lions, and the higher prey availability at rookery sites provides some advantage.
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Schaefer, M.,* J. S. Reif, J. D. Goldstein, C. N. Ryan, P. A. Fair, & G. D. Bossart. 2009. Serological evidence of exposure to selected viral, bacterial, and protozoal pathogens in free-ranging Atlantic bottlenose dolphins (Tursiops truncatus) from the Indian River Lagoon, Florida, and Charleston, South Carolina.  Aquatic Mammals 35(2):163-170.
 
* E-mail: aschaefer at hboi.fau.edu
 
Sera from free-ranging Atlantic bottlenose dol­phins (Tursiops truncatus) in the Indian River Lagoon, Florida (IRL) (n = 122), and the estuarine waters near Charleston, South Carolina (CHS) (n = 82) were collected from 2003 to 2007 and ana­lyzed for antibodies to several bacterial and viral pathogens. Serological evidence of exposure to Chlamydophila psittaci; Eastern, Western, and Venezuelan equine encephalitis viruses; and West Nile virus represents the first reports of these pathogens in cetacean populations. Antibodies to Eastern and Venezualan encephalitis viruses and to West Nile virus were detected only in IRL dol­phins. Positive titers to Toxoplasma gondii and Brucella abortus (rivanol and card tests) were identified in dolphins from both locations. The prevalence of antibodies to Brucella spp. on the card test was significantly higher in bottlenose dolphins sampled in the IRL compared to the CHS location. This study establishes baseline seroprev­alence for several zoonotic pathogens in these two populations.
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Hawkins, E.R.* & D. F. Gartside. 2009. Patterns of whistles emitted by wild Indo-Pacific bottlenose dolphins (Tursiops aduncus) during a provisioning program. Aquatic Mammals 35(2):171-186.  
 
E-mail: elizabeth.hawkins at scu.edu.au
 
To facilitate and coordinate the complexities of fission-fusion societies, Indo-Pacific bottlenose dolphins (Tursiops aduncus) have developed a multilayered acoustic communication system to effectively transmit signals in the marine environment. Among the many acoustic emissions produced by dolphins, whistles are thought to play a major communicative role. Little is understood about the functions of the diverse whistle repertoire of wild bottlenose dolphins and the influence human activities can have on these sounds. This study provides a detailed investigation into the use and diversity of whistles by a group of eight wild bottlenose dolphins that participate in a provisioning program at Tangalooma, Moreton Island, Australia. Acoustic recordings and concurrent behavioural observations were made during evening feeding sessions. Behaviours were divided into three activities: (1) milling, (2) scanning/foraging (excluding human provisioning), and (3) socialising. Pod separation occasions were also examined. Whistles were classified as either stereotyped or nonstereotyped and divided into five tonal classes based on the shape of the fundamental frequency: (1) sine, (2) up-sweep, (3) down-sweep, (4) flat, and (5) concave. Whistles were then catalogued into distinct whistles types. From 943 min of recordings, 5,682 whistles were analyzed that then were catalogued into 68 distinct whistle types of which 18 were stereotyped and 50 were nonstereotyped. The repetition rate (x = 1.12 whistles per min per dolphin [w/m/d]; SD = 0.61) and diversity of whistles varied between feeding sessions but were not related to the number of dolphins. Distinct whistle types were divided into common or uncommon categories to facilitate correspondence analysis to examine associations between whistles and behaviour activities. Results showed that around 38% of common whistles and 84% of uncommon whistles were closely associated with behaviour activities, particularly socialising and scanning/foraging. Sine whistles were the only tonal class associated with pod separation. This study provides further evidence of the communicative functions of whistles across the repertoire of wild bottlenose dolphins.
 
 
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Lanyon, J.M.*, H. L. Sneath, J. R. Ovenden, D. Broderick, & R. K. Bonde. 2009. Sexing sirenians: Validation of visual and molecular sex determination in both wild dugongs (Dugong dugon) and Florida manatees (Trichechus manatus latirostris). Aquatic Mammals 35(2):187-192.
 
* E-mail: j.lanyon at uq.edu.au
 
Sexing wild marine mammals that show little to no sexual dimorphism is challenging. For sire­nians that are difficult to catch or approach closely, molecular sexing from tissue biopsies offers an alternative method to visual discrimination. This paper reports the results of a field study to validate the use of two sexing methods: (1) visual discrim­ination of sex vs (2) molecular sexing based on a multiplex PCR assay which amplifies the male-specific SRY gene and differentiates ZFX and ZFY gametologues. Skin samples from 628 dug­ongs (Dugong dugon) and 100 Florida manatees (Trichechus manatus latirostris) were analysed and assigned as male or female based on molecu­lar sex. These individuals were also assigned a sex based on either direct observation of the genitalia and/or the association of the individual with a calf. Individuals of both species showed 93 to 96% con­gruence between visual and molecular sexing. For the remaining 4 to 7%, the discrepancies could be explained by human error. To mitigate this error rate, we recommend using both of these robust techniques, with routine inclusion of sex primers into microsatellite panels employed for identity, along with trained field observers and stringent sample handling.
 
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Mellor, L., L. N. Cooper*, J. Torre, R. L. Brownell, Jr. 2009. Paedomorphic ossification in porpoises with an emphasis on the vaquita (Phocoena sinus). Aquatic Mammals 35(2):193-202.
 
E-mail: l.noelle.cooper at gmail.com
 
Heterochrony, the change in timing of develop­mental processes, is thought to be a key process shaping the numerous limb morphologies of tet­rapods. Through a delayed offset in digit devel­opment, all cetaceans (i.e., whales, dolphins, and porpoises) have evolved supernumary phalan­ges (hyperphalangy). Moreover, some toothed cetaceans further alter digital morphologies by delayed endochondral and perichondral ossifica­tion of individual elements. In the harbor porpoise (Phocoena phocoena), these paedomorphic pat­terns have created poorly ossified phalangeal ele­ments. However, no studies have addressed this morphology in other porpoise taxa. This study documents the timing of carpal and digital epi­physeal ossification in the poorly studied vaquita (Phocoena sinus) based on radiographs (n = 18) of known-age specimens. Patterns of vaquita manus ossification were compared between other porpoise and delphinid taxa. Adult vaquitas are paedomorphic in carpal, metacarpal, and digital development as they maintain a juvenile ossifica­tion pattern relative to that of other porpoise spe­cies of equivalent ages. Vaquitas also ossify fewer carpal elements as compared to other porpoise and some delphinid cetaceans, and ossification arrests relative to that of the harbor porpoise. Vaquitas also display sexual dimorphism as females reach a greater body size and display more ossified ele­ments in the manus relative to their paedomorphic male cohorts
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Haarr, M.L., L. D. Charlton, J. M. Terhune*, & E. A. Trippel. 2009. Harbour porpoise (Phocoena phocoena) presence patterns at an aquaculture cage site in the Bay of Fundy, Canada. Aquatic Mammals 35(2): 203-211.
 
E-mail: terhune at unbsj.ca
 
 Finfish aquaculture is a prominent industry in the Bay of Fundy, Canada. The distribution of har­bour porpoise (Phocoena phocoena) in the Bay during the summer and fall may be impacted by the presence of offshore cages or the activities of workers on the site. Harbour porpoise presence near and within an aquaculture cage site was stud­ied using visual observations during the summer of 2006 and by monitoring echolocation signals using T-PODs during the summer and autumn of 2006 and 2007. At least one harbour porpoise was sighted per hour 61% of the time among or near the cages. Porpoise occasionally surfaced within the cage site when workers were present. Mother-calf pairs used the within-cages area proportionately more than adults and juveniles. The porpoise were temporarily displaced by high disturbance activi­ties such as cage cleaning with pressure hoses, but quickly returned to the area when the disturbance ended. Echolocation activity was lowest during the day, increased in the evening, and peaked between midnight and dawn. This pattern was evident on the offshore and inshore side of the cages and, to a lesser extent, at a non-aquaculture location farther along the coastline (2007 only). In August of both years, the echolocation patterns were similar, even though in 2007 there were no fish in the cages and much less worker activity than in 2006 when all 15 cages contained Atlantic salmon (Salmo salar). Echolocation activity near a T-POD typically lasted for no more than 10 min or for at least 1 h, suggesting that the porpoise were either passing by the area or staying to feed, respectively. The presence of the aquaculture cage site under study did not appear to be displacing harbour porpoise from the area except during short intervals when high disturbance activities such as a food delivery by barge or cage cleaning were occurring.
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Webster, T. A.*, S. M. Dawson, & E. Slooten. 2009. Evidence of sex segregation in Hector’s dolphin (Cephalorhynchus hectori). Aquatic Mammals 35(2):212-219. 
 
*E-mail: trudi.webster at xtra.co.nz
 
Segregation by sex is evident at a variety of levels in many birds, fishes, and mammals. Segregation has been observed in marine mammals to vary­ing degrees, but it was previously undocumented in Hector’s dolphin (Cephalorhynchus hectori). Forty-three groups (of group size ≤ 5) were sexed using an underwater pole-camera; 91% of groups consisting of two to five individuals (n = 32) were either all male or all female. Sexes were obtained from an additional seven groups containing calves. All of the adults associating with mothers and their young were female. This research suggests that Hector’s dolphin groups are highly segregated by sex. Sex segregation might have implications for reproduction in Hector’s dolphins, including difficulty in finding a mate as local populations decline.
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Yu, J. Y. Sun, & Z. Xia. 2009. The rescue, rehabilitation, and Release of a Stranded Finless Porpoise (Neophocaena phocaenoides sunameri) at Bohai Bay of China. Aquatic Mammals 35(2):220-225.
 
E-mail address: drxia at 126.com
 
A stranded female west Pacific finless porpoise (Neophocaena phocaenoides sunameri) was found in the shallows of Bohai Bay, China, on 30 March 2008. It was moderately dehydrated. After transportation to Beijing Aquarium, medical treatment and rehabilitation were conducted. Under microscopic examination, the ova of Nasitrema spp. and Zalophotrema hepaticum were found in the feces. This is a new host record for the trematodes Nasitrema spp. and Z. hepaticum infecting a finless porpoise. Antibiotics were administered to prevent secondary infection, while supportive therapies, including fluid and electrolyte supplements, were provided. The porpoise was released on 6 June 2008, approximately 18.5 km offshore in Xingang, Tianjin, China. This is the first report of a rescue, rehabilitation, and release of a stranded marine mammal in Bohai Bay, China.
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Fudge, D.S.*, L. J. Szewciw, & A. N. Schwalb. 2009. Morphology and development of blue whale baleen: An annotated translation of Tycho Tullberg’s classic 1883 paper. Aquatic Mammals 35(2):226-252.
 
*no email address provided with article. Address: Department of Integrative Biology, University of Guelph, 50 Stone Road East, Guelph, Ontario, N1G 2W1, Canada
 
Herein we present an annotated translation of the classic paper by Tycho Tullberg on the struc­ture and development of baleen in blue whales. The three blue whale fetuses on which this study was based were obtained from a whaling station in Norway during a time when blue whales were still abundant enough to support a whaling indus­try. The value of this text for the modern reader is that it provides a glimpse into the mechanisms of development of baleen in the largest rorqual whale, which is something that modern biolo­gists are unlikely to be able to replicate for a long time. Tullberg’s careful morphology, histology, and developmental thinking provide a coherent account of how the elaborate baleen racks develop from simple epidermal and dermal origins. The fig­ures, which we have reproduced here, are superb and provide a rare window into the morphology of blue whale baleen at three fetal stages. The histol­ogy is excellent for its time and provides insights into the various keratin tissue phases that make up the baleen plates and bristles as well as the enig­matic Zwischensubstanz that acts as a spacer and possible shock-absorber between plates.
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Silva, F. M. O., J. E. Vergara-Parente, J. K. N. Gomes, M. N. Teixeira, F. L. N. Attademo, & J. C. R. Silva. 2009. Blood chemistry of Antillean manatees (Trichechus manatus manatus): Age variations. Aquatic Mammals 35(2):253-258.
 
E-mail: fernanda.pxboi at gmail.com
 
The Antillean manatee (Trichechus manatus manatus) is the most endangered aquatic mammal in Brazil. Sampling blood data from such critically endangered marine mammal species is extremely challenging. Although several hematological studies have been developed for captive manatees, captivity studies addressing the environmental and physiological effects on blood values are scarce. The present work describes blood biochemistry values for captive Antillean manatee adults and calves and verifies the occurrence of possible physiological adjustments due to age, sex, and dietary influences. Blood from 13 clinically healthy manatees (eight calves and five adults) were analyzed for 13 blood serum chemistry parameters using a semi-automatic analyzer. Descriptive analysis was performed for all parameters, and differences between sex and age were determined. Calves had higher means of urea (6.29 ± 5.58 mg/dL), total proteins (5.07 ± 0.94 g/dL), globulin (3.06 ± 1.32 g/dL), and alanine aminotransferase (6.19 ± 2.18 U/mL), levels, and lower means of creatinine (1.42 ± 0.64 mg/dL), aspartate aminotransferase (7.24 ± 3.21 U/mL), phosphate (3.03 ± 1.63 mg/dL), and uric acid (0.71 ± 0.17 g/dL) than adults. Further studies are necessary, especially when considering handling and alimentary management in captivity, to provide important data for better monitoring and clinical management of manatees.
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Hawkins, E. R., & D. F. Gartside. 2009. Interactive behaviours of bottlenose dolphins (Tursiops aduncus) during encounters with vessels.  Aquatic Mammals 35(2):259-268. 
 
E-mail: elizabeth.hawkins at scu.edu.au
 
Bottlenose dolphins (Tursiops spp.) are one of the most frequently encountered cetaceans in coastal regions and form the focus of a growing commercial dolphin-watching industry. Bottlenose dolphins are renowned for approaching and interacting with vessels. By obtaining information on the occurrence of interactive behaviours, further insight into the influence of vessel encounters on dolphins can be gained. This research examined the interactive behaviours (defined as bow-riding, wake-riding, and sustained approaches) displayed by Indo-Pacific bottlenose dolphins (Tursiops aduncus) in the presence of different vessel types (motor vessel or sailing yacht) in a region with relatively low levels of commercial dolphin-based tourism activities. The patterns of acoustic emissions produced during these interactions were also recorded. Results indicated that a relatively small proportion of the population displayed interactive behaviours (22% of groups observed). Of the groups that displayed interactive behaviours, 59% contained at least one calf, and most were engaged in the behavioural state of milling (36%). The vessel type (p < 0.05) and vessel activity (p < 0.05) both significantly influenced the occurrence of interactive behaviour of the dolphins. More interactions per hour occurred with the motor vessel (0.32) compared to the yacht (0.26). The mean duration of interactions was 3 min (SD = 9.07). During interactions with vessels, dolphins emitted a diverse repertoire of whistles with a high repetition rate suggesting that either the group cohesion was affected or that there were higher levels of excitation. It is recommended that monitoring the levels and types of interactive behaviours of dolphins during vessel encounters may be useful to ensure that dolphin-watching activities do not negatively impact social cohesion and long-term survival of dolphin populations.
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Rivamonte, L. A. 2009. Bottlenose dolphin (Tursiops truncatus) double-slit pupil asymmetries enhance vision. Aquatic Mammals 35(2):269-280.
 
E-mail: lorenzo.andre.rivamonte at us.army.mil
 
Geometries of the iris, retinal cell distributions, and the optical characteristics of the lens and cornea have evolved to optimize the visual adaptations of the bottlenose dolphin (Tursiops truncatus) to the oceanic environment. Under high ambient light conditions, the operculum of the iris shields the lens and forms two asymmetrical slit pupils. Under these conditions, light entering the eye is channeled and focused onto the two areas of the retina having a finer retinal mosaic of ganglion cells (typically associated with higher image resolution). The paths of light determined by tracing rays in the reverse direction through these pupils coincide with a dolphin’s behaviorally observed preferred viewing directions. These rays aid in determining the interdependence between the graininess of the retinal mosaic and resolution spot sizes in the object space. For oblique forward and downward viewing directions in air, the larger temporal pupil admits light which passes through the weakly refractive margin of a bifocal lens, counterbalancing the optically strong cornea in air. In water, light passing through the optically strong lens core is focused from a wide lateral and downward field-of-vision. Although other explanations for comparable aerial and underwater vision remain plausible, a dolphin eye model incorporating a bifocal lens offers an explanation consistent with ophthalmoscopic refractive state measurements. The model is also consistent with visual acuity study results conducted in air and in water under both high and low ambient light levels. From insight gained after applying a common data analysis technique to visual acuity studies conducted by other researchers and tracing oblique rays through the asymmetric double-slit pupils, a re-examination of explanatory hypotheses for the paradoxical observations of comparable aerial and underwater vision is presented. Based in part on these findings and supportive evidence from dolphin vision researchers, the unique distinguishing characteristics of dolphin vision are summarized.
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Melillo, K. E.*, K. M. Dudzinski, & L. A. Cornick. 2009. Interactions between Atlantic spotted (Stenella frontalis) and bottlenose (Tursiops truncatus) dolphins off Bimini, The Bahamas, 2003-2007. Aquatic Mammals 35(2):281-291.
 
*E-mail: kmelillo at dolphincommunicationproject.org
 
Interspecific interactions have been observed in a variety of social animals. Functional explanations include foraging, anti-predatory, and social advantages. These behaviors are poorly understood in marine mammals but are increasingly studied phenomena in sympatric populations. Resident Atlantic spotted dolphins (Stenella frontalis) off Bimini, The Bahamas, have been the subject of ongoing photo-identification and behavioral studies since 2001. A lesser-known population of bottlenose dolphins (Tursiops truncatus) has been observed interacting with these S. frontalis since 2003. To examine the functional significance of these interactions, interspecific behaviors were documented with underwater video using focal animal sampling. Mating or sexual play were the primary activities observed in nearly 50% of interactions, with male T. truncatus as the initiators. Therefore, the most likely functional explanation for these interactions is social. We hypothesize that male T. truncatus which lack access to T. truncatus females because of sexual immaturity or low social status seek copulations with S. frontalis females as an alternative.
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Perrin, W. F.* 2009. Historical perspectives - Early days of the tuna/dolphin problem. Aquatic Mammals 35(2):292-305.
 
*E-mail: william.perrin at noaa.gov
 
Dr. Bill Perrin is with the National Marine Fisheries Service’s Southwest Fisheries Science Center. Much of his research has involved dolphins: life history, population and community ecology, and behavioral and fishing-gear research to reduce mortality. His article recounts the earlier days of the tuna/dolphin problem in the eastern tropical Pacific Ocean.
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Bloch, D. & B. Mikkelsen. 2009. A northernmost record of dwarf sperm whale (Kogia sima) (Owen, 1866) from the Faroe Islands. Aquatic Mammals 35(2): 306-307.
 
No email address was provided; Faroese Museum of Natural History, Fútalág 40, FO-100 Tórshavn, Faroe Islands
 
This was a letter to the editor of the journal. In summary, on 28 March 2008, a dwarf sperm whale (Kogia sima) was observed swimming in the vicinity of the village of Haraldsund, close to the embank­ment between Borðoy and Kunoy. The position of the locality is 62.27° N, -7.00° W, and with a depth of 20 to 25 m. The letter provides further details and is supported by photographic evidence.



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