[MARMAM] Abstracts - Aquatic Mammals, vol 36, issue 1 (2010)
dagmar_fertl at hotmail.com
Mon Mar 15 13:25:10 PDT 2010
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. Kathleen Dudzinski (managing editor: kdudzinski at dolphincommunicationproject.org) and Justin Gregg (co-editor; justin at dolphincommunication.com). 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.
dfertl at gmail.com
Balmer, B. C.*, L. H. Schwacke, and R. S. Wells. 2010. Linking dive behavior to satellite-linked tag condition for a bottlenose dolphin (Tursiops truncatus) along Florida's northern Gulf of Mexico coast. Aquatic Mammals 36(1):1-8.
*E-mail: bbalmer at mote.org
Satellite-linked telemetry is a valuable method to identify small cetacean movement patterns and dive behavior. Data collection from satellite-linked tracking is less labor intensive than comparable radio tracking studies in which intensive field work is required post-tagging. However, there are few studies that have assessed the effects of satellite-linked transmitter attachment and retention on the tagged individual. Dolphin X08, a 24-y-old, male bottlenose dolphin (Tursiops truncatus) captured and released along the northern Gulf coast of Florida during a health assessment project, was tagged with a SPLASH satellite-linked transmitter (Wildlife Computers, Redmond, WA, USA) to remotely obtain data on movement patterns and dive behavior. In addition to the satellite-linked transmitter, a VHF radio transmitter was mounted to X08's dorsal fin to provide short-term movement pattern data and to allow for position acquisition to observe X08 with the satellite-linked transmitter. X08's satellite-linked tag transmitted location data for 54 days and dive duration data for 35 of those days. X08's VHF tag transmitted for over 94 days and allowed for complete monitoring of the satellite-linked tag's life. Dive duration data changed throughout the course of the satellite-linked tag transmissions. These dive data, along with follow-up observations, suggest that as the stability of the satellite-linked tag on the dorsal fin decreased, the number of longer dives increased, possibly to mitigate the amount of time that the satellite-linked tag came into contact with the water surface. This study was the first to identify movement patterns and dive durations of a bottlenose dolphin along the northern Gulf coast of Florida as well as to monitor satellite-linked tag condition throughout the transmission period.
Graham, M. A.*, and M. Noonan. 2010. Call types and acoustic features associated with aggressive chase in the killer whale (Orcinus orca). Aquatic Mammals 36(1):9-18.
* E-mail: noonan at canisius.edu
Instances of aggressive chase over a 5-mo period were investigated in captive killer whales (Orcinus orca). Such episodes were found to be quite rare, occurring only eight times in 1,872 h of observation. A consistent vocal pattern was found to be associated with agonistic episodes that differed markedly from the pattern recorded during non-aggressive, time-matched control periods. In general, vocalizations associated with aggressive chase were characterized by amplitude and frequency modulated pulses of approximately 190 ms in duration. In addition, three specific call types were found to occur only during chase events. As a whole, these particular call types and associated features are offered as an acoustic signature of agonism in the killer whale. It is hoped that these sounds might aid researchers in interpreting heretofore enigmatic killer whale vocalizations recorded from wild populations.
Bashir, T.*, A. Khan, P. Gautam, and S. K. Behera. 2010. Abundance and prey availability assessment of Ganges River dolphin (Platanista gangetica gangetica) in a stretch of upper Ganges River, India. Aquatic Mammals 36(1):19-26.
* E-mail: tbashir at wii.gov.in
The present study was conducted between January and June 2007 to assess the abundance and density of Ganges River dolphin (Platanista ganget-ica gangetica) and their prey in a 28-km stretch of the River Ganges between Narora Barrage and Anupshahar. Two different sampling methods were used to estimate dolphin densities. Estimated density was 2.58 ± 0.40 individuals/km2 (mean ± 1 SE) using the direct count method and 4.97 ± 0.60 individuals/km2 using the boat-based, line-transect distance methods, with an encounter rate of 0.52 ± 0.068 individuals/km and detection probability of 0.647. No significant differences between the upstream and downstream counts (t = 1.29, df = 9, p > 0.05) were detected. The adult male to adult female ratio was 0.66: 1.00, whereas the calf to adult female ratio was 0.42: 1.00. We collected 16 fish species of length class varying from 3.5 to 20 cm (range of preferred size of dolphin prey) with a total density of 176.42 fish/km2 and a total average biomass of 5.36 kg/km2. Dolphin density showed a significant positive relationship (R2 = 0.587) with density of Reba fish (Cirrhinus reba) (β = 0.31, p = 0.00) and Baam fish (Mastacembelus armatus) (β = 0.50, p = 0.04) and also with water depth (β = 0.17, p = 0.03). Presence of dolphins varied across different water depth categories (χ2 = 106.38, df = 3, p < 0.01) and different parts of the river (χ2 = 21.68, df = 2, p = 0.00) with more than 50% of dolphin sightings occurring in confluences, indicating their preference for deep water pools.
Karamanlidis, A. A.*, V. Paravas, F. Trillmich, and P. Dendrinos. 2010. First observations of parturition and postpartum behavior in the Mediterranean monk seal (Monachus monachus) in the eastern Mediterranean. Aquatic Mammals 36(1):27-31.
* E-mail: akaramanlidis at gmail.com
Understanding reproductive behavior, especially the circumstances surrounding parturition and the events following the first days postpartum, is essential in developing effective conservation strategies for endangered pinnipeds. In the case of the critically endangered Mediterranean monk seal (Monachus monachus), difficulties in documenting events, such as parturition, are compounded by the very low population numbers and the inaccessibility of the habitat occupied by the species. In this study, the authors report the first observations of parturition for the species from the central Aegean Sea, Greece in the eastern Mediterranean Sea. Using a state-of-the-art infrared remote-monitoring system two births were documented and important information on the total duration of the events, the total duration of attempted suckling, as well as, information on the presentation of the pups, their sex and habitat were recorded. This new information on the reproductive biology of the species in this part of its range outline the importance of suitable reproductive caves for the conservation of the species and the urgency of protecting them. In addition, considering the high cost and logistics of the study, monitoring the species on a large scale to effectively protect it, will require the development of new, low-cost and time-efficient methodologies.
Filby, N. E.*, K. J. Sanderson, E. Martinez, and K. A. Stockin. 2010. Distribution and population demographics of common dolphins (Delphinus delphis) in the Gulf St. Vincent, South Australia. Aquatic Mammals 36(1):33-45.
*E-mail: nicole.filby at live.vu.edu.au
Within Australian waters, short-beaked common dolphins (Delphinus delphis) are exposed to a variety of human-induced impacts, including aquaculture and fisheries. Nonetheless, the occurrence and distribution of common dolphins within these waters remains unknown. Data detailed herein represent the first report of the occurrence and distribution of common dolphins from Australian waters. The density and relative abundance of common dolphins within Gulf St. Vincent (GSV), South Australia, was examined between September 2005 and May 2008 using systematic boat surveys. During 1,850 km of survey effort, a total of 108 independent groups, involving 564 common dolphins, were observed. Group size ranged from 2 to 21 individuals (mean = 5.26, SD = 3.687), with immature dolphins found in larger group sizes. Adults were the most frequent age class observed in this population (60.3%, n = 340), with neonates and calves observed most frequently between December and April. Sighting frequency was 3 groups/100 km² travelled, with an encounter rate of 16 common dolphins/100 km². The western longitude and southern latitude sections of GSV were used most frequently by this species, with most groups recorded in water depths of 35 to 40 m (mean = 37.2 m, SD = 1.4), and in areas 21 to 31 km from land (mean = 27.4 km, SD = 2.6). Common dolphin density was estimated to be 0.5 dolphins/100 km2, with a population estimate of 1,957 dolphins within their preferred habitat (waters deeper than 14 m). Results suggest the GSV is important for this species and that common dolphins use these waters as a nursery area.
Lanyon, J. M.*, H. L. Sneath, T. Long, and R. K. Bonde. 2010. Physiological response of wild dugongs (Dugong dugon) to out-of-water sampling for health assessment. Aquatic Mammals 36(1):46-58.
* E-mail: j.lanyon at uq.edu.au
The dugong (Dugong dugon) is a vulnerable marine mammal with large populations living in urban Queensland waters. A mark-recapture program for wild dugongs has been ongoing in southern Queensland since 2001. This program has involved capture and in-water sampling of more than 700 dugongs where animals have been held at the water surface for 5 min to be gene-tagged, measured, and biopsied. In 2008, this program expanded to examine more comprehensively body condition, reproductive status, and the health of wild dugongs in Moreton Bay. Using Sea World's research vessel, captured dugongs were lifted onto a boat and sampled out-of-water to obtain accurate body weights and morphometrics, collect blood and urine samples for baseline health parameters and hormone profiles, and ultrasound females for pregnancy status. In all, 30 dugongs, including two pregnant females, were sampled over 10 d and restrained on deck for up to 55 min each while biological data were collected. Each of the dugongs had their basic temperature-heart rate-respiration (THR) monitored throughout their period of handling, following protocols developed for the West Indian manatee (Trichechus manatus). This paper reports on the physiological response of captured dugongs during this out-of-water operation as indicated by their vital signs and the suitability of the manatee monitoring protocols to this related sirenian species. A recommendation is made that the range of vital signs of these wild dugongs be used as benchmark criteria of normal parameters for other studies that intend to sample dugongs out-of-water.
Berman-Kowalewski, M.*, F. M. D. Gulland, S. Wilkin, J. Calambokidis, B. Mate, J. Cordaro, D. Rotstein, J. St. Leger, P. Collins, K. Fahy, and S. Dover. 2010. Association between blue whale (Balaenoptera musculus) mortality and ship strikes along the California coast. Aquatic Mammals 36(1):59-66.
* E-mail: mberman at sbnature2.org
Blue whales (Balaenoptera musculus) are distributed worldwide, and although severely depleted by commercial whaling, their abundance off the California coast now appears to be increasing. Little is known about natural causes of mortality of blue whales, but human-related mortality continues despite legal protection. Ship strikes are a significant mortality factor for other species of baleen whale, and changes in shipping traffic have been advocated to minimize further deaths. Between 1988 and 2007, 21 blue whale deaths were reported along the California coast, typically one or two cases annually. Three pulses in strandings were observed, with three carcasses observed in fall 1988, three in 2002, and four in fall 2007. Two of the four animals in 2007 were first observed dead in the Santa Barbara Channel and had wounds typical of a ship strike. Blue whale strandings were spatially associated with locations of shipping lanes, especially those associated with the Ports of Los Angeles and Long Beach, and were most common in the fall months.
Yurk, H.*, O. Filatova, C. O. Matkin, L. G. Barrett-Lennard, and M. Brittain. 2010. Sequential habitat use by two resident killer whale (Orcinus orca) clans in Resurrection Bay, Alaska, as determined by remote acoustic monitoring. Aquatic Mammals 36(1):67-78.
*E-mail: yurk at zoology.ubc.ca
Killer whales (Orcinus orca) are sighted regularly in coastal Alaska during the summer, but little is known about their movements through the area during the winter when weather and light limit the use of boat-based surveys. Acoustic monitoring provides a practical alternative because each extended resident killer whale family group or pod has a unique dialect that can be discerned by differences in their repertoires of stereotyped calls. The repertoires of resident killer whale pods in the northern Gulf of Alaska were updated from earlier studies, and the results used to determine the identity of pods that were recorded on remote hydrophones in Resurrection Bay, Alaska, in the fall, winter, and spring of 1999 to 2004. In total, seven pods of resident killer whales were identified acoustically, comprising four related pods from AB clan and three from AD clan. The frequencies of occurrence of the clans differed between the November to March recording period when AB clan occupied the area, and the April-May period when AD clan was predominant. The sequential use of this habitat during periods of relative prey scarcity has the effect of limiting intergroup resource competition and is consistent with earlier findings that demonstrated divergent resource specialization by sympatric killer whale populations.
Lynn, B. L., C. Reichmuth, R. J. Schusterman, and F. M. D. Gulland. 2010. Filial imprinting in a Steller sea lion (Eumetopias jubatus). Aquatic Mammals 36(1):79-83.
* E-mail: brian.l.lynn at gmail.com
The Marine Mammal Center hand reared a male Steller sea lion (Eumetopias jubatus) after it was found abandoned as a neonate in June 2006. Following release in April 2007, the animal repeatedly approached humans on the shore, necessitating long-term captive placement. To evaluate the extent of this preference for human contact, we conducted three behavioral assessments: (1) a stationary preference test, (2) a following test, and (3) a vocal playback test. This sea lion demonstrated an overall penchant for human interaction and a strong preference for the voice of one of his early caretakers. Filial imprinting, a developmental phenomenon extensively studied in birds but less so in mammals, is suggested as the cause of this aberrant social behavior. The long-term effects of imprinting in mammals, including impacts on reproductive success, remain poorly understood. This observation with a Steller sea lion is the first documented case of probable imprinting in this species.
Schusterman, R. J. 2010. Historical perspectives: Pinniped psychobiology: The early years. Aquatic Mammals 36(1):84-110.
Dr. Ron Schusterman provides a historical perspective of, and his integral role in, the exploration of the sensory systems, perception, cognition, and communication of pinnipeds. Ron Schusterman passed away on February 11, 2010, during the final editorial work on this manuscript. The material presented in this article was partially drawn from writings for a book that he was working on about his life in science and with animals.
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