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Larson S.,Seattle Aquarium | Belting T.,Seattle Aquarium | Rifenbury K.,Sea For Life | Boutelle S.M.,Wildlife Contraception Center
Zoo Biology | Year: 2013

The sea otter (Enhydra lutris) is a popular exhibit animal in many zoos and aquariums worldwide. Captive sea otters from these populations are owned by the United States Fish and Wildlife Service (USFWS). The USFWS has requested that these sea otters be prevented from breeding in order to save captive space for wild rescued animals. Sea otters are often housed in mixed sex groups, therefore a chemical contraceptive method or surgical removal of gonads must be used to prevent potential pregnancy. The contraceptive, Suprelorin® or deslorelin, has been used in many different species to effectively suppress reproduction but duration of effect may vary not only between species but also individuals. Here, we report the effects of one to several consecutive deslorelin implants on gonadal reproductive hormones found in fecal samples from six captive sea otters (two males and four females) compared to two control otters (one male and one female) housed at three zoological institutions. We documented the longitudinal hormone signatures of many stages of the contraceptive cycle including pretreatment (PT), stimulatory phase (S), effective contraception (EC), and hormone reversal (HR) that was characterized by a return to normal hormone levels. Deslorelin was found to be an effective contraceptive in sea otters and was found to be reversible documented by a live birth following treatment, however the duration of suppression in females was much longer than expected with a 6-month and a 1-year implant lasting between 3 and 4 years in females. © 2012 Wiley Periodicals, Inc.

Nichols J.D.,U.S. Geological Survey | Hollmen T.E.,Sea For Life | Hollmen T.E.,University of Alaska Fairbanks | Grand J.B.,U.S. Geological Survey
EcoHealth | Year: 2016

Monitoring is best viewed as a component of some larger programme focused on science or conservation. The value of monitoring is determined by the extent to which it informs the parent process. Animal translocation programmes are typically designed to augment or establish viable animal populations without changing the local community in any detrimental way. Such programmes seek to minimize disease risk to local wild animals, to translocated animals, and in some cases to humans. Disease monitoring can inform translocation decisions by (1) providing information for state-dependent decisions, (2) assessing progress towards programme objectives, and (3) permitting learning in order to make better decisions in the future. Here we discuss specific decisions that can be informed by both pre-release and post-release disease monitoring programmes. We specify state variables and vital rates needed to inform these decisions. We then discuss monitoring data and analytic methods that can be used to estimate these state variables and vital rates. Our discussion is necessarily general, but hopefully provides a basis for tailoring disease monitoring approaches to specific translocation programmes. © 2016 International Association for Ecology and Health (outside the USA)

Fukuda M.,Sea For Life
Journal of the Yamashina Institute for Ornithology | Year: 2013

Black-tailed Gulls Larus crassirostris have a black band on the upper tail. I measured the length from the tip of the tail to the outermost edge of the black band (white fringe on tail edge) of 22 captive individuals in the Ueno Zoological Gardens. The length of the white fringe increased in relation to the age of each individual. Therefore, it was suggested that the age of Black-tailed Gulls can be determined by the length of the white fringe until at least four or five years of age. © Yamashina Institute for Ornithology.

Horning M.,Oregon State University | Mellish J.-A.E.,Sea For Life | Mellish J.-A.E.,University of Alaska Fairbanks
Endangered Species Research | Year: 2010

To directly determine mortality and predation in the endangered western Steller sea lion Eumetopias jubatus, we deployed implanted, satellite-linked post-mortem data transmitters in 21 juveniles. Data recovered from 4 of 5 detected mortalities exhibited precipitous drops in ambient temperatures followed by immediate onset of transmissions (N = 3), or gradual cooling and delayed transmissions (N = 1). Precipitous drop data sets were classified as acute death at sea by trauma. A model to estimate algor mortis (body cooling) as a function of mass and ambient conditions was validated through simulations on 4 carcasses. Model outputs suggest that cooling rate masses can be qualitatively distinguished if well outside the prediction uncertainties. The observed gradual cooling rate was best described by a modeled mass one-sixth the animal's mass at release, supporting the classification of the fourth event as acute death at sea by trauma. This suggests that at least 4 in 5 detected mortalities likely represent acute deaths at sea, probably due to predation. We conclude that precipitous drop events with immediate transmissions can be classified as acute death likely by predation, but gradual cooling events with delayed transmission should be reviewed on a case-by-case basis. In 3 cases that provided both ante-mortem and post-mortem locations from external and implanted transmitters, respectively, these differed by less than 17 km, illustrating that this technique provides spatially explicit data of predation on individual sea lions. © Inter-Research 2009.

Horning M.,Oregon State University | Mellish J.-A.E.,Sea For Life | Mellish J.-A.E.,University of Alaska Fairbanks
Fishery Bulletin | Year: 2014

Temperature data received post mortem in 2008–13 from 15 of 36 juvenile Steller sea lions (Eumetopias jubatus) that had been surgically implanted in 2005–11 with dual life history transmitters (LHX tags) indicated that all 15 animals died by predation. In 3 of those 15 cases, at least 1 of the 2 LHX tags was ingested by a cold-blooded predator, and those tags recorded, immediately after the sea lion’s death, temperatures that corresponded to deepwater values. These tags were regurgitated or passed 5–11 days later by predators. Once they sensed light and air, the tags commenced transmissions as they floated at the ocean surface, reporting temperatures that corresponded to regional sea-surface estimates. The circumstances related to the tag in a fourth case were ambiguous. In the remaining 11 cases, tags sensed light and air immediately after the sea lion’s death and reported temperatures that corresponded to estimates of regional sea-surface temperatures. In these 11 cases, circumstances did not allow for inferences on the species of predator. Among reported poikilotherm predators of Steller sea lions, only the Pacific sleeper shark (Somniosus pacificus) is known to have body core temperatures that are near ambient. The data from this study indicate that Pacific sleeper sharks need to be considered as a possible source of mortality of juvenile Steller sea lions in the region of the Gulf of Alaska. © 2014, National Marine Fisheries Service. All rights reserved.

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