Longitudinal study of northern fur seal (&lt;i&gt;Callorhinus ursinus&lt;/i&gt;) hematology

Kohyama, Kaoru; Kiyota, Masashi; Inoshima, Yasuo

doi:10.1292/jvms.20-0645

Cited by 3 publications

(2 citation statements)

References 31 publications

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“…There was a single report on northern fur seal rehabilitation in the northwest Pacific, which discussed the rescue and treatment of four individuals in South Korea over a 10-year period [20]. Similarly, in Japan, individual fur seals have been rescued and placed in permanent care [21].…”

Section: Otariidsmentioning

confidence: 99%

A Systematic Review of Global Marine Mammal Rehabilitation and Refloating, 2000–2023

Simeone,

Rousselet,

Atkin

et al. 2024

Sustainability

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Rehabilitation of marine mammals is performed throughout the world, yet the impact of rehabilitation on individuals and populations is questionable given the lack of robust information on the rehabilitation process and post-release monitoring in most cases. The goals of this study were to perform a systematic review of existing literature on marine mammal rehabilitation between 2000–2023 to determine the current state of rehabilitation and to evaluate the rehabilitation and conservation factors that could be used to build a framework to assess the health of rehabilitation programs worldwide. A total of 418 publications encompassing 52 species of marine mammal were included in the systematic review. Rehabilitation efforts focused mostly on pinnipeds, and North America was the most represented region. Data are scarce for both short- and long-term post-release survival across species. Reports about species threatened with extinction were significantly more likely to include information about conservation parameters than those species of least concern. A meta-analysis demonstrated a fairly strong fit of the dimensions of the proposed framework for a rehabilitation health index. Further refinement would strengthen the utility of this tool for both rehabilitation and conservation programs.

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Section: Otariidsmentioning

confidence: 99%

A Systematic Review of Global Marine Mammal Rehabilitation and Refloating, 2000–2023

Simeone,

Rousselet,

Atkin

et al. 2024

Sustainability

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“…Then, the pups participate in migration for a few years until they become involved in reproductive activities on breeding islands [6,15,17,39,57]. Because northern fur seals have a distinct life history pattern consisting of terrestrial breeding and oceanic migration, the physiological changes associated with their annual reproductive cycle and ontogeny are of particular interest for understanding their environmental adaptations [27]. However, owing to their oceanic distribution during the migration period, limited information is available on the reproductive physiology of immature or overwintering adult northern fur seals.…”

Section: Introductionmentioning

confidence: 99%

Fluctuations in serum steroid hormone concentrations and body mass during growth and sexual maturation in captive northern fur seals (<i>Callorhinus ursinus</i>)

Kohyama¹,

Inoshima

Kiyota

2022

The Journal of Veterinary Medical Science

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Northern fur seals (Callorhinus ursinus) have a distinct life history pattern comprising annual terrestrial breeding and oceanic migration, and the physiological changes associated with these patterns are of particular interest for understanding their environmental adaptations. However, owing to their oceanic distribution, limited information is available on the reproductive physiology of wild individuals during the immature stage and t he winter migration period. This study aimed to determine the relationships among the seasonal hormone profiles, body growth, age, and pregnancy using monthly serum samples collected over 3-5 years from two male and two female captive individuals during pubescence and sexual maturation. Small increases in the serum testosterone signaled puberty in males aged 3 and 4 years. Thereafter, males showed considerable increases in testosterone during breeding seasons, indicating sexual maturity. Immature female ser um progesterone was maintained at low levels, but after pubescence, females showed an increase in serum progesterone in August, the month next to the peak of delivery , followed by a decrease. In non-pregnant females, progesterone did not increase significa ntly until the next breeding season, but in pregnant females, they increased again from February to March and then gradually decreased. Immature males increased body mass constantly and reached puberty when their body mass exceeded 20 kg, and they showed s easonal weight fluctuations after puberty. These results provide fundamental information for determining sexual maturity and pregnancy in this species based on sex steroid hormones and body mass measurements.

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Blood Properties of Northern Fur Seals (<i>Callorhinus ursinus</i>) in Captivity and Comparison with Those of Three Arctocephalus Fur Seal Species

KOHYAMA,

INOSHIMA

2024

Jpn. J. Zoo Wildl. Med.

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The northern fur seal (Callorhinus ursinus) is the only extant species in the Callorhinus genus of the Otariidae family and inhabits the northern part of the North Pacific Ocean. These seals have a unique life cycle, spending two-thirds of the year migrating through the ocean and the remaining one-third on eight to nine islands in the northern part of the North Pacific, where they form large groups of several hundred to several thousand animals and give birth, mate, and rear their young. Owing to this unique life cycle, collection of blood samples is challenging throughout the year, and their annual average blood properties have not been reported. Izu Mito Sea Paradise, Japan, obtained permission from the Japan Fisheries Agency to breed northern fur seals. Since 1980, the facility has been conducting research to examine the blood properties of these seals to aid in their health management and as part of various studies. This review presents the annual average blood properties of captive northern fur seals over a 12year period from 2009, as data for wild individuals are not available. The data also include comparative hematological data from wild seals and three taxonomically related Arctocephalus fur seal species, namely the Guadalupe (Arctocephalus townsendi), Antarctic (Arctocephalus gazella), and South American (Arctocephalus australis) fur seals.

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Longitudinal study of northern fur seal (<i>Callorhinus ursinus</i>) hematology

Cited by 3 publications

References 31 publications

A Systematic Review of Global Marine Mammal Rehabilitation and Refloating, 2000–2023

A Systematic Review of Global Marine Mammal Rehabilitation and Refloating, 2000–2023

Fluctuations in serum steroid hormone concentrations and body mass during growth and sexual maturation in captive northern fur seals (<i>Callorhinus ursinus</i>)

Blood Properties of Northern Fur Seals (<i>Callorhinus ursinus</i>) in Captivity and Comparison with Those of Three Arctocephalus Fur Seal Species

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