Kaoru KOHYAMA's scientific contributions

Publications (9)

Article
Full-text available
Introduction Seal parapoxvirus (SPPV) infection has been reported among pinnipeds in aquaria in Japan; however, its seroprevalence is unknown. Therefore, an enzyme-linked immunosorbent assay (ELISA) was developed for serological diagnosis of SPPV infection. Material and Methods The gene encoding the major envelope protein of SPPV was cloned into t...
Article
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 av...
Article
Although the causes have not been specified yet, wild populations of northern fur seals (Callorhinus ursinus) have been decreasing, which is why conservation techniques such as captive breeding and health maintenance should be established. Hematological parameters can be used to maintain the health status of northern fur seals kept in captivity for...
Article
We examined the relationship between serum testosterone and faecal testosterone metabolite levels in a captive northern fur seal (Callorhinus ursinus) using time-resolved fluoroimmunoassay to develop non-invasive testosterone monitoring technique. We found a significant relationship between faecal testosterone metabolite and serum testosterone leve...
Article
Full-text available
Two cases of extralobar pulmonary sequestrations from a walrus (Odobenus rosmarus) and a Steller sea lion (Eumetopias jubatus) are described in the present study. Grossly, an independent, soft unilocular cystic mass was found within the abdominal cavities of both animals, adherent to the diaphragm in O. rosmarus and attached to the cardia of the st...
Article
Northern fur seals (Callorhinus ursinus) are endemic to the North Pacific Ocean. They were hunted for their fur and became endangered in the late 1800s, but their populations recovered following the introduction of protection laws. Recently, populations have been decreasing again, although the reasons are unclear. For individuals that are bred and...
Article
Full-text available
Diet preferences of three captive northern fur seals for seven prey items (Okhotsk atka mackerel, rainbow trout, common mackerel, walleye pollock, Pacific sand lance, horse mackerel, and Japanese common squid) were measured through repeated two-choice tests. Preference indices estimated from the paired consumption data using the normal Bradley-Terr...
Article
During establishment of primary cell culture from the kidney of a dead Pacific white-sided dolphin (Lagenorhynchus obliquidens), a cytopathic effect was observed. Polymerase chain reaction with a set of herpesvirus consensus primers yielded a fragment of the expected size. Nucleotide sequencing of the product indicated that the isolated virus was c...

Citations

... Table 4 provides an overview of circulating steroid hormone concentrations in species of suckling and weaned seals, and juvenile and adult seals. In general, concentrations in juvenile and adult pinnipeds appear to be higher than reported in the present grey seal pups [10,[27][28][29][30][31][32][33]66,67]. The observed differences are most likely due to developmental (age) and sex related to maturation of the animals, and the result of differences in the applied analytical techniques [33,66,67]. ...
... However, they do not use fatty tissues for thermoregulation or as energy reserved in large amounts, like mammals (Kohyama & Inoshima, 2017). On the other hand, most marine mammals, such as the Guadalupe fur seal, are characterized as having a fat layer for thermoregulation. ...
... Optimal foraging theory predicts that predators should select and prefer prey that maximizes energy intake while balancing the energetic costs associated with prey capture and handling, alongside digestion and metabolism (Stephens et al., 2007;Stephens & Krebs, 1986). Specifically, predators may select prey according to their nitrogen: carbon ratio (Jensen et al., 2012), energy density (Kiyota et al., 2013), body size (Johnson et al., 2012) or defences (Llewelyn et al., 2012). However, these prey characteristics are not necessarily independent of one another. ...
... Herpesvirus infections have been observed in a wide range of organisms, including mammals, birds, reptiles, fish, amphibians, and bivalves [1]. So far, Alpha-and/or Gammaherpesvirinae have been identified in eight cetacean families: Delphinidae, Kogiidae, Ziphiidae, Physeteridae, Monodontidae, Phocoenidae, Iniidae (odontocetes), and Balaenopteridae (mysticetes) [5][6][7][8][9][10][11]. Cetacean herpesvirus strains are usually classified according to the sequence of a part of a locus of their DNA polymerase (DNApol) gene [12]. ...