Distribution of the Steller sea lion Eumetopias jubatus during winter in the northern Sea of Japan, along the west coast of Hokkaido, based on aerial and land sighting surveys

Diets of Steller sea lions off the coast of Hokkaido, Japan: An inter‐decadal and geographic comparison

“…As a consequence of the recent recovery of the Asian stock of SSLs, including those in the Kurile Archipelago (Burkanov & Loughlin, ), the numbers migrating to the Hokkaido coast have increased, with an estimated population size of 5,800 (14.4%: coefficient of variation [CV]) individuals in the period 2005–2009, and 6,237 (12.3% CV) individuals between 2010 and 2013 (Hattori & Isono, ). Moreover, a trend of earlier arrival and remaining longer has been observed compared with the 1980s (Hoshino et al., ).…”

“…From the results of the RDA and PERMANOVAs indicated significant differences in the sampling areas, differences in the ontogenetic stage of SSLs were detected. In this latter regard, it is believed that the group composition on age and sex of SSLs in Hokkaido is not uniform (Hoshino et al., ; Itoo et al., ). Further, the results of the RDA show that SSLs collected in the northern region of the Sea of Japan were younger than those collected in the central region, which may explain the observed regional differences in the diets of SSLs.…”

The distribution of Steller sea lions (Eumetopias jubatus) in the Sea of Japan off Hokkaido, Japan: A preliminary report

“…Along the western coast of Hokkaido, two major haul‐out sites are known for the current wintering population: Ofuyu Point and Cape Kamui (Fig. 1; Hoshino et al . 2006).…”

“…On the other hand, very limited information has been available on the winter distribution of SSLs, because the number of active haul‐outs has been restricted in the Sea of Okhotsk by sea ice (Burkanov and Loughlin 2005). Hoshino et al (2006) reported that SSLs were concentrated in the central and northern areas along the western coast of Hokkaido in early February based on aerial sighting surveys, but the area surveyed was limited to the immediate coastal zone, and the offshore distribution of SSLs remains unknown. Therefore, we conducted an aerial survey covering both the inshore and offshore areas of the Sea of Japan in March 2005 to study the winter distribution of the SSLs.…”

“…Therefore, we conducted an aerial survey covering both the inshore and offshore areas of the Sea of Japan in March 2005 to study the winter distribution of the SSLs. Although the haul‐out number tends to peak from January to February (Hoshino et al . 2006), extreme weather conditions during this period restricted the surveys to March only, which is still well within the wintering season of SSLs.…”