|| 要旨トップ | 目次 |||日本生態学会第70回全国大会 (2023年3月、仙台) 講演要旨
一般講演（口頭発表） B01-07 （Oral presentation）
Spotted seals are commonly observed in the southern Sea of Okhotsk, Hokkaido. They conduct various ice-related activities (e.g., breeding, molting) on the ice during wintertime and haul out on the shores of the mainland or islands during the ice-free period. Sighting survey and interview determined their spatial use and distribution around the Hokkaido coast before the sea-ice season. However, their winter distribution and movement patterns are difficult to observe due to extreme weather and sea ice restrictions. To determine spotted seals’ winter migration, we deployed satellite tags (CTD-SRDL, SMRU Ltd, Scotland) on two female and two male rehabilitated juvenile seals in December 2021 in the Okhotsk Tokkari Center, Hokkaido. Except for one female seal, which was tracked for 26 days and stopped transmission at Lake Saroma, seals were tracked for over 100 days, and individual variations in migration routes were observed; one female moved eastward to Habomai Islands, one male conducted a round trip between Sakhalin and Hokkaido, and another moved north-westward to Tatar Strait. Predominate dive type has spatial difference and was affected by sea-ice extents; benthic and mid-water column dives highly occurred in coastal areas, while upper-water column dive frequently appeared offshore and in areas with dense sea-ice.