The Utilization of Space by Juvenile Spotted Seals (Phoca largha) from Peter the Great Bay (East Sea/Sea of Japan) Throughout the Year

Spotted seals (Phoca largha) exhibit an unusual ecological feature within the population of Peter the Great Bay (PGB). Following the breeding and molting seasons, one group performs long-distance foraging migrations, whereas another group remains in the bay year-round. To examine how space use differs between these two groups, nine satellite tags were deployed on juvenile spotted seals within PGB between 2017 and 2022: four seals were tagged at the rookery located on the Rimsky-Korsakov Archipelago (RKA), whereas the remaining five were tagged at the haul-out on the Verkhovskogo Islands (VI). Spotted seals tagged at RKA undertook long summer migrations toward the northeast of the East Sea/Sea of Japan and subsequently to the south of the Okhotsk Sea. Four spotted seals tagged at VI remained in PGB throughout the warm season. Seals were allocated to two clusters based on median speed during transit travel. The slower-moving group consisted of three spotted seals that remained in PGB; these seals also made fewer transit passages and used smaller areas of water.