Figure 1.
Rookeries where Steller sea lions were branded and region where brand-resight surveys were conducted.
Primary study area, from Chirikof Island to Forrester Island, where Steller sea lions in Alaska were branded at natal rookeries in 2000–2010 and resighted from 2000–2012 within the eastern Distinct Population Segment (DPS) and the western DPS. Also shown is the newest rookery (Biali Rocks) that was established in the early 2000s. Sub-regions (circled) within each DPS include: the Kodiak Island, Chiswell Island, and Prince William Sound areas, and northern and southern areas within Southeast Alaska.
Table 1.
Number of Steller sea lions branded as pups at their natal rookery in the eastern and western DPS within Alaska, 2000–2010.
Table 2.
Parameter structures for multistate mark-resight models used to predict the age-specific probabilities of Steller sea lions being present in the opposite DPS with models named after the age structure or , the transition probabilities; the structures of S and p were the same in all models.
Table 3.
Estimated annual age- and sex-specific occupancy probabilities for eastern DPS Steller sea lions being in their non-natal DPS during the breeding season; the estimates were derived from the best of 9 models for each set of estimates (see Table 2).
Table 4.
Estimated annual age- and sex-specific occupancy probabilities for western DPS Steller sea lions being in their non-natal DPS during the breeding season; the estimates were derived from the best of 9 models for each set of estimates (see Table 2).
Table 5.
Estimated seasonal age- and sex-specific occupancy probabilities for eastern DPS Steller sea lions being in their non-natal DPS during breeding (whole number) and non-breeding (+0.5) seasons; the estimates were derived from the best of 9 models for each set of estimates (see Table 2).
Table 6.
Estimated seasonal age- and sex-specific occupancy probabilities for western DPS Steller sea lions being in their non-natal DPS during breeding (whole number) and non-breeding (+0.5) seasons; the estimates were derived from the best of 9 models for each set of estimates (see Table 2).
Figure 2.
Occupancy probabilities of Steller sea lions being in non-natal DPS during breeding and non-breeding seasons.
Estimated seasonal age- and sex-specific occupancy probabilities for sea lions being in their non-natal Distinct Population Segment (DPS) during breeding (whole number) and non-breeding (+0.5) seasons. Dashed lines represent females and solid lines represent males. Graph A shows estimated probabilities of occupancy in the opposite DPS for EDPS sea lions from the northern (NORTH) and southern (SOUTH) sub-DPS within Southeast Alaska. Graph B shows estimated probabilities of occupancy in the opposite DPS for WDPS sea lions from sub-regions Kodiak Island (KOD), Chiswell Island (CHIS), and Prince William Sound (PWS) within the central Gulf of Alaska; see Figure 1.
Table 7.
Female Steller sea lions born in the western DPS that gave birth in the eastern DPS within Alaska, 2000–2012.
Table 8.
Number of female Steller sea lions branded at each rookery in Alaska, number seen in the non-natal DPS, number subsequently giving birth in the northern sub-DPS (Graves Rock and White Sisters), and distance from natal rookery to pupping rookery.
Figure 3.
Location and number of individual Steller sea lions resighted in their non-natal DPS.
Squares show location of eastern Distinct Population Segment (DPS) males in the West and circles represent western DPS male and female sea lion locations in the East. Not included on map are observations of a male WDPS SSL that was resighted in northern Washington.