Interseasonal and Interannual Measures of Maternal Care Among Individual Steller Sea Lions (Eumetopias Jubatus)

Seasonal influence on the response of the somatotropic axis to nutrient restriction and re‐alimentation in captive Steller sea lions (Eumetopias jubatus)

“…Further exacerbating the challenges of acquiring sufficient nutrients for growth in Steller sea lions are fluctuations in availability of prey resources (Sinclair and Zeppelin, 2002;Gende and Sigler, 2006;Womble and Sigler, 2006) and life history traits that include extended periods of fasting on shore during the summer breeding season (Gentry, '70;Higgins et al, '88;Rea et al, '98;Maniscalco et al, 2006). Although Steller sea lions are naturally subject to seasonal variation in prey availability and intake (Raum-Suryan et al, 2004;Gende and Sigler, 2006;Maniscalco et al, 2006), captive studies that have imposed nutrient restrictions outside the normal life history pattern of the species have demonstrated that season appears to have a substantial effect on the impact of episodes of nutritional stress on body condition and physiology (Rosen and Trites, 2005;Kumagai et al, 2006;Rosen and Kumagai, 2008). Recent research has also shown that juvenile Steller sea lions, unlike sub-adults, show no metabolic adaptations to fasting which could put them at greater risk during a period of nutrient restriction compared with older animals (Rea et al, 2007(Rea et al, , 2009.…”

A re-examination of the timing of pupping for Steller sea lions Eumetopias jubatus breeding on two islands in Alaska

“…For some pinniped species, older or prime-aged females give birth earlier in the season than younger females (Lunn & Boyd 1993, Gentry 1998, Boltnev & York 2001, Maniscalco et al 2006, Hastings & Jemison 2015. This was reported for Steller sea lions that breed on Chiswell Island, Alaska, and the Forrester Island Complex, Alaska (Maniscalco et al 2006, Hastings & Jemison 2015. For Antarctic fur seals it was suggested that, by returning earlier, older females could select the most suitable pupping sites (Lunn & Boyd 1993).…”

Seasonal changes in pelagic fish biomass around the Chiswell Island Steller sea lion rookery in 2003

“…The increased availability of adult pollock, herring and salmon in August is coincident with an increase in the duration of foraging trips by lactating Chiswell SSLs (Maniscalco et al, 2006). This suggests that female SSLs increase their foraging trip durations in response to increased prey availability.…”

“…In the northern GOA there is a sharp increase in the duration of foraging trips by lactating females in August (Maniscalco et al, 2006). Both of these observations are thought to be linked to seasonal changes in prey availability (Merrick and Loughlin, 1997;Maniscalco et al, 2006).…”

“…In the central Gulf of Alaska (GOA) and Aleutian Islands, female SSLs with dependent young increase their foraging effort over the course of the year by spending more time at sea, diving deeper and having greater home ranges in winter as compared with summer (Merrick and Loughlin, 1997). In the northern GOA there is a sharp increase in the duration of foraging trips by lactating females in August (Maniscalco et al, 2006). Both of these observations are thought to be linked to seasonal changes in prey availability (Merrick and Loughlin, 1997;Maniscalco et al, 2006).…”