Meeting Abstract
92.9 Wednesday, Jan. 7 Development of Endocrine and Immune Function in Endangered Steller Sea Lion Pups (Eumetopias jubatus) KEOGH, M.J.*; MANISCALCO, J.M.; ATKINSON, S.; University of Alaska Fairbanks; Alaska SeaLife Center; University of Alaska Fairbanks mandyk@alaskasealife.org
Several species of marine mammals and birds in the Northeast Pacific have been in decline since the mid-1970s including the endangered Steller sea lion (SSL; Eumetopias jubatus). A leading theory is the nutritional stress associated with a reduction in prey abundance or quality. The impact of limited resources would be greatest during periods of development and rapid growth. This study seeks to determine if body condition and maternal investment influences the immune and endocrine systems in SSL pups. At Chiswell Island, Alaska, a SSL rookery was monitored by a remote video camera enabling the determination of the age of pups, maternal investment, and survival rates. A total of 61 pups (24 female, 37 male) were sampled during 2005, 2007, and 2008 ranging in age from 5 to 38 days old. Each pup was measured, weighed, and branded. Blood samples were collected for complete blood cell counts, lymphocyte proliferation, serum chemistries and circulating hormone levels. Female pups were significantly smaller than males in mass (F= 26.7 4.1 kg, M=32.2 4.6 kg; F =16.276, p<0.001) and length (F=101.6 4.7 cm, M=108.0 4.9; F =17.331, p<0.001). Age also significantly effected mass (F =49.802, p<0.001) and length (F =17.331, p<0.001) with older pups being larger. While there was a significant difference between male and female pups in body condition these differences were not found in circulating hormones or lymphocyte proliferation. Circulating TT4 (F =6.007, p=0.017), FT4 (F =6.405, p=0.014), and T cell proliferation (F =4.984, p=0.038) decreased while leptin (F =5.679, p=0.020) increased with age. Further analysis will incorporate a body condition index to determine if overall condition significantly affects immune and endocrine parameters.
