Meeting Abstract

60.8  Tuesday, Jan. 6  Skeletal muscle lipids in Weddell seals (Leptonychotes weddellii): Differences in age class and possible response to resource limitations TRUMBLE, S.J.*; HAWKE, T.J.; PEARSON, L.E.; KANATOUS, S.B.; Baylor University; York University; University of Alaska Anchorage; Colorado State University stephen_trumble@baylor.edu

In this study, we investigated the intramuscular triglyceride (IMTG) profiles and oxidative metabolism substrates of a deep diving mammal, the Weddell seal. We sampled pups (4-6 wks), juveniles (12-15 mo) and non-lactating adults (> 15 mo) and tested for age-class, gender and yearly differences. No gender differences were observed in IMTG or oxidative metabolism substrates. While pup (6g/100g) muscles had consistently three times the IMTG stores than juveniles (2g/100g), no differences were observed between yearly IMTG stores. No yearly differences were found in citrate synthase (CS) and COX activity among age classes. However, differences were detected among age classes and between years in lactate dehydrogenase (LDH), lipoprotein lipase (LPL) and fatty acid synthase (FAS) from skeletal muscles sampled. Interestingly, IMTG stores of 2006 sampled adults (2g/100g) decreased 550% from 2005 levels (11g/100g). This finding appears to correlate with the receding ice coverage in the McMurdo Sound area and its impact on the population density of adults (increase of 62% in adult numbers in 2006). Assuming breeding aged or lacatating females had similar IMTG values implies these adult animals may be faced with a physiological bottleneck similar to that of juveniles. This suggests that numbers of Weddell seal adults may increase into the McMurdo Sound area with warmer ice-free conditions, impacting future reproductive success.