MEPS 366:271-279 (2008)  -  DOI: https://doi.org/10.3354/meps07617

ABSTRACT: We determined the fatty acid (FA) composition of the blubber of 82 New Zealand (NZ) sea lions caught as squid fishery by-catch between the years 2000 and 2006 on the Auckland Islands (51°S, 166°E) shelf. A combination of univariate and multivariate analyses showed significant variation in the FA composition between sexes and years. Blubber FA compositions of some males differed significantly from that of females, whereas blubber FA compositions of lactating (LF) and non-lactating females (NLF) were similar. Significant annual FA variation was revealed between the pooled years 2005/2006 and the previous years and between 2000 and 2004. Part of these differences can be attributed to different diets. Indeed, FA variation between the sexes suggests that males feed on deeper species than females, which is consistent with the current knowledge on the different diving behaviours between male and female otariids. Concerning annual variation, NZ sea lions are generalist predators, thus their diet is expected to follow the trends of prey stock availability. Nonetheless, FA metabolism is likely to cause some of the FA variation seen between sexes and years, because the deposition and mobilization of FAs would vary according to the nutritional and reproductive states of the individuals.

KEY WORDS: Fatty acid analysis · Phocarctos hookeri · Sex variation · Temporal variation · Fatty acid metabolism · Diet