MEPS 289:165-176 (2005)  -  doi:10.3354/meps289165

ABSTRACT: In marine zooplankton communities, appendicularians are second in abundance to copepods, and there is evidence that they are an important dietary component for larvae of several fish species. As various algal species upon which the appendicularian Oikopleura dioica grazes differ significantly in their fatty acid compositions, we have examined how this filter feeder translates diets that differ in quality or quantity into its own fatty acid composition. By feeding O. dioica diets containing either a single diatom or single flagellate species, we demonstrated that the fatty acid composition of O. dioica reflects dietary quality. Quantitative differences in the amount of fatty acids in the diet also directly led to quantitative differences in fatty acid content of the animal, consistent with differences in reproductive output reported earlier. Under the same dietary regimes, males differed from females in fatty acid composition. Among these differences, females had higher amounts of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), important for larval development. Analysis of fatty acid composition of fecal pellets revealed selective assimilation of some fatty acids by the animals, including EPA and DHA. Overall, consistent with data on other zooplanktonic filter feeders, the fatty acid composition of O. dioica reflected dietary composition, indicating that the nutritional quality of primary production would be transferred to predators of this component of zooplankton without substantial intermediary modifications.

KEY WORDS: Life history · Zooplankton · Filter feeding · Larval development · Flagellate · Diatom