Seasonal changes in the lipids of Mysis mixta (Mysidacea) from the hyperbenthos of a cold-ocean environment (Conception Bay, Newfoundland)

Total lipid (TL) and lipid class composition of Mysis mixta Lilljeborg from 240-m depth in a cold-water marine bay were studied throughout 1999 and 2000. The objective was to relate the seasonal lipid dynamics in an abundant and lipid-rich hyperbenthic species to its life cycle and to the annual phytoplankton bloom. Mysis mixta accumulated high levels of lipid reserves similar to those reached by other cold-water zooplankton. Greatest accumulation occurred in maturing females and males upon initiation of the spring bloom and continued for 6 months. The lowest TL level was similar to5% dry mass (DM) in small juveniles, post-spawned males, and spent females, and the highest level was 32% DM in females approaching full maturity (overall content range 0.3-16 mg.mysid(-1)). Most females accumulated lipid for 2 years before spawning, although a few females spawned 7 months early with a very low TL content. Seasonal variation in TL resulted primarily from net changes in triacylglycerol, the predominant neutral lipid. Seasonal and interannual variation in TL quantities in individuals and in areal concentrations of lipid in the hyperbenthic population indicates a strong trophic link between M. mixta and the pelagic production cycle.