SEASONAL LIPID DYNAMICS IN DOMINANT ANTARCTIC COPEPODS - ENERGY FOR OVERWINTERING OR REPRODUCTION

Copepodite stages V and females of four dominant Antarctic species of calanoid copepods were collected during various expeditions to the eas tern Weddell Sea in mid-winter, late winter to early spring, summer an d autumn. Analyses of total lipid content and sexual maturity showed s ome general similarities between species concerning the seasonal cycle of energy reserves and gonad maturation, but also revealed important interspecific differences in the life histories of these copepods, Cal anus propinquus and Metridia gerlachei exhibited a seasonal lipid patt ern with maxima in autumn and lipid minima during spring. Lipid decrea se in the females usually coincided with gonad maturation, which proce eded well before the onset of phytoplankton production. This basic pat tern was not as clearly discernible in the females of Calanoides acutu s and Rhincalanus gigas. In the Weddell Sea, C. propinquus and C. acut us reached much higher lipid levels and seemed to rely more on interna l energy depots than did M. gerlachei and R. gigas. The specific timin g of reproduction in the Weddell Sea also differed among the species. M. gerlachei had the longest reproductive period, probably extending f rom September to March, followed by C. propinquus (October-February) a nd C. acutus (November-March). In contrast, R. gigas seemed to reprodu ce only from late December to February in the eastern Weddell Sea. Our findings emphasize the importance of lipid reserves for fueling repro ductive processes before the spring phytoplankton bloom becomes availa ble. Only a smaller portion of the accumulated energy stores appears t o be utilized for metabolic maintenance during the food-limited winter period. Copyright (C) 1996 Elsevier Science Ltd.