Inter-Research
Marine Ecology Progress Series

ABSTRACT: The pelagic copepod Pseudocalanus elongatus Boeck was bred 3 times from nauplius stages I and II to maturity at 5, 10, 15 and 20*C and at 4 different rations of autotrophic and heterotrophic food. The rate of development of the copepods increased with increasing temperature and food supply. The shortest generation times (from egg to adult) were 59 d at 5*C and 19 d at 15*C. The generation time nearly doubled when food concentration was very low. At 20*C mortality rates were high and development did not proceed faster than at 15*C. At all food levels the stage duration was generally constant (nearly isochronal), but the last 1 or 2 developmental stages took longer. The relationship between development time and temperature is described by Belehrádek's functions at different food levels. This relationship predicts a generation time of approximately 45 d during spring bloom conditions in the North Sea and about 30 d during summer due to food limitation. Field estimates from the literature are too scarce to evaluate the presumption of food limitation during summer conditions. Some evidence of a low critical food level was found compared to other North Sea copepod species. Together with a fast development rate at low temperatures, this may explain the numerical dominance of P. elongatus in the North Sea and the northeast Atlantic Ocean.

KEY WORDS: Pseudocalanus . Copepods . Cultivation . Development . Temperature . Food

Published in MEPS Vol. 119 (1995) on March 23
Print ISSN: 0171-8630; Online ISSN: 1616-1599. Copyright © Inter-Research, Oldendorf/Luhe, 1995