Sex ratio and reproductive activity of benthic copepods in bathyal Sagami Bay (1430 m), central Japan

Sex ratios and reproductive activity of benthic copepod assemblages were investigated at the bathyal site (depth 1430 m) in Sagami Bay, central Japan. The ratio of adult females to adult males was approximately 3.5:1, significantly different from 1:1, although this parameter did not show a seasonal pattern. On the other hand, the percentage of ovigerous females among adult females and the ratio of nauplii to total copepods appeared to fluctuate seasonally in 1997 and 1998. Statistical tests, however, could not detect significant difference in either parameter. We discuss the possibility that the reproductive activity of copepods was enhanced by the increased supply of fresh phytodetritus to the sea floor.