INTERSPECIFIC DIFFERENCES IN THE DIEL VERTICAL MIGRATION OF MARINE COPEPODS - THE IMPLICATIONS OF SIZE, COLOR, AND MORPHOLOGY

Samples collected by continuous plankton recorders (CPRs) between 1948 and 1992 were used to describe the diel vertical migration (DVM) beha vior of 41 copepod taxa in the northeast Atlantic between 45 and 55 de grees N and 11 and 31 degrees W. A total of 13,622 samples, each repre senting similar to 18.5 km (10 nm) of tow, were analyzed. Since CPRs a re towed in near-surface waters, taxa that exhibit DVM occur predomina ntly in samples taken at night. Larger taxa showed significantly stron ger DVM, with body size explaining 47% of the intertaxa variation in D VM. For small taxa (<1 mm wide) the residual variation in DVM was corr elated with carotenoid pigment levels but not with body morphology, wi th more heavily pigmented taxa exhibiting DVM. For larger taxa (>1 mm wide) the residual variation in DVM was correlated with body morpholog y but not with carotenoid pigment levels, with more elongate copepods not exhibiting DVM.