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) behavior of 41 copepod taxa in the northeast Atlantic between 45 and 55?N and 11 and 31?W. A total of 13,622 samples, each representing - 18.5 km (10 nm) of tow, were analyzed. Since CPRs are towed in near-surface waters, taxa that exhibit DVM occur predominantly in samples taken at night. Larger taxa showed significantly stronger DVM, with body size explaining 47% of the intertaxa variation in DVM. For small taxa (< 1 mm wide) the residual variation in DVM was correlated with carotenoid pigment levels but not with body morphology, with more heavily pigmented taxa exhibiting DVM. For larger taxa (> 1 mm wide) the residual variation in DVM was correlated with body morphology but not with carotenoid pigment levels, with more elongate copepods not exhibiting DVM.