INTERANNUAL VARIATIONS IN COPEPOD NAUPLII PREY OF LARVAL FISH IN AN ALASKAN BAY

Depth specific abundance of copepod nauplii was monitored during the spring months of 1986 through 1989 in Auke Bay, southeast Alaska, to describe interannual fluctuations in prey concentration for larval walleye pollock (Theragra chalcogramma) and flathead sole (Hippoglossoides elassodon). The major cohorts of first-feeding pollock larvae were present in April and May, while flathead sole larvae were common from mid-May to early June. The larvae of both species feed on copepod nauplii and previous studies showed 10-20 nauplii 1-1 adequate for feeding. In April of all four years most larvae coexisted with nauplii concentrations 10 to 15 C. By early May in 1986, 1988, and 1989 nauplii were frequently over 20 C, while in 1987 corresponding values were 10 to 151-1 Nauplii concentrations were never low enough to cause mass starvation of competent walleye pollock larvae, and in all years food intake of some cohorts should not have been prey limited. In all years the average prey concentrations were high enough for successful feeding by flathead sole. © 1991 Conseil International pour l'Exploration de la Mer.