Early life history of capelin ( Mallotus villosus ) in the northwest Gulf of Alaska: a historical perspective based on larval collections, October 1977–March 1979

Abstract

Analyses of ichthyoplankton samples collected in the vicinity of Kodiak Island, Alaska, during the period October 1977–March 1979 provide new information on the spawning strategy and early life history of capelin in the Gulf of Alaska. Seasonal variation in abundance, length, and distribution of capelin larvae indicates that capelin populations in this area in 1978 spawned inshore during summer and autumn, and that spawning activity peaked during June–July. Distribution patterns of capelin larvae suggest that, subsequent to hatching and emergence into the plankton, larvae are transported from the bays and coastal zone around Kodiak Island into adjacent shelf waters, probably by tidal flushing and wind-induced surface currents. Mixing processes on the shelf seawards of Kodiak Island, reflecting variable current patterns there, are likely to enhance the dispersal of larvae as indicated by the uniformity observed among distribution patterns of several length categories. A comparison of larval abundance and length between bongo and neuston samples suggests that capelin larvae >30 mm standard length actively migrate to the surface layer. The observations represent a picture of capelin early life history during a period of abundance of adult capelin that has been linked to a cold phase in the oceanographic environment of the Gulf of Alaska.