Production of fish larvae and their prey in subarctic southeastern Hudson Bay

Abstract

In the ice-covered southeastern Hudson Bay (northern QuCbec, Canada), marine fish exhibited 2 distinct reproduction strategies. Sand lance Amrnodytes sp. and Arctic cod Boreogadus saida produced large numbers of small larvae that hatched before the ice break-up when the abundance of prey (copepod eggs and nauplii) was low. Feeding incidence was low and the larvae fed on relatively small prey. A morphometric index of condition suggested that the 2 species suffered from starvation at first feeding. This critical period was approximately synchronized with peak abundance of prey, possibly an adaptation to minimize starvation mortality. Shchaeidae and Cottidae produced small numbers of large larvae that fed efficiently on relatively large prey before yolk resorption. These larvae emerged after the ice break-up, when phytoplankton production was well under way and prey were abundant. Interannual variations in the timing between first feeding and the production of prey could influence recruitment in sand lance and Arctic cod but are unlikely to affect the early survival of Stichaeidae and Cottidae.