Abundance and distribution of pelagic 0-group cod (Gadus morhua) in Newfoundland waters: inshore versus offshore

Abstract

The Northern cod stock has previously been described as undergoing a large-scale denatant–contranatant migration during which spawning occurs primarily in the north off Labrador. Eggs and larvae are advected southward to the inshore areas along the NE coast of Newfoundland where they settle as juveniles, then there is a gradual return migration to the northern spawning areas. We examined abundance distributions of pelagic juvenile (0-group) cod in the fall between inshore and offshore areas to determine if these fish occurred predominantly inshore following pelagic drift. Comparison between areas demonstrated no differences in abundances and mean sizes. Our results do not support the concept of large-scale advection of eggs and larvae spawned offshore to inshore areas, but indicate that cod eggs spawned offshore remain offshore. Back calculations of spawning times indicate the pelagic juvenile cod sampled offshore were spawned predominantly in April, whereas fish caught inshore were spawned predominantly in May-June, as well as April. Estimates of spawning abundance indicate that the inshore areas along the NE coast of Newfoundland may represent <10% of eggs spawned annually. Historically, the offshore area appears to have been the primary habitat for pelagic juvenile cod.