Distribution and abundance of demersal juvenile cod (Gadus morhua) on the northeast Newfoundland Shelf and the Grand Banks (divisions 2J3KLNOP) : implications for stock identity and monitoring / G.R.... : Fs70-1/2000-092E-PDF

The distributions of juvenile cod in Divisions 2J3KLNO in the autumns of 1995-1998 and in Divisions 3LNOP in the springs of 1996-1998 (plus 1999 for Subdivision 3Ps only) were inferred from catches during resource assessment bottom-trawl surveys. Since autumn 1995 these surveys have been conducted with the Campelen 1800 shrimp trawl, which is far more effective at catching small cod than the Engel 145 Hi-rise trawl that it replaced. In 2J3KL, there was an ontogenetic change from a mainly coastal distribution at ages 0 and 1 to a more mid- and outer shelf distribution by ages 3 and 4. Of those year-classes observed with the autumn surveys, only the 1994 year-class was broadly distributed across the shelf, including much of 2J, by age 1. Subsequent year classes were distributed almost entirely inshore at age 1, and moved with increasing age onto the northeast Newfoundland Shelf in 3K and northern 3L, and to a much lesser extent into 2J. In 3P, age 1 cod were distributed mainly toward the coast and on western St. Pierre Bank, age 2 cod were more broadly distributed across the Division, and older fish were concentrated in the northwest and the southeast. The only distinct offshore aggregation of cod of ages 0 and 1 was seen on the plateau of Grant Bank in 3NO. The ontogenetic changes in distribution complicate the interpretation of stock structure and the monitoring of recruitment.

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