Research Document 1997/108

Assessment of 4X haddock in 1996 and the first half of 1997

By P.C.F. Hurley, G.A.P. Black, R. Mohn, P. Comeau

Abstract

Landings of 4X haddock in 1996 were 5,690t against a TAC of 6,500t. Mean length in both mobile and fixed gear landings decreased substantially in 1996 and remained about the same in the first half of 1997. Revised age data were available for commercial samples using new ageing criteria and these have resulted in a change in the view of exploitation levels through the 1980s and early 1990s. Results of a resource abundance survey conducted by the ITQ fleet in cooperation with DFO Science for the third year in 1997 compare well with the research vessel survey results and indicate that abundance is high in the inshore area off southwest Nova Scotia not covered by the research vessel. The 1993 and 1994 year-classes are both strong and have resulted in an increase in spawning stock biomass from a low of 19,000t in 1994 to 41,000t in 1997. There is a significant retrospective effect between early observations of large year-classes and subsequent estimates, even at age 4. If the estimates of the 1993 and 1994 year-classes are adjusted to account for this effect, then the F0.1 yield in 1998 will be 11,500t if only the 1994 year-class is adjusted and 9,500t if both year-classes are adjusted.

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