Research Document 1997/30

Assessment of the NAFO Division 4T Atlantic herring stock, 1996

By R.R. Claytor, C. LeBlanc, A. Sinclair, G. Poirier, L. Paulin

Abstract

The updated fall spawner F_0.1 fishing level for 1997 based on this assessment of the 1996 fishery is 49,186 tonnes. There is little change in the advice from last year's analysis of the 1995 fishery when the F_0.1 fishing level for 1997 was 48,540 tonnes. The 4+ biomass for fall spawners declined from 287,000 t in 1995 to 232,000 t in 1996, and 5+ biomass declined from 269,000 t in 1995 to 194,000 t in 1996. Fishing mortality on the fully recruited age (5 year olds) was 0.39 in 1996 exceeding the target of 0.30, weighted 4+ fishing mortality was 0.27, just below the expected weighted 4+ fishing mortality for 1996 of 0.28. Two below average year-classes are predominant in the fishery at this time, age 5s from the 1991 year-class and age 7 from the 1989 year-class. The incoming four year olds from the 1992 year-class appear to be average.

The updated spring spawner F_0.1 fishing level for 1997 based on this assessment of the 1996 fishery is 16,573 tonnes. This level is about 1,000 t higher than the F0.1 fishing level for 1997, 15,477 t, determined from last year's analysis of the 1995 fishery. The 4+ biomass for spring spawners declined from 112,000 tonnes in 1995 to 80,000 tonnes in 1996, while the 5+ biomass increased from 74,000 tonnes in 1995 to 77,000 tonnes in 1996. Fishing mortalities in 1996 were 0.44 for the fully recruited age (5 year olds) and 0.34 for weighted 4+. These levels were similar to the target of 0.44 for fully recruited ages and above the 0.3 target for weighted 4+. The 1990 and 1992 year-classes in the fishery at the present time are below average but the incoming four year olds appear to be above average.

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