Research Document - 2000/085

Population Status of Eastern Georges Bank Cod (Unit Areas 5Zj,m) for 1978-2000.

By J.J. Hunt and B. Hatt

Abstract

An analytical assessment of the Georges Bank cod stock in 5Zj,m was completed using updated catch-at-age and research survey indices. Results of the assessment provided statistically significant parameter estimates for the 2000 beginning-of-year population at ages 2 through 8. Bias and precision for the estimates were within acceptable limits. The adult biomass increased between 1995 and 1999 to about 18,600 t, primarily due to survival and growth of the 1992 and 1995 year-classes, but decreased slightly to 18,200 t in 2000. Exploitation decreased from more than 60% in the early 1990’s to slightly above the F_0.1 = 16% reference level in 1995 to 1997. It decreased further in 1998 to 15%, or slightly below the F_0.1 reference level and was 10% in 2000. Recruitment in recent years has been poor, with the 1992 and 1995 year-classes being only moderately stronger than adjacent year-classes. Estimates for the 1996 year-class at age one were somewhat higher than previous estimates. The 1997 and 1998 year-classes appear to be very weak. Projections for 2000 indicate a yield of about 3,700 t at the F_0.1 reference level. However, the stock biomass in 2001 will decline at this level of yield. Only at 2000 yields of 1,500 t or less is there a 50% or better chance of stable or increasing biomass. The stock biomass remains below a threshold of 25,000 t, above which chances of good recruitment are improved.

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