Research Document - 1999/077
Population status of eastern Gorges Bank cod (Unit areas 5Zj,m) for 1978-99.
By J.J. Hunt and T.L. Johnson
Abstract
An analytical assessment of the Georges Bank cod stock in 5Zj,m was completed using updated catch-at-age for 1978-98 and research survey indices. Results of the assessment provided statistically significant parameter estimates for the 1999 beginning-of-year population at ages 1 through 8. Bias and precision for the estimates were within acceptable limits. The adult biomass increased between 1995 and 1998 to about 19,200 t, primarily due to survival and growth of the 1992 and 1995 year-classes. Exploitation decreased from more than 60% in the early 1990's to slightly above the F0.1 = 16% reference level in 1995 to 1997. It decreased further in 1998 to 15%, or slightly below the F0.1 reference level. Recruitment in recent years has been poor, with the 1992 and 1995 year-classes being only moderately stronger than adjacent year-classes. The 1997 and 1998 year-classes appear to be very weak. Projections for 1999 indicate a yield of about 3,700 t at the F0.1 reference level. However, the stock biomass in 2000 may decline at this level of yield. The stock biomass remains below a threshold of 25,000 t, above which chances of good recruitment are improved.
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