Research Document - 2003/096

Population Status of Eastern Georges Bank Cod (Unit Areas 5Zj,m) for 1978-2004

By Hunt, J.J., Hatt, B. and O'Brien, L.

Abstract

An analytical assessment of the Georges Bank cod stock in 5Zj,m was completed using updated catch-at-age for ages 1-10 and research survey indices for ages 2-8. A benchmark ADAPT formulation, based on TRAC recommendations, was used to characterize the population. Results of the assessment provided statistically significant parameter estimates for the 2003 beginning-of-year population at ages 2 through 10. Bias and precision for the estimates were within acceptable limits. The adult biomass (3+) increased from the low of 8,700t in 1995 to about 18,500t at the beginning of 2001, primarily due to survival and growth of the 1995, 1996, and 1998 year-classes. Since 2001, adult biomass has declined to 16,000t at the beginning of 2002 and 13,300t at the beginning of 2003. Exploitation rate on ages 4-6 decreased from more than 50% in the mid-1990's to about the F0.1 level (F=0.18, 15% exploitation rate) in 1995 but has since been slightly higher, ranging between 16%-28%. A change in partial recruitment to the fishery has occurred since 1994 with reduced catchability on ages 5+. This change is due to the bycatch nature of the Canadian fishery and to management measures that reduced spatial and temporal access to the resource for both the Canadian and USA fisheries. Recruitment in recent years has been poor, with the 1996 and 1998 year-classes above the recent average. With an expected 2,800t total catch in 2003, projections for 2004 indicate a yield of about 1,300 t at F0.1 and stable stock biomass between 2003 and 2005. The adult stock biomass remains below a threshold of 25,000 t, above which chances of good recruitment are improved.

With the current poor recruitment and exploitation rates near the present levels, improvement in stock status is not expected in the near term.

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