Research Document - 1999/036

An Assessment of the Cod Stock in NAFO Subdivision 3Ps.

By J. Brattey, N.G. Cadigan, G.R. Lilly, E.F. Murphy, P.A. Shelton, and D.E. Stansbury

Abstract

This document summarizes scientific information used to determine the status of the cod stock in NAFO Subdivision 3Ps off the south coast of Newfoundland on 1 January 1999 and evaluates alternative TAC options for 1999. Primary sources of information were: a time series of abundance and biomass indices from Canadian (1978-1998) and French (1980-1991) winter/spring research vessel bottom-trawl surveys, reported landings from commercial fisheries including a 20,000 t fishery in 1998, a second fall industry trawl survey on St. Pierre Bank, inshore sentinel surveys (1995-1998), acoustic surveys in Placentia Bay and adjacent areas, data from recent mark-recapture experiments and genetic studies, and information from graduate student research projects. Sequential population analyses were carried out using combined inshore fixed gear and offshore fixed and mobile gear catches calibrated with French and Canadian research vessel survey data. The latter was divided into two time periods (February-March and April) and these treated as two separate indices. Survey catches from a known stock mixing area (Burgeo Bank -Hermitage Channel) were removed from the February-March series. The current population biomass is estimated to be 250,000 t and has increased substantially since the moratorium. Spawner biomass is currently estimated to be 145,000 t. Recent increases are largely due to the high survival and maturation of the strong 1989 and 1990 year classes combined with a reduction in the age at maturity. The 1992 year class also appears to be strong. A risk analyses showed that the probability of the spawner biomass falling below an arbitrary reference point of 100,000 t was 9% with a catch of 20,000 t in 1999. The probability of exceeding an average fishing mortality reference level of 0.25 over ages 7-14 in 1999 at this catch level was estimated to be 5%.

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