Science Advisory Report 2011/041
Stock Assessment of Northern (2J3KL) cod in 2011
- Total catch in 2010 is uncertain. Accurate catch information is needed to evaluate the impact of fishery removals on the stock status.
- Reported landings in 2010 were 2,902 t. This included 2,649 t in the stewardship fishery, 209 t in the sentinel surveys, and 44 t taken as by-catch, but excludes recreational fishery removals.
- There are no direct estimates of recreational landings for 2010. However, analysis of tag returns suggests that removals of commercial size fish from recreational fisheries during 2010 were 56% of the stewardship fishery removals. In addition, there was evidence of widespread discarding of small fish in the recreational fishery in 2009 and 2010.
- Based on a cohort analysis of the DFO autumn RV survey data, the recent increasing trends in total biomass and spawning stock biomass (SSB) have not continued. Total biomass increased during 2004 to 2009 but was unchanged in 2010. SSB increased from 2004 to 2008, but has since been unchanged.
- Total mortality declined substantially during 2003-05 and remained low to 2007 (< 20%). This has been an important factor in the recent increase in total biomass and SSB. However, total mortality has increased to approximately 40% in 2009 and 2010, and if this level of total mortality continues, prospects for further stock growth are diminished.
- The exploitation rate of offshore cod in the inshore based on tag returns was low and ranged between 3% and 6% during 2008-10.
- Recruitment has shown marginal improvement (2005 to 2007 year-classes); however, recruitment is still much lower than was observed in the 1980s.
- Sentinel catch rates in the northern area did not increase in 2010 and were near the 1995-2010 northern area average. Catches in this area depend on seasonal immigration of fishfrom offshore regions, including 2J where offshore biomass remains low. Sentinel and commercial catch rates are lower in the northern area than those in the central area.
- Sentinel catch rates in the central area did not increase in 2010 but remained above the 1995-2010 central area average. Catches in this area depend on resident inshore components and seasonal migrants from the offshore.
- Sentinel catch rates in the southern area declined in 2010 and were below the 1995-2010 southern area average. Catches in this area are partly dependent on seasonal immigration of fish from the offshore of 3KL, and from 3Ps where the stock has declined.
- During 2008-10, mean exploitation rates from tagging studies were low and ranged between 3% and 10% among inshore central and southern areas.
- Recent year-classes in the inshore have been poor relative to the 2000-02 year-classes.
- A conservation LRP has been established for Northern cod. Estimated SSB has been well below the LRP since the early 1990s. The estimate of 2010 SSB is 90% below the LRP.
- Current levels of removals have resulted in low exploitation rates and probably have had little impact on recent stock dynamics.
- At current levels of stock productivity (growth rates, recruitment, survival) the stock will not reach the LRP within the next five years.
- The application of the DFO fishery decision-making framework incorporating the precautionary approach would require catches in 2011 to be at the lowest possible level.
This Science Advisory Report has resulted from a Fisheries and Oceans Canada, Canadian Science Advisory Secretariat, Regional Advisory Meeting of March 22-23rd, 2011 on the Stock Assessment of Northern (2J3KL) Cod. Additional publications from this process will be posted as they become available on the DFO Canadian Science Advisory Secretariat website.
This document is available in PDF format. If the document is not accessible to you, please contact the Secretariat to obtain another appropriate format, such as regular print, large print, Braille or audio version.
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