Science Advisory Report  2009/010

Assessment of the cod stock in the northern gulf of St. Lawrence (3Pn,4RS) in 2008

Summary

• The 2008/2009 total allowable catch (TAC) was 7,000 tonnes (t). Preliminary landings available as of January 2009 totalled 6,183 .
• The recreational fishery landings in 2008 were estimated to be 67 t in 3Pn, 4R. There was no recreational catch estimate in 4S.
• Sentinel catch rates for both longlines and gillnets peaked in 2006. These indicators of biomass and abundance have declined over the past two years but remain above average.
• The DFO research vessel (RV) survey and the mobile gear sentinel survey abundance indices increased from 2007 to 2008 to about average values observed since the moratorium, but DFO survey indices were substantially below the values in the early 1990s.
• The DFO survey indicates that the abundance of age classes that support the fisheries have remained at about the same level since 2004, and slightly above the levels observed during the moratorium.
• DFO RV and sentinel survey estimates of fish at age 2 (2006 year-class) are the highest since the 1990s and this year-class appears widespread in 4R and 4S. However, it will not contribute to the fishery before 2011 and 2012.
• Growth, condition, and maturity-at-age and size declined in the late 1980s to reach their lowest levels in the early 1990s. Growth (of fish 6 years and younger) and condition have returned to levels observed in the 1980s.
• Surplus production was positive from 1974 to 1988 but has remained marginal thereafter. Current levels of total mortality and reproductive rates impede increase in population size.
• Majority of harvesters reported a decline in catch rates in 2007 and 2008, but they still feel the stock is in better condition than is indicated by the assessment.
• Total mortality of fish of age 4 and older remains high (54% annual).
• The exploitation rate estimated by the sequential population analysis (SPA) has increased since 2004 to reach 30% in 2008.
• Estimates of exploitation rates from tagging studies were 40% in 2007 and 21% in 2008.
• The limit reference point (LRP) for this stock has been recalculated, using new maturity data, as 140,000 t spawning stock biomass (SSB). The rationale is that, below this level, recruitment is substantially impaired.
• SSB is estimated at 32,000 t at the beginning of 2009, well below the LRP. To be consistent with the precautionary approach, management should have fishing mortality at the lowest possible level. This requires no directed fishery and measures to reduce by-catch of cod in other fisheries.
• Over the past decade, each time fishery catches exceeded 5,000 to 6,000 t, most indicators of total stock status suggested declines in mature biomass (spawning stock biomass). Hence, catches above that level do not seem sustainable at stock productivity over the past decade.
• If the management goal is to ensure continued growth in SSB then projections indicate that the catch should be less than 9,000 t in 2009. This catch implies an exploitation rate of 39% for fish of ages 7 and older, well above medium term sustainable levels.
• At status quo catch the SSB will increase by 10%. The catch at status quo fishing mortality is 7,000 t.
• With no fishery removals in 2009 and assuming current productivity and natural mortality (M), the spawning stock biomass would increase by 30% by 2010
• Fisheries in 2009 and beyond should be managed to protect the relatively strong 2006 year-class until those fish mature.

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