Science Advisory Report  2013/014

Stock Assessment of Northern (2J3KL) Cod in 2013

Summary

• Reported landings in 2012 were 3,305 t. This included 2,991 t in the stewardship fishery, 272 t in the sentinel survey, and 41 t taken as by-catch. Estimates of recreational landings are not provided for 2012; therefore total catch in 2012 is unknown.
• There is evidence from tagging data that the removals by the recreational fishery are substantial (>50 % of the stewardship fishery landings) in recent years. In addition, sampling of the recreational fishery at sea and on land demonstrates that there is widespread discarding of small fish.
• Accurate catch information is needed to fully evaluate the impact of all removals on stock status.
• Inshore catch rate indices from the Sentinel survey differ among northern, central, and southern areas.
• In the northern area catch rates had been low, but increased substantially in 2012.
• In the central area catch rates remained high, but show no trend during 2008-2012.
• In the southern area catch rates have been at an intermediate level and do not show a trend in recent years.
• Catch rates from fish harvesters’ log-books show trends similar to those in the sentinel survey, except log-books show an increasing trend in the central area over the 2011 and 2012 period.
• The DFO autumn research vessel survey indices increased more than threefold during 2003‑2008 and 2009, but this increasing trend has not continued in the most recent years.
• The spring research vessel survey index for Div. 3L is more variable than the autumn index for Div. 2J3KL but is generally consistent in terms of trends.
• The research vessel surveys in 2012 show an expansion of fish into southern Div. 2J and northern Div. 3K and continuing low abundance in central and southern Div. 3L.
• Based on a cohort analysis of the autumn research vessel survey data (SURBA; SURvey BAsed model), the spawning stock biomass (SSB) has increased from 1 % of the Limit Reference Point (LRP) in 2005 to 15 % of the LRP in 2012.
• SURBA estimates of total mortality were low (<20 %) during 2005-2007, increased to 55 % in 2009 then declined to 26 % in 2012.
• SURBA estimates of recent recruitment show improvement (2005-2009 year-classes); however, recruitment is still much lower than was observed in the 1980s.
• A spring acoustic survey of spawning cod in the Bonavista Corridor (offshore Div. 3KL border) conducted by the Centre for Fisheries Ecosystems Research at Memorial University gave an estimate of spawning biomass of 131,000 t. This is considered a partial estimate because not all of the spawning aggregation was surveyed.
• SURBA projections to 2016 were conducted assuming a range of total mortality rates. SSB in 2016 increases to 21 % of the LRP assuming mortality is 20 % lower than recent levels. SSB remains relatively stable if mortality remains at recent levels. SSB biomass decreases to 10 % of the LRP assuming a 20 % increase in mortality.
• Tagging estimates of mean exploitation rates during 2010‑2012 were low and ranged between 2 % and 6 % for all landings combined.
• Estimates of current exploitation rates show that fishery removals are a minor component of total mortality rates and have had little impact on recent stock dynamics. However, in keeping with the DFO fishery decision-making framework incorporating the precautionary approach, removals over the next four years should remain low to promote stock growth.

This Science Advisory Report is from the March 11-14th, 2013 Stock assessment of Northern (2J3KL) Cod. Additional publications from this meeting will be posted on the Fisheries and Oceans Canada (DFO) Science Advisory Schedule as they become available.

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