Science Advisory Report  2012/003

Assessment of snow crab in the southern Gulf of St. Lawrence (Areas 12, 19, 12E and 12F) and advice for the 2012 fishery

Summary

• Snow crab in fishing areas 12, 19, 12E, and 12F comprise a single biological population and the southern Gulf of St. Lawrence stock is considered as one unit for assessment purposes.
• The landings of snow crab from the southern Gulf of St. Lawrence in 2011 were 10,708 t from a quota of 10,677 t.
• The assessment in 2011 was conducted as per the recommendations of the Snow Crab Assessment Methods Framework Science Review held during November 21 to 25, 2011, in Moncton, N.B. The major changes to the assessment methodology were the expansion of the biomass estimation polygon (20 to 200 fathoms) to better cover the southern Gulf of St. Lawrence biological unit and the use of catches in weights directly to estimate biomass.
• The changes in methodology required a recalculation of the time series of biomass estimates for 1997 to 2010, exploitation rates, and the Precautionary Approach reference points.
• The exploitation rate of the 2011 fishery in the southern Gulf of St. Lawrence was 29.9%.
• The 2011 post-fishery survey biomass of commercial-sized adult male crabs was estimated at 63,162 t (95% C. I. 55,965 to 71,022 t), an increase of 76% from 2010. The available biomass for the 2012 fishery, derived from the 2011 survey, is within the healthy zone of the Precautionary Approach framework.
• The residual biomass (33,768 t) from the 2011 survey increased by 119% compared to 2010.
• Forty seven percent (47%) of the 2011 survey biomass, available for the 2012 fishery, is composed of new recruitment (29,394 t). The recruitment to the fishery in 2011 increased (44%) relative to the 2010 survey.
• An increasing trend in recruitment of commercial-sized adult male crab to the fishery is anticipated into the 2014 fishery.
• A risk analysis of catch options relative to reference points for the 2012 fishery is provided.

Fishery performance in 2011 by snow crab fishing area

Area 12:

• The 2011 landings in Area 12 were 8,618 t (quota of 8,585 t).
• The CPUE (expressed as kg per trap haul (kg/th)) in 2011 (53.0 kg/th) increased compared to 2010 (47.9 kg/th).
• The incidence of soft-shelled crab remained low at 6.2%, but 233 of 323 grids were closed towards the end of the fishing season in 2011.

Area 19:

• The 2011 landings in Area 19 were 1,701 t (quota of 1,703 t).
• The CPUE in 2011 (133.3 kg/th) increased compared to 2010 (122.1 kg/th) and represents the highest value observed since records began in 1987.
• The incidence of white-crab increased from 6.4% in 2010 to 11.5% in 2011 and no sectors within Area 19 were closed during the fishing season.

Area 12E:

• In Area 12E, the landings were 76 t (quota of 75 t).
• The CPUE in 2011 (31.5 kg/th) increased compared to 2010 (27.4 kg/th).
• The incidence of soft-shelled crab in 2011 decreased to 8.4%, compared to 14.7% in 2010. No grids were closed during the fishing season.

Area 12F:

• The 2011 landings in Area 12F were 313 t (quota of 314 t).
• The CPUE in 2011 (32.5 kg/th) increased compared to 2010 (29.3 kg/th).
• The incidence of soft-shelled crab decreased from 8.6% in 2010 to 2.6% in 2011. No sectors within Area 12F were closed during the fishing season.

This Science Advisory Report is from the Fisheries and Oceans Canada, Canadian Science Advisory Secretariat, regional advisory meeting of February 7-8, 2012 on the assessment of the status of the southern Gulf of St. Lawrence snow crab stock. Additional publications from this process will be posted as they become available on the DFO Science Advisory Schedule.

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