Science Advisory Report 2012/029
Assessment of Scallops (Placopecten magellanicus) in Scallop Fishing Area (SFA) 29 West of Longitude 65°30'W
- This scallop fishery has taken place in the portion of Scallop Fishing Area (SFA) 29 west of longitude 65°30′ W since 2001 and is currently conducted by two fleets: the Full Bay Fleet and a limited number of inshore East of Baccaro licence holders.
- As of 2010, the TAC and landings are reported as totals by subarea for both fleets combined. In 2010, a total of 198.2 t was landed against the Total Allowable Catch (TAC) of 200 t. In 2011, a total of 194.1 t was landed against the TAC of 200 t.
- The fishery in subareas A and E has been sporadic over time, and commercial catch rates in these areas have generally decreased since 2009. In subarea B, commercial catch rates for both the Full Bay and East of Baccaro fleets declined from 2009 to 2010 by 30%. From 2010 to 2011, catch rates increased by 12% for the Full Bay fleet; however, catch rates decreased by 6% for the East of Baccaro fleet. In subarea C, from 2009 to 2011, catch rates decrease by 32% and 21% for the Full Bay and East of Baccaro fleets, respectively. Catch rates in subarea D declined by 16% for both fleets between 2009 and 2011.
- All survey abundance indices show a general declining trend since the fishery began in 2001 (2004 in subarea D). Recruitment is presently low in all subareas.
- Somatic growth rates between the 2010 and 2011 surveys were lower than predicted in all subareas and were at or below zero in subareas C and D.
- Two methods were used to estimate exploitation rates in SFA 29 West: one from commercial catch rates (depletion model approach), representing more localized conditions, and one from the research survey (biomass dynamics model approach), which represents broader conditions. Trends in annual total fishing effort were also presented since effort is directly related to fishing mortality. Results from all three time series were generally consistent. Levels of exploitation in 2011 appeared to result in the removal of all surplus production and possibly caused biomass declines in subareas B and D.
- Advice on expected impacts for the 2012 fishery was based on exploitation levels relative to the harvest strategy in 2011. This is a status quo exploitation strategy, and catch would have to be reduced to allow for population biomass growth. Given current levels of recruitment and observed growth rates, a biomass increase for 2012 may not occur even if the fishery were closed.
- In subarea A, exploitation rates from the research survey and annual total fishing effort indicate increasing exploitation in 2010 and 2011. Landings of 18.1 t in 2012 are expected to result in no change in exploitation levels compared to 2011.
- In subarea B, the effort series and survey model estimates indicate that exploitation increased in 2010 and 2011; whereas, the depletion model showed a sharp increase in exploitation in 2010 and a decrease in 2011. Landings of 59.3 t in 2012 are expected to result in a modest decrease in exploitation.
- In subarea C, both the effort and depletion series indicates that there has been a slight decline in exploitation in 2010 and 2011; whereas, the survey series shows an increase from 2010 to 2011. Landings of 45.5 t in 2012 are expected to result in a modest decrease in exploitation.
- In subarea D, the effort series indicates that there has been a slight decline in exploitation in 2010 and 2011, the survey series shows an increase from 2010 to 2011, and the depletion series shows very little change from 2010 to 2011. Landings of 68.9 t are expected to result in a large increase in exploitation. A reduction in landings to 48 t is expected to keep the effort and exploitation in 2012 the same as in 2011.
- Discards of lobster by the SFA 29 West scallop fishery in 2011 were estimated at less than 0.1% of the weight of lobsters landed by the Lobster Fishing Area 34 lobster fleet in 2010/2011 in the area corresponding to SFA 29 West. All lobsters caught in the scallop fishery were released back into the water, the majority of which were estimated to be alive and uninjured.
This Science Advisory Report is from the March 26, 2012, Assessment of SFA 29 West of 65°30’ Scallop. Additional publications from this process will be posted as they become available on the DFO Science Advisory Schedule at www.dfo-mpo.gc.ca/csas-sccs/index-eng.htm.
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