Science Advisory Report 2017/005
Assessment of Northern Shrimp on the Eastern Scotian Shelf Shrimp Fishing Area (SFA)s 13-15)
- As of November 15, 2016, 3,026 mt of the 3,250 mt Total Allowable Catch (TAC) for 2016 had been landed.
- As predicted in recent assessments, the Eastern Scotian Shelf Shrimp stock has declined since 2014, as the 2007-2008 year-classes have now reached the end of their expected life span.
- The 2016 total biomass estimate declined 14% to 25,584 mt (± 5,079 mt, 95% Confidence Interval (CI)) from the 2015 estimate of 29,642 mt (± 7,324 mt, 95% CI).
- The 2016 Spawning Stock Biomass (SSB, females) point estimate declined 11% to 13,223 mt, and is now below the Upper Stock Reference (USR, 14,558 mt). Based on the precautionary approach as it is applied to Eastern Scotian Shelf Shrimp, this places the stock in the Cautious Zone.
- The 2016 TAC was reduced by 28% (from 4,500 mt in 2015 to 3,250 mt) to reflect declining fishable and spawning stock biomass resulting from the loss of the formerly abundant 2007-2008 year-classes. The precautionary TAC reduction helped to reduce both total and female exploitation to 12% and 16%, respectively.
- Belly-bag Age 1 abundance index values for 2015 and 2016 were the two lowest in the 15-year time-series, suggesting poor recruitment from the 2014 and 2015 year-classes.
- The abundance index for both Age 2 and Age 4 Shrimp decreased in 2016, which is consistent with the low belly-bag Age 1 abundance index values found in 2015 (i.e. 2014 year-class) and 2013 (i.e. 2012 year-class), respectively.
- The 2013 year-class increased the index of abundance for Age 3 male Shrimp to the second highest value in the time series in 2016.
- Ecosystem indicators, including sustained high bottom and sea surface temperatures and reductions in the abundance of sympatric species, suggest that conditions are currently unfavourable for coldwater species such as Shrimp.
- The overall mean summary indicator declined in 2016 and remains in the yellow zone due to declines in indicators representing abundance, productivity, and ecosystem characteristics.
- While Age 4+ males will increase in 2017, it is uncertain whether this will translate into an increase in the total biomass index in 2017. The 2013 year-class is not expected to recruit to the SSB until 2018. As a result, the SSB is not expected to begin to increase until 2018.
- Continuation of precautionary TAC reductions will help to maintain low exploitation rates and to protect more of the 2013 year-class until it can recruit to the SSB.
This Science Advisory Report is from the December 7, 2016, Stock Assessment of Eastern Scotian Shelf Shrimp in Shrimp Fishing Areas (SFAs) 13-15. 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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