Science Advisory Report  2012/077

Stock Assessment of NAFO Subdivision 3Ps Thorny Skate

Summary

• Thorny Skate in NAFO Subdivision 3Ps and adjacent Divisions 3LNO are considered to constitute a single stock.
• Life history characteristics of Thorny Skate result in low intrinsic rates of population growth; thereby leading to low resilience to fishing mortality.
• In Subdivision 3Ps, total reported landings averaged 1,308 t from 1994-2009. Landings during 2010 and 2011 averaged 808 t.
• The Canadian research survey abundance index for Subdivision 3Ps was relatively stable from 1993-2012, while the survey biomass index indicated a gradually increasing trend.
• In adjacent NAFO Divisions 3LNO, Canadian research survey indices declined rapidly until the early 1990s.  Similar to Subdivision 3Ps, the Canadian Divisions 3LNO survey abundance indices were relatively stable in 1993-2012, while the survey biomass indices have generally been increasing.
• The pre-recruitment index has been above average (1996-2011) for the past three years. However, it is unclear how the pre-recruitment index relates to spawning stock recruitment.
• The exploitation rate for Thorny Skate in Subdivision 3Ps is unknown; therefore, there is no scientific basis with which to recommend a particular TAC.

This Science Advisory Report has resulted from a Fisheries and Oceans Canada, Canadian Science Advisory Secretariat, Regional Advisory Meeting held on Oct. 9, 2012 regarding the stock assessment of Subdiv. 3Ps Thorny Skate.  Additional publications from this process will be posted as they become available on the DFO Science Advisory Secretariat website.

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