Science Advisory Report  2013/013

Assessment of Newfoundland and Labrador Snow Crab

Summary

• Total landings increased by 22 % from 44,000 t in 2005 to 53,500 t in 2009, and since declined marginally to 50,500 t in 2012, with an increase in the South (Div. 3LNOPs) and a decline in the North (Div. 2HJ3K).
• The multi-species trawl surveys indicate that the exploitable biomass declined from 2008 to 2011 and was unchanged in 2012.
• Recruitment has recently declined and is expected to decline further in the short term (2-3 years).
• Long-term recruitment prospects are unfavourable due to a recent warm oceanographic regime.

Divisions 2HJ

• Landings decreased by 37 % since 2008 to 1,600 t. Meanwhile effort increased by 55 % to 2011 before decreasing by 23 % in 2012. The TAC has not been taken in the past 2 years.
• CPUE most recently peaked in 2008, then declined steadily by half to 2011, and was unchanged in 2012. 
• The exploitable biomass, as indicated by the post-season trawl survey, declined steadily from 2006 to 2011 and was unchanged in 2012.
• Recruitment declined from 2006 to 2011, changed little in 2012, and is expected to remain low in the short term (2-3 years).  The post-season trawl survey pre-recruit index decreased sharply in 2005 and has since fluctuated without trend. 
• Long-term recruitment prospects are unfavourable due to a recent warm oceanographic regime.
• The exploitation rate index has increased steadily after 2007 to its highest level since 2004.
• The pre-recruit fishing mortality rate index has been at its highest level since 2004 during each of the past two years. The percentage of the catch handled and released in the fishery increased from about 10 % in 2008 to about 35 % in 2012 implying a potential increase in pre-recruit mortality.
• Maintaining the current level of fishery removals would likely result in little change in the exploitation rate in 2013 but would likely result in high mortality on soft-shelled immediate pre-recruits.

Division 3K Offshore

• Landings peaked at 12,600 t in 2009 but decreased by 52 % to 6,000 t in 2012. The TAC was not achieved in the past 3 years. Effort peaked in 2009 and has since declined by 31 %.
• CPUE declined by half from 2008 to 2011 and changed little in 2012.
• The exploitable biomass, as indicated by the post-season trap and trawl surveys, declined by more than half from 2008 to 2011 and was unchanged in 2012.
• Recruitment declined after 2008 and prospects remain poor in the short term (2‑3 years). Post-season pre-recruit biomass indices from both trap and trawl surveys have decreased by about 55 % after 2008. 
• Long-term recruitment prospects are unfavourable due to a recent warm oceanographic regime.
• The trawl survey-based exploitation rate index increased sharply from 2008 to 2010 and changed little in 2011 before decreasing in 2012.  
• The pre-recruit fishing mortality rate index increased from 2007 to 2011 but decreased in 2012. The percentage of the catch handled and released in the fishery increased from about 7 % in 2008 to about 20 % in 2012 implying a potential increase in pre-recruit mortality.
• Maintaining the current level of fishery removals would likely result in little change in the exploitation rate but would likely result in high mortality on soft-shelled immediate pre-recruits in 2013.

Division 3K Inshore

• Landings increased from 2,200 t in 2005 to 2,900 t in 2009, but decreased by 34 % to 1,900 t in 2012. The TAC was not taken in the past 4 years in two of the three management areas. Effort increased by 70 % from 2008 to 2011 before decreasing by 19 % in 2012.
• CPUE increased sharply from 2005 to a record high level in 2008, then declined by more than half before increasing slightly in 2012.
• The exploitable biomass, as indicated by the post-season trap survey, decreased from 2007 to 2009 and since changed little but there is considerable variability among management areas.
• While uncertain, recruitment prospects appear to have changed little and there is considerable variability among management areas.
• The trap survey-based exploitation rate index changed little between 2011 and 2012.
• Data are insufficient to estimate the pre-recruit fishing mortality rate index.
• Maintaining the current level of fishery removals would likely result in little change in the exploitation rate in 2013. However, it would likely result in high mortality on soft-shelled immediate pre-recruits in some management areas in 2013.

Divisions 3LNO Offshore

• Landings decreased by 11 % from 24,500 t in 2006 to 21,900 t in 2009 but since increased by 20 % to 26,200 t in 2012.  Effort increased by 80 % from 2000 to 2008 and has since declined by 23 %.
• VMS-based CPUE declined to its lowest level in 2008, but has since increased steadily to above the average of the series.
• The trawl survey index of exploitable biomass declined from 2009 to 2011 and changed little in 2012. The index from the trap survey, which tends to capture older-shelled crabs relatively better than new-shelled crabs in this area, peaked two years later in 2011 and changed little in 2012.
• Recruitment has recently peaked and will likely decrease in the short term (2-3 years).
• Long-term recruitment prospects are unfavourable due to a recent warm oceanographic regime.
• The exploitation rate index increased during the past two years following a sharp decrease from 2008 to 2010. 
• The pre-recruit fishing mortality rate index decreased from 2008 to 2011 but increased in 2012. The percentage of the catch handled and released in the fishery decreased from about 20 % in 2008 to 12 % in 2012, implying a potential decrease in pre-recruit mortality.
• Maintaining the current level of fishery removals would likely result in little change in the exploitation rate in 2013.

Division 3L Inshore

• Landings increased by 19 % from 6,100 t in 2005 to 7,300 t in 2010, and have since changed little, at 7,400 t in 2012. Effort increased by 24 % from 2008 to 2010 but has since declined by 22 %.
• CPUE increased sharply in 2012 to its highest level since 1995, after varying about the long term average for the previous 5 years.
• The post-season trap survey index suggests that the exploitable biomass increased in 2012 to its highest level in the time series.
• Recruitment has recently peaked and is in decline, although there is considerable variability among management areas.  Short-term (2-3 years) prospects are uncertain. 
• The trap survey-based exploitation rate index changed little in 2012 but there was considerable variability among management areas.
• Data are insufficient to estimate a pre-recruit fishing mortality rate index.
• Maintaining the current level of fishery removals would likely result in a decrease in the exploitation rate in 2013.

Subdivision 3Ps Offshore

• Landings almost doubled from 2,300 t in 2006 to a peak of 4,300 t in 2011, before decreasing by 14 % to 3,700 t in 2012.  Effort increased by 57 % from 2008 to 2011 before decreasing slightly in 2012.
• CPUE increased from 2005 to 2009 and has gradually declined since.
• The exploitable biomass, as indicated by both the spring trawl survey and the post-season trap survey indices, increased steadily from 2006 to 2009 before declining sharply from 2009 to 2011 and changed little in 2012.
• Recruitment has recently declined and is expected to decline further in the short term (2-3 years). Pre-recruit biomass indices from both trap and trawl surveys declined sharply from 2009 to 2011 and changed little in 2012.
• Long-term recruitment prospects are unfavourable due to a recent warm oceanographic regime.
• Exploitation and pre-recruit fishing mortality rates, as indicated by spring trawl survey indices, decreased from 2007 to 2009 but increased sharply to 2011 and changed little in 2012.
• Maintaining the current level of fishery removals would likely result in little change in the exploitation rate in 2013.

Subdivision 3Ps Inshore

• Landings peaked at 3,500 t in 1999, declined to 700 t in 2005, then more than tripled to 2,500 t in 2012. Effort declined from 2005 to 2010 and increased by 36 % to 2012.
• CPUE increased steadily from 2005 to 2010, its highest level since 1996, and has since changed little.
• The exploitable biomass, as indicated by the post-season trap survey index, increased substantially between 2006 and 2010 and has since changed little.
• Recruitment has recently decreased. The index of pre-recruit-sized males has recently decreased, suggesting a further decline in recruitment in the short term (2-3 years).
• The post-season trap survey-based exploitation rate index changed little during 2008 to 2011 but increased in 2012.
• Data are insufficient to estimate a pre-recruit fishing mortality rate index.
• Maintaining the current level of fishery removals would likely result in little change in the exploitation rate in 2013.

Division 4R Offshore

• Landings declined by 83 % from 190 t in 2007 to a historical low of 30 t in 2010, but increased back to 190 t in 2012.  Effort increased by a factor of four in 2011 following the historical low in 2010 and changed little in 2012. The TAC has not been taken since 2002.
• VMS-based CPUE declined from 2004 to its lowest level in 2009 before increasing to the average of the series in 2012.
• The exploitable biomass remains low relative to other areas. 
• Recruitment prospects are uncertain in the short term (2-3 years).
• Long term recruitment prospects are unfavourable due to a recent warm oceanographic regime.
• Data are insufficient to calculate the exploitation rate and pre-recruit fishing mortality rate indices.
• The effect of maintaining the current level of removals on the exploitation rate in 2013 is unknown.

Division 4R Inshore

• Landings declined by 80 % from 950 t in 2003 to a historical low of 190 t in 2010. They more than doubled to 450 t in 2011 and increased further to 550 t in 2012. Effort declined by 95 % from 2004 to 2010 and doubled in 2011 before decreasing substantially in 2012. The TAC has not been taken since 2002.
• CPUE declined by more than half from 2002 to 2007 and changed little to 2010 before more than doubling to 2012.
• The exploitable biomass, as indicated by the post-season trap survey, fluctuated at a low level from 2006 to 2010 but tripled in 2011 and changed little in 2012.
• Recruitment has recently increased and is expected to remain strong in 2013, but short-term (2-3 years) prospects are unfavourable.
• The post-season trap survey-based exploitation rate index decreased sharply in 2012.
• Data are insufficient to estimate a pre-recruit fishing mortality rate index.
• Maintaining the current level of fishery removals would likely result in little change in the exploitation rate in 2013.

This Science Advisory Report is from the February 27–March 6, 2013 regional peer review process on the assessment of Snow Crab. Additional publications from this process will be posted as they become available on the DFO Science Advisory Schedule.

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