Science Advisory Report  2012/008

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 changed little, at 53,000 t in 2011, with an increase in the South (Div 3LNOPs) and a decline in the North (2J3K).
• The multi-species trawl surveys indicate that the exploitable biomass has declined since 2009.
• Recruitment has recently declined and is expected to decline further in the short term.
• Long-term recruitment prospects are unfavourable due to a warming oceanographic regime.

Division 2H

• Landings declined by 95% from 190 t in 2007 to 10 t in 2011. The TAC has not been taken for three consecutive years.
• Fishery data are very limited. However, CPUE has declined steadily since 2006.
• The exploitable biomass is very low. The post-season trawl survey exploitable biomass index decreased by 94% since the 2006 peak.
• Recruitment has decreased since 2004 and is expected to be low over the next several years. There were no pre-recruit males captured in the 2010 or 2011 post-season trawl surveys.
• Long-term recruitment prospects are poor. There have been no small (<60mm carapace width) males captured in the post-season trawl surveys since 2001.

Division 2J

• Landings decreased by 21% since 2008 to 1,900 t while effort increased by 52%.
• CPUE most recently peaked in 2008 and has since decreased by half.
• The exploitable biomass has decreased in recent years. The post-season trawl survey exploitable biomass index peaked in 2006 and has since decreased by half.
• Recruitment has recently been in decline and is expected to remain low in the short term. 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 warming oceanographic regime.
• The exploitation rate index changed little in the past three years. The pre-recruit fishing mortality rate index has remained low in recent years, but increased to its highest level since 2004 during 2011.
• Maintaining the current level of fishery removals would likely increase the exploitation rate in 2012.

Division 3K Offshore

• Landings peaked at 12,600 t in 2009 but decreased by 35% to 8,200 t in 2011. The TAC was not achieved in the past 2 years. Effort changed little until it increased by 71% in 2009 before decreasing by 15% in 2010 and increasing marginally in 2011.
• CPUE has declined sharply since 2008.
• The exploitable biomass, as indicated by the post-season trap and trawl survey indices, declined by more than half since 2008.
• Recruitment decreased in 2011 and is expected to decrease further in 2012. Prospects remain poor in the short term. Post-season pre-recruit biomass indices from both trap and trawl surveys have decreased by about 40% since 2008.
• Long-term recruitment prospects are unfavourable due to a warming oceanographic regime.
• The trawl survey-based exploitation rate index declined sharply between 2006 and 2008 and has since increased back to the 2006 level. The pre-recruit fishing mortality rate index increased from 2007-2011.
• Maintaining the current level of fishery removals would likely result in an increase in the exploitation rate and high mortality on soft-shelled immediate pre-recruits in 2012.

Division 3K Inshore

• Landings increased from 2,700 t in 2005 to 3,600 t in 2009, but decreased by 31% to 2,500 t in 2011. The TAC was not taken in 3 of the 5 management areas in 2011. Effort has increased by 64% since 2008.
• CPUE increased sharply from 2005 to a record high level in 2008, but has since declined by more than half.
• The exploitable biomass, as indicated by the post-season trap survey index, decreased gradually between 2007 and 2010 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 increased sharply in 2010 and then returned to the 2007–2009 level in 2011. Data are insufficient to estimate the pre-recruit fishing mortality rate index.
• Maintaining the current level of removals would likely have little effect on the exploitation rate in 2012. However, it would likely result in increased wastage of soft-shelled immediate pre-recruits in some management areas in 2012.

Division 3LNO Offshore

• Landings decreased from 24,500t in 2007 to 22,000t in 2009 but since increased to 26,000t. Effort increased slightly in 2011 following a 2008-2010 decrease.
• VMS-based CPUE declined to its lowest level in 2008, but has since increased to the long-term average.
• Opposing survey trends create uncertainty about the exploitable biomass. The trawl survey index decreased by 34% since 2009 while the trap survey index increased by 21%.
• Recruitment has recently peaked and will likely decrease over the short term.
• Long-term recruitment prospects are unfavourable due to a warming oceanographic regime.
• The exploitation rate index increased in 2011 following a sharp decrease from 2008-2010 while the pre-recruit fishing mortality rate index has remained near its lowest level during the past three years.
• Maintaining the current level of removals would have an uncertain effect on the exploitation rate in 2012.

Division 3L Inshore

• Landings increased by 19% from 6,100 t in 2005 to 7,300 t in 2010 and decreased slightly to 7,100 t in 2011. Effort increased by 24% from 2008-2010 but decreased slightly in 2011.
• CPUE has remained at the long-term average for the past three years.
• The post-season trap survey index suggests that the exploitable biomass has changed little over the past 6 years.
• Overall, recruitment prospects have recently improved.
• The trap survey-based exploitation rate index decreased slightly in 2011. 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, but may increase mortality on soft-shelled immediate pre-recruits in some management areas in 2012.

Subdivision 3Ps Offshore

• Landings almost doubled from 2,300 t in 2006 to 4,300 t in 2011. Meanwhile, effort increased by 56 % since 2008.
• CPUE increased from 2005-2009 and has since declined slightly.
• The exploitable biomass, as indicated by both the spring trawl survey and the post-season trap survey indices, increased steadily from 2006-2009 and has since declined sharply to 2011.
• Recruitment has recently declined and is expected to decline further in the short term. Post-season pre-recruit biomass indices from both trap and trawl surveys declined sharply from 2009-2011.
• Long-term recruitment prospects are unfavourable due to a warming oceanographic regime.
• Exploitation and pre-recruit fishing mortality rates, as indicated by spring trawl survey indices, decreased from 2007-2009 but increased sharply to 2011.
• Maintaining the current level of fishery removals would likely result in an increase in the exploitation rate in 2012.

Subdivision 3Ps Inshore

• Landings more than tripled from 700 t in 2005 to 2,500 t in 2011. Meanwhile, effort declined from 2005-2010 and increased by 22% in 2011.
• CPUE increased steadily from 2005 to its highest level since 1996 in 2010 and decreased marginally in 2011.
• The exploitable biomass, as indicated by the post-season trap survey index, increased substantially between 2006 and 2010 and decreased in 2011.
• Recruitment decreased in 2011 and is expected to decrease further in the short term.
• The post-season trap survey-based exploitation rate index changed little during 2008-2011. Data are insufficient to estimate a pre-recruit fishing mortality rate index.
• Maintaining the current level of fishery removals would likely result in an increase in the exploitation rate in 2012.

Division 4R Offshore

• Landings declined by 83% from 190 t in 2007 to a historical low of 30 t in 2010, but increased to 150 t in 2011. Effort increased by a factor of four in 2011 following the historical low in 2010. The TAC has not been taken since 2002.
• CPUE declined from 2004 to a historical low in 2009, increased sharply in 2010, and fell to the 2009 level again in 2011.
• The exploitable biomass remains low.
• Recruitment has been low in recent years and prospects are uncertain.
• Data are insufficient to calculate exploitation rate and pre-recruit fishing mortality rate indices.
• The effect of maintaining the current level of removals on the exploitation rate in 2012 is unknown.

Division 4R Inshore

• Landings declined sharply by 80% from 950 t in 2003 to a historical low of 190 t in 2010 and increased to 450 t in 2011. Effort declined by 95% from 2004 to 2010 and doubled in 2011. The TAC has not been taken since 2003.
• CPUE declined from 2002-2007 and has since varied without trend below the long-term average.
• The post-season trap survey exploitable biomass index changed little from 2005-2009 but has increased greatly in the past two years.
• Recruitment has recently increased and short-term prospects remain promising in most management areas.
• The post-season trap survey-based exploitation rate index decreased from 2007-2010 but increased sharply in 2011. Data are insufficient to estimate a pre-recruit fishing mortality rate index.
• Increasing fishery removals in 2012 would likely have little effect on the exploitation rate but may increase mortality on soft-shelled immediate pre-recruits in some management areas.

This Science Advisory Report is from the February 21 – 24, 2012 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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