Science Advisory Report  2010/020

Assessment of Newfoundland and Labrador Snow Crab

Summary

• Total landings increased by 22% since 2005 to 53,500 t in 2009.
• The multi-species trawl surveys indicate that the overall exploitable biomass has recently increased due to recovery in the south (Div. 3LNOPs) while the north (Div. 2HJ3K) has decreased.
• Recruitment has recently increased overall due to recovery in the south.
• Longer-term recruitment prospects are uncertain.

Division 2H

• Landings declined by 53% from 190 t in 2007 to 90 t in 2009, while effort decreased by 24%.
• The exploitable biomass has decreased in recent years. The post-season trawl survey exploitable biomass index doubled between 2004 and 2006, but decreased by 66% to 2008. There was no trawl survey in 2009.
• Recruitment has decreased since 2004 and is expected to be low over the next several years.
• The effect of maintaining the current level of fishery removals on the exploitation rate in 2010 is unknown.

Division 2J

• Landings increased by 60% from 2005-2008.  They remained unchanged in 2009, while effort increased by 27%.
• CPUE increased from 2004-2008 to the long-term average, but decreased in 2009.
• The exploitable biomass has decreased in recent years.  The post-season trawl survey exploitable biomass index peaked in 2006 and has since declined steadily.
• Recruitment has recently declined and is expected to remain low for 2010. It is expected to change little in the short term following 2010.  The post-season trawl survey pre-recruit index decreased sharply in 2005 and has since fluctuated without trend
• The exploitation rate index and the pre-recruit fishing mortality index both declined sharply from 2003-2005.  While the pre-recruit index has remained low since that time, the exploitation rate index continued to decline to 2007 before increasing to 2009.
• Maintaining the current level of fishery removals while biomass is declining will result in an increase in the exploitation rate in 2010.

Division 3K Offshore

• After decreasing sharply to 6,000 t in 2005, landings more than doubled to 13,000 t in 2009.  Meanwhile effort declined sharply in 2005 and changed little until it increased by 70% in 2009.  Landings and effort have returned to pre-2005 levels.
• CPUE increased sharply from 2005 to a record high level in 2008, and then decreased sharply in 2009.
• The exploitable biomass decreased substantially since 2007. Post-season exploitable biomass indices from both trap and trawl surveys increased in 2006 and to 2007, respectively. Both indices then remained at high levels until they decreased abruptly in 2009.
• Recruitment decreased in 2009 as reflected by the abrupt decrease in the post-season exploitable biomass while landings increased little. It is expected to be further reduced for 2010, but longer term prospects remain uncertain.
• The trawl survey exploitation rate index increased slightly in 2009 following a decline since 2006. The pre-recruit fishing mortality index decreased sharply in 2006 and changed little until it more than doubled in 2009.
• 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 2010.

Division 3K Inshore

• Landings increased by 33% from 2,700 t in 2005 to 3,600 t in 2009. Effort declined from 2004 to 2008 and increased by 42% in 2009.
• CPUE increased sharply from 2005 to a record high level in 2008 but decreased in 2009.
• The exploitable biomass decreased in 2009.  The collaborative fall trap survey exploitable biomass index changed little during 2004-2008 before decreasing substantially in 2009.
• Recruitment decreased in 2009 as reflected by the substantial decrease in the post-season exploitable biomass while landings increased little.  It is expected to decrease further in 2010 and longer term prospects are uncertain.
• The trap survey-based exploitation rate index changed little since 2005. Data are insufficient to estimate pre-recruit mortality rates.
• Maintaining the current level of fishery removals would likely increase the exploitation rate in 2010.

3LNO Offshore

• Landings remained at 22,000-25,000 t since 2000. Effort increased steadily from 2000-2007 and changed little since.
• CPUE declined steadily from 2000-2008, to the lowest level since 1991, and was unchanged in 2009.
• The exploitable biomass has recently increased. The exploitable biomass index from the trawl survey declined steadily from 2001-2007 but has since more than doubled. The trap survey index declined steadily from 2004-2008 but increased in 2009.
• Both post-season surveys indicate that recruitment has been increasing and is expected to increase further over the next two to three years.
• Both the exploitation rate index and the pre-recruit fishing mortality rate index peaked in 2008 but decreased in 2009. The latter index was at its lowest level in 2009.
• Increased removals would not likely increase the exploitation rate in 2010.

3L Inshore

• Landings increased by 15% from 6100 t in 2005 to 7,000 t in 2009.  Effort decreased by 23% from 2005-2008, but increased by 11% in 2009.
• CPUE increased by 53% from 2004 to 2008 before decreasing slightly in 2009.
• The post-season trap survey index indicates the exploitable biomass has declined gradually since 2006.
• Overall, recruitment prospects have recently improved, but there is considerable spatial variability.
• The trap survey-based exploitation rate index changed little from 2005-2007 but has since increased.  Data are insufficient to estimate pre-recruit mortality rates.
• 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 areas in 2010.

Subdivision 3Ps Offshore

• Landings increased by 57% from 2,300 t in 2006 to 3,600 t in 2009.  Effort decreased by 26% in 2008 to its lowest level since 2001 and was unchanged in 2009.
• CPUE has increased by 72% since 2007 and is approaching the long-term average.
• The exploitable biomass has recently increased.  The pre-season trawl survey exploitable biomass index increased since 2007 while the post season trap survey index more than doubled since 2004.
• Recruitment has recently increased as reflected by an increase in biomass while landings increased.  Recruitment prospects remain promising for the short-term following 2010. Since 2005, the pre-season trawl survey pre-recruit index has steadily increased while the post-season trap survey index has varied without trend.
• Exploitation and pre-recruit mortality rate indices based on trap and trawl surveys have both decreased since 2007. The pre-recruit index is at its lowest level since 1996.
• Fishery removals could likely be marginally increased in 2010 without increasing the exploitation rate.

Subdivision 3Ps Inshore

• Landings more than doubled from 700 t in 2005 to 1,900 t in 2009 while effort declined slightly.
• CPUE more than doubled since 2005 to exceed the long-term average.
• The exploitable biomass appears to have peaked. The post-season trap survey exploitable biomass index increased substantially from 2006-2008 but decreased slightly in 2009.
• Recruitment has decreased for 2010 but longer-term prospects remain promising. The post-season trap survey pre-recruit biomass index peaked in 2007 and has since decreased to remain above the 2004-2006 level
• The post-season trap survey-based exploitation rate index fluctuated without trend during 2005-2009.  Data are insufficient to estimate pre-recruit fishing mortality rates.
• Maintaining the current level of fishery removals would likely result in a slight increase in the exploitation rate in 2010.

Division 4R Offshore

• Landings and effort have been variable in recent years after reaching historical lows in 2006.  The TAC has not been achieved since 2002.
• CPUE has remained below the long-term average since 2003.
• The exploitable biomass is low as reflected by poor fishery performance since 2004.
• Recruitment has been low in recent years.  Longer-term recruitment prospects are unknown.
• The effect of maintaining the current level of fishery removals on the exploitation rate is unknown.

Division 4R Inshore

• Landings and effort have steadily declined since 2004, to historical lows in 2009.  The TAC has not been achieved since 2002.
• CPUE has steadily declined since 2002 to its lowest level in 2009.
• Post-season trap survey catch rates show that the exploitable biomass has remained low since 2005.
• Recruitment is expected to remain low for 2010. It is expected to increase in the short term following 2010, but there is considerable spatial variability. 
• Maintaining the current level of fishery removals would have an unknown effect on the exploitation rate but may increase mortality on soft-shelled immediate pre-recruits in some areas in 2010.

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