Science Advisory Report  2014/037

Assessment of Newfoundland and Labrador Snow Crab

Summary

• Total landings have remained at 50,000–53,000 t since 2007. However, Div. 3LNO has accounted for a steadily increasing percentage in recent years, from about half in 2009 to two-thirds in the past two years.
• The overall exploitable biomass has changed little since the mid-2000’s. However, both the trap and trawl surveys indicate that Div. 3LNO has accounted for an increased percentage in recent years, from about 40% in 2008 to 75% in 2013.
• Overall, recruitment is expected to decline in the short term (2-3 years).
• A recent warm oceanographic regime suggests weak recruitment in the long term.

• Landings decreased by 45% since 2008, to 1,380 t. The TAC has not been taken in the past 3 years.
• Catch per unit effort (CPUE) declined steadily by half from 2008 to 2011, was unchanged in 2012, and increased in 2013.
• The exploitable biomass, as indicated by the post-season trawl survey, declined steadily from 2006 to 2011 and has changed little since.
• Recruitment declined from 2006 to 2011 and changed little since; prospects are uncertain in the short term (2-3 years). The post-season trawl survey pre-recruit index has changed little since 2005.
• A recent warm oceanographic regime suggests weak recruitment in the long term.
• The exploitation rate index increased steadily from 2007 to 2012 before decreasing in 2013.
• The pre-recruit fishing mortality rate index was at its highest level since 2004 during 2011 and 2012 but decreased by more than half in 2013. The percentage of the catch handled and released in the fishery decreased from 35% in 2012 to 20% in 2013, implying a decrease in pre-recruit mortality.
• Maintaining the current level of fishery removals would likely have little effect on the exploitation rate in 2014.

• Landings most recently peaked at 13,300 t in 2009 but declined by 51% to 6,500 t in 2012 before increasing to 6,600 t in 2013. Effort most recently peaked in 2009 and has since declined by 33%.
• CPUE declined by half from 2008 to 2011 and increased slightly since 2012.
• The exploitable biomass, as indicated by the post-season trap and trawl surveys, declined by more than two thirds since 2008.
• 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 70% since 2008.
• A recent warm oceanographic regime suggests weak recruitment in the long term.
• The trawl survey-based exploitation rate index was at its highest level since 2004 in 2010-2011. It decreased in 2012 before increasing again in 2013.
• The pre-recruit fishing mortality rate index increased from 2007 to 2011 but decreased in 2012 before increasing again in 2013. The percentage of the catch handled and released in the fishery decreased from about 20% in 2012 to about 10% in 2013, implying a decrease in pre-recruit mortality.
• Maintaining the current level of fishery removals would likely result in an increase in the exploitation rate in 2014.

• Landings declined by 34% from 2,900 t in 2009 to 1,900 t in 2012 and 2013. Effort increased by 70% from 2008 to 2011 before declining by 40% to 2013.
• CPUE declined by more than half from 2008 to 2011, and increased over the past two years.
• The exploitable biomass, as indicated by the post-season trap survey, decreased from 2007 to 2009 and has since fluctuated.
• Recruitment prospects are poor in the short term (2-3 years). The post-season trap survey pre-recruit biomass index decreased by more than half in 2013, to its lowest level in the time series.
• The post-season trap survey-based exploitation rate index has changed little throughout the time series.
• 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 2014.

• Landings decreased by 11% from 24,500 t in 2006 to 21,900 t in 2009 and then increased by 20% to 26,300 t in 2013. Effort increased by 83% from 2000 to 2008 and has since declined by 32%.
• VMS-based CPUE declined to its lowest level in 2008, and has since increased steadily to its highest level in the time series.
• The indices of exploitable biomass from post-season trap and trawl surveys diverged during 2009 to 2011 with the trap index increasing and the trawl index declining. However both indices have since increased slightly.
• Biological data from several sources indicate that recruitment will likely decrease in the short term.
• A recent warm oceanographic regime suggests weak recruitment in the long term.
• The exploitation rate index decreased marginally in 2013.
• The pre-recruit fishing mortality rate index decreased from 2008 to 2011, increased in 2012 and changed little in 2013. The percentage of the catch handled and released in the fishery decreased from about 20% in 2008 to 9% in 2013, implying a decrease in pre-recruit mortality.
• Maintaining the current level of fishery removals would likely result in little change in the exploitation rate in 2014.

• Landings increased by 19% from 6,100 t in 2005 to 7,300 t in 2010, and have since changed little, at 7,600 t in 2013. Effort increased from 2008 to 2010 and has since declined steadily.
• CPUE increased sharply since 2011 to its highest level.
• The post-season trap survey index suggests that the exploitable biomass increased steadily since 2008 to its highest level in the time series, with considerable variability among management areas.
• Recruitment has declined slightly since 2010, although there is considerable variability among management areas, and is expected to decline further in the short-term (2-3 years). The post-season trap survey pre-recruit biomass index decreased in 2013.
• The post-season trap survey-based exploitation rate index has changed little over the time series, with 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 little change in the exploitation rate in 2014.

• Landings almost doubled from 2,300 t in 2006 to a peak of 4,200 t in 2011, before declining by 16% to 3,500 t in 2013. Effort increased by 76% from 2008 to a record high level in 2013.
• CPUEincreased from 2005 to 2009 and has steadily declined since, to about its previous lowest level.
• 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 rapidly to its lowest level in 2013.
• 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 rapidly from 2009 to their lowest levels in 2013.
• A recent warm oceanographic regime suggests weak recruitment in the long term.
• The spring trawl survey-based exploitation rate index more than doubled from 2009-2012, before doubling again in 2013.
• The pre-recruit fishing mortality rate index has increased steadily since 2009 to about its previous highest level.
• Maintaining the current level of fishery removals would increase the exploitation rate in 2014.

• Landings more than tripled from 700 t in 2005 to 2,500 t in 2011 and remained at that level since. Effort declined substantially in 2005 and has since varied without trend.
• CPUEincreased steadily from 2005 to 2010, changed little in 2011–2012, then decreased slightly in 2013.
• The exploitable biomass, as indicated by the post-season trap survey index, increased substantially between 2006 and 2010, changed little in 2011-2012, then decreased by half in 2013.
• Recruitment decreased substantially in 2013 and is expected to remain low in the short term (2-3 years). The pre-recruit biomass has been declining since 2007.
• The post-season trap survey-based exploitation rate index has changed little in the past six years.
• Data are insufficient to estimate a pre-recruit fishing mortality rate index.
• Maintaining the current level of fishery removals would increase the exploitation rate in 2014.

• Landings declined by 83% from 190 t in 2007 to a historical low of 30 t in 2010, and increased to 300 t in 2013. Effort increased by almost a factor of 7 since 2010. The TAC has not been taken since 2002.
• VMS-based CPUE declined from 2004 to its lowest level in 2009 before increasing to its highest value in the time series in 2013.
• The exploitable biomass remains low relative to other areas.
• Recruitment prospects are uncertain in the short term (2-3 years).
• A recent warm oceanographic regime suggests weak recruitment in the long term.
• 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 2014 is unknown.

• Landings declined by 80% from 930 t in 2003 to a historical low of 160 t in 2010 and have since more than tripled to 600 t in 2013. Effort declined by 69% from 2004 to 2010 and doubled in 2011 before declining by 34% to 2013. The TAC has not been taken since 2002.
• CPUE increased sharply since 2010 to a record high level in 2013.
• The exploitable biomass, as indicated by the post-season trap survey index, fluctuated from 2006 to 2010, was three times as large in 2011, and changed little in 2012 before decreasing in 2013.
• Recruitment prospects are unfavourable in the short term (2-3 years). The trap survey pre-recruit biomass index more than doubled in 2009 and changed little until it decreased substantially to remain below pre-2009 level during 2012-2013.
• The post-season trap survey-based exploitation rate index decreased in 2012 and changed little in 2013.
• Data are insufficient to estimate a pre-recruit fishing mortality rate index.
• Maintaining the current level of fishery removals would increase the exploitation rate in 2014.

This Science Advisory Report is from the February 18-20, 2014 regional peer review process on Newfoundland and Labrador Snow Crab Assessment. 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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