Science Advisory Report 2017/049

Assessment of Greenland Halibut in the Gulf of St. Lawrence (4RST) in 2016

Summary

• Greenland Halibut landings reached 3,228 t (preliminary as of December 31) in 2016-2017 out of an allocation of 3,751 t. The fishing season will run until May 14, 2017.
• For the past 3 years, more than 83% of catches have been from the western Gulf. Landings are lower in Esquiman and negligible in northern Anticosti.
• Catch per unit effort (CPUE) from fishing is very high in the western Gulf, whereas it is lower in northern Anticosti and in Esquiman.
• In the gillnet directed fishery, bycatch estimated by at-sea observers represents on average 15% of the weight of the Greenland Halibut catch. Approximately one-third of these by-catches are landed.
• Size at sexual maturity decreased over the past two years to the lowest observed since 1990, 33 cm for males and 41 cm for females.
• Biomass indices from DFO research survey for fish over 40 cm decreased slightly in 2016 while the estimate for fish of 30 to 40 cm, pre-recruits to the fishery, has slightly increased. In both cases, the indices are comparable to the average of those series.
• The cohorts of 2012, 2013 and 2014 are very strong and will start recruiting to the fishery in 2018 while the 2015 cohort is very low. The growth of the 2013 and 2014 cohorts is slower than normal which could delay their recruitment to the fishery.
• Estimation the total biomass of Greenland Halibut by a preliminary population dynamics model (SCALE) shows a slight increase since 2013 and was at the highest value since 1990. The arrival of the cohorts 2012 and 2013 contributed to this increase.
• Deep water temperature increased in the Gulf of St. Lawrence and particularly in northern Anticosti and in Esquiman. For the last 4 or 5 years, fish were found on average at temperatures over 6°C, which is more than 1°C above the average between 1990 and 2015.
• Locally, in northern Anticosti and Esquiman, there is a decrease in catches, CPUE and biomass as well as an increase in bottom temperature, the situation is to be considered.
• The exploitable biomass of Greenland Halibut stock in 4RST has been high and stable since 2008. The landings of the past 10 years have helped to maintain a stable exploitation rate. The SCALE model projection indicates that exploitation biomass will remain stable, with an annual landing of 3,750 t for the next two seasons.

This Science Advisory Report is from the meeting of February 22, 2017 on the Assessment of Greenland Halibut in the Gulf of St. Lawrence (4RST). 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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