Science Advisory Report 2022/053

Assessment of the Green Sea Urchin Stocks in the Estuary and Northern Gulf of St. Lawrence in 2021

Summary

• Annual landings of green sea urchins in Quebec were sporadic and generally low (<  200 t) until 2005. They have remained above 415 t since 2006, except in 2009 (341 t), and peaked at 762 t in 2007 and 2016. Although landings have been reported for Areas 3, 7, 10, 11, 12 and 14 since 1991, they have been intermittent or small. Since 2007, among those areas only area 11 had average landings of 33.4 t from 2016 to 2020. Since 2004, nearly 98% of Quebec’s cumulative landings have come from Areas 8 and 9, with the largest proportion from subarea 9-1. Area 9 is the only green sea urchin harvesting area in Quebec that has commercial fishery status.

North Shore

Area 9

• From 2017 to 2021, average annual landings totalled 315.1 t and came almost exclusively from Batture aux Alouettes in subarea 9-1. Since 2018, the daily catch limit has dropped from 6,000 kg to 4,200 kg in subarea 9-1, which partly explains the 26.9% decrease in average landings relative to the 2012-2016 period (431.2 t).
• The total number of authorized fishing days (80 boat-days) for subarea 9-1 has been used every year since this measure first came into effect in 2010, except in 2020 (61 boat-days) due to the pandemic. The average fishing effort in diver-hours (dh) for the 2017-2021 period (967.0 dh) is comparable to what it was in 2012-2016 (977.8 dh).
• The annual CPUE decreased between 2017 and 2019 and has been relatively stable since then. The average CPUE for the 2017-2021 period (324.1 kg/dh) was 15.6% lower than that of the 2004-2016 historical series (384.1 kg/dh).
• The average size of landed sea urchins appears to have been stable since 2010 and ranges from 59 to 62 mm. The proportion of sublegal-sized sea urchins (< 50 mm) in landings is less than 5% on average.
• The results of the surveys conducted by DFO (2008 and 2010) and the Agence Mamu Innu Kaikusseth (AMIK 2016) indicate an increase in the biomass density of legal- and sublegal-sized sea urchins in 2016 relative to 2008 and 2010 in the area fished. A modal value of around 20 to 30 mm in diameter is seen in 2008, 2010 and 2016, indicating that recruitment to the fishery could continue. AMIK’s 2019 survey suggests some stability in the density of legal-sized sea urchins relative to 2016 for the entire Batture aux Alouettes.
• For Area 9 (subarea 9-1), keeping removals near the average level for 2017-2021 should not have a major impact on sea urchin abundance over the next three seasons.

Area 11

• Annual landings averaged 40.0 t from 2016 to 2019, for an average effort of 188.5 dh (26 boat-days). These are the highest landings since the start of the fishery. In 2020, only 6.7 t of sea urchins were landed, representing an effort of 5 boat-days over the 60-day fishing period. The 2021 data were not available at time of the assessment.
• The mean CPUE from 2017 to 2020 (211.9 kg/dh) is comparable to that of the 2002-2016 historical series (205.9 kg/dh).
• There has been a lack of size structure data since fishing started in the area.
• The lack of information prevents us from commenting on the status of the resource in Area 11.

Lower St. Lawrence and Gaspé Peninsula

Area 8

• Fishing has historically been conducted at the eastern tip of Île Verte (subarea 8D) and, since 2008, on the southeast side of the eastern tip of Île aux Lièvres and Batture de l’Île Blanche (subarea 8E). An annual TAC of 110.7 t has been in effect in subarea 8E since 2017.
• In subarea 8D, the fishing and landings data for the period prior to 2018 are unreliable or incomplete. From 2018 to 2021, landings averaged 103.3 t, for an average effort of 36 boat-days and a mean CPUE of 353.8 kg/dh. The average landed size appears to have been stable since 2012 and is between 59 and 62 mm. The proportion of sublegal-sized sea urchins in landings is less than 2% on average.
• In subarea 8E, annual landings averaged 105.7 t for the 2017-2021 period, which equals 95.5% of the TAC. The average effort in dh decreased by 4.1% relative to the 2012-2016 period, whereas the average effort in boat-days was comparable. The mean CPUE from 2017 to 2021 (148.5 kg/dh) remains below the historical average for 2003-2016 (234.7 kg/dh), but has been increasing since the historical low in 2019. The average size of landed sea urchins has varied from year to year, but there is no clear trend. The proportion of sublegal-sized sea urchins in landings is less than 2% on average.
• The survey conducted in 2021 by the Wolastoqiyik Wahsipekuk First Nation in subarea 8E showed an average density of legal-sized sea urchins of 2.5 individuals/m2 and 0.25 kg/m². The size distribution ranges from 15 to 94 mm in diameter, with an average of 46.1 mm. Sixty-two percent of individuals were sublegal-sized.
• For Area 8 (subareas 8D and E), keeping removals near the average level for 2017-2021 should not have a major impact on sea urchin abundance over the next three seasons.

This Science Advisory Report is from the regional peer review on June 15-16, 2022 on Assessment of the Green Sea Urchin stocks in the Northern Estuary and Gulf of St. Lawrence in 2022. Additional publications from this meeting will be posted on the Fisheries and Oceans Canada (DFO) Science Advisory Schedule as they become available.

Science Advisory Report 2022/053 (PDF, 1517 KB)

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