Science Advisory Report 2019/031

Assessment of the Îles-de-la-Madeleine Atlantic Surfclam stock in 2018

Summary

• The Atlantic Surfclam fishery in the Îles-de-la-Madeleine is conducted with hydraulic dredges in sub-areas 5A1 and 5B1 or using hand tools, on foot or while diving, in about 10 shellfish areas located in lagoons or near coasts.

Hydraulic dredge fishery

• Three beds were delineated in 5A1 and 5B1. The CGE and East beds are located in 5A1 and the North bed straddles sub-areas 5A1 and 5B1. Since 2009, harvesting has been focused on the North bed, whose known area is gradually increasing.
• Since 2013, the total allowable catches (TACs) have been reached in 5A1 (125 t) and 5B1 (113 t) and fishing effort is stable. The average size of landed clams has been over 130 mm for several years. The proportion of this bed dredged annually has ranged from 4.5% to 6.7% since 2010.
• Since 2002, fishing effort is sporadic and low in sub-areas 5A2 and 5B2; the clam stock status is therefore unknown in these two sub-areas.
• Yields and size structures in recent years have been stable on the North bed and the area dredged remains around 6%. Based on existing information, current landing levels could be maintained in sub-areas 5A1 and 5B1.
• The lack of information on recruitment for all beds is a source of uncertainty about the stock status.

Hand digging

• Commercial and recreational hand digging by divers and shore harvesters is well-developed in the Îles-de-la-Madeleine. However, the extent of manual recreational harvesting is not well known.
• Reported commercial hand digging landings vary with fishing effort. The averages for the last three years are 160 days and 42 t by diving and 113 days and 9 t for shore harvesters.
• Unreported hand harvesting is about 60 t per year, mainly for recreational harvesting.
• In one of the main exploited areas, A-12.1, the dive harvesting CPUE has been stable since 2016 and is at the 2005–2017 mean. The CPUE in A-09.5 has been fluctuating around its mean since 2014. Since 2008, the average size of landed clams has generally been around 131 mm in the sampled areas.
• The shore harvesting CPUE varies from area to area. In A-09.5, it is rather stable and was near the 2005–2017 mean in 2017 and 2018. The average size of surf clams landed is small compared with that of surf clams harvested by other methods. The average size over the last three years ranged from 111 mm to 120 mm, depending on the area.
• Based on this information, hand harvesting could be maintained at the current level. Any measures that will help better document hand digging are desirable.

This Science Advisory Report is from the February 28, 2019 Stock assessment of Atlantic Surfclam of the Magdalen Islands. 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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