Science Advisory Report 2016/022
Stock Assessment of Atlantic Surfclam of the Îles-de-la-Madeleine in 2015
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 sectors 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, all harvesting has been focused on the North bed, whose known area continues to grow as a result of exploration towards the north. There is no information on recruitment for any of these beds.
- Since 2002, there has been no dredge fishery in sub-area 5A2 and fishing effort is sporadic and low in sub-area 5B2; the clam stock status is therefore unknown in these two sub-areas.
- Since 2012, the total allowable catch (TAC) has been caught in 5A1 and 5B1. Fishing effort is below the reference average in both sub-areas.
- Catches per unit effort (CPUE) calculated for the entire North bed have been high and stable since 2009.
- In the last three years, the average size of landed clams was above the reference average in the North bed.
- Since 2009, between 5.6% and 9.3% of the North bed area has been dredged annually, and the yearly average for the last three years was 7.5%.
- Good yields and size structure stability in recent years are probably attributable to the constant movement of fishing effort to new areas of the North bed. However, the total size of this bed is not yet known. Based on existing information, current landing levels could be maintained.
Hand digging
- Commercial and recreational hand digging by divers and shore harvesters is a very popular, well-developed activity in the Îles-de-la-Madeleine. Commercial hand harvesting data from logbooks are most likely incomplete, and the extent of recreational hand digging is unknown. The estimate of unreported fishing activities can provide a rough idea of the missing landings. For 2013, this estimate is about 84 t for unreported hand harvesting; 2014 and 2015 data are not yet available.
- Known commercial hand digging landings vary with fishing effort. The averages for the last three years are 35 t and 231 days.
- Since 2010, CPUEs for commercial harvesting by divers and shore harvesters have been fairly stable, but both are generally below the reference average.
- Since 2008, the annual average size of clams collected by diving is near the reference average. Clams gathered by shore harvesters are smaller and their average size is smaller than that of clams harvested by other methods. However, clam size has risen since the minimum legal size was increased in 2014.
- 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 meeting held on February 23, 2016 on Stock assessment of Atlantic Surfclam of the Magdalen Islands. Additional publications from this meeting will be posted on the Fisheries and Oceans Canada Science Advisory Schedule as they become available.
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