Science Advisory Report  2010/016

Assessment of Atlantic surfclam in the coastal waters of the Îles-de-la-Madeleine in 2009

Summary

• The Atlantic surfclam fishery in the Îles-de-la-Madeleine is conducted with hydraulic dredges in sub-areas 5A1 and 5B or using hand tools, on foot or while diving, in about ten shellfish sectors located in lagoons or near coasts. The dredge fishery is still developing and is, in part, conducted on new portions of surfclam beds from one year to another.

Hydraulic Dredge Fishery (Sub-areas 5A1 and 5B)

• The total allowable catch (TAC), set at 113 tons (t) since 2002, has been reached virtually every year in sub-area 5A1. In 2009, landings in this sub-area totalled 116 t with a fishing effort of 44 days, which represents a 20% drop in effort compared to the average (2002 to 2008).
• Catch per unit effort (CPUE) fluctuates around the average in sub-area 5A1. In 2009, CPUE was of 163 kg per hour/meter (kg/hm), or 23% higher than average.
• Considering the stability of various commercial indicators over the last several years and having frequently reached the TAC, a 10% increase of the quota in sub-area 5A1 could be authorized for 2010.
• Prior to 2008, fishing in sub-area 5B was only occasional. However, in 2008, a bed was located north of the Îles-de-la-Madeleine, at the limit of sub-areas 5B and 5A1. This bed, 5B North, was mainly harvested in 2009.
• In 2009, landings from the 5B North bed totalled 152 t, fishing effort of 52 days and CPUE of 203 kg/hm.
• The commercial indicator values obtained on the 5B North bed were similar to those of sub-area 5A1 in 2009. However, given the small size of this bed, the harvesting pressure in 2009 was probably much higher on the 5B North bed than in sub-area 5A1.
• Given the similarity of indicators, it is recommended to implement, for the 5B North bed, conservation approaches similar to those used in sub-area 5A1, while considering the relative size of the beds.

Hand Digging

• The available information on hand digging of Atlantic surfclam, either on foot or while diving, is limited. This type of harvesting is very popular and well-developed and the harvesting effort is considerable. The average annual landings from recreational hand digging is estimated at about 131 t and exceeds the dredge yield in sub-area 5A1.
• The effort and CPUE data are very incomplete and it is difficult to assess the status of different beds harvested by hand digging. The few available logbooks show that the CPUE from commercial hand digging on foot have remained up around 23 kg/h since 2005, when calculated against all shellfish sectors. The CPUE from commercial harvesting while diving are much more inconsistent and average (2005 to 2008) 43 kg/h.
• Given the available information, it is recommended to limit the potential commercial and recreational hand digging effort to the current level.

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