The dataset represents known concentration areas of harvested or unharvested Atlantic surfclam (Spisula solidissima) in the Gulf of St. Lawrence, around the Magdalen Islands. The dataset was created for the National environmental emergencies center (NEEC) for preparation and response in case of an oil spill. Concentration areas were delineated using Fisheries and Oceans Canada (DFO) inventories conducted between 2000 and 2020, commercial fisheries data (logbooks and purchase receipts from 2002 to 2020 and observations at sea from 2005 to 2017), data from exploratory fisheries as well as interviews.

This layer is dependent on the inventories carried out and thus only represents the known areas of the Atlantic surfclam. This dataset does not represent the general distribution of the species nor the extent to which fishing is allowed. Most of the information comes from inventories that did not necessarily target this species, therefore its distribution is undoubtedly wider than what is recorded in this layer. In addition, the extent of shellfish beds can change over time in response to, among others, harvesting and recruitment rates. Some concentration areas were delimited based on interviews with people who locally know the resource but their delimitation remains approximate. The polygons delimited based on sampling data are more precise but might underestimate the concentration areas because sampling was made where the target resource was known to be more abundant without necessarily sampling the entire bed. Nonetheless, the precision is sufficient for resource protection and management needs in case of an environmental incident.

Data sources and references:

Bio-Conseil. 1986. Pêche exploratoire à la palourde (Spisula solidissima) aux Îles-de-la-Madeleine, automne 1985. Rapport final, Bio-Conseil, Pêches et Océans Canada. 24 p.

Bernier, L. and L. Poirier. 1979. Evaluation sommaire du stock de mactres de l'Atlantique, Spisula solidissima Dillwyn, des Îles-de-la-Madeleine (golfe du St-Laurent). Cahier d'information, ministère de l'Industrie et du Commerce. 42 p.

Bourget, E. and D. Messier. 1983. Macrobenthic density, biomass, and fauna of intertidal and subtidal sand in a Magdalen Islands lagoon, Gulf of St. Lawrence. Can. J. Zool. 61(11):2509-2518.

Brulotte, S. 2013. Évaluation des stocks de la mactre de l’Atlantique, Spisula solidissima, des eaux côtières des Îles-de-la-Madeleine – méthodologies et résultats. Secr. can. de consult. sci. du MPO. Doc. de rech. 2013/082: x + 58 p

.

Brulotte, S. 2016. Évaluation des stocks de mactre de l’Atlantique, Spisula solidissima, des Îles-de-la-Madeleine, Québec en 2015 – méthodologie et résultats. Secr. can. de consult. sci. du MPO. Doc. de rech. 2016/074. x + 51 p.

DFO. 2016. Stock Assessment of Atlantic Surfclam of the Îles-de-la-Madeleine in 2015. DFO Can. Sci. Advis. Sec. Sci. Advis. Rep. 2016/022.

DFO. 2019. Assessment of the Îles-de-la-Madeleine Atlantic Surfclam stock in 2018. DFO Can. Sci. Advis. Sec. Sci. Advis. Rep. 2019/031.

Fréchette, M. and M. Giguère. 1984. Rapport sur une pêche exploratoire à la palourde aux Îles-de-la-Madeleine en 1984. Pêches et Océans Canada. 17 p.

Hurlbut, T and D. Clay. 1990. Protocols for research vessel cruises within the Gulf region (demersal fish) (1970-1987). Can. Manuscr. Rep. Fish. Aquat. Sci. 2082:143p.

Hurtubise, S. (Fisheries Data [ZIFF] and At-Sea Observers Manager). Unpublished data. Fisheries and Oceans Canada.