Science Response 2011/006
Identification of Atlantic surfclam fishing areas off Grosse-Île (Magdalen Islands, Quebec) to avoid impacting lobster habitat
The economy in the Magdalen Islands is based on commercial fishing, but particularly on coastal species. With the decreased access to many offshore stocks (pelagic fish, groundfish, snow crab), the coastal area surrounding the archipelago is increasingly sought, increasing the likelihood of conflicts between different users. In fact, exceptionally serious conflicts took place in 2009 in the Grosse-Île area between Atlantic surfclam and lobster fishermen. In 2009, Atlantic surfclam fishermen, which for several years had focused their activities on the south side of the Islands, began to explore new areas between Pointe-de-l’Est and Grosse-Île. The arrival of these new fishermen using mobile gear in the vicinity of traditional lobster fishing grounds angered lobster fishermen who called for an end to this activity. Their concern was that the recurring passage of dredges could damage lobster habitat and potentially reduce lobster productivity. Fisheries Management is sensitive to this concern and they would like to introduce measures for managing the Atlantic surfclam fishery, and more typically the mobile gear fishery. Fisheries Management from the district office of Department of Fisheries and Oceans Canada in Îles-de-la-Madeleine (Québec) requested that DFO Science identifies and accurately locates the bottoms that represent lobster habitats on the one hand and Atlantic surfclam habitats on the other, and based on this information, delineates areas where Atlantic surfclam fishing with a hydraulic dredge would be acceptable.
To answer this question, the results from a multibeam survey conducted in the summer of 2010 by the Canadian Hydrographic Service (CHS) in the Grosse-Île area, where the conflict appeared between the two groups of fishermen were used. An SSRP was used because Fisheries Management was seeking an advice before the beginning of the Atlantic surfclam fishing season in 2011.
The main conclusions are as follows:
- The two fisheries that are the subject of the dispute, lobster and Atlantic surfclam, are not carried out in the same areas. The lobster fishery is conducted on rocky bottoms, while the surfclam fishery is done primarily on soft substrates.
- Although the bathymetric distribution of both species overlaps, the surfclam fishery is done at depths generally shallower than lobster.
- The conflict between the two groups of fishermen is largely due to the close juxtaposition of habitats for both species. The exploitation of a surfclam bed located very near a rocky reef is a problem because during fishing operations, certain dredge tows could encroach on the rocky substrate. This encroachment can cause habitat damage, especially in the case of sandstone, a weak rock which is frequently found in these areas. This type of rock can easily fracture when it comes in contact with a massive gear such as a dredge.
- The surfclam fishery restriction in defined areas will clearly confine the activity and avoid overlapping or encroachment on hard bottoms. The passage of dredgers would be strictly limited to primarily soft substrates and would be carried out away from rocky habitats. In such a context, the Atlantic surfclam fishery is not likely to cause any conflict.
This Science Response report is from the Fisheries and Oceans Canada, Canadian Science Advisory Secretariat, Regional Science Special Response Process (SSRP) of June 1, 2011 on the Identification of Atlantic surfclam fishing areas off Grosse-le (Magdalen Islands, Quebec) to avoid impacting lobster habitat.
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