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The return of oysters to the Bassin aux Huîtres
One day, the Madelinots will probably be able to return to gather oysters in the Bassin aux Huîtres on Grande Entrée Island in the Îles-de-la-Madeleine. But this day will arrive later than participants in a project to reintroduce the mollusc to the 1.5 km2 basin, which occupies nearly a quarter of the island’s area, had hoped.
Launched in 2007 after several years of preparation, this project is led by the Îles-de-la-Madeleine ZIP Committee, in collaboration with the Shared Management Committee of Bassin aux Huîtres. It is funded by Fisheries and Oceans Canada, and it is supported in other ways by that department, as well as by Quebec’s Ministère de l’Agriculture, des Pêcheries et de l’Alimentation and many volunteers. The project’s goal is to restore to the archipelago a resource that, for half a century, gave pleasure to many amateur pickers.
Oysters were seeded in this basin in 1937 and again in the 1970s. But several factors, including overexploitation, have led to a noticeable decline in oyster beds, leaving only a few specimens and putting the stock at risk. The only other place on the islands — and in Quebec — where oysters reproduce is Clarke Bay (also part of Grande Entrée Island), a habitat managed by Quebec`s Ministère des Ressources naturelles et de la Faune.
This stock in Clarke Bay was to be drawn on for the repopulation of Bassin aux Huîtres during the first stage, and a second controlled transfer was to come from an aquaculture site in a natural environment at Shippagan in New Brunswick.
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Photo: Îles-de-la-Madeleine ZIP Committee |
In fall 2007, after several preliminary stages, project participants undertook a first transfer of 1,500 oysters from Clarke Bay to Bassin aux Huîtres. Then, in June 2008, approximately 25,000 juvenile oysters, with an average length of 45 mm, arrived from Shippagan.
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Photo : Îles-de-la-Madeleine ZIP Committee |
Unfortunately, numerous efforts to date have not produced the expected results. Recent monitoring shows a high mortality rate of the seeded oysters, due largely to intense predation from starfishes. Although not optimal for the species, the environmental conditions in Bassin aux Huîtres seem favourable enough to sustain an oyster stock. If there is to be any subsequent transfer, there must be predation control, such as the construction of protective structures. This could contribute to the survival of the molluscs until they attain a size that makes them inaccessible to starfishes and that allows the oysters to reproduce and defend themselves against predators.
Is the project falling flat? “Not at all,” answers Jonas Sahlin, Project Manager. “We have acquired a lot of experience. These two transfers gave us a lot of information, which will be useful for other eventual seedings and for monitoring the existing population and the conditions in the entire basin.”
The next stage, which will be independent and carried out in a completely different context, should be the study of the underwater substrate and its improvement by, for example, depositing empty shells and limestone rocks to which the oyster larvae can attach themselves. Whatever happens, the citizens of Grande Entrée Island will be consulted concerning this possible project, according to Jonas Sahlin. “For our part, we do not believe that we are at the end of a project, but only at the end of one stage in a long-term program.”
For more information, contact:
Îles-de-la-Madeleine ZIP Committee
330, chemin Principal, bureau 209
Cap-aux-Meules, QC G4T 1C9
Tel.: 418-986-6633
E-mail: carto@zipdesiles.org
Date modified: 2008/12/08 – Important Notices
