Historical data of biodiversity of the Magdalen Islands Sea Scallop survey

A research survey of scallops (mainly sea scallop Placopecten magellanicus, but also Icelandic Scallop Chlamys islandica) using a dredge was carried out by DFO (Fisheries and Oceans Canada) every 1 or 2 years since 1992 in the Magdalen Islands (fishing area 20). The main objective of this research survey was to assess Sea Scallop stocks. Another objective was to document taxa associated with scallop habitat according to a fixed random sampling plan. Occurrences by species (or taxon) are presented by station. The taxonomic and geographical validity of the data was checked and the World Register of Marine Species served as the taxonomic authority for naming all taxa recorded during the survey. Epibenthic invertebrates (mainly molluscs, echinoderms and crustaceans) as well as demersal fish were identified from the dredge catches. The current data starting in 2021 are available at the following link : https://open.canada.ca/data/en/dataset/6529a4b0-f863-4568-ac71-1fa26cf68679

The study area is located south of the Magdalen Islands and the sampling of scallop beds is carried out at depths of 10 to 38 m, generally around 25 to 35 m. A random selection of sampling stations is carried out from a fixed station grid. Sampling is done along transects at these randomly drawn stations in the study area. Sampling is done with a lined Digby scallop dredge (20 mm mesh) over approximately 500 m along the seabed. The four baskets of the dredge are examined for all scallops. Next, a basket (the first on the starboard side) is sorted and examined for associated species. Most specimens are counted by taxon. The presence or relative abundance of undersized and numerous, or colonial, organisms is noted. Special cases are sometimes retained for taxonomic analysis, for example, ascidians (to monitor invasive species) and sponges (to document new species).