Seeing with both eyes: determining deep-sea coral distributions in the Northern Gulf of St. Lawrence using bycatch records and local ecological knowledge

This study used a combination of coral bycatch records and fish harvesters' local ecological knowledge (LEK) to identify 11 species/groups of deep-sea coral that occur in the Northern Gulf of St. Lawrence (NAFO Divisions... [ view full abstract ]

This study used a combination of coral bycatch records and fish harvesters' local ecological knowledge (LEK) to identify 11 species/groups of deep-sea coral that occur in the Northern Gulf of St. Lawrence (NAFO Divisions 4RS3Pn) in Eastern Canada and to map the distribution of seven of these. Coral bycatch records came from DFO (Fisheries & Oceans Canada) groundfish survey trawls and fisheries observer records, while the LEK of Northern Gulf fish harvesters was recorded during interviews and mapping exercises. Nephtheid soft corals and sea pens (Pennatulacea) were found to be the most common groups of deep-sea coral occurring in the Northern Gulf, with nephtheids being found at depths from 10-500m in all areas where hard substrates are available for attachment, and sea pens being found in large concentrations at the bottoms of the deeper-water channels, including the Laurentian Channel. Fish harvesters' LEK identified a greater diversity of corals than the bycatch records, while the bycatch records were more precise in the locations of encounters and taxonomy. Fish harvesters identified coral distributions missed by trawl surveys and fisheries observer records, specifically in coastal inshore areas that are not covered in regional survey trawls, such as Bay St. George, where Scleractinian cup corals and two species of large gorgonians were reported to occur by fish harvesters. Combining trawl survey data and LEK observations clarified the diversity and distribution of corals within the Northern Gulf of St. Lawrence, and emphasized the complementary nature of scientific surveys and fish harvester observations.