In the Gulf of St. Lawrence, Redfish has been under moratorium since 1995. However, highly abundant 2011-2013 cohorts will soon recruit to the commercial fishery, indicating a significant recovery. Total minimum trawlable biomass increased by 50% in DFO bottom trawl surveys from 2018 to 2019, and are now estimated at 4.5 million tonnes, representing 90% of the biomass of all captured organisms. However, the bottom trawl used in these surveys only samples about 5 meters height above the sea bed. Meanwhile, echosounders onboard the vessel recorded backscatter up to several hundreds of meters above the seafloor, indicating that the bottom-trawl index may underestimate total biomass.
The development of a Redfish acoustic index could provide a complementary method of quantifying stock status to inform management decisions for a large scale commercial fishery. This project will also improve our understanding of community dynamics between Redfish, their prey and competitors, as well as provide further knowledge of stock-recruitment dynamics. Furthermore, this project will deploy a midwater trawl, which causes less impact to fish habitat than a bottom trawl and may lead to a more efficient method of capturing Redfish for the commercial fishery. It is highly likely that the fishing industry will seek to certify the Redfish fishery. To do this, sustainable management tools based on rigorous knowledge are essential.
