Strong relationship between commercial catch of adult Atlantic halibut (Hippoglossus hippoglossus) and availability of suitable habitat for juveniles in the Northwest Atlantic Ocean

Atlantic halibut (Hippo-glossus hippoglossus) is an increasingly valued commercial fish and its recent population growth has attracted the attention of fisheries scientists and managers both within and outside Canada. With renewed transnational interests in this species, fishery managers have relied on existing, but limited, ecological information for multilateral discussions on shared allocations of catch. To address this dearth of information, we modeled species distribution using maximum entropy, where by survey catch data were related to environmental data to quantify habitat suitability. We then calculated the amount of suitable habitat for juvenile Atlantic halibut per Northwest Atlantic Fisheries Organization (NAFO) divisions, within and outside Canada's Exclusive Economic Zone. Among NAFO divisions, we found a strong relationship between the availability of suitable habitat for juvenile Atlantic halibut, and both current and historical fisheries landings. Results are consistent with the nursery-size hypothesis which states that the amount of available juvenile habitat is related to the level of adult production. The majority of occupied suitable habitat is found on the southwestern half of Canada's Scotian Shelf, whereas the U.S. and international waters off Newfoundland have ample suitable habitat to support larger populations. Quantifying habitat suitability and linking this suitability to stock abundance and distribution is an important step toward an ecosystem approach for the management of Atlantic halibut.