Research Document 2020/016

Gulf of St. Lawrence (4RST) Greenland Halibut Stock Status in 2018: Commercial Fishery and Research Survey Data

By Gauthier, J., Marquis, M.-C., Bourdages, H., Ouellette-Plante, J. and Nozères, C

Abstract

The Gulf of St. Lawrence Greenland halibut (Reinhardtius hippoglossoides) stock (NAFO Divisions 4RST) is assessed and managed on a two-year cycle. The indicators used for this assessment are taken from fishery statistical data, sampling of commercial catches and research surveys. This document presents the data, techniques, analyses and results used in a peer review meeting held on February 20 and 21, 2019 at the Maurice Lamontagne Institute.

The directed Greenland halibut fishery developed in the late 1970s. Since the closure of the mobile gear fishery in 1993, this fishery has been carried out almost exclusively with gillnets. Fishing effort is deployed in three main sectors: the western Gulf of St. Lawrence, the area north of Anticosti Island and Esquiman Channel. During the 2000-2018 period, the proportion of the effort expended in each of these three sectors was 67%, 6% and 24% respectively. The total allowable catch (TAC) remained fixed at 4,500 t between the management years 2004-2005 and 2017-2018. Landings have declined since the 2011-2012 season. In 2018, following a comprehensive interim-year assessment of the stock, the TAC was reduced by 25% for the 2018-2019 fishing season.

Preliminary landings in that year totalled 1,496 t, the lowest value in the last 16 years. The commercial fishery performance index shows a downward trend, with a 48% decrease in 2018 from the 2014-2016 peak, reaching the low values observed in 1999-2000. The biomass indices for fish over 40 cm—based on fishery independent data obtained from DFO's mobile gear surveys and the sentinel fisheries program—also point to a declining trend over the last ten years or so, with decreases of 62% and 77% respectively from the peak observed in the mid-2000s.

The Gulf of St. Lawrence ecosystem has undergone significant changes in recent decades. Warming and oxygen depletion of the deep waters of the Gulf could result in habitat loss and the degradation of habitat quality for Greenland halibut. Furthermore, the arrival of three exceptionally strong cohorts of redfish (2011 to 2013) could increase interspecific competition. These ecosystem conditions are not expected to change in the short term.

Research Document 2020/016 (PDF, 12,144 KB)

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