An evaluation of the collapse and recovery of the yellowtail flounder (Limanda ferruginea) stock on the Grand Bank

In 1994, the biomass of yellowtail flounder on the Grand Bank had declined to 20% of the biomass associated with the maximum sustainable yield (B-msy) because of overfishing in the 1980s, and the Northwest Atlantic Fisheries Organization (NAFO) declared a moratorium on fishing of this stock (and several others in the area). After 4 years of moratorium, the biomass had quadrupled, the fishery was reopened, and the biomass is now well above B-msy. Based on advice developed within a precautionary approach framework, total allowable catches were set corresponding to a fishing mortality of <= 0.67 x F-msy. When the fishery was reopened in 1998, several measures to reduce the fishing mortality and ensure continued recovery were introduced. We review and evaluate the science and the management strategies developed during the decline, collapse, and recovery, noting that yellowtail flounder is the only groundfish stock on the Grand Bank that has fully recovered after its collapse. Key management measures included the elimination of fishing by non-NAFO vessels, protection of strong year classes, and keeping the fishing mortality below 0.67 x F-msy. Although overfishing is viewed as causing the stock decline, productivity was strongly affected by climatic conditions during the collapse and recovery. Changes in water temperature coincided with major changes in the catch and fishing mortality.