Évaluation des stocks de crevette nordique de l'estuaire et du golfe du Saint-Laurent en 2021

Abstract

In 2020 and 2021, preliminary landings for all shrimp fishing areas were respectively 17 845 t and 17 217 t from a TAC of 17 999 t. Since 2008, the research survey shows a decrease in the area where northern shrimp concentrate. This minimum area has decreased from over 50 000 km2 to less than 30 000 km2. In the commercial fishery, the surface of the area where trawling activities took place has decreased from 15 000 km2 to 10 000 km2 since 2012. The male and female numbers per unit of effort (NPUE) from the commercial fishery for the last four years are decreasing in Estuary, stable in Esquiman, and increasing in Sept-Iles and Anticosti. They are comparable to or above the average of the historical series. The male and female abundances observed in the DFO survey show downward trends since 2005. The estimates for 2020 and 2021 are among the lowest of the historical series. In recent years, there has been a discrepancy between the indices from the fishery and those from the DFO survey. Fishermen have succeeded to maintain their NPUEs at average levels while the shrimp abundance indices reached their lowest historical level. This divergence suggests that the main stock status indicator is currently overestimated since it uses these two sources of information with equal weight. Exploitation rates in the Sept-Iles, Anticosti and Esquiman areas show an upward trend since 2003 and are above the average of the 1990-2010 reference period. The exploitation rate in the Estuary has been variable since 2016 and below the average (2008-2021) in 2021. The low abundance of juveniles and males observed in recent years and the downward trend in the size of females suggest a lower stock productivity. Warming of deep waters and increased predation by redfish appear to be important factors contributing to the decline of shrimp. These ecosystemic conditions are not expected to improve in the short to medium term. Under the precautionary approach, the main stock status indicator decreased slightly in all four areas in 2021. The indicators are very close to the upper stock reference point. The Estuary, Anticosti and Esquiman stocks are in the healthy zone, while the Sept-Iles stock is in the cautious zone. According to the harvest guidelines established as part of to the precautionary approach, the projected harvests for 2022 are 558 t for Estuary, 6 242 t for Sept-Iles, 5 424 t for Anticosti and 5 079 t for Esquiman. The sum of evidence (bias in the main stock status indicator, high exploitation rate, increase in predation and in deep waters temperature, and reduction in shrimp distribution area) shows that we are currently operating outside the framework in which the precautionary approach was developed. This situation has the consequence of increasing the risk for the sustainability of the stocks by using the current decision rules. The precautionary approach should be revised before the next assessment.