Incorporating the Effect of Deep-Sea Currents in the Stock Assessment of the Red Shrimp Aristeus Antennatus in the Northwest Mediterranean

Accounting for the effects of environmental variability is important for the stock assessment of many fishery resources. The red shrimp Aristeus antennatus is the most economically important deep-sea demersal resource in the Northwest Mediterranean. In Northeast Spain it is fished by bottom trawling, and annual landings are highly variable. These fluctuations have been related to the effect of strong deep-sea currents which vary at a decadal scale. Such currents cause a temporary fishery collapse and subsequent recovery. The collapse is either from increased natural mortality or decreased availability on the fishing grounds. The recovery is from a subsequent enhancement of the recruitment two years later, possibly resulting from increased transport of organic matter to the nursery ground in the deep basin. The aim of this work is to perform a stock assessment for the red shrimp using all available information (e.g., a fishery-independent survey, historical series of fishing effort and landings by shrimp size class), including environmental factors (e.g., speed, temperature and turbidity of deep-sea water). Our research demonstrates the utility of integrated models for advancing stock assessment methods and testing alternate hypotheses about environmental effects.