Status and perspectives for pikeperch (Sander lucioperca) stocks in the Baltic Sea region and central Europe

Abstract

Pikeperch (Sander lucioperca) is a European fresh and brackish water piscivorous fish, important as a key predator and a valuable fisheries species. Despite concerns that some stocks are depleting due to overfishing and environmental changes, stock assessments are implemented sporadically. We provide an overview of data collection and population assessments currently used for nine pikeperch stocks across six European countries and apply a unified assessment framework (Bayesian surplus production models) to evaluate population status and trends. Our results show that three stocks, including two in the Baltic Sea, are strongly depleted, with estimated biomasses considerably lower than the biomass at maximum sustainable yield (BMSY). Other stocks are close to their estimated BMSY. Further, recent population trends suggest that only one stock (Kvädöfjärden) is increasing, whereas three (Curonian Lagoon, Lipno, Galtfjärden) are rapidly declining. In most cases the stocks with a favorable status or signs of recovery were also those for which strong management strategies have been implemented. Importantly, although most stocks are strongly targeted by recreational fishing, estimates of recreational catch are highly uncertain. We highlight an urgent need to improve pikeperch scientific monitoring and assessment of recreational catches.