Abstract
Sustainable management of inland fisheries presents major challenges because it often involves complex and open access systems. Lake IJsselmeer is among the largest freshwater lakes in western Europe and supports active commercial fisheries. By 2012, excessive fishing effort had reduced the stocks of four key resident species: pikeperch ( Sander lucioperca ), perch ( Perca fluviatilis ), roach ( Rutilus rutilus ), and bream ( Abramis brama ) to historically low levels as indicated by both survey indices and commercial landings. In response, the Dutch government implemented major fishery management interventions in 2014: (I) reductions to gillnet fishing (15% of the available effort) and (II) previously unregulated seine fisheries targeting bream were limited from 135 to 7 days per year per license. To evaluate the impact of these management measures, time‐series analysis of spawning stock indices and population structures were performed. Our analysis, also including environmental changes in water temperature and phosphate levels, reveals that these major regulatory interventions were the primary driver of stock recovery, successfully halting declines in all four focal stocks and enabling the increase of both fish populations and commercial catches. The pikeperch population has shown a particularly sharp and sustained stock recovery, while increases in length‐based indicators in all four stocks suggest broader recovery patterns. This case study demonstrates how targeted regulatory measures can effectively reverse stock declines and support the recovery of fish populations in heavily exploited freshwater systems.