The effect of a large-scale fishing restriction on angling harvest: a case study of grayling

In Central Europe, European grayling Thymallus thymallus is an endangered and vanishing fish species with high recreational angling value. For that reason, in January 2016, the minimum legal angling size for grayling was increased from 30 to 40 cm in the Czech Republic. This study evaluated if the increase in minimum angling size had any effect on grayling harvest. Data from 229 fishing sites covering the years 2011–2017 were used in this study. The data originated from individual angling logbooks, collected in the regions of Prague and Central Bohemia, Czech Republic. Over the 7 yr, anglers visited the studied fishing sites 3.6 million times and harvested 105 000 salmonids. Grayling made up only 0.5% of the overall salmonid harvest. The fishing restriction caused a decrease in grayling harvest per visit. It also decreased the contribution of grayling to the overall harvest as well as the number of fishing sites where anglers successfully harvested graylings. Fish stocking was constant during the study period. Increased minimum angling size led to increased average body weight of harvested fish. In conclusion, the increase in minimum angling size significantly affected fish harvest and composition.