Age and growth of European eel, Anguilla Anguilla (Linnaeus, 1758), in Estonian lakes

Summary To investigate the difference in growth rates of eels in the studied water bodies (Vortsjarv, Ulemiste, Saadjarv, Vagula, Kaiavere and Kuremaa lakes, all in Estonia), 828 individual eel otoliths from the years 1999–2004 and 2008–2012 were examined for age determination. Anguilla anguilla captured in Lake Vortsjarv mostly by professional fyke nets (mesh size >36 mm in the cod end) showed the best growth rate (gR = 6.9 cm/year) and had a high Fulton condition factor (K = 0.19), indicating suitable growth conditions in the lake. However samples caught using the same type of gear from the smaller lakes situated near Vortsjarv, showed much slower gR (3 cm/year) and lower K (0.17) growth rates. The slowest gR (2.6 cm/year) was observed for specimens caught in Lake Kuremaa. Stocking densities are much higher in the small lakes of the region and have a direct effect on the growth rates.