Fisherman located in the village of Le Séchey
Due to the closed nature of its watershed, the fish species that inhabit Lac de Joux have all been introduced by the hand of man. These are mainly lake trout, pike, perch and perch. There are also Vandoise, Gardon and Tench. Much rarer are the Burbot and Grayling, which are very much affected by the eutrophication of its waters (overabundance of food in the ecosystem).