Quelques aspects de l'alimentation de deux poissons planctonophages du Lac Léman : le Corégone (Coregonus schinzii palea Cuv. et Val.) et le gardon (Rutilus rutilus L.)

Abstract

In order to compare their food, whitefish and roach were captured with trawls (roach only) and pelagic and bottom gill nets in Leman Lake from June 1984 to July 1985. In the pelagic area, the two species are strictly planctonophagic. They share the same trophic ressources from June to October. The principal eaten preys are Daphnia sp. then particularly Leptodora kindtii and Bythotrephes longimanus. The conclusion of a competition between these two species of fishes is not possibleon account of the lack of data on the biology of their principal preys.