Ecology of the Pelagic Fishes of Lake Titicaca, Peru-Bolivia

摘要: Gill nets set at three depths an open-water station in Lake Titicaca during August 1984 captured only two species of endemic killifishes (Orestias ispi and 0. mulleri) exotic silverside (Basilichthyes bonariensis). These segregated strongly by depth, with B. bonariensis mulleri occurring the surface bottom sets, respectively, being most abundant mid-water set. All were feeding on zooplankton, but also included benthic crustaceans its diet. Copepods selected large (>200 mm SL) bonariensis, whereas smaller size classes ate mainly cladocerans. cladocerans about equally represented average diet adult ispi, larvae contained copepods. Analysis egg size-frequency distributions gill-netted seine-netted samples suggested that both Orestias are fractional spawners. Horizontal trawls, made between 10 m bottom, collected larvae. Echo-sounding traces depth distribution pelagic fish fauna changed little a diel basis.