Feeding strategy of the non‐native rainbow trout, Oncorhynchus mykiss, in low‐order Patagonian streams

摘要: The dietary composition and feeding strategy of rainbow trout, Oncorhynchus mykiss (Walbaum), in two low-order Patagonian streams were studied. Benthic macroinvertebrate availability was estimated both riffles pools. Fish stomach contents examined to determine prey richness diversity, electivity, food-niche width, the employed by trout throughout year. Availability benthos varied seasonally with Ephemeroptera, Trichoptera, Plecoptera Diptera species dominating. Rainbow diet composed mainly benthic macroinvertebrates, followed terrestrial insects, fish, algae plants. Different size classes segregated use food resources reduce predation pressure. Elected included organisms displaying no high mobility. A plasticity allows buffer changes switching from a specialised generalised behaviour. Consequently, may exploit abundant but temporary opportunistically, which would explain their marked expansion environments.