Post-release and pre-spawning behaviour of simulated escaped adult rainbow trout Oncorhynhus mykiss in Lake ovre Fryken, Sweden

Using radio telemetry, the present study simulated the escape of 48 adult rainbow trout Oncorhynchus mykiss from a net-cage fish farm in the Lake ovre Fryken, Sweden. The post-release dispersal of O. mykiss was fast, showed long-range dispersal behaviour, low winter survival and lacked the ability to find suitable spawning habitats. Thus, the present study suggested that reproducing for the first time may be an obstacle to the establishment of escaped farmed O. mykiss.