Proliferative Kidney Disease (PKD) is discussed as contributing factor to the long-term decline of Swiss wild brown trout (Salmo trutta) populations. Therefore, stocking of wild trout in PKD positive rivers was thought to be necessary to maintain a stable fish population. In this project we examine population development over at least ten years after stop of stocking. In parallel, PKD prevalence and pathology is monitored. Three river systems in different cantons of Switzerland are involved in the project. Until now, PKD characteristics did not change over years, neither prevalence nor pathology. Nevertheless, brown trout population sizes rather increased since stocking interruption. By marking stocked brown trout at the last stocking event, we could show that stocked animals hardly survive the first two to three years in the wild. Survival probability was lower in PKD positive river stretches compared to PKD negative ones.
This project is funded by the federal office for the environment (00.0214.PZ /N282-1373)
Project lead: Heike Schmidt-Posthaus, PD, Dr. med vet, DECVP, FVH
Last updated: 2020/03/4
