Evaluating the Effects of River and Stream Restorations

This research is the first analysis of a large and long term study of stream restoration activity for Switzerland. This manuscript focuses on the largest Swiss canton of Graubünden (about twice the size of Rhode Island) which is primarily mountainous and rural in character and is a destination for recreational fishing. It contains 11,000 km of streams and over 600 lakes and ponds. Despite stocking efforts, trout catches in Switzerland have declined by as much as 50% since the 1980s potentially due to deteriorated ecological conditions although no single causative factor was identified. In canton Graubünden we observe a reduction in the number of anglers since 2002 though fishing intensity and catch per trip remain stable over time. We utilize the stream data to first establish the relationship between restoration events and trip-level catch totals by species and size. Our preliminary results suggest that the impact of the restoration on the downstream reaches include an increase in the size of the catch by 0.25 cm, an impact on the probability of a catch of 5% both statistically significan