Impact of Small Hydro-Power Plants on Salmonid Fishes Spawning Migrations

Abstract

In 2000 and 2005, fish ladders were built in Vilnia and Siesartis rivers providing fish access to another 10 and 25 km of the rivers respectively. The analysis of redd distribution and abundance in both rivers revealed that the construction of fish ladders significantly increased the number and share of redds above dams, however, a significant increase in redds above the dam occurred 2-4 years after fish ladders construction supporting homing behaviour as one of the most important factors for the recolonization of the newly accessible habitats. The tracking of radio tagged salmon and sea trout revealed that statistically, significantly more time, fishes spent in the middle part of fish ladders. Assessed fish ladders efficiency for migrating salmonids made 66%. Minor construction defects and lack of protection were the main factors reducing fishway efficiency. Based on radio tracking data, recommendations are given for minor changes in fish ladders construction and operating schedule to increase the efficiency of fish ladders.

Environmental Aspects of Implementation of Micro Hydro Power Plants – A Short Review

“…The disruption of longitudinal connectivity by dams can have severe impacts on migratory fish, especially salmonids (Stakėnas and Skrupskelis, 2009). Significant reductions in the numbers of salmonids were observed after the construction of small hydropower plants on small mountain rivers (Almodóvar and Nicola, 1999;Ovidio et al, 2004).…”