Assessing fish ladder effectiveness on the St. Croix River


Aquatic Ecosystem Health

Project Description

The Sipayik Environmental Department (SED) of the Passamaquoddy Tribe at Pleasant Point, Maine, in parallel with the yearly fish counts, conducted this multi-year study to determine the effectiveness of fish passages in the watershed in 2016 and 2017. Efficient fish passage is imperative for migrating fish to reach their spawning grounds in the lakes of the watershed. The study evaluated the three fish ladders in the basin by tracking fish through the ladders using passive integrated transponders and determining water quality near the dams (Milltown Dam, Woodland Dam, and Grand Falls Dam). These dams are the first obstacles that river herring and other fish encounter in the St. Croix Watershed, and are hypothesized to be significant obstacles to their upstream migration. SED installed tags on fish and an electronic fish counters to provide and understanding of fish (river herring) passage through these ladders. This study led the way for the next step in alewife restoration.




National Fish and Wildlife Foundation, US Fish and Wildlife Service, Bureau of Indian Affairs