Utilizing Passive Integrated Transponder (PIT) Telemetry to Evaluate Passage Performance of River Herring in the Saugatucket River, RI.

Kinney, Heather¹, Alex J. Haro², John O’Brien¹, Patrick McGee³, Corey Pelletier³, William Helt¹, ¹The Nature Conservancy, Providence, RI, ²USGS S.O. Conte Anadromous Fish Research Lab, Turners Falls, MA, ³RI DEM, DFW, West Kingston, RI

The Saugatucket River watershed in Rhode Island is the largest fluvial system contributing to Block Island Sound, providing passage for diadromous fish to important spawning and nursery habitat. Unconfined, this system has the potential to support river herring populations of over 200,000 spawning adults. Extensive efforts to improve the three fish ladders along the river, Main Street Dam (lower), Palisades Mill (middle), and Indian Lake (upper), have been ongoing with the most recent improvements completed in 2018. Continued assessments suggest the middle ladder is not working efficiently and plans are underway to modify it. Evaluating the upstream passage through each ladder and across the whole system is important to quantify low passage efficiency or delays, as well as track success of improvements made to the ladders. This study aims to use passive integrated transponder (PIT) telemetry to 1) evaluate river herring passage performance in two types of improved fish ladders and 2) compare the performance of a 1970s Denil fish ladder before and after improvements are made. Year one of this study focused on assessing the performance of the lower (Denil) and upper (pool-and-weir) ladders using two PIT telemetry systems with four PIT loop antennas per station. Transit time of 403 tagged fish was measured through and between each ladder from May- June 2022. In addition, two release locations were used to collect pre-improvement data at the middle fish ladder. Results from year one will be presented as well as a discussion on next steps.