Monday October 3, 2022

Daily Fly

Walleye have spread throughout the Columbia River basin following an unauthorized introduction to Lake Roosevelt in the mid-20th century. These fish have remained downstream of Idaho’s salmon and steelhead rivers until recently. Data collected at the Lower Granite Dam adult fish trap has shown that walleye have been moving through the fish ladder and likely passing over this dam since at least 2016 (2016=2; 2017=11; 2018=49; 2019=20; 2020=45; 2021=75).

The adult fish trap is located halfway up the fish ladder and allows biologists to trap and handle a portion of fish moving through the ladder. Because the adult trap collects only a portion of fish moving up the ladder, these numbers represent a fraction of what has actually passed upstream of the dam over the last handful of years. We estimate that 160 walleye in 2020 and 294 in 2021 passed over Lower Granite Dam, and passage in 2022 is shaping up to be the largest yet. Additionally, anglers are encountering walleye in Idaho’s anadromous waters with increasing frequency, including one fish caught over 80 miles up the Salmon River near the town of Riggins.

Read more >

Link copied successfully