Midwest Fish & Wildlife Conference 2018

AUTHORS. Nicholas Porter, University of Wisconsin-Stevens Point; Dr. Joshua Raabe, University of Wisconsin-Stevens Point; Dr. Daniel Isermann, U.S. Geological Survey, Wisconsin Cooperative Fishery Research Unit, Fisheries Analysis Center, College of Natural Resources, University of Wisconsin-Stevens Point; Darren Kramer, Northern Lake Michigan Unit Manager, Escanaba Field Office-Michigan DNR; Michael Donofrio, NR Region Team Supervisor, Wisconsin Department of Natural Resources; Robert Elliott, U.S. Fish & Wildlife Service

ABSTRACT. Lake Sturgeon Acipenser fulvescens are large, iconic, and long-lived fish that migrate from Lake Michigan into tributaries to spawn, but dams often impede access to historic spawning habitats. The Menominee Dam on the Menominee River, Michigan and Wisconsin, is only 3.9 km upriver from Green Bay; therefore, a fish elevator was constructed in 2014 to capture, sort, and trap-and-transfer Lake Sturgeon upstream of the two lowest dams. This is the first elevator specifically targeting Lake Sturgeon, so our first objective was to determine if environmental (e.g., season, photoperiod) or operating procedures (e.g., attraction flow, soak durations) influenced elevator captures. In Spring 2017, a total of 331 elevator lifts (742 h soak time) captured 90 sturgeon including 14 recaptures; mean total length was 1,354 mm and ranged from 991-1,765 mm. Preliminary data suggests higher attraction flow, longer soak times, diurnal operation, and a water temperature near 12.8 ºC may increase elevator efficiency. Relatively little is known about Lake Sturgeon behaviors near dams and how behaviors may influence captures or passage, so our second objective was to learn about movements near Menominee Dam. In Spring 2017, we captured and released 20 individuals downstream of the elevator that were tagged with both acoustic and radio transmitters. We used stationary acoustic receivers to quantify how many and how long tagged individuals were near the elevator, and radio telemetry to triangulate individuals at various times. Preliminary telemetry data indicates abundance of tagged fish peaked at the same time as elevator captures while radio telemetry data suggests that Lake Sturgeon prefer to reside just off the main current. Through additional sampling seasons and analyses, our study goals are to provide guidelines for operating the elevator that will optimize Lake Sturgeon captures and offer information on behaviors near dams that may benefit other managers considering passage.