Building a Fishway for Lake Sturgeon: Successful Testing of a Prototype Upstream Fishway on the Menominee River in Northern Wisconsin

Historically, lake sturgeon (Acipenser fulvescens) were abundant in Lake Michigan with free and unobstructed access to the feeding and spawning areas within its many tributaries. Construction and operation of hydroelectric dams has impeded this access. One method for re-establishing this lost connection is to create an artificial pathway such as a fish passage facility. To help answer some basic questions, such as will sturgeon use a fishway, we constructed a prototype fish passage structure below a hydroelectric dam on the Menominee River in northern Wisconsin. This hydroelectric facility is located near Amberg, Wisconsin and owned by We Energies. The structure was designed with a ramp to a surface entrance with a constant attraction velocity of 1.07 meters per second (mps). The structure was equipped with a Passive Integrated Transponder tag (PIT tag) reader antenna and underwater video cameras equipped with infrared lights. All monitoring equipment were installed and activated before the start of the 2009 spring spawning season (mid-April) and removed following the 2010 autumn migration (mid-October). PIT tag records indicated that 86 tagged lake sturgeon used the passage structure in 2009 and 112 in 2010, with many sturgeon going through the structure multiple times. Video data verified these results and also indicated that these sturgeon moved through the structure rather quickly (mean = 3 sec in camera view). Extrapolated to the whole sturgeon population, nearly 20% of the spawning population went through the prototype fishway in 2009 and 24% in 2010. For both years of the study, larger sturgeon were observed during the spring spawning season versus the remainder of the year, 25.4 centimeters longer on average. In 2010, the structure was fitted with a V-trap (45.7 cm gap width with 0.46 mps constant water velocity) to test whether these fish can be “trapped” in an elevator hopper. Those results indicate both small and large sturgeon (as small as 49.5 cm and as large as 142.2 cm, respectively) will pass through a 45.7 cm wide V-trap opening without hesitation. Video and PIT tag results indicated that sturgeon can be successfully attracted to and passed through a prototype upstream surface bypass, suggesting that these test parameters should be considered for use in any future upstream fish passage facilities currently planned for lake sturgeon in the Midwest.