Habitat use of adult lake sturgeon (Acipenser fulvescens) in pool 24 of the Mississippi River

Lake Sturgeon (Acipenser fulvescens) were nearly extirpated from Missouri waters in the early 1900's. The Missouri Department of Conservation started restocking lake sturgeon in 1984 and as of December 1, 2004 approximately 286,056 were released in Mark Twain Lake, the Missouri River and the Upper Mississippi River. We are lacking basic information needed to evaluate the current lake sturgeon population. The most critical information needed concerns adult lake sturgeon movement and habitat use, with special emphasis towards identifying spawning sites. Understanding habitat use, movement rates and natural recruitment are important for determining future stocking needs and assessing the current lake sturgeon population.;Twenty five lake sturgeon were captured and implanted with radio or acoustic transmitters and tracked on a weekly basis during warm months of the year and on a monthly basis during the cold months between Fall of 2004 through Fall of 2006. Data were also collected from passive receivers that record data continuously. I used Geographical Information Systems (GIS) to summarize lake sturgeon habitat use. Habitat availability was measured individually based on the estimates of each fish's home range, and I compared habitat use to availability using Johnson's (1980) technique. Lake sturgeon selected areas near Lock and Dam 22, but most fish used a variety of habitats. Side channels were the least selected habitat. Habitat selection was similar for all seasons, but home range locations varied with seasons. During winter, lake sturgeon used the downstream portions of the pool, and during summer frequented upstream portions of Pool 24. Lake sturgeon movement was highest in the spring and fall with minimal movement during the winter. No lake sturgeon spawning was documented during the study period.