Graduate Student: Luke Roffler Adviser: Dr. Brian Sloss
Lake sturgeon (Acipenser fulvescens) rehabilitation is currently underway in Lake Michigan by use of stream-side rearing facilities (SRFs). These SRFs are DNR facilities and are located on the Milwaukee River and Manitowoc River in Wisconsin and the Cedar River and Whitefish River in the Upper Peninsula of Michigan. The location of the SRFs allows the young sturgeon to imprint to the water of their release stream prior to stock out. This approach will help reestablish spawning runs in these streams when the sturgeon mature in 10-20 years and return for spawning. Lake sturgeon artificial rearing in Wisconsin traditionally occurred at the Wild Rose State Fish Hatchery in central Wisconsin.
Wild Rose and the SRFs vary not only in location, but also in spawning and rearing strategies. The SRF methods of one-to-one male-to-female spawning and family size equalization theoretically maximize the effective size of the hatchery population. This project will genetically evaluate the distinct strategies employed at Wild Rose and the SRFs and the relative maintenance of the genetic diversity present in the broodstock. This will be determined by measurement of allelic richness, allele frequencies, and heterozygosity. Also being assessed is whether the broodstock sampled from the Wolf River (WI) and Menominee River (MI) each year is representative of the river population, and the effect of sperm competition on the mixed milt crosses at Wild Rose and the resulting relative reproductive contributions from each male. The results of this study will indicate the most genetically appropriate spawning and rearing strategy for lake sturgeon rehabilitation in Lake Michigan. While the SRF approach is more appropriate than Wild Rose in regard to imprinting, neither type of facility has been assessed genetically. The results will also help determine whether the current capacity of the SRFs is adequate for the maintenance of genetic diversity or if larger facilities with greater capacity are necessary.
Pictures on this page provided by Luke Roffler
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