Identification and Genetic Diversity of Lake Sturgeon Larvae on Artificial Reefs in the Huron-Erie Corridor

• Main Author: Marranca, Jamie Marie
• Format: Text
• Language: unknown
• Published: The Research Repository @ WVU 2014
• Subjects: Wildlife conservation; Genetics; Aquatic sciences; Detroit; Ice Sheet
• Online Access: https://researchrepository.wvu.edu/etd/240; https://researchrepository.wvu.edu/cgi/viewcontent.cgi?article=1243&context=etd

There are 27 species of sturgeon worldwide and most are currently extinct, endangered or threatened. Lake sturgeon, Acipenser fulvescens, one of the oldest species on the planet, evolved about 136 million years ago, and have had little morphological change, and are endemic to the freshwater lakes and rivers created by receding glaciers of the Laurentian ice sheet. Lake sturgeon have seen immense habitat loss due to human development and industrialization has nearly decimated populations. Changes to water and habitat quality, along with overharvesting, have caused declines to nearly 1% of their original population size. The Huron-Erie Corridor (HEC), includes the St. Clair and Detroit rivers that connect the upper and lower Great Lakes. This area in particular has experienced adverse effects over nearly 200 years of human activities, including the removal of spawning habitat to accommodate shipping traffic. Conservation efforts include regulations, endangered species listing, and habitat reconstruction. The creation of artificial reefs may be a sustainable management option by allowing the fish to increase their population sizes naturally. Three artificial reefs were built in the HEC in hopes of replacing spawning habitat. To verify the success and efficacy of the artificial reefs, genetics were used to determine the source and numbers of adult lake sturgeon spawning on the reefs and to determine if genetic diversity is maintained in their offspring. The maintenance of genetic diversity is required to expand population sizes and prevent negative side effects, such as the founder effect, in future generations. Eggs were collected from each reef and hatched into larvae in the lab. DNA was extracted from larval tail clips and PCR was performed to amplify 12 microsatellite loci. The samples were run using a capillary electrophoresis to obtain allele sizes at each locus for each individual. Their genotypes were then compared to 22 previously studied adult lake sturgeon populations in the Great Lakes to determine where the parental population came from. The effective population sizes for each reef were calculated to determine how many adults successfully spawned on each reef. The larval genotypes were then compared to the source population to determine if there were any losses in genetic diversity by calculating observed heterozygosity, allelic richness, and inbreeding coefficients that are indicative of the founder effect. The St. Clair and Detroit River adult populations were found to be the source parental population for the larvae collected on all three artificial reefs. There were large numbers of contributing adults when compared to total population sizes within the Great Lakes. There was no loss in genetic diversity in the larval samples compared to their parents, and therefore no evidence of the founder effect. This supports continued protection of lake sturgeon spawning habitat as well as the construction of additional reefs in the HEC.