Spawning lake sturgeon in the Lower Fox River, Lake Michigan. - FWS photo by Rob Elliott

Green Bay Fishery Resources Office biologist Rob Elliott helped co-author a recent journal article in the Transactions of the American Fisheries Society that describes the genetic characteristics and structure of remnant lake sturgeon populations in the Upper Great Lakes. 

The results reported in this paper have significant implications for methods selected for rehabilitation of this species in the Great Lakes and represent a significant amount of cooperative work by a number of agencies, institutions, and researchers across the upper Great Lakes. 

Pat De Haan, past graduate student at Michigan State University, working under Dr. Kim Scribner, was lead author on this paper and used this work as part of his masters thesis.  De Haan worked out of the Green Bay FRO for two summers while working with Elliott on this project, and is currently employed at the USFWS Abernathy Fish Technology Center in Washington. 

As reported in the paper, significant variance in frequency of microsatellite alleles and mtDNA haplotypes provide evidence that remnant lake sturgeon populations in the upper Great Lakes basin are spatially genetically structured.  Most populations were found to differ significantly from one another, strongly suggesting that each is a reproductively separate group, most likely due to strong natal fidelity and associated homing at the time of spawning. 

Among the 11 populations studied, population assemblages of greater similarity were evident and corresponded to general basin of origin and watershed (southern Lake Superior, Green Bay waters of western Lake Michigan, and Michigan waters of Lakes Michigan and Huron).

Despite the dramatic declines in abundance and distribution of lake sturgeon over the last 150 years, current levels of genetic diversity in these remnant Great Lakes populations remains high, and there is no evidence suggesting population bottlenecks or genetic drift have contributed to losses in diversity or influenced the observed population structuring.  This is likely due to the species longevity and intermittent spawning behavior having buffered them from genetic losses over the relatively short time period since their decline (approximately 5 generations).

This work has provided an important foundation of information for the ongoing development of genetic conservation and related stocking guidelines for lake sturgeon in the Great Lakes that will help guide future rehabilitation actions and efforts.  Conserving the current genetic diversity should be an important objective of ongoing and future rehabilitation efforts that are focusing on increasing abundance of these remnant populations and reintroducing populations to waters where they have been extirpated.  Contact: Rob Elliott, USFWS, Green Bay FRO, robert_elliott@fws.gov.