Demographic and life history characteristics of remnant lake sturgeon populations in the Upper Great Lakes Basin: Inferences based on genetic analyses (Acipenser fulvescens)

While once abundant throughout the Great Lakes, lake sturgeon ( Acipenser fulvescens) have experienced dramatic population declines over the past 100 years. Declines are due mainly to anthropogenic activities including over-harvest, blockage of spawning habitat by dams, and loss of spawning habitat due to sedimentation and pollution. While the need for rehabilitation has been recognized, knowledge of many fundamental aspects of this species life history are currently lacking. The objectives of this study were to employ molecular genetic markers to (1) assess the degree of genetic variability and assess levels of population structure present between remnant lake sturgeon populations in the Upper Great Lakes Basin; (2) to determine parentage and describe the lake sturgeon mating system; (3) to examine the genetic consequences of a supportive breeding program designed to rehabilitate a declining lake sturgeon population. The results of this study show that a significant degree of population structure exists among remnant lake sturgeon populations. Using genetic determination of parentage, this study describes the lake sturgeon mating system and documents a high degree of polygyny and polyandry as well as variance in male and female reproductive success. Results of this study also indicate that a supportive breeding program for lake sturgeon has led to an overall increase in relatedness. Results and implications of these data are discussed in light of declining population numbers.