Genetic Evaluation of the Lake Sturgeon Reintroduction Program in the Mississippi and Missouri Rivers

Abstract

Over the past 20 years, there has been a growing awareness of the impact of genetic factors on the success of reintroduction programs for fish and other species. One primary genetic criterion to be considered in the design and implementation of reintroduction programs is the maximization of genetic diversity within reintroduced populations. Reintroduction has become an important management tool for the imperiled lake sturgeon Acipenser fulvescens. However, little published work has evaluated current lake sturgeon reintroduction programs in terms of their ability to transfer genetic diversity from source populations to reintroduced populations. We evaluated the success of an ongoing lake sturgeon reintroduction program based upon its ability to adequately transmit the genetic diversity of the Lake Winnebago source population into reintroduced populations in the Mississippi and Missouri rivers. Additionally, a nonreintroduced single year-class from a hatchery population established from the Lake Winnebago stock was included in this study to determine how much of a source population's genetic diversity could be captured in a single stocking event. Reintroduced populations exhibited levels of genetic diversity similar to that of their source population, and estimates of genetic differentiation revealed very little divergence between source and reintroduced population pairs. Significant levels of genetic differentiation between the Lake Winnebago and nonreintroduced hatchery fish, as well as evidence of a bottleneck within the hatchery fish, indicated that the small number of parents used in a single-year stocking event may not adequately exploit a source's available genetic diversity. Therefore, a multiple-year stocking strategy may be most appropriate for lake sturgeon reintroduction programs.