Genetic techniques inform conservation aquaculture of the endangered Kootenai River white sturgeon Acipenser transmontanus

Abstract

Large river-resident and diadromous fishes are globally threatened by environmen- tal degradation, overharvest, and a rapidly changing climate. Conservation aquaculture is a tool that, used in concert with ecological restoration and harvest regulation, can protect the unique genetic, morphological, and behavioral characteristics of imperiled populations. Although conser- vation aquaculture programs are designed to minimize genetic impacts on wild populations, founder effects, domestication, and inbreeding may occur. Genetic monitoring may be used in the context of adaptive management to reduce deleterious genetic impacts of captive breeding in wild populations. Here we use the conservation aquaculture program for the endangered Kootenai River white sturgeon Acipenser transmontanus as a case study to illustrate how genetic tools might improve captive breeding programs for large river fishes. We used microsatellite markers to reveal very low levels of genetic diversity in the Kootenai River white sturgeon relative to other populations across the species' range. We show that by using high numbers of broodstock, the conservation aquaculture program has captured 96% of the population's microsatellite diversity in hatchery-released progeny in only 10 yr. We validate the power of parentage analysis to iden- tify family relationships between individual white sturgeon using a panel of 18 microsatellite loci. Parentage analysis will become crucial for inbreeding avoidance in the Kootenai River white stur- geon aquaculture program in ~2020 to 2030, when the majority of broodstock available for captive breeding will originate from the hatchery.