Biology, Management, and Protection of North American Sturgeon

Abstract

<em>Abstract.</em>—The white sturgeon population <em>Acipenser transmontanus</em> in the Kootenai River was listed as endangered by the U.S. Fish and Wildlife Service (USFWS) in 1994 due to postglacial isolation and the virtual lack of recruitment since 1974. The Kootenai River White Sturgeon Conservation Aquaculture Program was initiated to preserve genetic variability, begin rebuilding natural age-class structure, and prevent extinction while measures are identified and implemented to restore natural recruitment. The program is part of a comprehensive recovery strategy detailed in the USFWS recovery plan for the Kootenai River population of white sturgeon. A breeding plan, including culture methods to minimize potential detrimental effects of conventional stocking programs, has been implemented to guide recovery, population management, and the systematic collection and spawning of wild adults before they are lost from the wild breeding population. Between 1990 and 2000, 33 families were produced from the mating of 51 wild white sturgeon broodstock. Genetic analysis indicated that five mitochondrial control region length variants represented in the wild white sturgeon population were represented in similar frequencies in the wild white sturgeon broodstock. A total of 2,702 hatchery-reared white sturgeon were released into the Kootenai River between 1992 and 1999. White sturgeon juveniles approved for release had no diagnostic disease symptoms and less than or equal to 10% prevalence of endemic pathogens. A total of 398 hatchery-reared fish were recaptured in the wild (14.7% of 2,702 stocked; single recapture events) during the 1993–1999 sampling period. The Kootenai River Conservation Aquaculture Program is currently meeting its objectives of reducing the threat of population extinction by providing frequent year classes from native broodstock, representing inherent within-population genetic diversity in its broodstock and progeny, and minimizing the introduction of disease into the recipient wild population.