Kootenai River White Sturgeon Studies, Annual Report FY 1993.

Abstract

This report evaluates natural spawning of white sturgeon in the Kootenai River before, during and after the 1993 augmented discharge period. To determine how altering the operation of Libby Dam may improve conditions for natural spawning of white sturgeon in the Kootenai River, discharge from Libby Dam (with no power peaking or load following) was increased to produce 20 kcfs ([plus minus] 2 kcfs) discharge at Bonners Ferry, Idaho, for a 14 day period June 2--16. Objectives of this research were to determine if white sturgeon spawned in the Kootenai River during 1993; and collect baseline biological data including timing, location, and habitat requirements of white sturgeon spawning in the Kootenai River in order to formulate and implement future flow regimes as effective recovery measures for white sturgeon. While sampling is not expected to collect a majority of white sturgeon eggs or larvae produced in a river, the fact that over 41,000 hours of sampling (combined gear) collected only 3 white sturgeon eggs and no larvae suggests that spawning conditions during 1993 were inadequate to benefit this population.