Problems with Collection and Interpretation of Sex Steroid Hormone Data from Wild Fish Exposed to Bleach Kraft Mill Effluent, 1995 Environmental Conference Proceedings

R.P. Schryer, S.M. Swanson, K. Holley & A.L. Leis - Golder Associates Ltd.

L. Steeves - Weyerhaeuser Canada Ltd.

T.A. Marchant - Univ. of Saskatchewan

Recent studies conducted in Canada on the effects of Bleach Kraft Mill Effluent (BKME) on fish sex steroid levels have shown decreases in the production of these hormones both during the period of gonadal development and spawning. This study was conducted to observe the sex steroid levels in longnose sucker (Catostomus catostomus) of the Wapiti River which receives secondary treated BKME from the Weyerhaeuser Canada Ltd. Grande Prairie mill. The program was conducted in two phases: 1) a late summer of 1993 phase and 2) a pre-, during and post-spawning phase in 1994. Blood serum for radio-immunoassays to determine sex steroid hormone levels, along with other life history data, were taken on 20 fish of each sex for each spawning stage. The program was repeated at a control site to obtain comparative data. Late summer results were non-conclusive. The spring spawning results showed a high degree of natural variability in the sex steroid hormone levels obtained among same sex fish of similar spawning stage. both within each site and between them. Sex steroid levels in fish exposed to secondary treated BKME were not depressed. Overall levels of sex steroids were comparable between the exposure and control sites.