The blood sex hormone levels in sexually mature male atlantic salmon (Salmo salar) in the Westfield River (pH 4.7) and the Medway River (pH 5.6), Nova Scotia.

Blood samples were taken from fourteen sexually mature (ripe) male Atlantic salmon (Salmo salar), eight from the acidic Westfield river (pH 4.7) and six from the less acidic (pH 5.6) Medway river to determine if there is any difference in sex hormone production in the fish in the two rivers. The plasma levels of the two principal male sex hormones, testosterone and 11-ketotestosterone, which normally peak at functional sexual maturity, were significantly lower in salmon from the more acidic Westfield river compared to those in salmon from the Medway river. Since these fish were of the same stock, and were in the same state of sexual maturation, it is suggested that the more acidic Westfield River has affected the production and/or utilization of sex hormones in this species.