Abstract
1. Selenium dioxide pretreatment prior to liver formation in Japanese ricefish (Oryzias latipes) failed to protect against mercuric chloride. The mercuric chloride LC50s and 95% confidence limits for selenium pretreated Oryzias latipes and for those not pretreated were 5.8 (5.6-6.1)mg/l; and 5.9 (5.5-6.2) mg/l, respectively. 2. Selenium pretreatment following liver formation was protective against mercuric chloride. The mercuric chloride LC50s and 95% confidence limits for selenium pretreated embryos and for those not pretreated were 7.6 (7.0-8.2) mg/l; and 6.5 (6.1-7.0 mg/l respectively. 3. The central roles of the liver, circulatory system and kidney in selenium protection against mercury are discussed. © 1980.