Submitted to: Book of Abstracts World Aquaculture Society
Publication Type: Abstract Only
Publication Acceptance Date: September 20, 2000
Publication Date: January 21, 2001
Citation: STRAUS, D.L., GRIFFIN, B.R. EFFECT OF ALKALINITY ON THE ACUTE TOXICITY OF COPPER SULFATE TO BLUE TILAPIA.. AQUACULTURE CONFERENCE PROCEEDINGS. 2001. p.617. Technical Abstract: Copper sulfate is used extensively in aquaculture as a therapeutant for Ichthyophthiriasis. The effectiveness of this compound is diminished as the total alkalinity of waters increase. The acute toxicity of copper to many species has been studied, however there is a paucity of data for blue tilapia (Tilapia aurea). Blue tilapia were exposed to copper sulfate in a series of static toxicity tests conducted with waters having a wide range of total alkalinity and hardness values. Estimates of mean 96 h LC50 values were 0.2, 0.7, 6.0 and 45.7 mg/L (as Cu) in waters having total alkalinities of 16, 57, 112 and 225 mg/L CaCO3, respectively. As illustrated in the figure, the toxicity of copper is reduced logarithmically as a linear function of total alkalinity. Copper sulfate is the compound of choice to control ichthyophthiriasis because of its effectiveness and low cost, but it can be extremely toxic to fish in water of low alkalinity. This information will help extension personnel formulate safer and more effective application rates for copper sulfate in blue tilapia farming.