Daniela VASILE^1*, Magadalena TENCIU², Neculai PATRICHE², Marieta COSTACHE³, Dragomir COPREAN^1,4, Anca DINISCHIOTU³ & Lucica TOFAN^1
1‘’Ovidius’’ University Constanta, Romania/ *Corresponding author e-mail: vasile_dany@yahoo.com
²Institute of Research and Development for Aquatic Ecology, Fishing and Aquaculture (IRDAEFA) Galati, Romania
³University of Bucharest, Romania
⁴The Academy of Romanian Scientists

THE ACUTE TOXICITY OF COPPER AND ZINC ON THE PROTECTED STELLATE STURGEON JUVENILES
(ACIPENSER STELLATUS PALLAS, 1771)

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Pollution represents one of the main reasons for the decline of sturgeons in the Danube River, together with overfishing, damming, poaching, habitat lost, lack of effective management. Although water pollution by heavy metals in the Danube is considered to be very high, there is no specific data available on its impact on sturgeons Acipenser stellatus (stellate sturgeon), one of the three anadromous sturgeons existing presently in the Danube, which is critically endangered under IUCN Red List 2010 (International Union for Conservation of Nature) and listened in Appendix II of CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora). Nowadays it is believed to be extinct from the upper and middle Danube. The aim of this study was to assess the acute toxicity of copper and zinc on stellate sturgeon juveniles by semi-static renewal test, according to OECD (Organisation for Economic Cooperation and Development) guidance, using dechlorinated tap water with a hardness of 340 mg/l CaCO3. The LC50 values for copper and zinc ions, were determined to be 0.547 mg/l for Cu²⁺ and 34.22 mg/l for Zn²⁺ respectively, according to the probit method. Even if the calcium ions offer a clear protection against copper and zinc toxicity in the conditions of high water hardness, Acipenser stellatus species, remains very sensitive to the toxicity of these two metallic ions, with LC50 values lower than for other fish species.