Effects of Exposure to Ammonia in Water: Determination of the Sublethal and Lethal Levels in Siberian Sturgeon, Acipenser baerii

The initial aim of this work was to situate the sensitivity of the Siberian sturgeon (Acipenser baerii B.) to ammonia compared with other species. Ammonia toxicity in the Siberian sturgeon was analysed, and the 24 h LC50 was performed for different weight groups. This sensitivity is currently determined by normalized tests of short duration, even if their practical application is difficult. During exposure to high levels of ammonia, we also observed alterations of the branchial tissue and modifications in haematological characteristics, in the behaviour of the fishes and tetany. Thus, the interpretation of these observations remains difficult, and we propose an experimental protocol under controlled conditions of pH, oxygen partial pressure PO2, carbon dioxide partial pressure PCO2, temperature and ammonia concentrations in water for 72 h duration to perform additional experiments in physiology and biochemistry.