AN EARLY EMBRYO MODEL OF STERLET (ACIPENSER RUTHENUS) FOR THE ASSESSMENT OF LEAD EFFECTS

The objective of the study was to devise a 96 h test of sterlet embryos (Acipenser ruthenus) in order to evaluate if this species is suitable for water pollution investigation as an evaluation tool. Replicate concentrations of lead acetate were selected from 400, 200, 100 and 50 mu gL(-1). Each mirror-aquarium was filled with 10 L of lead acetate dilutions, excluding the control, the free sterlet embryos were inserted as follows: 50 / aquarium, i.e. 100 / concentration and control group). The fish were examined at time 0, then at: 12, 24, 48, 72 and 96 hours, every change in behavior or in the body somatic was statistically analyzed, according to ANOVA (significant when p < 0.05, or less). Evaluation revealed significant connection among the embryos length (p < 0.05), weight (p = 0.01; p < 0.01) and the dead embryos proved the deleterious feature of lead at 400 and 200 mu gL(-1). The main critical points were: the delayed resorption of the yolk sac; deformed tail; undeveloped eyes; massive haemorrhages; atypical / altered pigmentation and exitus observed at 12 h. Although A. ruthenus is not considered as a standard subject in the pollution assays, it was observed that, changes can be applied for early fish stages as a parallel to other accepted tests.