A short-term swimming speed alteration test with nauplii of Artemia franciscana

The presence of toxicant needs to be assessed within short time in order to effectively protect the aquatic environment from serious threat. Based on the observation that at high temperatures aquatic organisms become more vulnerable to stressors than those maintained at room temperature, a new test was developed. The proposed bioassay consisted in the evaluation of the swimming speed alteration (SSA) of nauplii of Anemia franciscana incubated at 39 degrees C (+/- 1) for 6 h, using a Swimming Behavior Recorder system (SBA). A comparative ecotoxicological study between the 6 h SSA test and the 24 h mortality test was carried out in order to validate the new method in terms of sensitivity by means of EC50 values. The bioassay was applied to screen different toxicants: K2Cr2O7, Cu(SO4)(2), NaClO, SDS and Sertraline hydrochloride. The EC50, calculated for the short-term SSA test and those of the mortality test showed comparable values. For all toxicants, the 6 h SSA test was proved to be as sensitive as the 24 h mortality test. The method developed in this study is the first temperature-based toxicity test with nauplii of Artemia franciscana and it represents an attractive assay in ecotoxicology because of its convenience in terms of time and costs, feasibility and sensitivity.