[A change of the medium salinity as a functional load for evaluation of physiological state of the crayfish Astacus leptodactylus].
The necessity of developing criteria for evaluation of the functional state of benthic invertebrates for toxicological studies or for their use as biosensors in systems of the water quality biomonitoring is emphasized. It is proposed to evaluate the organism state with aid of standard test actions dosed by strength and duration. For freshwater crayfish, such action--the functional load--can be the medium salinity change by 1%o, which can be achieved by addition of sodium chloride. Peculiarities of the response reaction of the crayfish cardiac system to such action have been shown by non-invasive method of recording of cardiac activity.