Change of salinity of medium as a function loading in estimating functional state of the crayfish Astacus leptodactylus

Benthic invertebrates are widely used in toxicological research and in automated biomonitoring systems for assessing water quality. However, development of criteria of physiological performance is still required for identification of candidate animals. Assessment of an organism's performance proposed in the paper is based on standard test treatments of different magnitude and exposure time. With freshwater crustaceans, such a treatment (functional stress) may be performed by changing water salinity by 1aEuro degrees through addition of sodium chloride. A non-invasive cardiac rhythm recording method has been used to reveal the response of the cardiovascular system of crayfish to this treatment.