[The effect of SDS, sodium dodecyl sulfate, on the metabolism and swimming capacity of Cyprinus carpio].

Synthetic agents are important sources of pollution in Brazil, especially in the large urban centers. Of these, SDS has been largely employed as a reference substance in toxicity tests with aquatic organisms. Studies on the effect of this substance on the physiology and behavior of fish are scanty. In this study the metabolism and swimming capacity of Cyprinus carpio, at a given swimming velocity (10.15 cm/sec), were analyzed in relation to acute exposition to different concentrations of SDS (1 ppm, 5 ppm, 10 ppm). The metabolism and swimming capacity of a fish are the product of many integrated complex physiological processes that can be directly related to variations in environmental conditions. The results show that oxygen consumption increases while swimming capacity decreases with increasing concentrations of SDS in all size classes studied. At the highest concentration employed (10 ppm), swimming capacity was reduced 5 times and oxygen consumption increased 2.8 times in relation to the control. In general, the pollutant effects on swimming activity are more pronounced in smaller fish whereas the effects on oxygen consumption is more pronounced in larger ones.