The trout farm effect on Dinocras megacephala (Plecoptera: Perlidae) larvae: Antioxidative defense

Abstract

Trout production represents a major agricultural activity in Serbia. Organic compounds are drained into the environment, usually without previous sedimentation, thus affecting the stream biota. Considering that biological monitoring is commonly based on aquatic macroinvertebrates as target organisms, the authors used larvae of Dinocras megacephala to estimate trout farm effects on the mass of the larvae and their antioxidative defense in pollution stress conditions. Four locations were chosen along the channel of the Raka River, 2 upstream (L1, L2) and 2 downstream (L3, L4) from the trout farm outlet. Basic physical and chemical water parameters were measured. Superoxide dismutase (SOD) and catalase (CAT) activity changes were analyzed to determine the level of oxidative stress caused by the increase of organic compounds originating from the trout farm. Dissolved oxygen concentration decreased from the upstream to downstream locations. Furthermore, the concentration of ionized ammonia was almost 10 times higher at the downstream locations than at the upstream locations. Larval mass, as well as CAT activity, was significantly higher at L3 compared with the other 3 locations. Activity of SOD was significantly higher at L3 than at L1. The results indicate that higher concentrations of organic compounds from the trout farm induce clear changes in the status of the antioxidant defense of D. megacephala larvae.