Aquaculture-related stress on rainbow trout (Oncorhynchus mykiss) and Arctic char (Salvelinus alpinus)

Recent expansions in aquaculture characterize it as one of the fastest growing segments of the U.S. agricultural sector. Expansion has been facilitated by increased production of many important aquatic species including catfish, salmon, trout, tilapia, shrimp, oysters, and crawfish. West Virginia aquaculture, also an expanding industry, is currently characterized by small-scale, widely dispersed farms. To facilitate future expansion of aquaculture in West Virginia, focuses on product quality as well as production efficiency, identification of limiting factors and investigation into new or alternative management techniques are needed. Objectives of this project were to determine the effects of nitrite and carbon dioxide on the survival and physiological responses of rainbow trout and to evaluate the effectiveness of fish transport with anesthesia on reducing the physiological responses of Arctic char. Results from this project indicate that nitrite toxicity is affected by elevations in environmental carbon dioxide, and conversely, carbon dioxide tolerance is affected by environmental nitrite concentrations. Results also indicate that the anesthetic treatments investigated in this project (AQUI-S(TM), ice-slurry, and carbon dioxide) were not effective in consistently reducing the physiological responses of Arctic char during a simulated transport. We feel that additional experiments examining the interacting effects of nitrite and carbon dioxide on fish are needed to identify the physiological mechanisms or effects that lead to increased nitrite and carbon dioxide toxicities in fish, and additional experiments evaluating efficient procedures of reducing physiological responses of fish during transport is also needed.