Benfeidl MCAldrich DVCanadian Journal of Fisheries and Aquatic Sciences2010-02-152010-02-151994 Aprhttp://hdl.handle.net/1969.3/23509784-791Responses of postlarval brown shrimp (Penaeus aztecus) to pentachlorophenol (0-450 mug.L-1) were measured in synthetic seawater and estuarine water using a laminar-flow choice chamber. This chamber provides individual postlarvae with equal exposure to two parallel olfactant streams separated by a steep concentration gradient. Shrimp detected and avoided pentachlorophenol concentrations above 91 mug.L-1 in synthetic seawater. This detection threshold reflects limitations in statistical power, and with increased replication the physiological threshold could probably be resolved at a much lower concentration. Pentachlorophenol appeared to be more repellent when dissolved in estuarine water from Galveston Bay, Texas. The 96-h LC50 for pentachlorophenol was 317 mug.L-1 which suggests that postlarvae are capable of avoiding acutely toxic concentrations of this pollutant. For postlarvae of this species, behavioral avoidance appears to provide a more sensitive indicator of pollutant responses than the conventional toxicity bioassayWATERFISHATTRACTIONPOLLUTANTSJournal