Effects of varying levels of noise and vibration on behavioral and physiological stress responses in two species of freshwater aquarium fish: Fathead minnows (Pimephales promelas) and bluegill sunfish (Lepomis macrochirus).

Aquariums provide beautiful underwater environments for an array of fish species, but to maintain optimum water quality and aesthetically pleasing displays, a variety of mechanical systems that unintentionally produce noise, including pumps, filters, skimmers, bubblers, etc., are necessary. The objectives of this study are to measure the acoustic properties of noise in an aquarium and examine the effects of different noise levels on the stress experienced by two species of freshwater fishes: fathead minnows (Pimephales promelas), hearing specialists, and bluegill sunfish (Lepomis macrochirus), hearing generalists. We conducted a noise mapping of several fish galleries at the Shedd Aquarium using a BK 2560 SPL meter; Leq, SEL, and minimum & maximum decibel levels were measured up to 2 kHz using a DolphinEar hydrophone. We then tested the effects of four noise levels on the stress experienced by these two fish species by measuring oxygen consumption/respiration rates with Loligo respirometry chambers and cortisol release rate with a noninvasive radioimmunoassay that measures free cortisol in water samples [Ellis et al. 2004]. These measurements will help to evaluate the effects of noise in standard aquarium settings on fish welfare and may aid in the determination and regulation of acceptable anthropogenic noise levels in aquariums.