|Davidson, John -|
|Mazik, Patricia -|
Submitted to: Hatchery International Magazine
Publication Type: Trade Journal
Publication Acceptance Date: April 22, 2009
Publication Date: N/A
Technical Abstract: Intensive aquaculture systems, particularly recycle systems with all their pumps, blowers, and filters can be noisy, but the potential effects of this underwater noise on fish have not been evaluated. Earlier field and laboratory studies have shown that fish behavior and physiology can be adversely affected by noise, therefore, it is possible that chronic exposure to noise in aquaculture production systems could increase stress, reduce growth rates, and lower survival. Recently, researchers at the Freshwater Institute examined the effects of culture system noise on the growth, condition factor, feed conversion efficiency, and survival of rainbow trout, Oncorhynchus mykiss, following earlier work that had evaluated the effects of production noise (at 115, 130, 150 dB re 1uPa RMS) on the same species. Their study further evaluated the effects of noise at 115 and 150 dB, with 4 replicates per treatment, which provided more statistical power. They also analyzed additional parameters, including growth rates of individually PIT-tagged fish. These two treatments represent sound levels lower than those recorded in an intensive culture system, and near the upper levels known to occur in recycle systems. The results of the study imply that growth and survival of rainbow trout are unlikely to be affected by continuous noise levels commonly experienced in intensive aquaculture systems, but also shows that growth could be inhibited briefly by sudden increases in noise. These results should not be generalized -- other species of fish have different hearing abilities: hearing specialists such as catfish, carp, and minnows could respond much differently.