Fish sound production in freshwater habitats of New England: Widespread occurrence of air movements sounds.

We conducted a roving survey of five major river systems and adjacent, creek, lake, and pond habitats located within the northeastern United States. Fish sounds were recorded in 49% of 175 locations. Air movement sounds, including fast repetitive tick (FRT), occurred at 41% of the locations. Sluggish creeks had the highest occurrence of fish sounds (71%). Although highly variable, creeks and brooks had the lowest noise levels and rivers the highest. Fish sounds were more frequent in low noise habitats than high noise habitats, but the effect of masking on detection is not clear. Within main-stem river habitats, fish sound diversity tended to increase along a gradient from high elevation to the sea. Follow-up studies validated air movement sounds produced by alewife, white sucker, and brook, brown and rainbow trout through direct observation or in observations where only single species were present. Sounds produced by all five species are of the “air movement” type which is poorly understood but occurs widely in freshwater habitats. Although air movement sounds are likely incidental to physiological processes, they appear to be uniquely identifiable to species and, hence, hold promise for passive acoustic studies of freshwater soundscapes and fish behavior.