Does Human-Caused Underwater Noise Hurt Fish?

Here's a little scientific affirmation of the old "Be quiet, or you'll scare the fish!" line your dad used to give you...

From this story on Wired Science:
After years of growing concern about the effects of marine noise on whales, scientists are finally asking what noise could do to fish. Whether they're harmed isn't yet known, but it's certainly a possibility. The oceans are an increasingly clamorous place, with boat motors and sonar and explosions and construction creating a din at frequencies used by fish. "If you're walking down the street and someone is jackhammering, you walk across the street and go around. What happens to a fish?" said University of Maryland aquatic noise specialist Arthur Popper. "How fish respond to sound is the big question for all of us." Popper co-authored a review of the field's patchy, question-filled literature in the June Trends in Ecology and Evolution, marking a shift in thinking about ocean noise.

_Until recently, researchers and environmentalists who thought at all about aquatic noise were focused on marine mammals and especially whales, which can be debilitated by sonar and engine noise. But the world's 21,000 fish species also rely on sound. Many use it to communicate, and almost all rely on acoustics to navigate a dark, often turbid world. What Jacques Cousteau called "The Silent World" is actually full of natural noise, from fish calls to the sound of their bodies moving through water. To that natural din, human activity has added roughly 10 decibels of ambient commotion in the last half-century. At construction sites for offshore oil platforms, wind farms and river bridges, where explosions and pile drivers can hit 250 decibels repeatedly for months or years on end, the noise is even more intense.

All this has concerned researchers like Popper, who warn that scientists simply don't know how fish respond. "It might be that fish are well-adapted to noise. Maybe it's not a problem. We don't know," said Rob McCauley, a marine biologist at Australia's Curtin University of Technology. "The work that's been done has only scratched the surface."_