Noisy neighbors - fish distracted by water sports

By Martin Leggett - 01 Mar 2011 22:41:0 GMT
Noisy neighbors - fish distracted by water sports

As if fish haven't got enough to contend with, being over-fished out of an increasingly acidic ocean (courtesy of human actions on both counts) it now seems that their noisy human neighbors are putting them off of their food too. The UK's University of Bristol has reported the results of a study, published Friday, into how fish respond to the noises, that human activity puts out into the marine environment. And it seems that the human racket can cause fish to fluff their foraging.

The team were investigating the impact of noise, as part of a wider assessment on the impact to sea creatures of anthropogenic noise. In order to test how the fish reacted, they played noises through underwater loud-speakers, whilst the fish, three-spined stickle-backs, consumed food provided for them.

What they found was that the fish made more mistakes, and were less efficient at foraging, than when conditions were peaceful. This was noticeable even for brief periods of noise.

The lead author, Dr Julia Purser, compared the fish's behavior to that of humans facing intrusive construction-site noise, saying ''these sticklebacks seemed unable to keep their mind fully on the job at hand, attending to random items of tank debris and mishandling food items more frequently when noise was played.''

In their natural setting, such distractions could be serious, causing the fish to swallow harmful particles, or to be more prone to predation - inefficient foraging would require them to be out of their safe-havens for longer.

The noise levels tested, while described as equivalent to that of a speedboat, probably do not equate to the levels, intensity or duration of noise experienced by aquatic animals in the real world. There the noise levels are likely to be more persistent and repeated.

So further research is being conducted by Dr Purser and co-author, Dr Andy Radford. He said ''Noise pollution is a rapidly increasing issue of global concern, especially underwater. ..we know relatively little about how fish are affected, despite their critical importance as a food source for the burgeoning human population.''