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February 28, 2011

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Noise distracts fish from dinner: study

Feb. 28, 2011
Courtesy of the University of Bristol
and World Science staff

At least one spe­cies of fish can’t track down food as well when un­der­wa­ter noise is an­noy­ing it, a new study in­di­cates.

The find­ings are rel­e­vant as sci­en­tists grow in­creas­ingly con­cerned about the ef­fects on sea life of noise made by boats.

Re­search­ers used un­der­wa­ter speak­ers to play noise at lev­els si­m­i­lar to those pro­duced by recrea­t­ional speed­boats. Three-spined stick­le­backs in a large fish tank, ex­posed to the noise for as lit­tle as ten sec­onds, more for­ag­ing mis­takes and were less ef­fi­cient at con­sum­ing the avail­a­ble food com­pared to those in qui­et con­di­tions, they found.

“Much as you or I might strug­gle to con­cen­trate on a dif­fi­cult as­sign­ment when faced with loud con­struc­tion noise, these stick­le­back 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,” said Jul­ia Purs­er of the Uni­vers­ity of Bris­tol, U.K., the stu­dy’s lead au­thor. The find­ings are pub­lished in the re­search jour­nal P­LoS One.

In the wild, the din probably in­creases the chances of fish eat­ing harm­ful items or of get­ting eat­en in turn by some­thing else, she added, not­ing that real-world un­der­wa­ter noise of­ten lasts much long­er than that in the stu­dy.

“Noise pol­lu­tion is a rap­idly in­creas­ing is­sue of glob­al con­cern, es­pe­cially un­der­wa­ter,” said Co-au­thor An­dy Rad­ford, al­so of the uni­vers­ity. “Although lots of re­search has con­sid­ered the po­ten­tial im­pacts on ma­rine mam­mals, we know rel­a­tively lit­tle about how fish are af­fect­ed, de­spite their crit­i­cal im­por­tance as a food source for the bur­geon­ing hu­man popula­t­ion. Our study sug­gests there could be a much wid­er range of det­ri­men­tal ef­fects than pre­vi­ously thought, and so there is a vi­tal need for fur­ther re­search.”

Purs­er added: “this study il­lus­trates the im­por­tance of not only look­ing for the more ob­vi­ous im­me­di­ate ef­fects of noise, such as hear­ing deficits and dra­mat­ic be­havioural changes as­so­ci­at­ed with stress, but al­so ex­am­in­ing the more sub­tle but none­the­less im­por­tant and po­ten­tially dam­ag­ing im­pacts on the eve­ry­day be­hav­iour of an­i­mals.”

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At least one species of fish can’t track down food as well when underwater noise is annoying it, a new study indicates. The findings are relevant as scientists grow increasingly concerned about the effects of noise made by boats on sea life. Researchers used underwater speakers to play noise at levels similar to those produced by recreational speedboats. Three-three-spined sticklebacks in a large fish tank, exposed to the noise for as little as ten seconds, more foraging mistakes and were less efficient at consuming the available food compared to those in quiet conditions, they found. “Much as you or I might struggle to concentrate on a difficult assignment when faced with loud construction noise, these stickleback 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,” said Julia Purser of the University of Bristol, U.K., the study’s lead author. The findings are published in the research journal PLoS One. In the wild, such distraction probably increases the chances of fish eating harmful items or of getting eaten in turn by something else, she added, noting that real-world underwater noise often lasts much longer than the exposures used the study. “Noise pollution is a rapidly increasing issue of global concern, especially underwater,” said Co-author Andy Radford, also of the university. “Although lots of research has considered the potential impacts on marine mammals, we know relatively little about how fish are affected, despite their critical importance as a food source for the burgeoning human population. Our study suggests there could be a much wider range of detrimental effects than previously thought, and so there is a vital need for further research.” Purser added: “this study illustrates the importance of not only looking for the more obvious immediate effects of noise, such as hearing deficits and dramatic behavioural changes associated with stress, but also examining the more subtle but nonetheless important and potentially damaging impacts on the everyday behaviour of animals.”