Commercial activity causing acoustic harassment to marine life
Human activity—especially ships, seismic surveys, air guns, pile drivers, dynamite fishing, drilling platforms, speedboats and surfing—have made the world’s oceans an unbearably noisy place for marine life, according to a review of the impact of anthropogenic ocean noise published in the journal Science, which was reported by Sabrina Imbler in The New York Times.
The study is a collaboration among 25 authors from across the globe and various fields of marine acoustics. It is the largest synthesis of evidence on the effects of oceanic noise pollution, the NYT reports. Anthropogenic noise drowns out the natural soundscapes, putting marine life under immense stress. In the case of baby clown fish, the noise can even doom them to wander the seas without direction, unable to find their way home, the report mentions.
“In the ocean, visual cues disappear after tens of yards, and chemical cues dissipate after hundreds of yards. But sound can travel thousands of miles and link animals across oceanic basins and in darkness… As a result, many marine species are impeccably adapted to detect and communicate with sound,” the report mentions. The study maps out how underwater noise affects marine life, including zooplankton and jellyfish.
The authors screened more than 10,000 papers, and patterns emerged demonstrating the detrimental effects of noise on marine life.
“Marine life can adapt to noise pollution by swimming, crawling or oozing away from it, which means some animals are more successful than others. Whales can learn to skirt busy shipping lanes and fish can dodge the thrum of an approaching fishing vessel, but benthic creatures like slow-moving sea cucumbers have little recourse,” the report says.
The noise has the ability to badly limit certain animals. The report adds: “The forced evacuation reduces population sizes as more animals give up territory and compete for the same pools of resources. And certain species that are bound to limited biogeographic ranges, such as the endangered Maui dolphin, have nowhere else to go.”
Quieter propeller designs, bubble curtains, which can wrap around a pile driver and insulate sound, are some of the innovative solutions mentioned in the report, which also sounds a note of caution against deep-sea mining that could become a major source of underwater noise.