Earlier this month, researchers found that some blue whales change their behavior when exposed to military sonar. Military sonar has been blamed for many mass strandings, but it isn’t the only noise in the ocean that affects marine life and marine mammals aren’t the only creatures bothered by noise.
A study published a few weeks ago reveals that noise from passing ships has multiple negative impacts on the common shore crab (Carcinus maenas). Researchers from the Universities of Exeter and Bristol found that ship noise disrupts feeding for the crabs and that when threatened, they took longer to retreat to shelter, increasing the potential for predation.
“Crabs feeding on mussels were often distracted when ship noise was playing compared to quiet harbour recordings,” explained Matt Wale from the University of Bristol in a statement. “Furthermore, crabs took longer to retreat to shelter after simulated attacks in noisy treatments, and if turned upside-down they flipped back far quicker in noisy conditions rather than turning slowly to avoid attracting attention of potential predators.”
A previous study from the same research team found that ship noise also increases the metabolic rate and energy needs of common shore crabs. If the crabs require more energy and get distracted by noise when feeding, they will spend more time feeding to compensate. The more time they spend feeding, the higher their risk of becoming a meal for something else. This “elevated predation risk” could threaten the very survival of the species.
Fish are usually attracted to reefs by the sounds the reef inhabitants produce. In fact, they normally use sound from fish and other reef residents to find a suitable habitat, but when a reef is contaminated with boat noise, the fisher are more likely to swim away from the reef.
But it’s important to remember that the ocean would still be a very noisy place even without noise pollution from us humans.
To make that point, listen to the recordings from Oregon State University (OSU) of an iceberg breaking in two (although the cause of breaking, moving icebergs might be due to human-induced climate change, but that’s another story). You won’t believe how loud it is.
“We call the sounds ‘icequakes’ because the process and ensuing sounds are much like those produced by earthquakes,” explained Robert Dziak, a marine geologist at OSU’s Hatfield Marine Science Center in a news release.
The sounds produced by a breaking iceberg can be so loud that hydrophones near the equator actually record them. Check it out:
To learn more, read some of these related posts:
- Researchers Record Whales’ Reaction to Sonar
- Sonar and Marine Mammals: A Summary
- Ship noise impairs feeding and heightens predation risk for crabs
- How Does Noise Affect Fish?
- Ship noise makes crabs get crabby
- Boat noise stops fish finding home
- Long Before Human Noise Pollution, Oceans Were Loud as a Rock Concert
- The sounds of science – melting of iceberg creates surprising ocean din
- Conservationists Call For Quiet: The Ocean Is Too Loud!
Copyright © 2013 by Marine Science Today, a publication of Marine Science Today LLC.