Water may seem to muffle noise when people go underwater, but this isn't the case in the open ocean. Aquatic animals are exposed to more noise pollution than at any time in history due to human activity.
Humans are affecting sea life with noise pollution.
Underwater Noise Pollution
Researchers from the University of Saskatchewan studied the effect of noise pollution on marine life. They determined that noise pollution can limit an animal's ability to process chemical information released after an attack on shoal mates. Scientists analyzed the effect of noise from small motorboats on coral reef fish in the Great Barrier Reef in Australia.
Researchers published the study in the journal Proceedings of the Royal Society B. They trained young damselfish to recognize the smell of a the dottyback, which is a predator, as a threat. One group was trained using boat noises in the background, and the other group was trained using ambient ocean sounds.
Fish that were trained in the noisy environment showed no reactions when being exposed to the dottyback. Those that were trained without the boat noises in the background reacted frightfully when exposed to the predator. Fish show fright by reducing activity and foraging.
Scientists attempted the same type of training but instead added sight to the mix of three common predators, again with and without boat noises. The noise had a large effect on the first. Three days after being released back into the wild, only 20 percent of the fish trained with boat noises were still alive. Almost 70 percent of the fish trained in an ambient environment was alive.
The fish used in the study had a hard time learning while being in a noisy environment. Scientists concluded that the fish have failed to learn and weren't affected by the stress of being exposed to the sounds. Boat noises have an effect on the learning of fish.
The researchers from the study suggest that quiet zones should be introduced to help wildlife in the area. They also suggest adding more speed restrictions and using muffler or low-volume engine models.
Effects Of Noise Pollution
Sounds that are affecting sea life include motors, the ping from SONAR, and the noise from offshore development. These noises can cause acoustic trauma and death to aquatic animals. Other noise such as shipping boats don't kill animals directly but affects their ability to find food, mate, or recognize predators.
Fish make noises such as chirps, pops, knocks, and grunts using their teeth, swim bladders, or fins. Noise can mask a fish's ability to hear the sounds that other fish make. These noises can distract and confuse fish, which can potentially cause them death.