Oceans and seas are no longer “The Silent World" referred to in the 1953 book by well-known author and underwater film maker Jacques Cousteau. Since the book was written, the waters under the sea have become increasingly noisy. The increase in the number of ocean traveling ships, underwater construction, use of sonar by the military and the use of air guns by offshore drilling companies is having a detrimental noisy effect on marine animals, fish and mammals.
Underwater creatures depend on their sense of sound for navigation, avoidance of predators, reproduction and feeding. When underwater sound is polluted, marine life is disrupted. Here are just a few examples of the dangers of under the sea noise pollution.
Marine mammals like whales and dolphins depend on their sense of hearing to communicate with each other and for their sense of location. Mass strandings and beachings of these animals have been attributed to undersea sonar that disrupts their hearing and sense of direction. Many have been examined after death and found to have bleeding in their brain as well as their ears.
Whales and dolphins have died from what appears to be decompression sickness due to coming to the surface too quickly after a dive. Researchers have connected these deaths with the use of underwater sonar. There is strong evidence that the unnatural noise inspires the mammals to rise rapidly to the surface to get away from the noise. Instead, they suffer and die.
Common Shore Crabs
Ship noises have a negative effect on common shore crabs. They get distracted when they are feeding and spend more time foraging for food. They also have a delayed retreat reaction when confronted with predators and their natural “play dead" response disappears.
Squid and other Cephalopods.
Squid and other sea creatures such as cuttlefish and octopus, are being killed by under the sea noise pollution. Primarily affected by air guns used to search for offshore gas and oil, the fish are found with extreme lesions to their auditory organs so that they are rendered deaf. The fish depend on their sense of hearing for balance and spatial orientation. When they lose their balance and spatial orientation, they cannot hunt for food, evade predators or reproduce. They have also been found with internal injuries believed due to underwater sonar.
Fish in General
Ordinary fish have strong reaction to exposure to loud underwater sounds from ships, sonar and other unnatural underwater noises. They go to deeper areas of the ocean and they either become more active than usual or motionless. Their ears are severely damaged and their movements are disrupted, such as movement during the night and day become reversed.
So What Can we Do?
Reconsider what you choose to do as recreation. If you are going to be using a speed boat or motor boat, choose an area where less wildlife will be disturbed.
There are some ways others are helping as well. The National Oceanic and Atmospheric Administration is seeking to document man-made noises in the water to track how big of a problem this really is.