Right-side up, then upside down,
Little Ray loved to act the clown.
The young stingray showed off for friends,
Who cheered his leaps and flips and bends.
(“Little Ray & Shark Patch Things Up”)
Some ocean sounds present a noise pollution threat for marine life.
Rolling tides and gentle waves are not the only ocean sounds heard in the sea. It is full of the naturally occurring sounds of fish barks, bubbles, groans, grunts, hoots, moans, thumps and some splashing noises. Sounds made by several sea mammals are familiar to humans; seals, sea lions, walruses, dolphins and whales. Many people have heard dolphins and whales chirp, squeak, click and make whistling sounds through their blow holes. Because they are different, but related mammals, some dolphin sounds may not be possible for porpoises to make. Unlike dolphin and whale sounds, humans cannot hear porpoise sounds.
Most fish can hear or sense all of these naturally occurring sounds of marine life and the water in which they reside. Dolphins, porpoises and whales depend upon these ocean sounds to navigate, find food and communicate in an environment where sight and smell are not very useful. Unnatural sound presents a noise pollution threat that interferes with useful sounds needed for the survival of marine life.
Natural ocean sounds can cause some fish to flee and may draw aggressive species in for an attack. Stingrays will flee sound vibrations, such as those made by shuffling feet in the sand. Sharks are known to attack flapping sounds that could be indicative of weak prey. When whales slap their tales, fish may herd together for safety. This gives many eyes to the school. It also provides a confusing mass from which some predators cannot distinguish individual prey. With a whale, however, the whole school may get eaten as a group.
It is the unnatural, loud ocean sounds that are stressful for marine life. These noise pollution threats include the recreational sounds of loud music, boat engines, and depth sounding devices. The extremely loud and unnatural ocean sounds of military sonar blasts, oil drilling booms, ship engines and undersea construction present increasingly severe and increasingly common noise pollution threats. These noises can affect the physiology and behavior of marine life. Some noises can seriously injure or kill marine life. To combat this problem, NOAA is mapping a strategy for the reduction of these oceanic noise pollution threats to marine life.