To contend with the ever increasing level of noise in the oceans, North Atlantic right whales have recently learned to yell in louder voices to each other. Some biologists are now speculating if orca whales living in our San Juan Islands kayaking routes must do the same.
The discovery of the right whales yelling in the Gulf of Maine was made by recording both the whales’ calls and the background noise using audio data recorders attached to the whales with suction cups. The underwater background noise ranged from 92 to 143 decibels – enough to cause pain to human ears and the equivalent of a rush hour freeway up to a jet engine at 100 meters. The whales altered their calls to compensate for the background noise, taking them from 120dB to 150dB – just as humans do when talking in a loud places.
The main source of the background noise in the Gulf of Maine is commercial shipping that produces a constant low frequency roar. Shipping noise is a particular problem for baleen whales like the right whale, because their calls are roughly the same pitch. The San Juan Islands have less commercial shipping but many dozens of commercial whale watching boats that create higher frequency sounds that are probably much more disruptive to the killer whales’ communications and echo-locations.
Noise levels in the oceans have risen a hundredfold over the past 60 years according to studies conducted off the west coast of the US. Of particular concern are the new navy sonar devices that are much louder than ever before, and seismic testing, both of which have resulted in deaths when used near “toothed whale” species (the suborder that includes several whale families such as beaked whales, sperm whales, and members of the dolphin family including the orca whale). Environmentalists have fought in court to limit their uses near whales with very limited success despite the many documented deaths, including some in the San Juan Islands of Washington state.
Baleen whales rely on their calls for social purposes, to attract mates, and keep in contact with calves. Toothed whales use their calls for the same reasons in addition to coordinating hunts. They use high frequency clicks for echolocation, their main method of finding prey and navigating safely. Unfortunately, we don’t know how much these critical behaviors are being affected by today’s noisy ocean.
If you enjoy watching whales, be sure to do it from silent sea kayaks. Sea Quest’s whale watching kayaking tours do not contribute to the rising noise pollution, nor do they use nasty fuels that leave both air and water pollution in the whales home. Choose the environmentally sound way to watch whales – go on a sea kayaking tour!
The Whale and Dolphin Conservation Society based in the United Kingdom, is launching a campaign called “Oceans of Noise”. They are attempting to tackle the increasing problem of noise pollution in the sea. The WDCS is proposing an action plan to regulate submarine noise pollution, and says a worldwide treaty is needed.
The International Whaling Commission said there is "compelling evidence" that entire populations of marine mammals area at potential risk from increasingly intense man-made underwater noise. Its scientific committee said low-frequency ambient marine noise levels had increased in the northern hemisphere by 100 times over the last 60 years. The key sources of undersea noise they are most concerned about are commercial shipping, the search for oil and gas, and low-frequency military sonars.
They claim evidence shows it leading to hearing loss in whales, dolphins and porpoises, causing them to strand on beaches where they typically die a slow death. They also believe excessive noise is seriously interfering with cetaceans’ ability to communicate with each other, especially mothers and calves. And that these noise sources are blotting out biologically important sounds essential for both predators and their prey. Their biologists have observed whales fleeing and avoiding loud noise sources up to hundreds of miles away as sound travels so quickly through the water.
“If you want to be a friend of the earth, you have to be an enemy of the people.” T.C. Boyle
To their credit, the US Navy and oil industry have been funding some research to study the effects on whales from their new powerful sonars and other loud undersea sounds. Several stranding incidents of whales beaching themselves and dying after sonar use has prompted the need to learn more about these dangers. Peter Tyack, a senior scientist at Woods Hole Oceanographic Institution, just published his study on beaked whales in the online journal PLoS ONE. He found that the whales immediately stopped hunting when sonar began, then moved about 10 miles away and would not return for several days. He also discovered that the whales threshold of tolerance was only 140db instead of the 160db level used in current regulations. Click here to read Beaked Whales Respond to Simulated and Actual Navy Sonar.
I have always had a fascination with oceans and sea creatures. I love to read about them and the world beneath the surface. I enjoyed this post very much. Thanks a lot for sharing.