Too Much Noise from Ships Is A Disturbance

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A new research says that the passing ship’s noise affects the communication between sea animals such as killer whales and dolphins.

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The growth in commercial shipping has raised the intensity of low-frequency noise almost 10-fold since the 1960s.  Noise from the passing ship is a serious problem for the sea animals such as Whales and Dolphins.  The underwater din hinders the communications and their ability to find prey.

The low rumble of passing ships connects to the disturbance of large whales for a long time.

  • Underwater microphones were used by the researchers to measure the noise created by about 1,600 individual ships as they passed through Haro Strait, in Washington state.
  • A two-year study captured the sound made by 12 different types of vessel, including cruise ships, container ships and military vehicles, that passed through the strait about 20 times a day.

Findings:

  • Noise also occurs at medium and higher frequencies, including at 20,000Hz where killer whales, also known as orcas, hear best.
  • The noise from the passing ships could be hindering the ability of killer whales to communicate and echolocate – the process of using sound to bounce off objects such as prey and identify where they are.
  • Dolphins and porpoises operate at higher frequencies, may be suffering the same problems.
  • The noise poses a threat to a population of just 84 killer whales forage up the US west coast and into Puget Sound.
  • Some ships are quieter than others, but the average intensity of noise next to all the ships was 173 underwater decibels.
  • The new research underlines the threat posed to smaller whales, dolphins and porpoises.

Scott Veirs of Beamreach, who headed the research, said: “The main concern of this is that even a slight increase in sound may make echolocation more difficult for whales.  That’s worrying because their prey, chinook salmon, is already quite scarce.  Hearing a click off a salmon is probably one of the most challenging things a killer whale does.  Hearing that subtle click is harder if there’s a lot of noise around you.”

Source: The Guardian

 

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