Researchers have known for decades that humpback whales sing complicated songs. Their songs can be as long as 30 minutes, and a whale may repeat the song for two or more hours. Songs can be heard at distances of hundreds of kilometers. There is evidence that whales use variations in the songs to tell other whales about the location of food and predators. Only the male humpbacks sing, which has led some researchers to think that songs are also used to attract a mate.
The whale songs may be threatened by noise pollution. In the past 50 years, ocean noise has increased due to human activity. Goods are transported across the ocean in larger ships than ever before. Large ships use bigger engines. They produce low-frequency noise by stirring up air bubbles with their propellers. Unfortunately, whales also use low-frequency sound in their songs, perhaps because these sounds carry farther than high-frequency sounds in the ocean. Propeller noise from large ships is loud enough to interfere with whale songs at a distance of 20 kilometers.
Regulations Are Needed to Reduce Noise Pollution From Large Ships
Whales use their songs in ways that affect their survival—eating, mating, and avoiding predators. Studies often focus on the effects of noise from a single ship, but in routes taken by ocean freighters, noise from many ships combines to produce a higher volume. Ocean freighters often travel near whale migration routes, so even noise that affects whales at a distance of 20 kilometers may have an impact on whale survival. If regulations are delayed until research can prove that noise pollution affects whales, it may be too late to help the whales. Many kinds of whales are on the endangered species list, so it is important to err on the side of safety.
Regulations Are Not Needed to Reduce Noise Pollution From Large Ships
Whale songs can be lengthy and are often repeated, so the effect of noise from ships is limited because ships quickly move out of an area. One study showed that whales changed the rhythm and tempo of their songs in response to noise from large ships, but there was no evidence that the communication was less effective. Also, it is expensive to modify ship propellers to reduce low-frequency noise. If less-developed countries cannot afford to modify ships, regulations will not be effective in reducing ocean noise levels.
Defining the Issue In your own words, describe the major issue that needs to be resolved about ocean noise pollution.
Analyzing the Viewpoints List three arguments for those who think regulations should require large ships to reduce noise pollution. List three arguments for those who think regulations are not necessary.
Forming Your Opinion Explain which argument you find most convincing.