Noise from ships are causing the cessation, and it may negatively impact the whales’ chances of survival.
Humpback whales produce haunting songs whose acoustics travel for miles within their ocean habitat. The reason behind why they do so aren’t known, but researchers surmise that that whales do it to communicate with others and to find mates. Lately, though, their eerily beautiful melodies are being shortened and silenced in reaction to human activities that create noise in their environment.
EcoWatch reports that Japanese researchers discovered that the gentle giants became silent or shortened their song whenever they hear shipping noises. Think of a chirping cricket when you walk too close to it, and you can kind of get the idea.
The study, published in in the journal PLOS ONE, was conducted by the Hokkaido University in Japan and the Ogasawara Whale Watching Association. During the study that lasted from February to May 2017, researchers utilized underwater recorders to observe how a ship passing the humpbacks affected their whalesongs.
The humpback whales examined for the study consisted of a pod around the Ogasawara Islands, and the research team recorded the whalesong of one to three of the males a day. By the end of the study, there were a total of 26 recorded in all.
Researchers were able to determine after listening to the recordings that there were few of the male humpbacks that sang once they were within a 500-meter range of a shipping lane “than elsewhere” whenever the ship went through a remote area. At a distance of 1200 meters, the whales had a tendency to reduce or cease singing until the ship passed them by. None of the humpbacks resumed singing again until 30 minutes after the vessel passed.
The authors of the study wrote the following.
“Humpback whales seemed to stop singing temporarily rather than modifying sound characteristics of their song under the noise, generated by a passenger-cargo liner.”
“Ceasing vocalization and moving away could be cost-effective adaptations to the fast-moving noise source.”
Assistant professor in Florida Tech’s Department of Ocean Engineering and Marine Sciences, Spencer Fire, told reporters that the study involving the humpbacks was “solid.” Fire stated that the study emphasized how noise from ships and boats are negatively affecting the humpbacks. He said that there are most likely consequences to the whale population because delays in their ability to communicate may halt their attempts to breed.
Fire added that it might additionally force the humpback whales to resettle in habitats “where they may be chasing food that moves too fast, or that doesn’t have high enough nutritional content. And usually, energy intake is what makes or breaks animal survival.”
What’s more, it’s not just humpback whales that the ocean noise pollution affects negatively. The symphony of sounds that other breeds of whales besides the humpback and dolphins use play a critical role in their survival. The creatures use the sounds to find food, navigate and communicate with one another. Other noise pollution that affects marine mammals come from military exercises and sonar.
To keep the unique sounds such as the humpback whales’ mournful songs from disappearing forever, regulation is sorely needed. Federal angencies, such as NOAA’s Ocean Noise Strategy Roadmap, was established to reduce noise pollution impact on marine mammals. The 10-year strategy, which was started in 2016, will probably find information from the humpback whale study useful in their decade-long fight.
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