Effects of Sound on Marine Animals

I spent the majority of my summers growing up in Hawaii. Due to the Hawaiian lifestyle and proximity to the ocean, I became fascinated with marine life. This fascination has led me to research the effects of sound on marine animals. I believe that sound affects marine animals’ communication, location abilities, and mating habits. Marine animals depend on sound for a variety of different things, such as communication, hunting, and echolocation. Sound serves different functions for different species. Do these different species interfere with each other or are they separated by sound frequency?

The major problem for scientists studying marine life is the ocean’s vastness. They cannot properly explore and perform experiments so they rely on sound to study life in the ocean. Sound travels efficiently underwater, allowing it to reach far and deep where humans cannot reach. The use of acoustics to study marine life is called marine bioacoustics. Scientists can use acoustic energy to study marine animals’ communication, prey detection, locating obstacles, and navigation (Au 2008, 3). Marine animals use all sounds to aid their survival whether they are from a biological, natural, or a human source. Some sounds such as those produced by predators, prey, or conspecifics, carry special meaning to animals.

For example, dolphins communicate using “a complicated system of whistles, squeaks, moans, trills, and clicks produced by muscles within the blowhole” (Adriazola 2011). Each dolphin has its own unique sound that they use to find each other. Dolphins hunt using echolocation, or sonar. They send out a series of clicks that travel up to 600 feet along the sea floor. As the sounds bounce off objects, they reveal the location of the prey. (Dolphin Communication – YouTube)

dolphin hearing

Humpback whales sing songs for up to twenty minutes and repeat the same song again and again. Males in a region will sing the same song but the song changes each year. The exact purpose for these songs is unclear. Marine biologist Nan Hauser believes that whales use these songs to mark their territory. Other scientists believe that they use songs to hunt and find a mate. Submarines and ships produce sounds that interfere with whale song. This forces the whales to be up to ten times louder, or they are left in confusion.

Katy Payne is a prominent researcher of whale song. She discovered that whales actually compose songs that change each year. Katy Payne did an interview for On Being with Krista Tippett in 2015. In this excerpt from their conversation, Ms. Payne discusses how she discovered that whales compose songs.

PAYNE: Well, nobody told me I was going to have to earn my living through what I did in college. And I loved music, and I wanted to learn a good deal more about that than I’d been able to learn back in the farming days. And then after college, I was married to a biologist, Roger Payne, who became very interested in studying whales and when we went to sea, we heard for the first time the wonderful sounds that humpback whales make in the ocean. At that time, nobody knew about them.

TIPPETT: Really? Nobody knew about the song?

PAYNE: No, they didn’t, they didn’t know it was a song. This was something we realized. You listen for a very long time and you hear these long sequences of phrases and notes begin to repeat and you say, “Oh, that was a song.” So, we were the first, and I spent 15 years then listening to these ever-changing songs of whales, and by the time I was through, people were calling me a biologist.

TIPPETT: Is that what it means when you are referred to — they call you a self-trained acoustic biologist?

PAYNE: Oh yeah, that’s pretty good.

TIPPETT: Is that what it means, that you just started doing this?

PAYNE: Well I guess it does!

PAYNE: Of course, many animals make sounds, everything from crickets to humans to whales, birds, of course, frogs. And these sounds, in the case of animals, are thought of in relation to reproduction and courtship. In humans, although they may serve exactly the same function, they’re thought of in relation to aesthetics.

TIPPETT: Right.

PAYNE: And one of the aspects of my work has been to say, “Look, we don’t have to have two languages for this.”

TIPPETT: So something that’s written about you is that you discovered that whale song is always changing. I mean, what is the significance of that?

PAYNE: Well, the significance is that whales, like people, are composers. The songs are very complex. They consist of six to eight themes. Each theme has a melodic phrase that repeats over and over again and then changes to the next one.

[Sounds of whales singing]

PAYNE: And so it would continue as a sequence of events, which then, as a whole, repeat song after song after song. But if you keep listening for months on end, and then for years on end, you discover that the song — each facet of it — is continually evolving to something slightly different. And all the whales in the ocean or in that singing population are changing their song in the same way. So that was something I discovered, and at the end of the day, I had studied 32 years’ worth of songs, many of them in two different populations.

In the Presence of Elephants and Whales

The underwater acoustic environment contains a multitude of competing sounds. Marine animals are constantly interfering with each others’ communication. Though interspecies communication is very limited, it is a crucial aspect of survival. Predatory sounds serve as a warning for prey to avoid and, on the contrary, predators use their prey’s sounds to hunt. Not only are marine animals competing with each other for sonic communication, they also have to deal with manmade sounds. Ocean noise continues to increase drastically due to ships, oilrigs, and underwater construction.

The propulsion of ships causes the dominant manmade sound in the ocean. Ship noise is falls between the frequencies of 20-Hz to 200-Hz which is the same frequency band as baleen whales. Due to ships, the ambient water noise in this frequency band has increased 10- to 100-fold (Tyack 2008, 549). This causes concern from scientists that the range of baleen whale communication has been significantly reduced. Other human sounds interfere with marine animals. Often marine animals avoid manmade sounds by kilometers, preventing them from inhabiting certain areas of the ocean. Also scientists have noticed that animals react to manmade sounds similarly to sounds from predators.

The underwater acoustic environment contains many sounds. All these sounds affect marine animals in some way. Some are used for communication, others provide a warning, and others just interfere with communication. The drastic increase of manmade sounds in the ocean is a serious problem. These sounds reduce the distance that marine animals can communicate and displace animals from certain regions of the ocean.

Bibliography

Adriazola, Diego. 2011. “Dolphins’ Communication.” YouTube. Accessed 5 November 2015. https://www.youtube.com/watch?v=JODHKHzr85U

Au, Whitlow W. L., and Mardi C. Hastings. 2008; 2009. Principles of Marine Bioacoustics. 1. Aufl. ed. New York: Springer.

“Humpback Whales Communicate Through Sound Without Vocal Chords.” 2013. YouTube. Accessed 5 November 2015. https://www.youtube.com/watch?v=NBUVr5-EX5w&list=PLGuRrrZklgNZ0r8OmymKgQkM-eWHMuwdc&index=3

Katy Payne. 2015. “In the Presence of Elephants and Whales.” Soundcloud.

McCarthy, Elena. 2004. International Regulation of Underwater Sound: Establishing Rules and Standards to Address Ocean Noise Pollution. Boston: Kluwer Academic Publishers.

National Research Council (U.S.). Committee on Potential Impacts of Ambient Noise in the Ocean on Marine Mammals. 2003. Ocean Noise and Marine Mammals. Washington, D.C: National Academies Press.

Natural Environment Research Council (Great Britain.). Working Group on Underwater Acoustics. 1971. Underwater Acoustics: A Report by the Natural Environment Research Council Working Group on Underwater Acoustics 6. London: Natural Environment Research Council.

Preisig, J. C., and M. P. Johnson. 2001. “Signal Detection for Communications in the Underwater Acoustic Environment”. IEEE Journal of Oceanic Engineering 26 (4): 572-85.

Rothenberg, David. 2008. “Whale Music: Anatomy of an Interspecies Duet.” Leonardo Music Journal 18 (1): 47-53.

Tyack, Peter L. 2008. “Implications For Marine Mammals of Large-scale Changes in the Marine Acoustic Environment.” Journal of Mammalogy 89 (3): 549-58.

“Whale Communication Affected by Man-made Noise.” 2012. YouTube. Accessed 5 November 2015.

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