Whale Calls Among Familes May Be Disrupted By Sound Of Ship Engines With Similar Frequencies
The calls of whales to their young and their communication across long distances among family groups may be disrupted by the sound of ship engines that have similar audio frequencies. An analysis of three months of recordings from large underwater microphones near Australia's Great Barrier Reef have scientists concerned that vessel engine noise could interfere with whale communications, according to The Sydney Morning Herald.
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The recordings were analyzed by Colin Simpfendorfer, director of the Centre for Sustainable Tropical Fisheries and Aquaculture at James Cook University in Australia. The sounds were divided into the three main groups of whale and marine life sounds, the rumble of ship engines, and weather-related background noises. "The low-frequency noise created by the vessels is about the same as that used by whales to communicate," said Simpfendorfer. "One of the things we've wanted to highlight is that increasing traffic may in the future lead to concerns."
The audio research being done by scientists is in its early stages, so while any impact on whale groups can't yet be determined, further study is important because of the critical role of whale communication, he said. "They use the sound to coordinate family groups, communicate with calves, those sorts of things."
The mystery and complexity of whale vocalizing is an area of extensive study by scientists, including biologist Jim Darling, a researcher at the Whale Trust in Maui, Hawaii, who has studied humpback whales and their singing for 30 years, and said the communication goes across many miles.
"For some years, we've known about the structure of the humpback whale song," Darling said in the video "Why Do Humpback Whales Sing?" on the Voices in ihe Sea website. "These are sequences of sounds which are repeated over and over again, yet they progressively change or evolve as they're being sung, and all the singers in a population sing the same version at any one time."
The most common vocal interaction has been determined to be a signal between male humpback whales, who meet briefly with other males, stop vocalizing, interact, and then depart. They often travel several miles in different directions, then join other singing whales and have additional interactions, said Darling. They might form a trio and join another group, which may include a female, sometimes with a calf. "Where we're at now is taking all the clues we have and beginning to ask the question, 'why do they sing?'" said Darling. "We have a ways to go with that question."
Determining whether vessel engine sounds disrupt whale communication is important for the many varieties of vocal whales. Belugas are among the most vocal of all whales, according to the video "The Voice of the Beluga Whale" on the Voices in the Sea website. "These highly social animals make a great variety of whistles, chirps, creaks, and even vowel-like sounds to communicate with one another," according to the video. "They were known by early Arctic whalers as sea canaries, because their calls could be heard even through the hulls of ships."
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