A RARE example of an undersea dawn chorus has been recorded off the coast of southern England during an experiment to measure ambient noise in the oceans. It found that marine organisms in the area increase their chatter at sunrise and sunset, though only in the summer.
Marine choruses were discovered by American scientists developing sonar systems during the second world war. Since then many examples have been found in tropical waters, where evening choruses are common.
Dawn choruses, on the other hand, are much less common, particularly in temperate waters, says Doug Cato, a bioacoustician at the Defence Science and Technology Organisation in Australia. Cato has been recording marine choruses for 40 years.
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Edward Harland, a consultant at Chickerell Bioacoustics in Dorset, made the latest discovery while investigating undersea noise as a tool to assess the impact of marine engineering projects on the ocean environment. Exactly what is making the cacophony of clicking he recorded isn鈥檛 clear. Harland has ruled out shrimp, which are known to create choruses elsewhere. 鈥淭here are too few in these waters,鈥� he says. Other potential culprits include corkwing wrasse and goby.
Identifying the performer won鈥檛 be easy, says Cato, and trying to make reference recordings won鈥檛 help. 鈥淧lacing fish in a tank to record their sounds often doesn鈥檛 work because they may not vocalise,鈥� he says.
Read more: Oceanology: Farther, deeper, faster
