Using sounds to communicate
Could deep-sea fish be using sound to communicate? Researchers from the University of Massachusetts Amherst believe they could be. Incredibly, very little research has been performed in the area of deep-sea fish vocalizations. There’s only been a handful of papers published on the subject as the big problem is (or rather was) the cost of recording equipment that could be deployed to great depths to actually capture the sound. With recent technological advances, inexpensive sound equipment is now available to do exactly this.
What the researchers did was repurpose a Nomad Jukebox (an inexpensive digital recorder) and connect it to a couple hydrophones.
These electronic components were then sealed inside deep-water trawl floats that had a working depth of almost 2,000 feet which were then deployed in strings of commercial deep-water crab traps along Welkers Canyon which is off the coast southeast of Rhode Island. The devices were then retrieved 24 hours later when the crab traps were hauled back in by the commercial fishing fleet.
“The recording contained a wealth of biological sounds including sounds from fin whales, humpback whales, pilot whales, and dolphins, as well as frequent examples of at least 12 unique unidentified sounds that we attribute either to undescribed cetacean or fish sounds” commented the scientists. “Most individual biological sound types were infrequent, but several distinct sounds labelled “drumming”, “duck-like”, “unknown 3”, and “unknown 6” occurred throughout the night and early morning hours. Most unidentified sounds that we attributed to biological sources had fundamental frequencies below 1200 Hz, well within the range expected for fishes. However, at this time we have insufficient data to distinguish between fish sounds and undescribed low frequency cetacean sounds.”
The researchers have placed sound files of many of the sounds they encountered during this study up on their website fishecology.org. Some samples of what they recorded can be found here.
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