From growls to pulses to booms, whales, fish and crustaceans all produce sounds. In fact, more than 800 species of fish are capable of making noises for a variety of functions such as courtship and mating, defending their turf or responding to threats.
Each of these species has a characteristic waveform that is unique to their “calls.” As such, detecting structures in these signals can be used to identify the sounds of different species.
Classifying sounds produced by fish will help to understand how they respond to environmental changes and anthropogenic disturbances, such as ocean noise and fishing activity, as well as environmental changes associated with warming waters due to climate change or red tides that now frequently occur on the west coast of Florida.
Passive acoustics is a measuring method used to detect sounds or vibrations created by marine mammals in the wild. Although this technology has helped to shed light on fish habitat preference as well as their movements, no studies have yet been able to illustrate their detailed behavior.
Selecting the gregarious Goliath grouper (Epinephelus itajara) for their study, researchers from Florida Atlantic University implemented and deployed a novel automated detector and localization model to find underwater marine organisms using their low-frequency pulse sounds. Pulses associated with fish sounds can be categorized in terms of the number of pulses, pulse period, frequency, oscillogram shape, or a descriptive name or onomatopoeic word like a growl, pulse train or boom.
The Goliath grouper is one of the largest grouper species reaching up to 800 pounds. They produce low frequency (peak of 60 hertz) loud “booms” using their swim bladder and surrounding muscles. These booms display a “polycyclic” waveform, which rapidly increases in amplitude for up to one or two wave cycles and then declines exponentially.
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