Danionella cerebrum, a translucent fish species of only 12 mm length, produces high amplitude sounds exceeding 140 dB (re. 1 µPa, at a distance of one body length) — comparable to a jet engine during take-off in 100 m distance.
“The snapping shrimp can generate a popping sound of up to 250 dB with its claws,” said Dr. Ralf Britz, an ichthyologist at the Senckenberg Natural History Collections.
“The mating calls of the flightless kakapo reach 130 dB, and elephants can produce noise of up to 125 dB with their trunks.
“Fishes, on the other hand, are generally considered to be rather quiet members of the animal kingdom.”
“However, there are certain fish species that can be surprisingly loud. For example, the male plainfin midshipman fish attracts its females with an audible vibrato of around 100 Hz and 130 dB.”
In the new study, Dr. Britz and his colleagues examined Danionella cerebrum, a miniature teleost fish with the smallest known vertebrate brain.
“This tiny fish can produce sounds of over 140 dB at a distance of 10 to 12 mm — this is comparable to the noise a human perceives of an airplane during take-off at a distance of 100 m and quite unusual for an animal of such diminutive size,” Dr. Britz said.
“We tried to understand how the fish manages this and what mechanisms are responsible for this achievement.”
Using a combination of high-speed video, micro-computed tomography, gene expression analysis, and finite difference methods, the researchers found that Danionella cerebrum males possess a unique sound-generating apparatus that includes drumming cartilage, a specialized rib, and a fatigue-resistant muscle.
“This apparatus accelerates the drumming cartilage with a force of over 2,000g and shoots it against the swim bladder to produce a rapid, loud pulse,” Dr. Britz said.
“These pulses are strung together to produce calls with either bilaterally alternating or…
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