NAVY ANNOYED

Te Awamutu Courier, Volume 72, Issue 6243, 17 June 1946, Page 4

NAVY ANNOYED

NOISE-MAKING FISH SOUND DEVICES AFFECTED 'The fish in the sea are a noisy lot and their chattering and singing has become a matter of real concern to the U-S. Navy. They make so much noise that it threatens to interfere with such devices as sonic submarine locators and acqustic mines. Ari investigation has just been completed in Chesepeake Bay and along the South Atlantic coast to find which denizens of the deep are the worst offenders. The results of their investigation have now been reported to the American Association for the Advancement of Science, meeting here, by M. B. Dobrin of the Naval Ordnance Laboratory at Anacostia, Md. The main object was to determine the type and intensity of the noise produced by the various species so that they could be taken into account in designing instruments. The worst offender, Dobrin found, was the common croaker or drumfish, whose noise “resembles the sound of an electric drill being driven into asphalt. This sound is made by special muscles drumming against the air bladder, and; is audible 25 feet away.” Most remarkable of all the noise makers was the toadfish, “a sluggish, ill-tempered, nest-building bottomdweller. The sound is an intermittent, low-pitched musical blast of about half a second duration. Somewhat similar to a boat whistle.” Specimens of most of the noisemaking fishes were captured and studied in the laboratorory. But the toadfish became absolutely silent in captivity. The researchers established that it did make a noise when a hydrophone showed sounds coming from one spot on the bottom for weeks at a time. The toadfish is the only fish so lazy that it will stay in one spot so long. The hogfish, as its name indicates, is' a grunter—the grunt produced by gnashing the teeth. The spot is closely related to the croaker but makes a different noise, described as “a series of rauccias honks.” Another noisemaker is the sea robbin, whose sound is a “rhythmic squawk, squeal or cackle.”