Notes on the Sound-Producing Marine Fishes of Louisiana

Abstract

D URING the winter and summer of 1929-30, the writer, working in the field with the fishermen of the Louisiana coast, was afforded considerable opportunity to collect the fishes of the coastal waters. A number of the species were found to be capable of producing sound. Since aquarium facilities were lacking, notes were made on the vocal species as they were taken alive from the hook, seine or otter-trawl; a few of the fishes were kept under observation for a time in water-buckets or other small containers. These observations were supplemented by the examination of preserved material. At no time did the writer hear any vocal sounds attributable to fishes uncaptured and undisturbed. He is therefore unable to offer any evidence as to the function of vocalization, except to point out that, whatever other conditions call forth the production of sound by fishes, those stimuli attendant on capture and handling seem to excite noisemaking in fishes capable of it. The major exceptions to this rule which he has noted are among the batrachoidids: not a single individual, among nine of Porichthys porossissimus and among several of Opsanus tau observed, made the swim-bladder noise of which these fishes are reported to be capable (Tower, 1908; Hubbs, 1920; Greene, 1924). It must be noted, however, that a certain number of the individuals of each of the species which usually produce sound on capture did not do so. The sounds produced on capture by vocal fishes, i.e., those possessing organs apparently specially adapted to the end of sound-production, did not seem to the writer to be produced involuntarily during the convulsive undirected contractions of all the muscles, as has been the impression of some observers (Sorensen, 1894). The fishes, in the intervals between flurries, often remained perfectly passive except for respiratory and sound-producing movements; fishes held firmly in the hand, making no struggle, usually became exceedingly vocal. It seems probable that such fishes are excited to produce sound in response to stimuli in their natural environment, which are comparable with those supplied by capture by man, and that this response, only in the special case of capture by man, becomes of no apparent adaptive value.