. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 326 ROBERT E. KNOWLTON AND JAMES M. MOULTON Individual snaps as they occur under the sea are essentially the same as those produced under laboratory conditions, but because of the great numbers of shrimp present, conditions under which the sounds are produced, and interfering water noise, differences in the spectra do exist. Where relatively few snapping shrimps occur and where water noise is at a minimum, the spectrum of a single snap is quite similar to that produced by an animal under laboratory conditions. Recordings of
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 326 ROBERT E. KNOWLTON AND JAMES M. MOULTON Individual snaps as they occur under the sea are essentially the same as those produced under laboratory conditions, but because of the great numbers of shrimp present, conditions under which the sounds are produced, and interfering water noise, differences in the spectra do exist. Where relatively few snapping shrimps occur and where water noise is at a minimum, the spectrum of a single snap is quite similar to that produced by an animal under laboratory conditions. Recordings of S. minus snaps were made at the Bermuda Biological Station. The specimen was put in a wooden float (1 X 2 ft.) placed in sea water to a depth of 1 foot. A snap was recorded with the float 4 feet from the hydrophone (Fig. 13). Another snap was recorded when the float was 6 inches from the hydrophone, and still another with the specimen held in the hand 6 inches from the hydrophone. The spectra of these three snaps (Fig. 17) are almost identical. Thus, recording conditions do not significantly alter the spectrum of the snap. The main components of the 5". minus snap lie in the frequency range 0-5 345678 FREQUENCY (KC) 10 FIGURE 17. Spectra of three single Synalphens minus snaps. Synalpheus species are known to be prolific in the Bahamas and probably are the principal sound producers in this region. The laboratory records (Fig. 13) indicate that the point of highest intensity for Synalpheus lies in the range 1-2 kc, but the field records (Fig. 12) are most intense from 4 to 7 kc. When Synalpheus is not occupying a sponge pore, as in the laboratory recordings, its snap is most intense in the lower frequencies. But when, as in the waters of Bimini, it occupies its natural habitat within a sponge pore, the snapping noise be- comes higher pitched, , its components are most intense at higher frequencies. This seems to indicate that variability in shrimp spectra around the
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
