ASA 125th Meeting Ottawa 1993 May

4aAB4. Living sounds from the sea.

Helen M. Walkinshaw

Box 72, Peapack, NJ 07977

In mid-1951, with initial support by ONR, Bell Telephone Laboratories began an exploratory program of undersea acoustics research that lasted some 40 years. As a result, a diverse collection of in situ recordings of marine life slowly accrued from chance encounters during other planned experiments. Most have been identified as marine mammals---various species of whales and porpoise---a few remain unknown even now. The precise mechanism for producing certain very low frequency sounds (20 Hz and below) also remains unclear. The original recordings were made on several bottomed and off-bottom suspensions of hydrophones with effective bandwidths of from 5--400 Hz and 10--1000 Hz. Their installation depths ranged from 220 to below 2000 fathoms, cable-connected to shore, enabling continuous monitoring of the undersea environment. Four samples are presented. Locale and circumstances of their acquisition are described, as are geographic scope and observed seasonal occurences. Copies of the original recordings are available for study.