Past research concluded that nonstridulating pink shrimp (Penaeus duorarum) found in the Gulf of Mexico did not make sound in the sonic range, but might produce ultrasonic sound via friction between parts of the exoskeleton [W. R. Gehring, Sea Grant Bulletin #5 (1971)]. Recordings of ``frying'' noises over known penaeid shrimp beds led to speculation that the shrimp were mechanically producing the ``frying'' portion of the ambient noise, and that passive sonar might be used as a tool for penaeid shrimp detection and estimation of population densities [W. E. Evans, Acoustics Signature Catalog, 82--141 (1982)]. Sound production by nonstridulating white shrimp (Penaeus setiferus) of the Gulf of Mexico was studied using passive sonar. Video and hydrophone recordings were made of captive shrimp populations with known densities. Hydrophone recordings of wild populations were made pre- and postshrimp trawls, and trawl catch data were noted. Results showed that the captive shrimp produced detectable mechanical sound primarily via escape movements and possibly mastication. Initial comparison suggests that wild shrimp and captive shrimp sounds are similar. It is hoped that the final results of analysis will confirm that wild penaeid shrimp population density calculations are feasible using passive sonar data.