A study was conducted between June and August 1982 to collect, freeze mark, obtain biological data from, and release 50 Atlantic bottlenose dolphins, Tursiops truncatus, in the Mississippi Sound, U.S.A. The purpose of the study was 1) to establish a data base for blood chemistry, microbiology, age, genetics, endocrinology, and morphometrics for dolphins inhabiting the Sound, and 2) to determine herd discreteness, social dynamics, and movements in the Mississippi Sound of selected herds.

Preliminary results indicate that all the above mentioned parameters tested fall within the ranges established for Tursiops truncatus. There appeared to be several herds in the Sound that frequently intermingled amongst each other.  Marked animals have been observed to travel extensively within the Sound on a daily basis.  There appears to be a seasonal abundance (April through September) of these mammals in the Sound.  In the winter months (October through March) most of the animals leave the defined boundaries of the Sound and presumably stay a few miles south of the barrier islands that delineate the south margin of the Mississippi Sound.  Resighting studies are currently in progress to further study the movements and migration patterns of' these marine mammals.