The Photographic Determination of Group Size, Composition, and Stability of Coastal Porpoises ( <i>Tursiops truncatus</i> )

Abstract

During a 21-month study, 53 individual bottle-nosed porpoises were recognized by photographs of their dorsal fins. They traveled in small subgroups (mean size = 15) composed of a stable core of five animals plus other individuals that varied greatly from sighting to sighting.