Observations of Captive and Wild Cetaceans

Abstract

During the first months of operation (March, 1954 to Sept. 1955) of the new oceanarium, Marineland of the Pacific, we have had numerous opportunities to observe the dolphins and porpoises of California waters. In addition, we have recorded the behavior of captive Atlantic bottlenose dolphins ( Tursiops truncatus ). Many members of the staff at Marineland have assisted in making these observations. We are particularly grateful to Frank Brocato, Captain of the collecting vessel, Geronimo , and his assistant, Frank Calandrino, for their help in compiling the field observations. We wish to thank Dr. Leonard L. Mortimer D.V.M., for his assistance and suggestions during treatment of captive animals. Dr. Raymond Gilmore has given us much assistance and has critically reviewed the manuscript. We follow Norman and Fraser (1940) in their definition of the terms porpoise and dolphin; porpoise refers to members of the Delphinidae which are small, beakless, and with triangular dorsal fins and tricuspid teeth. Dolphin is used for the remainder of the family, except those larger forms dignified by the name, whale . This species ( Lagenorhynchus obliquidens Gill, Pl. I, Top) and the common dolphin ( Delphinus bairdi ) have been observed many times more than these data indicate, particularly during the months before Marineland of the Pacific was completed. These observations serve to strengthen the conclusions we draw here. Plate 1 Top: Captive Lagenorhynchus obliquidens , in company with Tursiops truncatus , in the circular tank at Marineland of the Pacific. Bottom: Transporting a specimen of Delphinus bairdi . Photo by William Eccles. Seasonal movements .—The Pacific white-sided dolphin is probably the most common cetacean species in southern California waters. Schools scattered over areas as large as four square miles that numbered an estimated 1000 animals have been sighted in the channel between Santa Catalina Island and the mainland. Diffuse schools such …