The Physiological Ecology of Tunas documents the proceedings of the Tuna Physiology Workshop held at the National Marine Fisheries Service Southwest Fisheries Center at La JoDa, California, January 10-15, 1977. The contributions made by researchers at the workshop are organized into seven chapters. The first chapter includes studies on the morphological diversity and muscle-tissue-specific enzymatic attributes of scombrids. Papers in the second chapter deal with the integrated aspects of tuna behavior and capabilities that result from their complex cardiovascular system. The third chapter contains studies on skipjack tuna white muscle and the locomotor muscles of Scomber and Katsuwonus. The fourth chapter focuses on the thermal biology of tunas while the fifth chapter examines the hydromechanics of tuna propulsion. The sixth chapter provides information on energetic costs of tunas, and observations on physiological demands and correlates. It culminates with a conceptual model for the complex life cycle of the extant "ultimate tuna," the Atlantic bluefin tuna. The seventh chapter discusses applications of tuna physiology studies.