The sharsk are part of the major group of non-bony fishes known as elasmobranchs which include the skates and rays. The sharks are primarily carnivores and many of the larger species apparently are the top predators in their environment. This role is not widely appreciated and not well understood. In fact, the exact position and role of most of the species of sharks in the marine ecosystem is poorly known despite the large size and spectacularity of most kinds of sharks. The main areas of shark research discussed at the Monterey Conference included those which, in the past, had been judged to be of most interest to the U.S. Navy. These research areas have a more direct bearing on the capabilities of sharks to act as predators on humans. The results of these discussions constitute the main portion of this report.

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The importance of toxins and other phanuacologically active com pounds obtained from marine animals cannot be emphasized enough. The use of these chemicals for defense or attack of other life fonus are of interest in themselves; however, they are of great importance in our understanding of their mechanisms of action in view of possible application in the defense of man (no doubt a predator) and in biol ogy and medicine. The toxin of the flat fish Pardachirus presented in some of the papers of this book is an example of a defense mechanism based on secretion of a toxin that could possibly be extended to being used to defend man himself from sharks, the marine predators par ex cellence. August, 1984 J. ZADUNAISKY Preface The study of toxins, drugs, and pollutants in the marine environment, and their impact on human life existed already in Babylon and Assyria, Egypt, Persia, India, China, Japan, Greece, Rome and South America. Nevertheless, less is known about ethnic marine biology than about ethnobotany. Only recently however, have active biotoxins been used as molecular probes in neuropharmacology, offering intriguing new insights into nervous activity and muscular functions. It is clear from the presentations at this meeting that much remains to be done, and certainly new, more pharmacologically oriented find ings lie ahead.

Some species of sharks, because they are large, agile predators, are extremely dangerous to humans in water. During World War II, the long-time goal of an effective shark repellent was partially realized by the U.S. Navy's development of "Shark Chaser," a copper acetate-negrosine dye mixture. But neither Shark Chaser nor other noxious or even extre