ABSTRACT

Organisms perceive the quality of their environment by sensory systems whose output is amplified and used to direct behavior. Repellents, as well as attractants, must act by stimulating a sensory system. To pose the question of whether an effective shark repellent can be developed is to ask if man can fit himself to life in the underwater environment, as has been done by many natural inhabitants of the sea. Chemical recognition and detection of chemical gradients are involved in many behavioral responses of organisms. Have organisms developed natural repellents that utilize the shark's system for chemical recognition? Although further experimentation will be beneficial, a milky secretion from flatfish of the genus Pardachirus seems to be a natural repellent that protects the fish from predation by sharks. An accumulation of anecdotal stories concerning the lack of natural predators for fireflies, plus a newly acquired knowledge that a manageable small shark species was available in Beaufort, led to the following experiments.