A Report on the Billfishes of the Central Pacific Ocean

Interest in the 11 species of billfishes has steadily mounted since World War II, and, as they have come under increasing fishing pressure, arguments have arisen concerning the effects of fishing on their stocks. As large predators, the billfishes are difficult to study; our knowledge is largely restricted to catch statistics, anatomy, diet, and development of their young. The large marlins show great sexual dimorphism in size, and their sex ratio may diverge from the 1 : 1 condition. The catch of some species is strongly seasonal. Spawning is poorly understood, although the young stages have been identified. Analyses of length-frequency distributions and tagging returns suggest rapid growth, short lives, and extensive migrations. Abundance seems to decline after heavy fishing, but better statistics are needed before the true effects of fishing can be judged.