UC San Diego Library – Scripps Digital Collection

This paper represents the final portion of a series of descriptions of the tunas and tuna-like fishes of the Pacific. It describes two species of bonito, the Peruvian and the Oriental, whose relationship to the two previously described species, the California and the Mexican, was obscure.

One of the most abundant sources of protein food is found in the "Scombroid" group of fishes, including such fish as the tuna, skipjack, bonito and mackerel. These are streamlined, pelagic, schooling fishes distributed, in greater or less abundance, in almost every ocean of the world. Although widely distributed and generally similar in appearance, there is reason to suspect that in some instances individual species are confined to a given ocean or to a restricted portion of that ocean, and that the stocks of the world are made up of such distinct groups. In other instances it appears that species are in reality cosmopolitan. If our fishery resources are to be intelligently exploited, management will require a precise knowledge of the composition of the total stock and the geographical range of the component species.

Such knowledge is the framework into which life history studies must be fitted. The recognition of larval and juvenile stages, the significance of spawning areas and nursery grounds become productive assets when properly correlated with individual species. The aggregate of such knowledge will provide another measure of abundance to guide those responsible for sustained exploitation. To this end numerous state and federal—domestic and foreign—research agencies have, within recent years, directed their concerted efforts to collecting the necessary information concerning the tunas and tuna-like fishes. The information obtained from this study is presented as a further contribution towards the eventual understanding of the stocks of tuna-like fishes and the relationships of the stock from different areas.