Analysis of the Taxonomic Characters of Young Scombrid Fishes, Genus Thunnus

Abstract

The young stages of fishes of the family Scombridae are among the most difficult to identify to generic levels and particularly to the species level. These stages are, for the most part, easily identified to the proper family, but the eggs are unknown except for a few species This paper reports on our studies which attempt to solve some of these identification problems for the larvae and transforming stages. A great deal of research has been done in this area by us and others; but our recent findings cast grave doubts on the identification methods that have been used in the past. To give some indication of the amount of work already directed to these problems, a recent bibliography of young scombrids covering the years 1880--1970 lists 170 papers dealing with aspects of the identification of eggs, larvae, and juveniles (Richards and Klawe, 1972).