ABSTRACT
For the appropriate stock management of highly migratory fish species, it is essential to collect ecological information, such as species distribution and migration patterns, and understand their subpopulation structure and inter-population interactions in a quantitative manner. It is particularly important to identify the marine areas in which the populations contributing to reproduction originate, as well as the migration route they take before reproduction, so that an optimal management strategy can be determined. Ecological information on many migratory fish species, including tunas (Thunnus spp.), have been obtained by several approaches such as the mark-recapture method, bio-logging method, and genetic population structure analysis, to determine individual migratory patterns and population structure.
