ABSTRACT
Knowledge of the horizontal movements of highly migratory species such as tunas in the genus Thunnus is essential for understanding their life history. This information is important for population stock assessments, a prerequisite for maintaining a sustainable population. Tunas travel large distances within tropical to subarctic waters throughout their life. One of the largest, the Pacific bluefin tuna (PBF) T. orientalis has a wide and continuous distribution across the Pacific Ocean from the northwestern to eastern Pacific. In the Southern Pacific Ocean, PBF are also found in New Zealand waters, although less is known regarding the migration pathways to this region. Their wide seasonal migrations and size variations due to rapid growth make it difficult to analyze the entire migration pattern within one tagging study.
