Background. Bigeye tuna, Thunnus obesus (Lowe, 1839); yellowfin tuna, Thunnus albacares (Bonnaterre, 1788); and albacore, Thunnus alalunga (Bonnaterre, 1788), are very important species for world fisheries. It is crucial to the future existence of those economically important species that the best possible biological data on the species is provided to fisheries managers. Materials and methods. The weight–length relations (WLRs) for bigeye tuna, yellowfin tuna, and albacore, collected in the Atlantic, Indian, and eastern Pacific oceans were studied using commonly accepted methodology. Results. Significant differences can be found from the fork length distributions and the WLRs of the above 3 tuna species and the relations of gilled-gutted and whole weight of bigeye and yellowfin tunas collected from the Atlantic, Indian, and Eastern Pacific Oceans. Significant differences of fork length distributions can be found for bigeye tuna, yellowfin tuna, and albacore from the three areas. The growth exponents (b) of bigeye tuna, yellowfin tuna, and albacore collected from the Atlantic, Indian, and eastern Pacific oceans register significant deviations from isometric value of 3. Conclusion. The date collected will be useful for the fisheries management of the three species studied.

bigeye tuna, yellowfin tuna, albacore, weight–length relation, Thunnus