Global population structure of yellowfin tuna, Thunnus albacares, inferred from allozyme and mitochondrial DNA variation

• Published in: Fishery bulletin (Washington, D.C.) Vol. 95; no. 3; pp. 566 - 575
• Main Authors: Ward, R D, Elliott, NG, Innes, B H, Smolenski, A J, Grewe, P M
• Format: Journal Article
• Language: English
• Published: 01.07.1997
• Subjects: Marine; Thunnus albacares; ISW, Indian Ocean; I, Pacific; A, Atlantic
• ISSN: 0090-0656

Yellowfin tuna, Thunnus albacares, were sampled from one region of the Atlantic Ocean, two regions of the Indian Ocean, and six regions of the Pacific Ocean. One of the Indian Ocean collections could not be allozymically analyzed; the remaining eight collections were examined for four polymorphic allozyme loci (ADA*, FH*, GPI-A*, and GPI-B*, n=540 to 677). All nine collections were examined for mitochondrial DNA variation (n=767), with two restriction enzymes (Bcl I and Eco RI) that detect polymorphic restriction sites in yellowfin tuna. Allele frequencies at three of the allozyme loci were homogeneous across collections, whereas GPI-A* showed highly significant differentiation (P<0.001). The GPI-A* data, taken together with the geographic location of the collections, suggested the existence of at least four yellowfin tuna stocks: Atlantic Ocean, Indian Ocean, west-central Pacific Ocean, and east Pacific Ocean. Mitochondrial DNA differentiation was more limited, but spatial heterogeneity of the 24 observed haplotypes over the nine regions (P=0.048) and three oceans (P=0.009) was significant. The mtDNA data did not differentiate west-central Pacific Ocean collections from east Pacific Ocean collections but did support the separation of Atlantic Ocean, Indian Ocean, and Pacific Ocean stocks.