Morphometric comparison of the yellowfin tuna taken from the Equatorial Pacific
Kurogane, K.; Hiyama, Y.
Bull Japanese Soc Sci Fish 23(7/8): 388-393
Several samples of yellowfin tuna, Neothunnus macropterus, from the Equatorial Pacific ranging from 130 W to 130 E were com-pared in 16 different body characters. Specimens of yellowfin taken from the same area in different years show difference in maxillary length, anal length and spread caudal, but generally they have considerably similar morphometrical characteristics. There is a much greater degree of separation between 170[degree] W and 150[degree]E and between 160[degree] W and 130[degree] W than between 150[degree] E and 130[degree] E and between 170[degree] W and 160[degree] W. The specimens of yellowfin from the area of 160[degree] W have a shorter head, a more anterior ventral and pectoral fin than those from the eastward and westward regions. In eye diameter, 2d dorsal and anal length, the measurement is the greatest in the Western Pacific and the least in the Eastern Pacific. It is probable that there is at least 3 independent populations with some mixing between each other.