Evidence of Population Structure in the Giant Mottled Eel, Anguilla marmorata, Using Total Number of Vertebrae
The population structure of the most widely distributed anguillid eel, Anguilla marmorata, was evaluated using a statistical analysis of total number of vertebrae. A total of 1166 specimens from 13 representative localities in the Indo-Pacific region from Réunion Island to Tahiti and from New Caledonia to Japan were examined in this analysis that also included previously published data. The specimens from Micronesia showed a remarkable difference from those collected at the 12 other localities, and those from Tahiti showed a significant difference from those collected at ten other localities, but not New Caledonia and Samoa. Furthermore, significant differences were found between the North Pacific Ocean region, except Ambon Island, and South Pacific Ocean regions and Réunion Island, while there were few differences between specimens from the Indian and South Pacific Ocean regions. It appears likely, based on this morphological analysis and the geographic range of this species, that there are at least four or more populations of A. marmorata as has been indicated previously by molecular genetic research.Abstract
Map showing the range of Anguilla marmorata (thick lines on coastlines), with the collection localities of specimens examined by Ege (1939) shown with open circles and the collection localities of this study with solid circles. The three different races of A. marmorata proposed by Ege (1939) based on variation of the number of prehaemal vertebrae are shown with black lines, and the population structure found by the genetic analysis of A. marmorata by Ishikawa et al. (2004) using mtDNA and nuclear DNA is shown with dashed lines.
The general pattern of currents in the western North Pacific, central Indonesian Seas, and eastern Indian Ocean after Lukas et al. (1991), Reverdin et al. (1994), and Gordon (2005). The spawning area of the North Pacific population of Anguilla marmorata discussed in the text is shown with a dark oval. The North Equatorial Current (NEC), Mindanao Eddy (ME), Halmahera Eddy (HE), North Equatorial Countercurrent (NECC), South Equatorial Current (SEC), Indonesian Throughflow (ITF), South Java Current (SJC), and Sulawesi Island (SI) are labeled.
Contributor Notes
Associate Editor: J. M. Quattro.