Spatial and Temporal Population Genetic Structure of the Giant Mottled Eel Anguilla Marmorata in the Northwestern Pacific

西北太平洋鱸鰻族群遺傳結構之時空分析

10.29822/JFST.201212.0006

鄭志成(Chih-Chen Cheng)；Nico Jose Leander；沈康寧(Kang-Ning Shen)；曾萬年(Wann-Nian Tzeng)

鰻線 ； 呂宋鰻 ； 微衛星DNA ； 遺傳多樣性 ； 黑潮 ； Elver ； Anguilla luzonensis ； Microsatellite DNA ； Genetic variability ； Kuroshio

臺灣水產學會刊

39卷4期（2012 / 12 / 01）

269 - 282

英文

The giant mottled eel Anguilla marmorata is a diadromous fish that grows in the freshwater and spawns in the ocean. This freshwater eel species is widely distributed in the Indo-Pacific and western Pacific Oceans. The population of A. japonica in the northwestern Pacific has shown no spatial and temporal genetic structure while that of A. marmorata, which is also transported by the same current system, is still unclear. In this study, 5 microsatellite loci were used to analyze the genetic variability and the population genetic structure of 223 A. marmorata elvers collected from the Philippines, Taiwan and Japan. In order to eliminate the probability of species admixture with A. luzonensis in the samples due to their morphological resemblance during elver stage, all of the specimens were screened using species-specific mtDNA cytochrome b PCR. The results showed that our samples was comprised of just a single species, A. marmorata and its population in the western Pacific do not have any significant genetic differentiation (FST = 0.002; P ＞ 0.05), even if the Japanese specimens were collected 10 years ago. Hierarchical AMOVA also suggested that the population genetic structure among seasons in Taiwan was not significant (FST = 0.003; P ＞ 0.05). This study indicated that the population genetic structure of A. marmorata in the western Pacific is stable in both spatial and temporal scales. The random dispersal of their leptocephalus and their year round spawning behavior might inhibit the population differentiation.

The giant mottled eel Anguilla marmorata is a diadromous fish that grows in the freshwater and spawns in the ocean. This freshwater eel species is widely distributed in the Indo-Pacific and western Pacific Oceans. The population of A. japonica in the northwestern Pacific has shown no spatial and temporal genetic structure while that of A. marmorata, which is also transported by the same current system, is still unclear. In this study, 5 microsatellite loci were used to analyze the genetic variability and the population genetic structure of 223 A. marmorata elvers collected from the Philippines, Taiwan and Japan. In order to eliminate the probability of species admixture with A. luzonensis in the samples due to their morphological resemblance during elver stage, all of the specimens were screened using species-specific mtDNA cytochrome b PCR. The results showed that our samples was comprised of just a single species, A. marmorata and its population in the western Pacific do not have any significant genetic differentiation (FST = 0.002; P ＞ 0.05), even if the Japanese specimens were collected 10 years ago. Hierarchical AMOVA also suggested that the population genetic structure among seasons in Taiwan was not significant (FST = 0.003; P ＞ 0.05). This study indicated that the population genetic structure of A. marmorata in the western Pacific is stable in both spatial and temporal scales. The random dispersal of their leptocephalus and their year round spawning behavior might inhibit the population differentiation.