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Vol. 49 No. 2, 2010
Morphological and Molecular Analyses Reveal Separations among Spatiotemporal Populations of Anchovy (Engraulis japonicus) in the Southern East China Sea
Chih-Shin Chen1, Chih-Hsiang Tzeng2, and Tai-Sheng Chiu2,*
1Institute of Marine Affairs and Resource Management, National Taiwan Ocean University, Keelung 20224, Taiwan
2Institute of Zoology, Department of Life Science, National Taiwan University, Taipei 106, Taiwan
Chih-Shin Chen, Chih-Hsiang Tzeng, and Tai-Sheng Chiu (2010) Coastal and oceanic populations of Japanese anchovy (Engraulis japonicus)
occur in the southern East China Sea. The distributions of the
larval stages of these populations provide a bases for subdividing
anchovy into 3 spatiotemporal stocks for the management of local
Taiwanese fisheries: spring coastal (sprW) and oceanic (sprE) stocks
respectively in the western and eastern seas of Taiwan, and an autumn
stock (autE) in Ilan Bay, northeastern Taiwan. Using larval
morphological analyses to evaluate population similarities, we found
subtle differences between the sprE and sprW geographic stocks, but
strong intra-geographic differences between sprE and autE seasonal
stocks. Molecular analyses, based on fragments of 740 bp
(positions 200-939) of the mitochondrial DNA cytochrome b
gene, revealed a substantial amount of genetic variations among
populations. Analysis of molecular variance indicated significant
differences among stocks, primarily due to the sympatric contrast
between sprE and autE (FST = 0.073, p < 0.001), rather than due to geographic subdivisions, such as sprE vs. sprW (FST = 0.039) or sprW vs. autE (FST
= 0.007). These results indicate the presence of a unique oceanic
stock in eastern Taiwan in spring that is separated from the other
populations. This spatiotemporal heterogeneity suggests a dynamic
state of larval recruitment along the coast of northern Taiwan.
We propose a dispersal route for larval anchovy from the Taiwan Strait
to the northern coast, or active migration by adult anchovies in
accordance with oceanographic patterns in the southern East China Sea.
Key words: Anchovy, Morphometry, Mitochondrial DNA, Stock, Cohort migration.
*Correspondence: Tel: 886-2-33662448. Fax: 886-2-23634014. E-mail:tschiu@ntu.edu.tw
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