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Sympatric spawning but allopatric distribution of Anguilla japonica and Anguilla marmorata: temperature- and oceanic current-dependent sieving.

Han YS, Yambot AV, Zhang H, Hung CL - PLoS ONE (2012)

Bottom Line: The composition ratio of these 2 eel species showed a significant latitude cline, matching the 24 °C sea surface temperature isotherm in winter.A. marmorata prefer high water temperatures and die at low water temperatures.In contrast, A. japonica can endure low water temperatures, but their recruitment is inhibited by high water temperatures.

View Article: PubMed Central - PubMed

Affiliation: Institute of Fisheries Science, College of Life Science, National Taiwan University, Taipei, Taiwan. yshan@ntu.edu.tw

ABSTRACT
Anguilla japonica and Anguilla marmorata share overlapping spawning sites, similar drifting routes, and comparable larval durations. However, they exhibit allopatric geographical distributions in East Asia. To clarify this ecological discrepancy, glass eels from estuaries in Taiwan, the Philippines, Indonesia, and China were collected monthly, and the survival rate of A. marmorata under varying water salinities and temperatures was examined. The composition ratio of these 2 eel species showed a significant latitude cline, matching the 24 °C sea surface temperature isotherm in winter. Both species had opposing temperature preferences for recruitment. A. marmorata prefer high water temperatures and die at low water temperatures. In contrast, A. japonica can endure low water temperatures, but their recruitment is inhibited by high water temperatures. Thus, A. japonica glass eels, which mainly spawn in summer, are preferably recruited to Taiwan, China, Korea, and Japan by the Kuroshio and its branch waters in winter. Meanwhile, A. marmorata glass eels, which spawn throughout the year, are mostly screened out in East Asia in areas with low-temperature coastal waters in winter. During summer, the strong northward currents from the South China Sea and Changjiang River discharge markedly block the Kuroshio invasion and thus restrict the approach of A. marmorata glass eels to the coasts of China and Korea. The differences in the preferences of the recruitment temperature for glass eels combined with the availability of oceanic currents shape the real geographic distribution of Anguilla japonica and Anguilla marmorata, making them "temperate" and "tropical" eels, respectively.

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Map showing the relative abundances of A. japonica and A. marmorata in East Asia.The sampling locations of the glass eels are indicated by asterisks. No. 1: Yakushima Is., n = 2050 (Yamamoto et al., 2001); No. 2: Danshui R., n = 2547; No. 3: Yilan R., n = 3279; No. 4: Tungkang R., n = 673; No. 5: Siouguluan R., n = 7170; No. 6: Cagayan R., n = 1974 (Tabeta et al., 1976); No. 7: Cagayan area., n = 2075; No. 8: Buayan R., n = 552; No. 9: Manado, n = 350; No. 10: Poigar R., n = 4997 (Arai et al., 1999).
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pone-0037484-g001: Map showing the relative abundances of A. japonica and A. marmorata in East Asia.The sampling locations of the glass eels are indicated by asterisks. No. 1: Yakushima Is., n = 2050 (Yamamoto et al., 2001); No. 2: Danshui R., n = 2547; No. 3: Yilan R., n = 3279; No. 4: Tungkang R., n = 673; No. 5: Siouguluan R., n = 7170; No. 6: Cagayan R., n = 1974 (Tabeta et al., 1976); No. 7: Cagayan area., n = 2075; No. 8: Buayan R., n = 552; No. 9: Manado, n = 350; No. 10: Poigar R., n = 4997 (Arai et al., 1999).

Mentions: Glass eels from Taiwan were collected monthly from the estuaries of the Danshui River (Northwestern Taiwan), Donggang River (Southwestern Taiwan), Yilan River (Northeastern Taiwan), and Siouguluan River (Eastern Taiwan) (Fig. 1). Glass eels were caught using fyke nets at night between February 2009 and December 2011. One to three samplings taking 2 hours each were performed every month at each location. The data for each monthly collection were averaged. By using fyke nets, glass eels from the Philippines were collected from the estuary of the Cagayan River in northern Luzon Island and from the Buayan River in Mindanao Island (Fig. 1). Between July 2008 and April 2010, glass eels were purchased every month from the local fishermen. Glass eels were also collected from Manado in Indonesia (by using hand nets) and Shanghai in China (by using fyke nets) (Fig. 1). After collection, the glass eels were immediately preserved in 95% ethanol. Glass eel collections are allowed in these countries without need of any permission.


Sympatric spawning but allopatric distribution of Anguilla japonica and Anguilla marmorata: temperature- and oceanic current-dependent sieving.

Han YS, Yambot AV, Zhang H, Hung CL - PLoS ONE (2012)

Map showing the relative abundances of A. japonica and A. marmorata in East Asia.The sampling locations of the glass eels are indicated by asterisks. No. 1: Yakushima Is., n = 2050 (Yamamoto et al., 2001); No. 2: Danshui R., n = 2547; No. 3: Yilan R., n = 3279; No. 4: Tungkang R., n = 673; No. 5: Siouguluan R., n = 7170; No. 6: Cagayan R., n = 1974 (Tabeta et al., 1976); No. 7: Cagayan area., n = 2075; No. 8: Buayan R., n = 552; No. 9: Manado, n = 350; No. 10: Poigar R., n = 4997 (Arai et al., 1999).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3366981&req=5

pone-0037484-g001: Map showing the relative abundances of A. japonica and A. marmorata in East Asia.The sampling locations of the glass eels are indicated by asterisks. No. 1: Yakushima Is., n = 2050 (Yamamoto et al., 2001); No. 2: Danshui R., n = 2547; No. 3: Yilan R., n = 3279; No. 4: Tungkang R., n = 673; No. 5: Siouguluan R., n = 7170; No. 6: Cagayan R., n = 1974 (Tabeta et al., 1976); No. 7: Cagayan area., n = 2075; No. 8: Buayan R., n = 552; No. 9: Manado, n = 350; No. 10: Poigar R., n = 4997 (Arai et al., 1999).
Mentions: Glass eels from Taiwan were collected monthly from the estuaries of the Danshui River (Northwestern Taiwan), Donggang River (Southwestern Taiwan), Yilan River (Northeastern Taiwan), and Siouguluan River (Eastern Taiwan) (Fig. 1). Glass eels were caught using fyke nets at night between February 2009 and December 2011. One to three samplings taking 2 hours each were performed every month at each location. The data for each monthly collection were averaged. By using fyke nets, glass eels from the Philippines were collected from the estuary of the Cagayan River in northern Luzon Island and from the Buayan River in Mindanao Island (Fig. 1). Between July 2008 and April 2010, glass eels were purchased every month from the local fishermen. Glass eels were also collected from Manado in Indonesia (by using hand nets) and Shanghai in China (by using fyke nets) (Fig. 1). After collection, the glass eels were immediately preserved in 95% ethanol. Glass eel collections are allowed in these countries without need of any permission.

Bottom Line: The composition ratio of these 2 eel species showed a significant latitude cline, matching the 24 °C sea surface temperature isotherm in winter.A. marmorata prefer high water temperatures and die at low water temperatures.In contrast, A. japonica can endure low water temperatures, but their recruitment is inhibited by high water temperatures.

View Article: PubMed Central - PubMed

Affiliation: Institute of Fisheries Science, College of Life Science, National Taiwan University, Taipei, Taiwan. yshan@ntu.edu.tw

ABSTRACT
Anguilla japonica and Anguilla marmorata share overlapping spawning sites, similar drifting routes, and comparable larval durations. However, they exhibit allopatric geographical distributions in East Asia. To clarify this ecological discrepancy, glass eels from estuaries in Taiwan, the Philippines, Indonesia, and China were collected monthly, and the survival rate of A. marmorata under varying water salinities and temperatures was examined. The composition ratio of these 2 eel species showed a significant latitude cline, matching the 24 °C sea surface temperature isotherm in winter. Both species had opposing temperature preferences for recruitment. A. marmorata prefer high water temperatures and die at low water temperatures. In contrast, A. japonica can endure low water temperatures, but their recruitment is inhibited by high water temperatures. Thus, A. japonica glass eels, which mainly spawn in summer, are preferably recruited to Taiwan, China, Korea, and Japan by the Kuroshio and its branch waters in winter. Meanwhile, A. marmorata glass eels, which spawn throughout the year, are mostly screened out in East Asia in areas with low-temperature coastal waters in winter. During summer, the strong northward currents from the South China Sea and Changjiang River discharge markedly block the Kuroshio invasion and thus restrict the approach of A. marmorata glass eels to the coasts of China and Korea. The differences in the preferences of the recruitment temperature for glass eels combined with the availability of oceanic currents shape the real geographic distribution of Anguilla japonica and Anguilla marmorata, making them "temperate" and "tropical" eels, respectively.

Show MeSH