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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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Water temperature preferences for A. japonica and A. marmorata recruitments.
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pone-0037484-g005: Water temperature preferences for A. japonica and A. marmorata recruitments.

Mentions: A. japonica glass eels spawn mainly in summer and are distributed in Taiwan, China, Korea, and Japan [40], [41]. Their recruitment occurs first in Taiwan around late October and ends in Northern China and the western coast of Korea around May [24]. The distribution of A. japonica glass eels matches the recorded flow of oceanic currents, indicating the strong dependence of larval transportation on available oceanic currents (Fig. 4B) [5]. Sinclair [42] proposed the “member–vagrant” hypothesis, which states that the marine larvae that survive to settle in appropriate habitats are retained by indicated oceanic currents; in this case, A. japonica glass eels transported to the appropriate habitats are “members,” while those transported to unsuitable habitats are “vagrants.” The recruitment of A. japonica glass eels preferably occurs in estuaries with mean SSTs <24°C (Fig. 5); those transported by the Mindanao Current and Kuroshio to non-preferable areas may not actively perform upstream migration in estuaries and are thus retained at sea. Although yellow-stage eels are able to survive in brackish water and seawater [43]–[45], seawater seems to be an unsuitable niche for marine anguillid eels since very few adults can be caught in the seawaters of tropical areas.


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)

Water temperature preferences for A. japonica and A. marmorata recruitments.
© Copyright Policy
Related In: Results  -  Collection

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

pone-0037484-g005: Water temperature preferences for A. japonica and A. marmorata recruitments.
Mentions: A. japonica glass eels spawn mainly in summer and are distributed in Taiwan, China, Korea, and Japan [40], [41]. Their recruitment occurs first in Taiwan around late October and ends in Northern China and the western coast of Korea around May [24]. The distribution of A. japonica glass eels matches the recorded flow of oceanic currents, indicating the strong dependence of larval transportation on available oceanic currents (Fig. 4B) [5]. Sinclair [42] proposed the “member–vagrant” hypothesis, which states that the marine larvae that survive to settle in appropriate habitats are retained by indicated oceanic currents; in this case, A. japonica glass eels transported to the appropriate habitats are “members,” while those transported to unsuitable habitats are “vagrants.” The recruitment of A. japonica glass eels preferably occurs in estuaries with mean SSTs <24°C (Fig. 5); those transported by the Mindanao Current and Kuroshio to non-preferable areas may not actively perform upstream migration in estuaries and are thus retained at sea. Although yellow-stage eels are able to survive in brackish water and seawater [43]–[45], seawater seems to be an unsuitable niche for marine anguillid eels since very few adults can be caught in the seawaters of tropical areas.

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