https://scholars.lib.ntu.edu.tw/handle/123456789/137286
標題: | The sex-ratio reversal of the Japanese eel Anguilla japonica in the Kaoping River of Taiwan: The effect of cultured eels and its implication | 作者: | Chu, Yu-Wei Han, Yu-San Wang, Chia-Hui You, Chen-Feng Tzeng, Wann-Nian |
關鍵字: | Elemental signature; Japanese eel; Otolith; Sex ratio; Typhoon Mindulle | 公開日期: | 2006 | 卷: | 261 | 期: | 4 | 起(迄)頁: | 1230-1238 | 來源出版物: | Aquaculture | 摘要: | The sex ratio of wild Japanese eels in the Kaoping River of southwestern Taiwan has been extremely skewed towards females in the recent years. However, the sex ratio skewed towards males after Typhoon Mindulle, July 2, 2004 then recovered to the previous female-dominated status in the following year. To determine why the sex ratio drastically changed, eels captured in the river were examined by both morphologic characteristics and otolith elemental signatures by solution-based inductively coupled plasma mass spectrometry (SB-ICPMS) and laser-ablation ICPMS (LA-ICPMS). Most of the eels collected in the river after the typhoon had a blue-gray colored back, with morphology and sex ratio similar to that of cultured eels, which differed from wild yellow eels which had a green colored back. The chemical signature in otoliths of eels with a blue-gray colored back was similar to that of cultured eels, with significantly lower Sr/Ca ratios but slightly higher Mn/Ca ratios than for wild eels. This confirmed that the reversal in eel sex ratio in the Kaoping River estuary resulted from cultured eels that had escaped from eel farms. Eel farmers estimated that about 30,000 eels escaped during the typhoon, sufficient to reverse the sex ratio of the eels in the river. Furthermore, silver eels caught in the estuary in the winter 2004 were also mostly males. The chemical signature in otoliths of these silver eels was similar to that of escaped cultured eels. Their morphology and mean GSIs, however, were comparable to wild silver eels. Thus, cultured eels that have escaped from eel farms can silver normally in the wild. Consequently, cultured eels may help to balance the sex ratio of the wild eel population and may contribute to the spawning stock of Japanese eel. © 2006 Elsevier B.V. All rights reserved. |
URI: | https://www.scopus.com/inward/record.uri?eid=2-s2.0-33751319873&doi=10.1016%2fj.aquaculture.2006.09.014&partnerID=40&md5=a26ae7a78845e6a5a39fe20875abba90 http://ntur.lib.ntu.edu.tw//handle/246246/162411 |
ISSN: | 00448486 | DOI: | 10.1016/j.aquaculture.2006.09.014 | SDG/關鍵字: | eel; morphology; otolith; sex ratio; sex reversal; typhoon; Asia; Eurasia; Far East; Kaoping River; Taiwan; Anguilla japonica |
顯示於: | 生命科學系 |
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