Seasonal Occurrence of Anguillid Elvers in Cagayan River, Luzon Island, the Philippines
Seasonal Occurrence of Anguillid Elvers in Cagayan River, Luzon Island, the Philippines
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菲律宾吕宋岛卡加延河鳗鱼的季节性出现
DOI：
10.2331/suisan.42.421
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发表时间：
1976
影响因子：
0.4
通讯作者：
T. Imamura
中科院分区：
文献类型：
--
作者：
O. Tabeta;Tsutomu Tanimoto;T. Takai;I. Matsui;T. Imamura
对 1970 年至 1974 年从菲律宾吕宋岛卡加延河口和邻近鳗鱼池塘采集的约 5400 份鳗鱼幼鱼标本进行了研究，特别是物种组成及其季节性发生情况。所得结果如下： 1)根据椎骨断面计数，将幼鱼和幼鱼鉴定为Anguilla celebesensis、A. marmorata、A. japonica和A. bicolor pacifica。 2）除了椎骨的截面计数外，发现尾部皮肤色素沉着对于早期菲律宾鳗鱼的特异性识别很有用。 3) 幼虫全年大部分时间都出现在河口，以3月和8月最为丰富。 4)优势幼虫之一的A. marmorata主要出现在上半年，高峰期为3月；而另一种优势幼虫A. celebensis则全年大部分时间都有发现，高峰期为8月。 5)本次观测中的小种太平洋紫苏和日本紫苏主要出现在10月至2月以及1月和2月。
Some 5400 specimens of anguillid elvers and youngs collected in 1970-1974 from the Cagayan Estuary of Luzon Island, the Philippines, and the neighbouring eel ponds were studied, especially on species composition and their seasonal occurrence. The results obtained are as follows: 1) The elvers and youngs, based on sectional counts of vertebrae, were identified as Anguilla celebesensis, A. marmorata, A. japonica and A. bicolor pacifica. 2) Besides sectional counts of the vertebrae, the caudal cutaneous pigmentation was found to be useful for specific identification of the Philippine eels in the early elver stage. 3) The elvers occurred in the Estuary during most of the year, and were most abundant in March and August. 4) A. marmorata, one of the dominant elvers, was found mainly in the first half of the year, with a peak in March, while A. celebesensis, another dominant elver, was seen during most of the year, attaining its peak in August. 5) A. bicolor pacifica and A. japonica, the minor species in the present observation, appeared mainly in October to February, and January and February, respectively.