Diel vertical distribution ofAnguilla japonica leptocephali
Diel vertical distribution ofAnguilla japonica leptocephali
复制标题
细头鳗鲡昼夜垂直分布
DOI：
10.1007/bf02678565
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发表时间：
1998
影响因子：
1.2
通讯作者：
K. Tsukamoto
中科院分区：
文献类型：
--
作者：
T. Otake;T. Inagaki;Hiroshi Hasumoto;N. Mochioka;K. Tsukamoto
讨论 根据 Castonguay 和 McCleave (1987) 的报道，日本鳗鱼 (Anguilla japonica leptocepha) [i (10-20 mm TL) 白天和夜间垂直分布的差异表明它们可能会进行昼夜垂直迁移[br] 大西洋鳗鱼（A. Ivstrata 和 A. anguiIla）的长度大于 5 mm TL。后两种物种的TL~ 范围为5.0 至19.9 mm，主要出现在白天100 至150 m 和夜间50 至100 m 之间，与A. japonica leptocephali 的分布模式相似。白天捕获的细头粳稻比夜间捕获的要少得多。白天回避视觉可能是白天捕获量低的一个主要原因，因为大于 10mm TL 的日本细头蠹具有功能性的眼睛（Uematsu 等，1994）。然而，Castonguay 和 McCleave (1987) 在对大西洋物种的细头虫进行采样时，认为白天的视觉回避并不重要。本研究中使用的采样装置（MTD 网系统：0.5 m 2 开口）比 Castonguay 和 McCleave（1987）使用的 2 m 直径环形网（3.1 m 2 开口）小得多。与更大的采样设备的直接比较可以澄清这一点。采样区的海水属于最清澈的，即Jerlov%分类的I类（Jerlov，1968），其中有足够的光强度（超过10-~/~ W cm 2 ）使鱼类视觉穿透至400m深（Nicol，1989）。这表明视觉回避对
DiscussionDifferences observed in day-and night-time vertical distribution of Anguilla japonica leptocepha [i (10-20 mm TL) suggested that they may undergo diel vertical migration, as reported by Castonguay and McCleave (1987)[br Atlantic eels (A. Ivstrata and A. anguiIla) greater than 5 mm TL. The latter two species, ranging from 5.0 to 19.9 mm TL~ mostly occurred between 100 and 150m by day and between 50 and 100 m by night, a similar distribution pattern to that suggested for A. japonica leptocephali. Much fewer A. japonica leptocephali were caught by day than by night. Visual avoidance by day may have been a major reason for the low daytime catch numbers, because A. japonica leptocephali greater than 10mm TL have functional eyes (Uematsu et al., 1994). However, visual avoidance by day was evaluated as unimportant during the sampling of leptocephali of the Atlantic species by Castonguay and McCleave (1987). The sampling gear (MTD net system: 0.5 m 2 mouth opening) used in the present study was considerably smaller than the 2-m diameter ring net (3.1 m 2 mouth opening) used by Castonguay and McCleave (1987). Direct comparisons with larger sampling gear would clarify this. The sea water of the sampling area is classified as the clearest, ie category I of Jerlov% classification (Jerlov, 1968) in which enough light intensity (over 10-~/~ W cm 2) for fish vision penetrates to 400m deep (Nicol, 1989). It suggests that visual avoidance effects equally in the