Water depth modifies relative predation risk for a motile fish taxon in Bahamian tidal creeks
Water depth modifies relative predation risk for a motile fish taxon in Bahamian tidal creeks
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水深改变了巴哈马潮汐溪中能动鱼类分类群的相对捕食风险
DOI：
10.1007/bf03036517
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发表时间：
2007
影响因子：
2.7
通讯作者：
D. Arrington
中科院分区：
文献类型：
--
作者：
A. Rypel;C. Layman;D. Arrington
研究了不同水深对毛虾(Eucinostomus spp.)在巴哈马安德罗斯岛的六个潮汐小溪里。相对捕食风险通过与水下目测普查相结合的系链方案来确定。在一个实验中，我们发现相对捕食风险随着水深的增加而可预测地增加(R2=0.83)，而被拴系的莫加拉的存活率随着水深的增加而下降(R2=0.71)。我们确定了三个深度区，包含不同程度的捕食威胁：避难区(0-19厘米)、过渡区(20-69厘米)和捕食区(>；70厘米)。对莫加拉的捕食很少发生在避难区(2%被捕食)，总是在捕食区(100%被捕食)。在这项研究中没有研究的其他因素(例如红树林复杂性、捕食者密度)可能驱动过渡区内相对捕食风险的变异性。在第二个实验中，我们直接检测了水深对单个小溪中从高潮到低潮的固定位置相对捕食风险的影响。平均相对捕食风险在潮汐较高、水深较深时显著较高。实验结果表明，利用活动猎物开发浅水避难所可以显著降低捕食风险。我们预计，活动鱼类的分布至少部分受到空间动态浅水避难所的影响。
We evaluated the influence of water depth on relative predation risk for mojarra (Eucinostomus spp.) in six tidal creeks on Andros Island, Bahamas. Relative predation risk was determined using a tethering protocol combined with underwater visual census. In one experiment, we found that relative predation risk increased predictably with water depth (r2 = 0.83), and survival of tethered mojarra decreased with water depth (r2 = 0.71). We identified three depth zones containing differing levels of predation threat: refugia (0–19 cm), transition (20–69 cm), and predation (> 70 cm). Predation on mojarra rarely occurred within the refugia zone (2% eaten) and always in the predation zone (100% eaten). Additional factors not examined in this study (e.g., mangrove complexity, predator density) likely drive variability of relative predation risk within the transition zone. In a second experiment, we directly examined influence of water depth on relative predation risk at fixed locations from high tide to low tide in a single creek. Mean relative predation risk was significantly higher during higher tides at deeper water depths. Results provide experimental evidence that exploitation of shallow water refugia by motile prey can significantly reduce predation risk. We expect the distribution of motile fishes is at least partially influenced by spatially-dynamic shallow water refugia.