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首页> 外文期刊>Fisheries Research >Acoustic monitoring of salmonid density, target strength, and trajectoriesat two dams on the Columbia River, using a split-beam scanning system
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Acoustic monitoring of salmonid density, target strength, and trajectoriesat two dams on the Columbia River, using a split-beam scanning system

机译：使用分束扫描系统对哥伦比亚河上两个水坝的鲑鱼密度，目标强度和轨迹进行声学监测

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Horizontal acoustic scanning was used at two hydropower dams on the Columbia River to monitor downstream migrating juvenile salmonids. Two split-beam systems with computer-controlled rotating capabilities monitored the fish movement patterns in the forebay areas of the Rocky Reach and Rock Island dams. Scanning consisted of 15 or 17 horizontal aiming angles, separated in 10 degrees increments each monitored for 4 min, and tilted downwards from the horizontal at either 10 degrees or 15 degrees. Scanning was carried out for 24 h/day for periods of five days in May 1995 and was part of a larger study which lasted from 4-6 weeks. Estimates of mean fish density, target strength and trajectory were made for 5-m range cells within each horizontal scanning angle. Results show that fish movement patterns differed in the two dams. At Rocky Reach Dam, fish followed a circular trajectory pattern which was similar to the observed pattern of river flow and fish target strengths were higher in areas of low water velocity. At Rock Island Dam, fish behavior differed according to whether turbine units were operating or not. When turbines were in operation, fish moved towards the flow which contrasted with their milling behavior when the turbines were not operating. The fish target strengths were also greater in the latter situation. The difference in body aspect being insonified may account for this random acoustic aspect of milling fish compared with primarily head/dorsal aspect of fish oriented to the operational turbines.
机译：在哥伦比亚河上的两个水电大坝上使用了水平声波扫描，以监测下游迁移的幼鲑鱼。两个具有计算机控制的旋转功能的分束系统监控了落基河和Rock Island水坝前湾地区的鱼类运动方式。扫描包括15个或17个水平瞄准角，以10度的增量分开，每次监控4分钟，然后从水平方向以10度或15度向下倾斜。扫描在1995年5月进行，每天进行24小时，为期5天，是持续4-6周的较大研究的一部分。在每个水平扫描角度内对5米范围内的单元格进行平均鱼密度，目标强度和轨迹的估计。结果表明，两个大坝的鱼类运动方式不同。在洛基河大坝，鱼类遵循圆形轨迹模式，与观察到的河流流量模式相似，在水速低的地区，鱼类的目标强度更高。在Rock Island大坝，鱼的行为根据涡轮机单元是否运行而有所不同。当涡轮机运转时，鱼流向水流，这与涡轮机不运转时的碾磨行为形成对比。在后一种情况下，鱼类的目标优势也更大。与面向操作涡轮机的鱼的头/背方面相比，被声处理的身体方面的差异可解释碾磨鱼的这种随机声学方面。

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