Sonar estimates of daytime activity levels of Euphausia pacifica in Saanich Inlet
Sonar estimates of daytime activity levels of Euphausia pacifica in Saanich Inlet
复制标题
声纳估计萨尼奇湾太平洋磷虾白天活动水平
DOI：
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发表时间：
1999
期刊：
影响因子：
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通讯作者：
A. D. Robertis
中科院分区：
文献类型：
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作者：
J. Jaffe;M. Ohman;A. D. Robertis
1996年7月至8月和1997年，在萨尼奇湾的分层水域部署了三维多波束跟踪声纳系统（FishTV），以实地评估磷虾的游泳行为。这里，使用一种新算法根据声纳帧对中声学目标的不相关位移来估计动物的游泳速度，并且帧之间的时间延迟增加。假设磷虾进行各向同性运动，声纳在一维（范围）的卓越空间分辨率用于推断三维运动。我们将该算法应用于白天在六次不同场合记录的 10 000 - 25 000 只磷虾鱼群的声纳轨迹。动物运动用速度的概率密度函数来描述，这表明大约 60-70% 的动物运动小于或等于 0.3-1.2 cm·s-1。这些分布意味着非常低的游泳速度和静止行为。体内的活动能力有限...
A three-dimensional multibeam tracking sonar system (FishTV) was deployed in the stratified waters of Saanich Inlet in July-August of 1996 and 1997 to assess the swimming behavior of euphausiids in situ. Here, a new algorithm is used to estimate swimming velocities of animals from the uncorrelated displacements of acoustic targets in pairs of sonar frames with increasing time delays between frames. Assuming isotropic motions of euphausiids, the superior spatial resolution of the sonar in one dimension (range) is used to infer the three-dimensional motions. We applied the algorithm to sonar tracks of groups of 10 000 - 25 000 euphausiids recorded in the daytime at depths just above the oxycline on six different occasions. The animal movements were described with a probability density function for velocity which suggests that about 60-70% of the animals were moving less than or equal to 0.3-1.2 cm·s-1. These distributions imply remarkably low swimming speeds and quiescent behavior. Limited motility in the d...