Three-dimensional movements of harbour seals in a tidally energetic channel: Application of a novel sonar tracking system
Three-dimensional movements of harbour seals in a tidally energetic channel: Application of a novel sonar tracking system
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DOI：
10.1002/aqc.3017
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发表时间：
2019-04-01
影响因子：
2.4
通讯作者：
Gillespie, Douglas
中科院分区：
文献类型：
--
作者：
Hastie, Gordon D.;Bivins, Matt;Gillespie, Douglas
要了解海洋捕食者如何利用栖息地，我们需要从三个方面考虑它们的行为。最近的研究表明，海洋哺乳动物经常利用潮汐能量的位置觅食，但数据通常仅限于对水面动物的观察。可再生能源行业也对这些地区感兴趣，以部署潮汐能涡轮机;这导致人们担心对海洋哺乳动物的潜在影响。测量水下动物运动的方法是有限的;然而，主动声纳可以成像海洋哺乳动物，并可能测量潮汐能量位置的三维运动。在这里，一个双720 kHz的声纳系统的开发，调查的三维运动的港口海豹（Phoca vitulina）在潮汐充满活力的渠道。密封的估计平均深度（距表面的距离）为12.0 m（95%置信区间[CI]：11.6-12.4 m），大部分时间在表面和距表面约10-12 m处。当以距海床的距离表示时，平均距离为18.5 m（95% CI：18.0-18.9 m），大部分时间都在距海床14 m处度过。海豹运动的方向通常与潮汐流相同，平均水平速度在0.51 - 3.13 m s（-1）之间（95% CI = 1.24-1.54 m s（-1））。每个海豹轨迹的平均垂直速度（负值和正值分别代表下降和上升）范围在-1.76和+0.88 m s（-1）之间（95% CI：-0.23至+0.03 m s（-1））。这些结果提供了一个基础，了解海豹如何利用动态潮汐环境，并建议港海豹的行为可以显着不同的潮汐能量较低的栖息地。这些结果也有重要的影响，预测与这些动态栖息地的潜水海豹和潮汐涡轮机之间的相互作用的风险。
Understanding how marine predators utilize habitats requires that we consider their behaviour in three dimensions. Recent research has shown that marine mammals often make use of tidally energetic locations for foraging, yet data are generally limited to observations of animals at the water surface. Such areas are also of interest to the renewable energy industry for the deployment of tidal-stream energy turbines; this has led to concerns about potential impacts on marine mammals. Methods for measuring animal movements underwater are limited; however, active sonar can image marine mammals and could potentially measure three-dimensional movements in tidally energetic locations. Here, a dual 720 kHz sonar system was developed to investigate the three-dimensional movements of harbour seals (Phoca vitulina) in a tidally energetic channel. Estimated mean depth (distance from the surface) of seals was 12.0 m (95% confidence intervals [CIs]: 11.6-12.4 m), and the majority of time was spent at the surface and at approximately 10-12 m distance from the surface. When expressed as distances from the sea bed, mean distance was 18.5 m (95% CI: 18.0-18.9 m), and the majority of time was spent at 14 m from the sea bed. Seal movements were generally in the same direction as the tidal flow with mean horizontal speeds of between 0.51 and 3.13 m s(-1) (95% CIs = 1.24-1.54 m s(-1)). Mean vertical velocities (where negative and positive values represent a descent and ascent respectively) for each seal track ranged between -1.76 and +0.88 m s(-1) (95% CIs: -0.23 to +0.03 m s(-1)). These results provide a basis for understanding how seals utilize a dynamic tidal environment and suggest that harbour seal behaviour can be markedly different to less tidally energetic habitats. The results also have important implications for the prediction of risk associated with interactions between diving seals and tidal turbines in these dynamic habitats.