Walker Emily, Rivoirard Jacques, Gaspar Philippe, Bez Nicolas
Ecol Appl. 2015 Apr;25(3):826-33. doi: 10.1890/14-0193.1.
In the open ocean, movements of migratory fish populations are typically surveyed using tagging methods that are subject to low sample sizes for archive tags, except for a few notable examples, and poor temporal resolution for conventional tags. Alternatively, one can infer patterns of movement of migratory fish by tracking movements of their predators, i.e., fishing vessels, whose navigational systems (e.g., GPS) provide accurate and frequent VMS (vessel monitoring system) records of movement in pursuit of prey. In this paper, we develop a state-space model that infers the foraging activities of fishing vessels from their tracks. Second, we link foraging activities to probabilities of tuna presence. Finally, using multivariate geostatistical interpolation (cokriging) we map the probability of tuna presence together with their estimation variances and produce a time series of indices of abundance. While the segmentation of the trajectories is validated by observers' data, the present VMS-index is compared to catch rate and proved to be useful for management perspectives. The approach reported in this manuscript extends beyond the case study considered. It can be applied to any foragers that engage in an attempt of capture when they see prey and for whom this attempt is linked to a tractable change in behavior.
在公海中，洄游鱼类种群的活动通常使用标记方法进行调查，除了少数显著的例子外，存档标签的样本量较低，而传统标签的时间分辨率较差。或者，可以通过追踪其捕食者（即渔船）的活动来推断洄游鱼类的活动模式，这些渔船的导航系统（如全球定位系统）提供了准确且频繁的船舶监测系统（VMS）记录，以记录其追捕猎物时的活动。在本文中，我们开发了一种状态空间模型，该模型可根据渔船的航迹推断其觅食活动。其次，我们将觅食活动与金枪鱼出现的概率联系起来。最后，使用多元地质统计插值（协同克里金法），我们绘制了金枪鱼出现的概率及其估计方差，并生成了丰度指数的时间序列。虽然轨迹的分段通过观测者的数据得到了验证，但目前的VMS指数与渔获率进行了比较，并被证明从管理角度来看是有用的。本手稿中报道的方法超出了所考虑的案例研究范围。它可以应用于任何在看到猎物时进行捕获尝试且这种尝试与行为上易于处理的变化相关的觅食者。
