Department of Oceanography, Dalhousie University, 1355 Oxford Street, P.O. Box 15000, Halifax, Nova Scotia B3H 4R2 Canada.
Ecol Appl. 2012 Oct;22(7):2021-33. doi: 10.1890/11-1841.1.
Vessel strikes are the primary source of known mortality for the endangered North Atlantic right whale (Eubalaena glacialis). Multi-institutional efforts to reduce mortality associated with vessel strikes include vessel-routing amendments such as the International Maritime Organization voluntary "area to be avoided" (ATBA) in the Roseway Basin right whale feeding habitat on the southwestern Scotian Shelf. Though relative probabilities of lethal vessel strikes have been estimated and published, absolute probabilities remain unknown. We used a modeling approach to determine the regional effect of the ATBA, by estimating reductions in the expected number of lethal vessel strikes. This analysis differs from others in that it explicitly includes a spatiotemporal analysis of real-time transits of vessels through a population of simulated, swimming right whales. Combining automatic identification system (AIS) vessel navigation data and an observationally based whale movement model allowed us to determine the spatial and temporal intersection of vessels and whales, from which various probability estimates of lethal vessel strikes are derived. We estimate one lethal vessel strike every 0.775-2.07 years prior to ATBA implementation, consistent with and more constrained than previous estimates of every 2-16 years. Following implementation, a lethal vessel strike is expected every 41 years. When whale abundance is held constant across years, we estimate that voluntary vessel compliance with the ATBA results in an 82% reduction in the per capita rate of lethal strikes; very similar to a previously published estimate of 82% reduction in the relative risk of a lethal vessel strike. The models we developed can inform decision-making and policy design, based on their ability to provide absolute, population-corrected, time-varying estimates of lethal vessel strikes, and they are easily transported to other regions and situations.
船舶碰撞是濒危北大西洋露脊鲸（Eubalaena glacialis）已知死亡的主要原因。为了减少与船舶碰撞相关的死亡率，多个机构进行了合作，包括对船舶航线进行修改，如在西南斯科舍浅滩罗塞韦湾右鲸觅食栖息地实施国际海事组织自愿性“避免区”（ATBA）。虽然已经估计并公布了致命船舶碰撞的相对概率，但绝对概率仍不清楚。我们使用建模方法来确定 ATBA 的区域影响，通过估计预期的致命船舶碰撞数量的减少来实现。与其他方法不同，这种分析明确包括了对通过模拟游动右鲸群体的船舶实时过境进行时空分析。结合自动识别系统（AIS）船舶导航数据和基于观测的鲸鱼运动模型，我们可以确定船舶和鲸鱼的空间和时间交叉点，从中得出各种致命船舶碰撞的概率估计。在实施 ATBA 之前，我们估计每 0.775-2.07 年会发生一次致命的船舶碰撞，与之前每 2-16 年发生一次的估计一致，但更具约束性。实施后，预计每 41 年会发生一次致命的船舶碰撞。当鲸鱼数量在各年保持不变时，我们估计船舶自愿遵守 ATBA 会使每头鲸鱼的致命撞击率降低 82%；这与之前发表的估计非常相似，即致命船舶碰撞的相对风险降低了 82%。我们开发的模型可以根据其提供的致命船舶碰撞的绝对、群体校正、时变估计的能力，为决策和政策设计提供信息，并且很容易推广到其他地区和情况。
