There is increasing focus on the impacts of whale-watching on marine mammal species around the world. In the inland waters of Washington State and British Columbia, a region known as the Salish Sea, killer whales (Orcinus orca) are protected by regulations to help mitigate the acoustic and physical disturbance from small vessels. Most recently, the State of Washington implemented a commercial whale-watching licensing program that restricts viewing hours of whale-watching vessels within one-half nautical mile of endangered Southern Resident killer whales to four hours a day during three months of the year. During the development of these regulations, an identified data gap was regarding the “sentinel effect”, a question of whether the presence of commercial whale-watching vessels can help mitigate speed and distance incidents by private vessels via modeling correct viewing behavior and/or by directly contacting vessels to prevent such incidents from occurring. This pilot study conducted five months of boat-based and shore-based data collection on vessel incidents in the proximity of two killer whale populations in the Salish Sea. A negative binomial model predicts a significant decrease in mean estimated incidents per hour by private vessels in the presence of commercial whale-watching vessels, while there was no significant difference in the presence of boater education vessels. This study provides the first quantitative support for the sentinel effect, a finding that should be analyzed further in ongoing studies and incorporated into the adaptive management of vessel regulations, especially those that restrict only commercial whale-watching vessels.

人们越来越关注观鲸对世界各地海洋哺乳动物物种的影响。在华盛顿州和不列颠哥伦比亚省的内陆水域，一个被称为萨利希海的地区，虎鲸（Orcinusorca) 受到法规的保护，以帮助减轻来自小型船只的声学和物理干扰。最近，华盛顿州实施了一项商业观鲸许可计划，该计划将一年中三个月内在濒临灭绝的南方居民虎鲸半海里范围内的观鲸船的观赏时间限制为每天四小时。在这些法规的制定过程中，一个确定的数据缺口是关于“哨兵效应”，即商业观鲸船的存在是否可以通过模拟正确的观察行为和/或直接联系船舶以防止此类事件的发生。这项试点研究对萨利希海两个虎鲸种群附近的船只事故进行了为期五个月的船基和岸基数据收集。负二项式模型预测，在有商业观鲸船的情况下，私人船只每小时的平均估计事故数将显着减少，而在有划船教育船的情况下则没有显着差异。这项研究为哨兵效应提供了第一个定量支持，这一发现应在正在进行的研究中进一步分析，并纳入船舶法规的适应性管理中，特别是那些仅限制商业观鲸船的法规。负二项式模型预测，在有商业观鲸船的情况下，私人船只每小时的平均估计事故数将显着减少，而在有划船教育船的情况下则没有显着差异。这项研究为哨兵效应提供了第一个定量支持，这一发现应在正在进行的研究中进一步分析，并纳入船舶法规的适应性管理中，特别是那些仅限制商业观鲸船的法规。负二项式模型预测，在有商业观鲸船的情况下，私人船只每小时的平均估计事故数将显着减少，而在有划船教育船的情况下则没有显着差异。这项研究为哨兵效应提供了第一个定量支持，这一发现应在正在进行的研究中进一步分析，并纳入船舶法规的适应性管理中，特别是那些仅限制商业观鲸船的法规。