The Aleutian Archipelago and surrounding waters have enormous ecological, cultural, and commercial significance. As one of the shortest routes between North American and Asian ports, the North Pacific Great Circle Route, which crosses through the Aleutian Archipelago, is traveled by thousands of large cargo ships and tanker vessels every year. To reduce maritime risks and enhance navigational safety, the International Maritime Organization built upon earlier offshore routing efforts by designating five Areas To Be Avoided (ATBAs) in the Aleutian Islands in 2016. The ATBAs are designed to keep large vessels at least 50 nautical miles (93 km) from shore unless calling at a local port or transiting an authorized pass between islands. However, very few studies have examined the effectiveness of ATBAs as a mechanism for changing vessel behavior and thereby reducing the ecological impacts of maritime commerce. In this study, we use 4 years of satellite-based vessel tracking data to assess the effectiveness of the Aleutian ATBAs since their implementation in 2016. We determined whether vessels transiting the North Pacific Great Circle Route changed behavior after ATBA implementation, both in terms of overall route selection and in terms of compliance with each ATBA boundary. We found a total of 2,252 unique tankers and cargo vessels >400 gross tons transited the study region, completing a total of 8,794 voyages. To quantify routing changes of individual vessels, we analyzed the 767 vessels that transited the study region both before and after implementation. The percentage of voyages transiting through the boundaries of what would become ATBAs decreased from 76.3% in 2014–2015 (prior to ATBA designation) to 11.8% in 2016–2017 (after implementation). All five Aleutian ATBAs had significant increases in compliance, with the West ATBA showing the most dramatic increase, from 32.1% to 95.0%. We discuss the framework for ATBA enforcement and highlight the value of local institutional capacity for real-time monitoring. Overall, our results indicate that ATBAs represent a viable strategy for risk mitigation in sensitive ecological areas and that through monitoring, spatial protections influence vessel route decisions on multiple spatial scales.

中文翻译：

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空间管理措施改变阿留申群岛的船只行为

阿留申群岛及周边水域具有巨大的生态、文化和商业意义。作为北美和亚洲港口之间最短航线之一，穿越阿留申群岛的北太平洋大环航线每年有数千艘大型货船和油轮经过。为了降低海上风险和提高航行安全，国际海事组织在早期的海上航线工作的基础上，于 2016 年在阿留申群岛指定了五个要避开的区域 (ATBA)。 ATBA 旨在使大型船舶保持至少 50 海里的距离（ 93 公里），除非在当地港口停靠或在岛屿之间过境。然而，很少有研究检验 ATBA 作为改变船舶行为的机制的有效性，从而减少海上贸易对生态的影响。在这项研究中，我们使用 4 年的基于卫星的船舶跟踪数据来评估自 2016 年实施以来阿留申 ATBA 的有效性。我们确定了在 ATBA 实施后通过北太平洋大环线的船舶是否改变了行为，无论是在总体路线选择以及与每个 ATBA 边界的合规性。我们发现共有 2,252 艘独特的油轮和大于 400 总吨的货船通过研究区域，完成了 8,794 次航行。为了量化个别船只的航线变化，我们分析了实施前后经过研究区域的 767 艘船只。通过将成为 ATBA 边界的航次的百分比从 2014-2015 年（ATBA 指定之前）的 76.3% 下降到 2016-2017 年（实施后）的 11.8%。所有五个阿留申 ATBA 的合规性都有显着增加，其中西部 ATBA 的增加最为显着，从 32.1% 增加到 95.0%。我们讨论了 ATBA 执法框架，并强调了当地机构实时监控能力的价值。总体而言，我们的结果表明，ATBA 代表了在敏感生态区减轻风险的可行策略，并且通过监测，空间保护在多个空间尺度上影响船舶航线决策。所有五个阿留申 ATBA 的合规性都有显着增加，其中西部 ATBA 的增加最为显着，从 32.1% 增加到 95.0%。我们讨论了 ATBA 执法框架，并强调了当地机构实时监控能力的价值。总体而言，我们的结果表明，ATBA 代表了在敏感生态区减轻风险的可行策略，并且通过监测，空间保护在多个空间尺度上影响船舶航线决策。所有五个阿留申 ATBA 的合规性都有显着增加，其中西部 ATBA 的增加最为显着，从 32.1% 增加到 95.0%。我们讨论了 ATBA 执法框架，并强调了当地机构实时监控能力的价值。总体而言，我们的结果表明，ATBA 代表了在敏感生态区减轻风险的可行策略，并且通过监测，空间保护在多个空间尺度上影响船舶航线决策。