ABSTRACT: Species conservation relies on understanding population demographics, yet this information is lacking for many species and populations. Four stocks of common bottlenose dolphins Tursiops truncatus inhabiting the waters surrounding the main Hawaiian Islands (USA) are exposed to anthropogenic disturbances including fisheries interactions, tourism, naval activities, ocean noise, and contaminants. Although these stocks are managed under the Marine Mammal Protection Act, a demographic assessment has not been undertaken since 2006, and there is currently no information on population trends. We combined regular survey effort with citizen science contributions to estimate apparent survival and annual abundance within each stock using photographs collected between 2000 and 2018. Over this time period, we collected 2818 high-quality identifications of 765 distinctive individuals across all 4 stocks. Analyses of inter-annual movements indicated that individuals exhibit restricted habitat use within stocks, which contributed to non-random sampling. Annual abundance estimates ranged from the 10s to the low 100s. Apparent survival ranged from 0.84 to 0.9, with lower-than-expected estimates in all stocks. Annual abundance estimates declined in 3 of the 4 stocks; however, this decline was not significant for the Kaua‘i/Ni‘ihau and O‘ahu stocks, and may be an artifact of sampling design in all stocks. Given the small population size for these stocks, it is important to closely monitor trends in abundance as a first step in mitigating negative effects of anthropogenic activities. Future efforts should focus on consistent geographic coverage in all stocks to decrease model uncertainty and improve trend assessment.

中文翻译：

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标记回收的估计表明主要夏威夷群岛的普通宽吻海豚种群数量减少

摘要：物种保护依赖于了解人口统计数据，但是许多物种和种群都缺乏这种信息。四只普通的宽吻海豚种群Tursiops truncatus居住在夏威夷主要群岛（美国）周围水域的居民受到人为干扰，包括渔业相互作用，旅游业，海军活动，海洋噪声和污染物。尽管这些种群是根据《海洋哺乳动物保护法》进行管理的，但自2006年以来就没有进行过人口评估，目前还没有有关人口趋势的信息。我们使用2000年至2018年之间收集的照片，将常规调查工作与公民科学贡献相结合，以估计每只种群的表观存活率和年度丰度。在此期间，我们收集了所有4种种群中765种独特个体的2818个高质量识别。对年际移动的分析表明，个体在种群内的栖息地使用受到限制，这导致了非随机抽样。年度丰度估计范围从10到低100。表观存活率介于0.84至0.9之间，所有股票的预期均低于预期。4只股票中有3只的年度丰度估计值下降；但是，对于Kaua'i / Ni'ihau和O'ahu股票而言，这种下降并不明显，并且可能是所有股票中抽样设计的产物。鉴于这些种群的人口规模很小，重要的是要密切监测其数量的变化趋势，以此作为减轻人为活动负面影响的第一步。未来的工作应集中在所有股票的一致地理覆盖范围上，以减少模型不确定性并改善趋势评估。4只股票中有3只的年度丰度估计值下降；但是，对于Kaua'i / Ni'ihau和O'ahu股票而言，这种下降并不明显，并且可能是所有股票中抽样设计的产物。鉴于这些种群的人口规模很小，重要的是要密切监测其数量的变化趋势，以此作为减轻人为活动负面影响的第一步。未来的工作应集中在所有股票的一致地理覆盖范围上，以减少模型不确定性并改善趋势评估。4只股票中有3只的年度丰富度估计值下降了；但是，对于Kaua'i / Ni'ihau和O'ahu股票而言，这种下降并不明显，并且可能是所有股票中抽样设计的产物。鉴于这些种群的人口规模很小，重要的是要密切监测其数量的变化趋势，以此作为减轻人为活动负面影响的第一步。未来的工作应集中在所有股票的一致地理覆盖范围上，以减少模型不确定性并改善趋势评估。