SummaryGlobal seabird populations are in decline, with nearly half of all seabird species currently in an extinction crisis. Understanding long-term seabird population trends is an essential first step to inform conservation actions. In this study, we assembled historical breeding records of seabirds throughout the Japanese archipelago and quantified the long-term population trends of 10 major breeding seabird species using a hierarchical Bayesian state-space model. The model revealed that six species had increasing or no detectable trends (Short-tailed Albatross Phoebastria albatrus, Leach’s Storm Petrel Oceanodroma leucorhoa, Pelagic Cormorant Phalacrocorax pelagicus, Japanese Cormorant Phalacrocorax capillatus, Spectacled Guillemot Cepphus carbo, and Rhinoceros Auklet Cerorhinca monocerata). However, decreasing trends were found not only in nationally threatened species (Common Murre Uria aalge, and Tufted Puffin Fratercula cirrhata) but also common species that are often described as abundant (Black-tailed Gull Larus crassirostris and Slaty-backed Gull Larus schistisagus). These declining species have declined to 3–35% of baseline levels over the past 30 years. This study provides the first evidence of long-term declines in common and widespread seabirds in Japan.

中文翻译：

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日本常见的繁殖海鸟数量长期下降

摘要全球海鸟种群正在下降，近一半的海鸟物种目前处于灭绝危机中。了解海鸟种群的长期趋势是为保护行动提供信息的重要的第一步。在这项研究中，我们收集了整个日本列岛海鸟的历史繁殖记录，并使用分级贝叶斯状态空间模型量化了 10 种主​​要繁殖海鸟物种的长期种群趋势。该模型显示，六种物种有增加或没有可检测到的趋势（短尾信天翁Phoebastria albatrus, 利奇的风暴海燕白带海藻, 远洋鸬鹚浮游鱼, 日本鸬鹚鲶鱼, 眼镜海鸥炭疽杆菌，和犀牛 Auklet单角犀牛）。然而，不仅在国家受威胁的物种（Common Murre尿藻, 和簇绒海雀蚧壳虫）还有经常被描述为丰富的常见物种（黑尾鸥海鸥和板岩海鸥石斑鸥）。在过去 30 年中，这些数量下降的物种已下降到基线水平的 3-35%。这项研究提供了日本常见和广泛海鸟长期下降的第一个证据。