1. The European oyster (Ostrea edulis) is under significant threat across its natural distribution range and even functionally extinct in some regions, such as in the German North Sea. Due to its ecological significance in terms of biodiversity and other ecosystem services, the species, and the habitat it provides, are defined as highly endangered by the OSPAR Convention.
2. Restoration measures are gaining momentum in Europe and conclusive recommendations for large‐scale biogenic reef restoration are relevant for example within the Marine Strategy Framework Directive and the Habitats Directive.
3. This study examined whether present‐day environmental conditions of sublittoral offshore waters are ecologically suitable for the return of European oysters. Seed oysters (shell length ~2 mm) were deployed in cages in offshore field experiments in 10–26 m water depth.
4. Survival, growth, and condition were investigated over the course of 2 years. Survival was high, even over winter. Growth was excellent, with oysters reaching a mean length of 55.0 ± 7.2 mm shell length and 19.2 ± 6.1 g wet weight after 2 years.
5. The formation of firmly aggregated oysters was observed and confirms O. edulis as a reef‐building species.
6. The overall condition of oysters in the field was excellent, identified by high condition indices and early reproductive activity.
7. These findings are highly relevant for future restoration measures in the North Sea as they confirm that present‐day environmental conditions and small, hatchery‐produced seed oysters are suitable of supporting sustainable and successful restoration efforts even in sublittoral offshore waters.

中文翻译：

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本地人的回归：重新引入德国近海的欧洲牡蛎的生存，生长和状况

1. 欧洲牡蛎（Ostrea edulis）在其自然分布范围内正受到严重威胁，甚至在某些地区（例如德国北海）已经灭绝。由于其在生物多样性和其他生态系统服务方面的生态意义，因此，《 OSPAR公约》将其及其提供的物种和栖息地定为高度濒危物种。
2. 在欧洲，恢复措施正在蓬勃发展，有关大规模生物礁恢复的结论性建议与之相关，例如在《海洋战略框架指令》和《人居指令》中。
3. 这项研究调查了目前沿岸近海环境条件是否在生态上适合于欧洲牡蛎的归还。在水深10-26 m的近海野外试验中，将牡蛎（壳长约2 mm）部署在网箱中。
4. 在2年的时间里调查生存，生长和状况。即使在冬天，生存率也很高。牡蛎的生长非常出色，两年后平均体长为55.0±7.2 mm壳长，湿重为19.2±6.1 g。
5. 观察到形成了牢固聚集的牡蛎，这证实了食用牡蛎为造礁物种。
6. 牡蛎的整体状况非常好，可以通过高条件指数和早期生殖活动来确定。
7. 这些发现与北海未来的恢复措施高度相关，因为它们证实了当今的环境条件以及由孵化场生产的小型牡蛎即使在沿海近岸水域中也能够支持可持续和成功的恢复工作。