1. Oyster reefs are among the most threatened marine habitats globally. In Europe, oyster reefs have been extirpated from most locations within their historical range. Active restoration of the native oyster (Ostrea edulis) in Europe has grown substantially in recent years. In sharing experiences between oyster restoration projects in Europe at the Native Oyster Restoration Alliance conference, NORA2, in Edinburgh in May 2019, it became apparent that a number of similar barriers are experienced.
2. This study identified the top 40 questions, which, if answered, would have the greatest influence on the policy and practice of oyster restoration in Europe. Initially 71 people were consulted across 28 institutions and 11 European countries to generate 194 questions. An established process of one round of pre‐workshop voting followed by a one‐day online workshop and two post‐workshop rounds of voting resulted in the final 40 questions.
3. Questions were broadly grouped into the following 10 themes: baselines, site selection, restoration methods, quantifying benefits, disease management, biosecurity, genetic diversity and population differentiation, policy and management, novel technologies, and current and future threats.
4. We anticipate that this list will provide a starting point for developing collaborative projects across the NORA network, as well as assisting policy makers and funders with identifying key areas that need to be addressed in order to overcome existing barriers to scaling up oyster restoration in Europe.

中文翻译：

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四十个对欧洲本土牡蛎礁恢复政策和实践重要的问题

1. 牡蛎礁是全球受威胁最大的海洋栖息地之一。在欧洲，牡蛎礁已在其历史范围内的绝大部分地点被灭绝。近年来，欧洲对牡蛎（Ostrea edulis）的积极恢复已大大增加。在2019年5月于爱丁堡举行的原生牡蛎恢复联盟会议NORA2上分享欧洲牡蛎恢复项目的经验时，很明显也遇到了许多类似的障碍。
2. 这项研究确定了最重要的40个问题，如果回答这些问题，将对欧洲牡蛎恢复的政策和实践产生最大的影响。最初，在28个机构和11个欧洲国家中咨询了71个人，提出了194个问题。经过确定的过程，即一轮车间前的投票，随后为期一天的在线研讨会和两次车间后的投票，最终产生了40个问题。
3. 问题大致分为以下10个主题：基线，地点选择，恢复方法，量化收益，疾病管理，生物安全，遗传多样性和种群分化，政策和管理，新技术以及当前和未来的威胁。
4. 我们希望这份清单将为在NORA网络上开展合作项目提供起点，并协助政策制定者和资助者确定需要解决的关键领域，从而克服在欧洲扩大牡蛎养殖规模的现有障碍。