Unexplained oyster mass mortalities threaten to destabilize the oyster industry on Canada's west coast if left unexplored. A range of potentially causative factors have been identified by the industry and the scientific community but the effects and magnitudes of these factors on oyster mortality risks remain unknown. Through a structured expert elicitation questionnaire, this study presents industry and scientific experts' calibrated judgements of cause of this multifactorial problem. We document low agreement among scientists and oyster growers with regards to important causative groups of factors. There is some agreement that factors like water temperature, seasonality, bacterial pathogens, affect oysters suspended in water and reared in trays, particularly if they are large oysters. However, both scientists and growers harbored differing views about the age and size of oysters susceptible to mass mortalities and the role of food availability and gametogenesis in contributing to mass mortalities. We discuss potential sources of these differing opinions and misconceptions. Our findings also highlight the need for additional research to resolve some of the uncertainty in experts' perceptions of cause. Risk communication efforts in the future should focus on these differing perspectives to work toward mutually viable decisions and solutions.

中文翻译：

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不列颠哥伦比亚省海岸牡蛎死亡原因的归因：牡蛎种植者和科学家的观点

如果不加以探索，不明原因的牡蛎大规模死亡可能会破坏加拿大西海岸牡蛎产业的稳定。业界和科学界已经确定了一系列潜在的致病因素，但这些因素对牡蛎死亡风险的影响和程度仍然未知。通过结构化的专家启发问卷，本研究呈现了行业和科学专家对这一多因素问题原因的校准判断。我们记录了科学家和牡蛎种植者对于重要的致病因素组的共识程度较低。人们一致认为，水温、季节性、细菌病原体等因素会影响悬浮在水中和在托盘中饲养的牡蛎，特别是大型牡蛎。然而，科学家和种植者对于容易造成大规模死亡的牡蛎的年龄和大小以及食物供应和配子发生在导致大规模死亡中的作用持有不同的看法。我们讨论这些不同意见和误解的潜在来源。我们的研究结果还强调需要进行额外的研究来解决专家对原因的看法中的一些不确定性。未来的风险沟通工作应侧重于这些不同的观点，以制定相互可行的决策和解决方案。