The collapse of oyster populations and the fisheries they support has been a worldwide phenomenon, but studies of oyster demography in situ prior to and after the collapse have been rare. We used time series of stage-based counts of eastern oysters Crassostrea virginica in Apalachicola Bay, Florida, to help understand how abundance and demographic rates may have changed in the decade after the 2012 collapse relative to the period before the collapse. We relied on a Bayesian hierarchical model in which the latent stage structure of the oyster population (i.e., densities of spat, sublegal oysters, and legal oysters) was governed by a system process and where the count data represented summaries of that latent structure. Count data were sufficient to conduct this on two large oyster bars that had some of the highest precollapse oyster densities. We also examined nine other bars with less data for any temporal trends in postcollapse abundance that might be associated with recent restoration efforts. Among the 11 bars examined, oyster densities were often increasing prior to the collapse and were very low, without detectable trends, afterward. Based on our demographic analyses, mortality rates of Apalachicola Bay oysters in the decade after the collapse generally exceeded (often greatly so) those during the precollapse period for all oyster stages. On the other hand, spat settlement rates apparently were increasing prior to the collapse and remained high during the postcollapse period. Simulations of postcollapse demography suggest that without improved survival rates, further declines of the oyster population can be expected. We discuss these findings in light of ongoing restoration and management efforts and suggest ways in which rapid transitions to undesirable socio-ecological regimes might be avoided in the future.

中文翻译：

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佛罗里达州阿巴拉契科拉湾坍塌前后牡蛎的人口统计，使用基于阶段的计数

牡蛎种群和它们所支持的渔业的崩溃是一个世界性的现象，但在崩溃前后对牡蛎种群数量的现场研究很少见。我们使用了东部牡蛎Crassostrea virginica的基于阶段计数的时间序列在佛罗里达州的阿巴拉契科拉湾，以帮助了解相对于崩溃前的时期，2012 年崩溃后的十年中丰富度和人口比率可能发生了怎样的变化。我们依赖于贝叶斯分层模型，其中牡蛎种群的潜在阶段结构（即卵、亚合法牡蛎和合法牡蛎的密度）由系统过程控制，其中计数数据代表该潜在结构的摘要。计数数据足以在两个大型牡蛎条上进行这项工作，这两个大牡蛎条具有一些最高的预塌陷牡蛎密度。我们还检查了其他九个数据较少的条形图，以了解可能与最近的恢复工作相关的坍塌后丰度的任何时间趋势。在检查的 11 个酒吧中，牡蛎密度在倒塌之前经常增加并且非常低，之后没有可检测的趋势。根据我们的人口统计分析，阿巴拉契科拉湾牡蛎在崩溃后十年内的死亡率普遍超过（通常大大超过）所有牡蛎阶段崩溃前的死亡率。另一方面，在倒塌之前，争端沉降率显然在增加，并在倒塌后时期保持在高位。对坍塌后人口统计的模拟表明，如果存活率不提高，牡蛎种群数量预计会进一步下降。我们根据正在进行的恢复和管理工作讨论了这些发现，并提出了未来可能避免快速过渡到不良社会生态制度的方法。崩溃后十年内阿巴拉契科拉湾牡蛎的死亡率普遍超过（通常大大高于）所有牡蛎阶段崩溃前的死亡率。另一方面，在倒塌之前，争端沉降率显然在增加，并在倒塌后时期保持在高位。对坍塌后人口统计的模拟表明，如果存活率不提高，牡蛎种群数量预计会进一步下降。我们根据正在进行的恢复和管理工作讨论了这些发现，并提出了未来可能避免快速过渡到不良社会生态制度的方法。崩溃后十年内阿巴拉契科拉湾牡蛎的死亡率普遍超过（通常大大高于）所有牡蛎阶段崩溃前的死亡率。另一方面，在倒塌之前，争端沉降率显然在增加，并在倒塌后时期保持在高位。对坍塌后人口统计的模拟表明，如果存活率不提高，牡蛎种群数量预计会进一步下降。我们根据正在进行的恢复和管理工作讨论了这些发现，并提出了未来可能避免快速过渡到不良社会生态制度的方法。卵沉降率显然在崩溃前增加，并在崩溃后时期保持高位。对坍塌后人口统计的模拟表明，如果存活率不提高，牡蛎种群数量预计会进一步下降。我们根据正在进行的恢复和管理工作讨论了这些发现，并提出了未来可能避免快速过渡到不良社会生态制度的方法。卵沉降率显然在崩溃前增加，并在崩溃后时期保持高位。对坍塌后人口统计的模拟表明，如果存活率不提高，牡蛎种群数量预计会进一步下降。我们根据正在进行的恢复和管理工作讨论了这些发现，并提出了未来可能避免快速过渡到不良社会生态制度的方法。