Eastern oysters growing in deltaic Louisiana estuaries in the northern Gulf of Mexico must tolerate considerable salinity variation from natural climate variability (e.g., rainfall and stream run-off pushing isohalines offshore; tropical storms pushing isohalines inshore) and man-made diversions and siphons releasing freshwater from the Mississippi River. These salinity variations are predicted to increase with future climate change because of the increased frequency of stronger storms and also in response to proposed large-scale river diversions. Increased Mississippi River flow into coastal estuaries from river diversions, along with potential changes in rainfall and stream run-off from climate change will alter spatial and temporal salinity patterns. In this study we used an individual Dynamic Energy Budget model to predict growth and reproductive potential of eastern oysters across observed and simulated salinity gradients corresponding to different climate and river management scenarios. We used validated model outputs of salinity from a coupled hydrology-hydrodynamic model to assess the current impacts of Davis Pond diversion discharge on oysters located downstream. Under a high diversion discharge scenario oyster growth potential was reduced by 9%, 4%, and 1% in Upper, Mid, and Lower Bay locations, respectively, as compared to a limited discharge year. Reproductive outputs decreased by 34% and 2% in the Upper and Lower Bay locations, respectively, and increased by 2% at the Mid Bay site. In scenarios combining predicted increased temperature with the effect of diversions, all oysters located in the Upper and Mid Bay sites died due to severe summer conditions (high temperatures combined with low salinity). Overall, oysters in down-estuary locations, influenced by both estuarine river management and gulf conditions demonstrated significant tolerance to changing salinity and temperature conditions from diversions alone and when combined with climate change. In contrast, oysters located up-estuary, and exposed to more extreme salinity impacts from river management, demonstrated potentially lethal impacts through direct mortality, and reduced sustainability through decrease in reproductive output. These predictions at the individual level may translate into less sustainable populations in the most extreme scenarios; restoration and production plans may benefit from accounting for these impacts on reproductive output particularly as decision makers seek to restore critical oyster areas.

在墨西哥湾北部的路易斯安那州三角洲河口生长的东部牡蛎必须忍受与自然气候变化（例如，降雨和溪流径流推动近海等值线；热带风暴将沿海等值线推入）以及人为的分流和虹吸释放出淡水有关的盐度变化从密西西比河。这些盐度变化预计会随着未来气候变化而增加，这是因为强风暴的频率增加以及对拟议的大规模河流改道的响应。引水使密西西比河流入沿海河口的流量增加，加上降雨和气候变化引起的径流的潜在变化，将改变时空盐度格局。在这项研究中，我们使用了一个单独的动态能源预算模型来预测东部牡蛎在观察到的和模拟的盐度梯度（对应于不同的气候和河流管理情景）下的生长和繁殖潜力。我们使用来自水文-水动力耦合模型的盐度验证模型输出来评估戴维斯池塘分流排放物对下游牡蛎的当前影响。在高分流排放情况下，与有限的排放年份相比，上湾，中湾和下湾地区的牡蛎生长潜力分别降低了9％，4％和1％。上海湾和下海湾地区的生殖产出分别下降了34％和2％，中海湾地区的生殖产出增长了2％。在结合预测的温度升高和转移影响的情况下，由于夏季严酷的条件（高温和低盐度），所有位于上海湾和中海湾站点的牡蛎都死亡了。总体而言，河口下游的牡蛎受河口河流管理和海湾条件的影响，表现出对单独盐分和与气候变化相结合的盐分和温度条件变化的显着耐受能力。相反，牡蛎位于河口上方，受到河流管理带来的更严重的盐度影响，它们通过直接死亡率显示出潜在的致命影响，并通过减少生殖产量而降低了可持续性。在最极端的情况下，个人层面的这些预测可能会导致人口的可持续性降低；