Eastern oyster farm production has increased dramatically in the northeastern United States in recent decades. Farming methods vary, but different configurations of off‐bottom “rack‐and‐bag” gear are commonly used and there is little published research on how different methods affect oyster growth. Field experiments were conducted during 2016–2018 on two farm sites in New Hampshire to assess the effects on oyster growth and mortality of different gear deployment configurations: (1) bag height above the bottom; (2) different combinations of oyster seed size, bag mesh size, and stocking density; (3) rack‐and‐bag versus bottom tray; (4) oyster seed size and over‐winter mortality; and (5) envelope‐ versus box‐style bags. Bag stocking density consistently had the strongest effect, with oyster growth being up to 3 times faster in bags that were stocked at 0.5 L compared with 2.0 L of wet oysters. Additionally, stocking density had a stronger effect on the oysters that were in 6‐mm mesh bags than on those that were in 4‐mm mesh bags. Oysters that were in bags in the top level of the rack grew significantly faster in one experiment but not in another. There was no significant difference in oyster growth comparing rack‐and‐bag and bottom trays. The over‐winter mortality of oysters that were raised in rack‐and‐bag gear averaged 17% in one experiment and 46% in another. Early growth was similar for oysters that were deployed in box‐ and envelope‐style bags, but by the final measurement (at 2.4 months) oysters in the box‐style bags were 18% larger. The major findings were interpreted in the context of the notion that food supply and the factors affecting it have strong effects on the growth of farmed oysters, so this dynamic should drive strategies to improve gear deployment methods. Additionally, the typical situation of widely varying differences in uncontrollable factors (e.g., currents or phytoplankton concentrations) among sites and their effects on gear deployment methods may best be addressed by site‐specific empirical studies that are conducted by farmers.

中文翻译：

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东非牡蛎Crassostrea virginica在新罕布什尔州（美国）的生长和死亡率

近几十年来，美国东北部东部牡蛎养殖场的产量急剧增加。养殖方法各不相同，但通常使用底下“机架和袋式”渔具的不同配置，而且很少有关于不同方法如何影响牡蛎生长的已发表研究。在2016-2018年期间，在新罕布什尔州的两个农场进行了田间试验，以评估不同渔具配置对牡蛎生长和死亡率的影响：（1）袋底上方的袋子高度；（2）牡蛎种子大小，袋目大小和放养密度的不同组合；（3）机架袋与底部托盘的对比；（4）牡蛎种子大小和越冬死亡率；（5）信封式和盒式袋。袋装密度始终是最强的影响，牡蛎生长速度为0.5升时，牡蛎的生长速度比湿牡蛎为2.0升时高3倍。此外，放养密度对6毫米网眼袋牡蛎的影响要强于对4毫米网眼袋牡蛎的影响。在一个实验中，放在架子最高层的袋子中的牡蛎的生长速度显着加快，而在另一实验中却没有。与货架和底部托盘相比，牡蛎生长没有显着差异。在一个实验中，用袋装齿轮养生的牡蛎的越冬死亡率平均为17％，而在另一个实验中为46％。部署在盒装和信封式袋子中的牡蛎的早期生长相似，但通过最终测量（在2.4个月时），盒式袋子中的牡蛎大了18％。主要发现是根据以下观念来解释的：食物供应及其影响因素对养殖牡蛎的生长有很大影响，因此这种动态应推动采取策略来改进渔具部署方法。此外，农民之间进行的针对具体地点的实证研究可以最好地解决地点之间不可控因素（例如，水流或浮游植物浓度）之间差异大的典型情况及其对渔具部署方法的影响。