Bolbophorus damnificus has caused epizootics in catfish aquaculture since the mid-1990s. To mitigate the losses that are associated with trematode infestations, research has focused on eradicating snails from ponds. Whole-pond treatments with 0.64–1.27 mg/L Cu have been effective in killing snails; however, Cu can be toxic to fish and may result in oxygen depletions due to its algacidal properties. Given these constraints, the potential for repeated low doses of Cu as a safe, yet effective snail treatment was investigated. Adult marsh rams-horn snails Planorbella trivolvis received four weekly doses of 0, 0.10, 0.19, 0.38, and 0.76 mg/L Cu. All of the snails died after the first treatment of 0.76 mg/L Cu. The lowest doses of 0.10 and 0.19 mg/L Cu resulted in 68% and 88% cumulative mortality, respectively. This experiment was repeated with laboratory-reared adult marsh rams-horn snails in two different laboratories, resulting in 100% mortality in the 0.38 mg/L Cu treatment. A second study evaluated the effects of repeated Cu doses on egg and juvenile snail survival. Two weekly doses of 0.19 mg/L Cu were enough to kill embryos, and all of the doses ≥0.05 mg/L Cu prevented the snails from hatching. In a pond trial, 0.51 mg/L Cu killed 100% of the adult snails after two doses. The lowest dose of 0.13 mg/L Cu killed 60% of the snails after three doses. Repeated weekly doses <0.38 mg/L Cu may reduce adult snail populations, prevent eggs from hatching, and be safer for fish than a single dose of 0.64–1.27 mg/L Cu. These data also suggest that weekly doses <0.05 mg/L Cu may suppress marsh rams-horn snail populations by limiting hatching and impeding juvenile survival.

中文翻译：

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多重、低剂量硫酸铜处理对 Marsh Rams-Horn Snail 的影响

自 1990 年代中期以来，Bolbophorusdamificus已在鲶鱼养殖中引起流行病。为了减轻与吸虫侵扰相关的损失，研究重点是从池塘中根除蜗牛。用 0.64–1.27 mg/L 铜进行全池处理可有效杀死蜗牛；然而，铜可能对鱼有毒，并可能由于其藻酸特性而导致缺氧。鉴于这些限制，研究了重复使用低剂量铜作为安全而有效的蜗牛治疗的潜力。成年沼泽公羊角蜗牛Planorbella trivolvis接受四次每周剂量的 0、0.10、0.19、0.38 和 0.76 mg/L Cu。第一次处理0.76 mg/L Cu后，所有蜗牛均死亡。0.10 和 0.19 毫克/升铜的最低剂量分别导致 68% 和 88% 的累积死亡率。在两个不同的实验室对实验室饲养的成年沼泽公羊角蜗牛重复该实验，结果在 0.38 mg/L 铜处理中死亡率为 100%。第二项研究评估了重复服用 Cu 剂量对蛋和蜗牛幼体存活率的影响。每周两次的 0.19 mg/L Cu 剂量足以杀死胚胎，并且所有剂量≥0.05 mg/L Cu 都能阻止蜗牛孵化。在池塘试验中，0.51 mg/L 铜在两次给药后可杀死 100% 的成年蜗牛。最低剂量的 0.13 mg/L Cu 在三个剂量后杀死了 60% 的蜗牛。重复每周剂量 <0。38 mg/L Cu 可减少成年蜗牛种群，防止卵孵化，并且比单剂量 0.64–1.27 mg/L Cu 对鱼更安全。这些数据还表明，每周剂量 <0.05 mg/L 的铜可能会通过限制孵化和阻碍幼体存活来抑制沼泽公羊角蜗牛种群。