Abstract Horne AJ. 2019. Hypolimnetic oxygenation 1: win–win solution for massive salmonid mortalities in a reservoir tailwater hatchery on the Mokelumne River, California. Lake Reserv Manage. 35:308–322. More than 300,000 hatchery fish supplied with deep hypolimnetic water from Camanche Reservoir, California died during two short, late summer events during the 1987–1992 drought. A criminal complaint cited the water agency for negligence. Fisheries agencies blamed the fish kills on low water levels but retaining more water would cut supplies to 1.4 million city residents, downstream farmers, and wild river fish. The reservoir was assumed to be unproductive due to its undeveloped mountain watershed but no measurements had been made. Hydrogen sulfide (H2S) was suspected as the toxic agent since it acts rapidly. Later examination of sediment redox indicated the potential for H2S formation which was confirmed by odor. A cure for H2S in the hatchery and river below the dam was a Hypolimnetic Oxygenation System (HOS). In addition, a management system was devised to guarantee a minimum volume of cool (<16.4 C), oxygenated, hypolimnetic water. The two management strategies (HOS and cool pool) greatly improved conditions. H2S was eliminated, fish moved into deep water in the reservoir, and no fish kills have occurred in 24 yr. The HOS was superior to permanganate treatments or maintaining high reservoir water levels during droughts. The criminal lawsuit was settled, no one went to jail, and inter-agency cooperation improved. Following HOS operation, Chinook salmon returns rose significantly (p < 0.05) from 3550/yr to 7660/yr (2009) and 19,867/yr (2018), with 10,000/yr spawning naturally in the river. Returns during a recent drought increased tenfold. Endangered steelhead trout returns rose from 8/yr to 1,168/yr (2017).

中文翻译：

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低浓度氧合 1：加利福尼亚州莫克勒姆河水库尾水孵化场大规模鲑鱼死亡的双赢解决方案

摘要霍恩 AJ。2019. Hypolimnetic 氧合 1：双赢解决方案在加利福尼亚州 Mokelumne 河的水库尾水孵化场中大量鲑鱼死亡。湖泊保护区管理。35:308-322。在 1987 年至 1992 年干旱期间的两次短暂的夏末事件中，超过 300,000 条孵化鱼从加利福尼亚卡曼奇水库提供了深水淹水。一项刑事诉讼援引水务局的疏忽。渔业机构将鱼类死亡归咎于低水位，但保留更多的水将减少对 140 万城市居民、下游农民和野生河鱼的供应。由于其未开发的山区流域，该水库被假定为无生产能力，但尚未进行测量。硫化氢 (H2S) 被怀疑是有毒物质，因为它作用迅速。后来对沉积物氧化还原的检查表明有可能形成 H2S，这通过气味得到证实。大坝下方孵化场和河流中硫化氢的解决方法是使用低浓度氧合系统 (HOS)。此外，还设计了一个管理系统，以保证最小量的凉爽 (<16.4 C)、含氧、低水温水。两种管理策略（居屋和凉池）大大改善了条件。H2S被清除，鱼进入水库深水区，24年未发生鱼类死亡。HOS 优于高锰酸盐处理或在干旱期间保持高水库水位。刑事诉讼了结，无人入狱，机构间合作得到改善。在居屋运营后，奇努克鲑鱼的回报从 3550 条/年显着上升（p < 0.05）至 7660 条/年（2009 年）和 19,867 条/年（2018 年），每年有 10,000 只在河中自然产卵。在最近的干旱期间，回报增加了十倍。濒临灭绝的硬头鳟鱼的回报率从 8 条/年上升到 1,168 条/年（2017 年）。