A 40+ year programme to monitor brown trout, Salmo trutta L. (populations at 25 groundwater‐fed stream sites in southeast Minnesota, USA, was initiated to identify population trends, evaluate management actions and test ecological theories regulating populations. Significant increases between 1970 and 2018 were found for total biomass (an average of 5% annually) and abundance of juveniles (7%), all adults (7%) and adults ≥305 mm (3%). Sites managed with instream habitat projects had an additional 30% higher abundance for trout ≥305 mm and 57% higher for trout ≥355 mm. Sites managed with a catch‐and‐release regulation had nearly 130% higher abundance of trout ≥305 mm and 100% higher for trout ≥355 mm. Trout recruitment was temporally synchronous over the 9,200 km² area but not associated with spatial distance. There was little support for stock–recruitment relationships, and density‐dependent growth was only detected at half of the study sites. Increasing abundance trends represent a fisheries management success and suggest that these populations were largely regulated by a coupling of abiotic factors managed at two spatial scales: watershed (improved land use practices facilitating greater water infiltration) and instream (habitat improvement projects).

中文翻译：

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使用长期（40年以上）趋势数据来评估对褐鳟，鲑鳟，地下水喂养河流中种群的管理行动

发起了一项为期40多年的计划，以监测鳟鱼（Salmo trutta L。）（美国明尼苏达州东南部25个由地下水喂养的溪流点的种群），以发现种群趋势，评估管理行动并检验调节种群的生态学理论。1970年以来的显着增长在2018年发现了总生物量（平均每年5％）和幼鱼数量（7％），所有成年（7％）和≥305mm的成年动物（3％），通过河内栖息地项目管理的地点又增加了30个≥305 mm的鳟鱼丰度高出％，≥355 mm的鳟鱼丰度高出57％。实行捕捞和放行规定的场所，≥305 mm的鳟鱼丰度高出近130％，≥355 mm的鳟鱼丰度高近100％。在9,200 km ^2上募集在时间上是同步的面积，但与空间距离​​无关。几乎没有人支持招聘关系，密度依赖型增长仅在一半的研究地点被发现。丰度趋势的增加代表着渔业管理的成功，并表明这些种群在很大程度上受到两个空间尺度上管理的非生物因素的耦合的控制：分水岭（改善的土地利用做法，促进了更大的水渗透）和河川（栖息地改善项目）。