North Temperate Lakes LTER: Fish Lengths and Weights 1981 - current

Data are collected annually to enable us to track the fish assemblages of eleven primary lakes (Allequash, Big Muskellunge, Crystal, Sparkling, Trout, bog lakes 27-02 [Crystal Bog] and 12-15 [Trout Bog], Mendota, Monona, Wingra and Fish). Sampling on Lakes Monona, Wingra, and Fish started in 1995; sampling on other lakes started in 1981. Sampling is done at six littoral zone sites per lake with seine, minnow or crayfish traps, and fyke nets; a boat-mounted electrofishing system samples four littoral transects. Vertically hung gill nets are used to obtain two pelagic samples per lake from the deepest point. A trammel net samples across the thermocline at two sites per lake. In the bog lakes only fyke nets and minnow traps are deployed. Parameters measured include species-level identification and lengths for all fish caught, and weight and scale samples from a subset. Dominant species vary from lake to lake. Perch, rockbass, and bluegill are common, with walleye, large and smallmouth bass, northern pike and muskellunge as major piscivores. Cisco have been present in the pelagic waters of four lakes, and an exotic species, rainbow smelt, is present in two. The bog lakes contain mudminnows. Sampling Frequency: annually Number of sites: 11

本数据集按年度采集，用于追踪11处主要湖泊的鱼类群落（fish assemblages）组成，涉及湖泊包括Allequash湖、Big Muskellunge湖、Crystal湖、Sparkling湖、Trout湖，以及编号为27-02的沼泽湖[Crystal Bog（水晶沼泽）]与编号为12-15的沼泽湖[Trout Bog（鳟鱼沼泽）]，另有Mendota湖、Monona湖、Wingra湖及Fish湖。Monona湖、Wingra湖与Fish湖的采样工作始于1995年，其余湖泊的采样则于1981年启动。采样实施方式如下：每个湖泊设置6处沿岸带（littoral zone）采样点，采用围网（seine）、小型鱼类诱捕笼（minnow traps）、螯虾诱捕笼（crayfish traps）及法伊克网（fyke nets）开展采样；同时借助船载电渔系统（boat-mounted electrofishing system）对4处沿岸样带（littoral transects）进行采样。通过垂直悬挂的刺网（gill nets）在每个湖泊的最深处采集2份远洋层（pelagic）样本。使用三重刺网（trammel net）在每个湖泊的2处位点跨越温跃层（thermocline）进行采样。仅在沼泽湖中布设法伊克网与小型鱼类诱捕笼。本次采集的测定参数包括所有捕获鱼类的物种水平鉴定（species-level identification）与体长测量，同时从部分采样个体中获取体重与鳞片样品。不同湖泊的优势物种存在显著差异：鲈鱼（Perch）、岩鲈（rockbass）与蓝鳃太阳鱼（bluegill）为常见物种，大眼梭鲈（walleye）、大口黑鲈（largemouth bass）、小口黑鲈（smallmouth bass）、白斑狗鱼（northern pike）及北美狗鱼（muskellunge）为主要肉食性鱼类（piscivores）。西斯科鱼（Cisco）曾分布于4处湖泊的远洋水域，外来物种（exotic species）彩虹胡瓜鱼（rainbow smelt）则现身于2处湖泊中。沼泽湖中可见泥小鱼（mudminnows）。采样频率：每年1次；采样湖泊总数：11处。