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.
Beach seining was discontinued after the 2019 season. The only sampling done in 2020 were a single gill-netting replicate in Sparkling, Crystal, and Trout lakes. Sampling in Fish Lake was missed in 2021 due to significant lake level changes. Data from the two bogs is missing in 2022.
Sampling Frequency: annually Number of sites: 11.

本数据集按年度采集数据，用于追踪11个主要湖泊的鱼类群落组成，涵盖的湖泊包括Allequash湖、Big Muskellunge湖、Crystal湖、Sparkling湖、Trout湖、27-02号泥炭湖（bog lakes，又称Crystal泥炭湖）与12-15号泥炭湖（bog lakes，又称Trout泥炭湖）、Mendota湖、Monona湖、Wingra湖及Fish湖。其中，Monona湖、Wingra湖与Fish湖的采样工作始于1995年，其余湖泊的采样自1981年起开展。
采样方案设置为：每个湖泊布设6个沿岸带（littoral zone）采样点，采用围网（seine）、小鱼笼、螯虾笼与陷网（fyke net）开展采样；同时借助船载电鱼系统对4条沿岸样带进行采样。研究人员使用垂直悬挂的刺网（gill net），在每个湖泊的最深点位采集2份远洋带（pelagic zone）样本；使用三层刺网（trammel net），在每个湖泊的2个采样位点跨越温跃层（thermocline）实施采样。仅在泥炭湖中部署陷网与小鱼笼。
本次采样的测量参数涵盖所有捕获鱼类的物种鉴定结果与体长数据，同时从部分采样个体中采集体重与鳞片样本。各湖泊的优势物种存在显著差异：鲈鱼、岩鲈与蓝鳃太阳鱼为常见物种，大眼梭鲈（walleye）、大口黑鲈（largemouth bass）、小口黑鲈（smallmouth bass）、北美狗鱼（northern pike）与北美大梭鱼（muskellunge）为主要食鱼性鱼类（piscivore）。湖白鲑（Cisco）曾现身于4个湖泊的远洋水域，外来物种胡瓜鱼（rainbow smelt）则分布于2个湖泊中。泥炭湖内均有泥小鲤（mudminnow）分布。
2019年度采样季结束后，海滩围网（beach seining）采样被终止。2020年仅在Sparkling湖、Crystal湖与Trout湖各完成1次刺网重复采样。2021年因湖泊水位发生显著变化，未能开展Fish湖的采样工作。2022年两个泥炭湖的采样数据缺失。
采样频率：每年；采样位点总数：11个。