North Temperate Lakes LTER: Fish Abundance 1981 - current

This data set is a derived data set based on fish catch data. 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 three 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. Derived data sets include species richness, catch per unit effort, and size distribution by species, lake, and year. 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 the exotic species, rainbow smelt, is present in two. The bog lakes contain mudminnows. Protocol used to generate data:  Day seines were only used in 1981 and have been eliminated from this data set to make sampling effort across years comparable. Number caught for each species is summed over repetitions of a gear within a lake and over depth For information on fish stocking by Wisconsin Department of Natural Resouces in LTER lakes in Dane and Vilas counties, see http://infotrek.er.usgs.gov/doc/wdnr_biology/Public_Stocking/StateMapHot... Sampling Frequency: annually Number of sites: 11

本数据集为基于渔获数据构建的衍生数据集。数据每年采集一次，用于追踪11处主要湖泊的鱼类群落组成，涵盖以下湖泊：Allequash湖、Big Muskellunge湖、Crystal湖、Sparkling湖、Trout湖、两处泥炭湖（27-02号[Crystal Bog]与12-15号[Trout Bog]）、Mendota湖、Monona湖、Wingra湖以及Fish湖。其中Monona湖、Wingra湖与Fish湖的采样工作始于1995年，其余湖泊的采样则于1981年启动。
每座湖泊设置6处沿岸带（littoral zone）采样点，采用围网、小型鱼类诱捕笼、螯虾诱捕笼以及框刺网（fyke net）开展采样；同时使用船载电捕鱼系统对3条沿岸样带进行采样。采用垂直悬挂的刺网，在每座湖泊的最深水域采集2份远洋带样本；每座湖泊设置2处跨越温跃层的采样点，使用三层刺网（trammel net）完成采样。仅在泥炭湖中布设框刺网与小型鱼类诱捕笼。
本次采集的测量参数涵盖：所有渔获鱼类的物种鉴定结果与体长数据，以及部分个体的体重与鳞片样本。衍生数据集涵盖物种丰富度、单位捕捞努力量渔获量（catch per unit effort），以及按物种、湖泊与年份分类的体长分布数据。
各湖泊的优势物种存在显著差异。鲈属鱼类、岩钝鲈与蓝鳃太阳鱼为常见物种，大眼梭鲈（walleye）、大口黑鲈、小口黑鲈、北美狗鱼与北美大梭鲈（muskellunge）为主要食鱼性鱼类。西斯科白鲑（Cisco）仅在4座湖泊的远洋水域有分布，外来物种彩虹胡瓜鱼（rainbow smelt）见于2座湖泊；泥炭湖中则分布有泥小鲑（mudminnows）。
数据生成所遵循的规程说明如下：1981年仅使用过白昼围网，为确保不同年份的采样努力量（sampling effort）具有可比性，现已将该时段的白昼围网采样数据从本数据集中剔除。针对单座湖泊内同一渔具的多次采样，以及不同深度的采样数据，均会对各物种的捕获数量进行求和汇总。
如需查询威斯康星州自然资源部（Wisconsin Department of Natural Resources）对戴恩县与维拉斯县境内长期生态研究站（Long-Term Ecological Research, LTER）湖泊的鱼类放养相关信息，请访问：http://infotrek.er.usgs.gov/doc/wdnr_biology/Public_Stocking/StateMapHot...
采样频率：每年1次；采样站点总数：11处。