North Temperate Lakes LTER: Fish Abundance 1981 - current (Reformatted to a Darwin Core Archive)

This data package is formatted as a Darwin Core Archive (DwC-A, event core). For more information on Darwin Core see https://www.tdwg.org/standards/dwc/. This Level 2 data package was derived from the Level 1 data package found here: https://pasta.lternet.edu/package/metadata/eml/edi/303/2, which was derived from the Level 0 data package found here: https://pasta.lternet.edu/package/metadata/eml/knb-lter-ntl/7/39. The abstract below was extracted from the Level 0 data package and is included for context: 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. The absence of a species in a given lake/year indicates none were caught and the catch per unit effort is zero. 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/StateMapHotspotsAllYears.htm. The only sampling done in 2020 were a single gill-netting replicate in Sparkling, Crystal, and Trout lakes. Sampling Frequency: annually. Number of sites: 11.

本数据包采用达尔文核心档案（Darwin Core Archive，DwC-A，事件核心）格式构建。有关达尔文核心标准的详细信息，请参阅https://www.tdwg.org/standards/dwc/。本二级数据包源自此处的一级数据包：https://pasta.lternet.edu/package/metadata/eml/edi/303/2，而该一级数据包又源自此处的零级数据包：https://pasta.lternet.edu/package/metadata/eml/knb-lter-ntl/7/39。以下摘要从零级数据包中提取，用于提供背景信息：本数据集为基于鱼类渔获数据的衍生数据集。数据每年采集一次，用于追踪11个主要湖泊的鱼类群落组成，包括Allequash湖、Big Muskellunge湖、Crystal湖、Sparkling湖、Trout湖、沼泽湖27-02[Crystal Bog]与12-15[Trout Bog]、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，其余湖泊的采样始于1981年。采样采用以下方式：每个湖泊设置6个沿岸带采样点，使用围网、小型鱼类诱捕笼或螯虾诱捕笼、双囊网（fyke nets）进行采样；同时搭载船载电渔系统开展3条沿岸样带的采样。使用垂直悬挂的刺网在每个湖泊的最深点位采集2个远洋带样本。使用三层刺网在每个湖泊的2个位点跨越温跃层进行采样。沼泽湖仅使用双囊网与小型鱼类诱捕笼开展采样。本次测定的参数包括：所有捕获鱼类的物种鉴定结果与体长数据，以及部分样本的体重与鳞片样本。衍生数据集包含物种丰富度、单位捕捞努力量渔获量（catch per unit effort），以及按物种、湖泊与年份划分的体长分布。不同湖泊的优势物种存在差异：鲈鱼（perch）、岩鲈（rockbass）与蓝鳃太阳鱼（bluegill）为常见物种，大眼梭鲈（walleye）、大口黑鲈与小口黑鲈（large and smallmouth bass）、北美狗鱼（northern pike）与北美梭子鱼（muskellunge）为主要的食鱼性鱼类。西鲱（cisco）曾在4个湖泊的远洋带出现，而外来物种彩虹胡瓜鱼（rainbow smelt）见于2个湖泊。沼泽湖群落中含有泥鳉（mudminnows）。数据生成流程说明：日间围网仅在1981年使用，为使各年度采样努力量具有可比性，本数据集已剔除该采样方式。将同一湖泊内同一渔具的重复采样、不同深度的渔获量按物种求和。若某物种在特定湖泊/年份未被捕获，则记录为未检出，其单位捕捞努力量渔获量为0。有关威斯康星州自然资源部（Wisconsin Department of Natural Resources）对戴恩县与维拉斯县长期生态研究（Long Term Ecological Research, LTER）湖泊的鱼类放养信息，请参阅http://infotrek.er.usgs.gov/doc/wdnr_biology/Public_Stocking/StateMapHotspotsAllYears.htm。2020年仅对Sparkling湖、Crystal湖与Trout湖开展了1次刺网重复采样。采样频率：每年1次。采样点位总数：11个。