Indices of biological integrity (IBIs) have been developed for a wide variety of locales and ecological systems to describe their biological condition. Due to variability in geophysical and chemical conditions, IBIs are often developed regionally and applied to similar ecological systems. Researchers in Minnesota previously developed a fish IBI (FIBI) for lakes; however, its application was limited to lakes 40–200 ha surface area and located in central Minnesota. The objectives of this study were to develop FIBIs and ecologically meaningful thresholds for application to a broader suite of Minnesota lakes with surface areas 40–4,050 ha. Fish communities in 419 lakes throughout Minnesota were sampled using gill nets, trap nets, backpack electrofishers, and beach seines between mid-June and early-September 2005–2013. Fish species were assigned to functional groups based on family, tolerance, primary feeding niche, special habitat use, and whether they were native to Minnesota. Lakes were classified into seven groups based on their geophysical and chemical attributes, and four groups were ultimately used in FIBI development. A suite of potential metrics was evaluated for each of the four FIBIs based on their relationships to measures of human-induced watershed and in-lake stressors and 8–15 were retained for each FIBI. Metrics that were retained were summed, and composite scores were scaled 0–100. Biological Condition Gradient (BCG) models were developed for each FIBI. The BCG models established thresholds for impairment and exceptional condition. The FIBIs and thresholds are being used to guide clean water planning, restoration, and protection efforts and to complement pollutant-based water quality sampling efforts in lakes during the Minnesota watershed assessment process.

已经针对各种地区和生态系统开发了生物完整性指标（IBI），以描述其生物学状况。由于地球物理和化学条件的变化，IBI通常在区域内开发并应用于类似的生态系统。明尼苏达州的研究人员以前为湖泊开发了鱼类IBI（FIBI）；但是，它的应用仅限于位于明尼苏达州中部的40-200公顷表面积的湖泊。这项研究的目的是开发FIBIs和具有生态意义的阈值，以适用于表面积为40至4050公顷的更广泛的明尼苏达州湖泊。在2005-2013年6月中旬至9月初之间，使用刺网，诱捕网，背包电钓者和海滩围网对明尼苏达州整个419个湖泊的鱼类群落进行了采样。根据家庭，耐受性，主要摄食生态位，特殊的栖息地用途以及它们是否为明尼苏达州来将鱼类分为功能组。根据湖泊的地球物理和化学属性将其分为七个组，最终将四个组用于FIBI开发。根据四个FIBI与人为分水岭和湖内压力源的度量之间的关系，评估了一组潜在指标，每个FIBI保留了8-15个度量。将保留的度量标准相加，然后将综合得分定为0-100。为每个FIBI开发了生物条件梯度（BCG）模型。BCG模型确定了损伤和异常情况的阈值。FIBI和阈值用于指导清洁水的规划，恢复，