Lake Index of Biological Integrity Assessments

In FY23 Department of Natural Resources (DNR) staff completed 135 Fish Index of Biological Integrity (FIBI) surveys and 102 habitat surveys (31 shoreline habitat and 71 oxythermal habitat). FIBI surveys are designed to representatively sample entire lake fish communities, game and nongame fishes, in nearshore and deep-water zones. Habitat surveys evaluate the impact of shoreline activities on fish communities or cold, oxygenated water available for coldwater fishes. FIBI survey information was used by MN Pollution Control Agency (MPCA) for 42 lake assessments in three major watersheds throughout Minnesota. Assessments determine biological condition for identifying lakes considered as impaired, lakes vulnerable to future impairment, and lakes of exceptional biological quality. DNR published watershed stressor identification reports for lakes in four watersheds. DNR drafted new biological and water quality standards and two technical support documents outlining the science behind the new standards in collaboration with MPCA. The new standards will protect coldwater fishes and their habitat and lakes with exceptionally healthy and diverse fish communities. DNR expanded FIBI program work to the far northeastern part of the state, completing over 30 surveys in the Lake Superior North Watershed. FIBI survey data and reports, assessment results, and stressor identification reports are available on the DNR website, MPCA website, and as a criterion of lake health in the Watershed Health Assessment Framework online tool. FIBI data is used for prioritization in Watershed Restoration and Protection Strategies and in Comprehensive Watershed Plans.

Department of Natural Resources (DNR) staff completed 137 Fish Index of Biological Integrity (FIBI) surveys and 61 habitat surveys. FIBI surveys are designed to representatively sample entire lake fish communities, game and nongame fishes, in nearshore and deep-water zones. Habitat surveys evaluate the impact of shoreline activities on fish communities or cold, oxygenated water available for coldwater fishes. FIBI survey information was used by MN Pollution Control Agency (MPCA) for 113 lake assessments in two major watersheds including 39 lakes within the seven-county Twin Cities metropolitan area. Assessments determine biological condition for identifying lakes considered as impaired, lakes vulnerable to future impairment, and lakes of exceptional biological quality. DNR delivered watershed stressor identification reports for lakes in five watersheds to MPCA for publication. DNR drafted new biological and water quality standards and two technical support documents outlining the science behind the new standards in collaboration with MPCA. The new standards will protect coldwater fishes and their habitat and lakes with exceptionally healthy and diverse fish communities. FIBI survey data and reports, assessment results, and stressor identification reports are available on the DNR website, MPCA website, and as a criterion of lake health in the Watershed Health Assessment Framework online tool. FIBI data is used for prioritization in Watershed Restoration and Protection Strategies and in Comprehensive Watershed Plans.

Fish: DNR staff completed 117 fish Index of Biological Integrity (FIBI) surveys and 75 shoreline habitat surveys (survey work was reduced due to COVID-19 related staffing and fieldwork limitations). FIBI surveys are designed to representatively sample game and nongame fish communities in nearshore and deep-water zones. Habitat surveys evaluate the impact of shoreline activities on fish communities. FIBI survey information was used by MPCA for 106 lake assessments in six major watersheds including lakes within the seven-county metropolitan area. Assessments determined biological condition identified impaired lakes lakes vulnerable to future impairment and lakes of exceptional biological quality. We published stressor identification reports for lakes in six watersheds. We drafted standards and technical support documents to protect cold-water fish habitat and exceptionally diverse fish communities. FIBI data is used for prioritization in Watershed Restoration and Protection Strategies and Watershed Plans.

Aquatic Plants: DNR biologists analyzed and delivered aquatic plant data to assist with the stressor identification process for lakes that are impaired for biology. Due to COVID-19 restrictions DNR biologists focused efforts on shoreline habitat surveys and delineation of emergent and floating-leaf plant stands. We completed 13 near-shore plant surveys seven floating and emergent plant surveys and one point-intercept plant survey. These data are used for evaluating shoreland development as a lake stressor. Also because accurate plant identification is essential for these assessments we continued to provide training and technical support on plant identification and survey methods to other DNR programs that contribute aquatic plant data used to inform the aquatic plant IBI. As COVID-19 related policies prevented in person training sessions we developed web-based modules to facilitate training.

Fish: DNR staff completed 72 fish Index of Biological Integrity (FIBI) surveys and 64 shoreline habitat surveys (survey work was reduced due to COVID-19 related fieldwork limitations and a budget cut). FIBI surveys are designed to representatively sample game and nongame fish communities in nearshore and deep water zones. Habitat surveys evaluate the impact of shoreline activities on fish communities. FIBI survey information was used by MPCA for 46 lake assessments in four major watersheds including lakes within the seven-county metropolitan area. Assessments determined biological condition identified impaired lakes lakes vulnerable to future impairment and lakes of exceptional biological quality. We published stressor identification reports for three watersheds. We worked with MPCA to draft standards and supporting science to protect cold-water fish habitat and exceptionally diverse fish communities. FIBI data is used for prioritization in Watershed Restoration and Protection Strategies.

Aquatic Plants: DNR biologists analyzed and delivered aquatic plant data to help the MPCA determine whether lakes meet water quality standards. To match the MPCA’s watershed assessment schedule DNR biologists conducted surveys at 30 priority lakes to collect the data needed for plant IBI analysis and development. This included shoreline habitat surveys and delineation of emergent and floating-leaf plant stands—two types of data needed to develop plant IBI metrics for evaluating shoreland development as a lake water quality stressor. Since accurate plant identification is essential for plant IBI surveys we continued to provide training and technical support on plant identification and survey methods to other DNR programs that contribute aquatic plant data used to inform the aquatic plant IBI. Because COVID-19 related policies prevented our ability to hold in person training sessions we developed web based training modules to facilitate training opportunities.

In FY19 DNR Fisheries staff completed 144 Fish Index of Biological Integrity (FIBI) surveys on lakes. FIBI surveys sample game and nongame fish communities in nearshore and deep water zones. We conducted 110 shoreline habitat surveys to evaluate the impact of shoreline activities on fish communities. The MPCA used the FIBI information in watershed assessments for 80 lakes in six major watersheds bringing the total to over 450 lakes assessed. The information was used to determine if the lakes meet standards to identify lakes vulnerable to future impairment and identify lakes of exceptional biological quality as priorities for protection in Watershed Restoration and Protection Strategies. We published stressor identification reports for two additional watersheds for lakes designated as impaired or vulnerable to future impairment based on FIBI results. Finally we continued refining FIBI tools with a focus on developing standards to protect lakes that support cold-water habitat and exceptional fish communities.

In FY19 DNR biologists organized analyzed and delivered aquatic plant data to help the MPCA determine—together with information from the fish IBI surveys described above—whether the lakes meet water quality standards. To match the MPCA’s watershed assessment schedule DNR biologists conducted detailed field surveys at 57 priority lakes that lacked the data needed for plant IBI analysis and development. This included shoreline habitat surveys and delineation of emergent and floating-leaf plant stands—two types of data needed to develop plant IBI metrics for evaluating shoreland development as a lake water quality stressor. Since accurate plant identification is essential for plant IBI surveys we continued to provide training and technical support on plant identification and survey methods to other DNR programs which has led to the combined sampling of 156 total lakes that will be used for IBI analysis and development.

Fish: In FY18 DNR biologists completed 160 fish Index of Biological Integrity (IBI) surveys in lakes. The surveys are designed to representatively sample fish communities including game and nongame fish in nearshore and deep water zones. We also conducted 109 shoreline habitat surveys to evaluate the impact of shoreline activities on fish community metrics. The MN Pollution Control Agency (MPCA) used the resulting information to assess 189 lakes in four major watersheds–specifically to determine whether the lakes meet water quality standards to identify and evaluate lakes vulnerable to future impairment and to identify lakes of exceptional biological quality as priorities for protection. We produced stressor identification reports for three watersheds for lakes designated as impaired or vulnerable to future impairment based on last year’s fish IBI results. Finally we continued refining fish IBI tools and developing metrics suitable for lakes that support cold-water habitat.

Aquatic Plants: In FY18 DNR biologists organized analyzed and delivered aquatic plant data to help the MPCA determine—together with fish IBI information—whether the lakes meet water quality standards. To match the MPCA’s watershed assessment schedule DNR biologists conducted detailed surveys at 75 priority lakes to collect the data needed for plant IBI analysis and development. This included shoreline habitat surveys and delineation of emergent and floating-leaf plant stands—two types of data needed to develop plant IBI metrics for evaluating shoreland development as a lake water quality stressor. Since accurate plant identification is essential for plant IBI surveys we continued to provide training and technical support on plant identification and survey methods to other DNR programs that contribute aquatic plant data.

Fish: In FY17 DNR staff completed 157 Index of Biological Integrity (IBI) surveys of fish. The surveys include near-shore fish communities as well as game and nongame fish in shallow and deep water zones. Staff also conducted 112 shoreline habitat surveys to evaluate the impact of shoreland activities on fish community metrics. The MN Pollution Control Agency (MPCA) used the resulting information in watershed assessments for 54 lakes in three major watersheds. The information was used to determine whether the lakes meet water quality standards identify and analyze lakes vulnerable to future impairment and identify lakes of exceptional biological quality as priorities for protection in Watershed Restoration and Protection Strategies (WRAPS). DNR staff produced stressor identification reports for six watersheds in which 28 lakes were designated as impaired or vulnerable to future impairment based on Fish IBI score. Finally DNR staff continued refining Fish IBI tools and developing metrics suitable for lakes that support cold-water habitat.
Aquatic Plants: In FY17 DNR biologists organized analyzed and delivered aquatic plant data to help the MPCA determine – together with information from the Fish IBI surveys described above—whether the lakes meet water quality standards. To match the MPCA’s watershed assessment schedule DNR biologists focused on lakes in the Mississippi River-Brainerd Mississippi River-Sartell Otter Tail River and Kettle River watersheds conducting detailed field surveys at 50 priority lakes that lacked the data needed for IBI analysis. This included shoreline habitat surveys and delineation of emergent and floating-leaf plant stands—two types of data needed to develop IBI metrics for evaluating shoreland development as a lake water quality stressor. Finally because accurate plant identification is essential for IBI surveys we continued to provide training and technical support on plant identification and survey methods to other DNR

Fish: In FY16 DNR biologists will complete approximately 135 Fish Index of Biological Integrity (IBI) surveys which include near-shore fish communities and game and nongame fish surveys in shallow and deep water zones. About 75 shoreline habitat surveys will be conducted for stressor ID purposes. Fish IBI survey information will be used as part of the Minnesota Pollution Control Agency (MPCA)’s watershed assessments for approximately 56 lakes in three major watersheds. Based on the Fish IBI lakes will be designated as impaired or meeting standards. In addition the list of lakes of exceptional biological quality will be updated to help identify which lakes are priorities for protection in the development of Watershed Restoration and Protection Strategies. We will produce stressor ID reports for six watersheds; for about 25 lakes designated as impaired or vulnerable to future impairment based on their Fish IBI score.

Aquatic Plants: In FY16 EWR biologists organized analyzed and delivered aquatic plant data which the MPCA used to determine whether lakes are meeting water quality standards. We provided training and technical support to staff in other DNR programs that collect aquatic plant and data and do shoreline habitat surveys. Specifically we trained 51 DNR Fisheries staff in shoreline habitat survey methods and 50 EWR and Fisheries staff in aquatic plant identification. We targeted intensive detailed field surveys at 13 priority lakes in the Mississippi River-Brainerd North Fork Crow River Crow Wing River and Sauk River watersheds where there were not enough data to do a quality IBI assessment. We surveyed shoreline habitat on 47 lakes in the Mississippi River-Brainerd Mississippi River-Grand Rapids and Ottertail River watersheds and delineated emergent plant stands on 47 lakes in the Mississippi River-Brainerd watershed. These data will help us develop additional IBI metrics for non-nutrient stressors.

Fish IBI: In FY15 DNR biologists completed 136 fish index of biological integrity (IBI) surveys which included near-shore fish communities and game and nongame fish surveys in shallow and deep water zones. We also finalized four fish IBI tools and established biological impairment thresholds for the fish IBIs. The Minnesota Pollution Control Agency (MPCA) used fish IBI survey information in their watershed assessments for 81 lakes in four major watersheds. Based on the fish IBI lakes were determined to be impaired or meeting standards. We also made a list of lakes of exceptional biological quality which is being used to identify protection priorities in MPCA’s Watershed Restorations and Protection Strategies. We took on a new task of determining which factors are contributing to fish IBI impairments on lakes; we drafted 9 stressor ID reports for the MPCA.

Aquatic Plant IBI: In FY15 EWR biologists organized analyzed and delivered aquatic plant data on 152 lakes in priority watersheds. A variety of DNR programs collect lake plant data; we used these data for the plant IBI assessments. To help maintain this important data source we finalized survey protocols for aquatic plant IBI assessments wrote a manual of these standardized survey methods and held training workshops for 150 DNR Fish and Wildlife staff involved in lake plant surveys. In addition we did more detailed in-lake surveys on eight priority lakes in the Rum River Watershed where there was not enough existing plant data to calculate an IBI. Biologists surveyed shoreline habitat and/or delineated emergent plant stands on 25 lakes in the Rum River and Mississippi River-Brainerd watersheds We also made progress enhancing software to gather and manage data which will make it easier for more biologists from other DNR programs to survey shoreline habitat and/or delineate emergent plant stands.

In FY14 DNR biologists completed 124 fish IBI surveys on 121 lakes which include near-shore fish communities as well as game and nongame fish surveys in the shallow and deep water zones. Biologists also developed tools for incorporating fish IBI information into the watershed assessment process in coordination with MPCA.

FY14 (primarily summer of 2013) was the first year of transitioning from sampling for tool development to sampling primarily as part of a watershed assessment within the MNPCA schedule. Due to the logistics of working in selected watersheds vs. statewide fewer lakes were sampled. We also increased survey effort on many lakes targeted larger lakes which take more time to sample and added new gear targeting sensitive pelagic fish species on several lakes.

In FY14 DNR biologists developed and conducted special IBI vegetation surveys on approximately 20 lakes throughout the state. These surveys were targeted for data collection in the shoreline and near-shore zones where data are currently lacking. Surveys included rapid shoreline habitat assessments delineation of emergent and floating-leaf plant beds and quantitative assessments of in-lake plant communities. A centralized database for these data has been created.

In FY13 DNR biologists completed 146 fish IBI surveys which include near-shore fish communities as well as game and nongame fish surveys in the shallow and deep water zones. Biologists also developed tools for incorporating fish IBI information into the watershed assessment process in coordination with MPCA. The number of surveys was smaller than originally proposed due to changes in study design to add different methods of fish collection (e.g. vertical gill nets small mesh trap nets electrofishing) and improve efficiency and data quality. An unseasonably cool spring caused water temperatures to be too cool to effectively sample near-shore fish communities.

In FY12 DNR biologists completed 180 fish IBI surveys on 162 lakes. Surveys target the entire fish community including nongame and game fish living in the nearshore area and offshore Eighteen lakes received additional surveys for quality control purposes. Biologists also developed tools for incorporating fish IBI information into the watershed assessment process in coordination with MPCA.

In FY11 DNR biologists completed 228 nearshore assessments on 204 lakes for nearshore fish communities. Littoral and pelagic game and nongame fish surveys were also completed.

In FY10 DNR biologists assessed 22 lakes for nearshore nongame fish populations. DNR Fisheries management staff were trained to do nearshore nongame fish population assessments in preparation for transition of assessment program from the Division of Ecological and Water Resources to the Division of Fish and Wildlife.