This layer shows the <b>Fish IBI (Index of Biotic Integrity) Scores</b> for MN lakes as calculated by DNR Fisheries. Scores range from 0-100, with higher scores indicating higher biotic integrity. Attributes correspond to the <U>most recent IBI survey</u> for each lake. An <i>IBI (Index of Biotic Integrity)</i> is a biologically-based, multi-metric method for measuring the integrity of aquatic systems. Minnesota DNR Fisheries Research has developed a fish-based lake IBI that incorporates fish data collected by various methods (trap nets, gill nets, shoreline seines, and backpack electrofishing units) into 8-15 metrics in three categories: <b>species richness, community assemblage, and trophic composition </b> <i>(see Section 5: Attributes)</i>. Each metric represents an aspect of the biological assemblage structure, function, or other measurable characteristic that changes in some predictable way with increased human-induced stress. Fish IBI scores respond to differences in land use patterns, trophic state, and aquatic vegetation. Validation studies indicate that the fish-based lake IBI scores function as a measure of fish community response to human disturbance across a gradient of lakes. Continuing work by DNR Fisheries will expand the application of this IBI to more lake types and will validate this tool as a viable method for assessing lake impairment as part of Minnesota's 303(d) <i>Impaired Waters</i> assessments. These scores should be considered as '<u>preliminary</u>' and are subject to change as the IBI tools are further developed and refined. <b>This dataset only includes lakes over 100 acres and within lake classes 20-43, with few exceptions for lakes very close to 100 acres</b>. Additional scores will be added to this dataset annually. For more reference information, see <i>(Section 5: Attributes -- Detailed Citation)</i>. <b>Related table:</b> <i>env_ibi_lakes_all_surveys_events_polygon_relate </i> IBI scores for additional years can be found in this table. <b>To access related table records:</b> <li>Open the layer attribute table and select a lake polygon record</li> <li>From the <i>Related Table dropdown (2nd icon on bar just above table)</i>, choose table <b>Lake IBI Scores: To IBI Scores - All Surveys</b></li> <li> The related table will open and the corresponding records for the selected lake will be highlighted.</li> <li>Note: You can also select records from the related table and find the lakes that correspond to those records by reversing the process above (i.e., Choose <i>Related Tables dropdown (2nd icon)</i>, choose table <b>Lake IBI Scores: Back to IBI Lakes</b>) </li> You can also access scores from all years by clicking on the lake of interest with the <b>Identify Tool</b> and expanding the related tabular information.