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Biotic IndexThe Biotic Index combines the aquatic grasses, Benthic Index of Biotic Integrity, and Phytoplankton Index of Biotic Integrity into a single overarching score.
Chesapeake Bay - Indicator Details:
Index Map
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This map shows the 2008 Biotic Index scores for each of the 15 reporting regions. Highest Biotic Index scores occurred in the Upper Bay and Upper Western Shore regions. These regions were generally characterized by good aquatic grasses and benthic community scores. The lowest Biotic Index scores occurred in the Patuxent River, Upper Eastern Shore, and Choptank River regions. Biotic Index scores increased in 8 regions in 2008 compared to 2007 and decreased in 6. There is incomplete monitoring data available for the Elizabeth River.
This map shows Biotic Index values for each of the regions. Biotic Index for each reporting region is the average of the aquatic grasses, Benthic Index of Biotic Integrity, and Phytoplankton Index of Biotic Integrity scores.
Ranking
Comparison of Bay Health Index scores for 2010 (
) compared to (
)
| Score (%) | |
| 0 20 40 60 80 100 |
| Upper Bay | |
| Lower Bay | |
| Rappahannock River | |
| Upper Western Shore | |
| Lower Eastern Shore (Tangier) | |
| Overall Bay | |
| James River | |
| Mid Bay | |
| Potomac River | |
| York River | |
| Upper Eastern Shore | |
| Patuxent River | |
| Choptank River | |
| Patapsco and Back Rivers | |
| Lower Western Shore (MD) | |
| Elizabeth River | Insufficient Data Insufficient Data |
This figure ranks each region from best to worst for the Biotic Index. Highest ranked region in 2008 was the Upper Western Shore, with a score of 85% (good). Second highest ranked region, was the upper Bay, but at 65% was 20% points lower than the Upper Western Shore. High Biotic Index Scores in these two regions are generally due to good aquatic grasses and benthic community scores. The Choptank River, Patuxent River, and Upper Eastern Shore regions had the lowest Biotic Index scores in 2008, all scoring less than 20%, or very poor. Biotic index scores increased in 8 regions in 2008 compared to 2007 and decreased in 6. There is incomplete monitoring data available for the Elizabeth River.
Excel SpreadsheetTrends Graph
This graph is dynamic, you can: a) show and hide items by clicking them in the legend, b) select year range (click and drag), and c) 
export as an image.
Excel Spreadsheet