The 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
This map shows the 2007 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 moderate–good aquatic grasses and benthic community scores. Lowest Biotic Index scores (poor biological health) occurred in the Patuxent and Lower Western Shore (MD) regions. Biotic index scores increased in 8 regions in 2007 compared to 2006 and decreased in 6 (incomplete monitoring data available for the Elizabeth River).
This map shows the 2007 Biotic Index values for each of the regions. Biotic Index for each reporting region is the average of the bay grass, Benthic Index of Biotic Integrity and Phytoplankton Index Biotic Integrity scores.
Ranking
| Score (%) | |
| 0 20 40 60 80 100 |
| Upper Western Shore | |
| Upper Bay | |
| Lower Bay | |
| Overall Bay | |
| James River | |
| Rappahannock River | |
| Mid Bay | |
| Potomac River | |
| Patapsco and Back Rivers | |
| Lower Eastern Shore (Tangier) | |
| Choptank River | |
| Upper Eastern Shore | |
| York River | |
| Lower Western Shore (MD) | |
| Patuxent River | |
| Elizabeth River | Insufficient Data |
This figure ranks each region from best to worst for the Biotic Index. The Upper Western Shore and Upper Bay regions had the highest Biotic Index with a moderate-good score. The moderate-good score was largely due to aquatic grasses and Benthic IBI scores. The Patuxent River and Lower Western Shore regions had the lowest Biotic Index with very poor scores. Biotic Index scores increased in 8 regions in 2007 compared to 2006 and decreased in 6 (incomplete monitoring data available for the Elizabeth River).
Trends Graph
This graph is dynamic, you can check and uncheck regions (
checkboxes in legend), select year range (
click and drag), and export as an image (right click).