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 2006 Biotic Index scores for each the 15 reporting regions. Highest Biotic Index scores occurred in the Upper Bay, Lower Bay, and Lower Eastern Shore (Tangier) regions. These regions were generally characterized by moderate condition Bay grasses, benthic and phytoplankton community health. Lowest Biotic Index scores (poor biological health) occurred in the Patuxent, Choptank, and Patapsco and Back Rivers regions.
This map shows the 2006 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
Comparison of Bay Health Index scores for 2006 (
| Score (%) | |
| 0 20 40 60 80 100 |
| Upper Bay | |
| Lower Bay | |
| Lower Eastern Shore (Tangier) | |
| Overall Bay | |
| James River | |
| Upper Eastern Shore | |
| Mid Bay | |
| Elizabeth River | Insufficient Data |
| Upper Western Shore | |
| Potomac River | |
| Rappahannock River | |
| Lower Western Shore (MD) | |
| York River | |
| Patuxent River | |
| Choptank River | |
| Patapsco and Back Rivers |
This figure ranks each region from best to worst for the Biotic Index. The Upper Bay had the highest Biotic Index with a moderate score, and the Patapsco and Back Rivers had the lowest Biotic Index with a very poor score. The Choptank River also scored very poorly. About half of the regions had a score of poor for the Biotic Index.
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).