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Browse History: Aquatic Grasses (2008) | Bay Health Index (2008) | Benthic Index of Biotic Integrity (2008) | Biotic Index (2008)
Indicator Icon Biotic Index

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:





  Indicator Selection Diagram


Index Map

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.

Creating this map
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 2008 () compared to
()


Score Legend
 Score (%)
 0               20               40               60               80              100
  
Upper Western Shore  
Upper Bay  
Lower Bay  
Overall Bay  
Mid Bay  
Potomac River  
Rappahannock River  
Lower Eastern Shore (Tangier)  
James River  
Lower Western Shore (MD)  
Patapsco and Back Rivers  
York River  
Upper Eastern Shore  
Patuxent River  
Choptank River  
Elizabeth River  
 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 Spreadsheet