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Browse History: Aquatic Grasses (2009) | Bay Health Index (2009) | Benthic Index of Biotic Integrity (2009) | Biotic Index (2009)
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 2009 Biotic Index scores for each of the 15 reporting regions. Highest Biotic Index scores occurred in the Upper Western Shore, Upper Bay, and Lower Bay regions. These regions were generally characterized by good aquatic grasses and benthic community scores. The lowest Biotic Index score occurred in the Patuxent River region. Biotic Index scores increased in 10 regions in 2009 compared to 2008 and decreased in three. The James River score stayed the same and 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 2009 () compared to
()


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

This figure ranks each region from best to worst for the Biotic Index. Highest ranked region in 2009 was the Upper Western Shore, with a score of 79% (moderate-good). The second and third highest ranked regions were the Upper Bay and Lower Bay at 66% and 64%, respectively. High Biotic Index Scores in these two regions are generally due to good aquatic grasses and benthic community scores. The Patuxent River region had the lowest Biotic Index score in 2009, scoring 14% which is classified as very poor. Biotic Index scores increased in 10 regions in 2009 compared to 2008 and decreased in 3. The James River score stayed the same and there is incomplete monitoring data available for the Elizabeth River.



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