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Benthic Index of Biotic IntegrityThe Benthic Index of Biotic Integrity (BIBI) measures the condition of the benthic community (e.g. clams and others) living in or on the soft bottom areas of the Bay. These organisms are a key food source for many species including perch, spot, and croaker.
Chesapeake Bay - Indicator Details:
Threshold Map
High Resolution Raster Version (PNG)Overall, benthic condition within Chesapeake Bay during 2010 was moderate, which was not a significant change from 2009. The highest scoring region in 2010 was the Upper Bay region, where benthic condition was classified as moderately good. Second best Benthic IBI occurred in the Lower Bay region where conditions are classified as moderately good. Lowest scores occurred in the Rappahannock River, Mid Bay, and Lower Western Shore (MD) regions, where the Benthic IBI condition was classified as poor or very poor.
Samples for assessing benthic community (bottom habitat) were collected at approximately 250 sites in August and September by the Chesapeake Bay Benthic Monitoring Program. Data from each sampling station is used to calculate a Benthic Index of Biotic Integrity (BIBI) score. The proportion of the reporting regions area meeting the Benthic Index of Biological Integrity score is calculated and mapped.
Data Map
This map shows the Benthic Index of Biotic Integrity (Benthic IBI) values for the summer of 2010. This Benthic IBI evaluates the health of the benthic community, or bottom-dwelling community (in soft-bottomed areas only). Values between 1 and 3 are considered to be degraded relative to reference communities, while values between 3 and 5 are considered to be close to reference community condition (i.e., moderate to good condition).
Stations with relatively good benthic community health tended to be in the Upper Bay, Lower Bay, and James River regions. Areas with poor Benthic IBI scores can be seen in many regions including the Rappahannock River, Mid Bay, and the smaller tributaries within the Lower Western Shore (MD) region. The Upper Western Shore benthic community declined sharply this year.
Samples for assessing the Benthic Index of Biotic Integrity (soft bottom community condition) were collected at approximately 250 sites in August and September. Data from each sampling station is used to calculate a Benthic IBI score which ranges from 1 (poor benthic condition) to 5 (good benthic condition).
Ranking
Comparison of Bay Health Index scores for 2010 (
) compared to (
)
| Score (%) | |
| 0 20 40 60 80 100 |
| Upper Bay | |
| Lower Bay | |
| James River | |
| Lower Eastern Shore (Tangier) | |
| Overall Bay | |
| Patapsco and Back Rivers | |
| York River | |
| Potomac River | |
| Choptank River | |
| Upper Eastern Shore | |
| Upper Western Shore | |
| Patuxent River | |
| Mid Bay | |
| Rappahannock River | |
| Lower Western Shore (MD) | 0 |
| Elizabeth River | Insufficient Data |
This figure ranks each region from best to worst for the indicator Benthic Index of Biotic Integrity (Benthic IBI). The Benthic IBI evaluates the health of the benthic community, or bottom-dwelling community (soft-bottomed areas only).
The highest scoring region in 2010 was the Upper Bay, where benthic condition was classified as moderately good. The second best Benthic IBI occurred in the Lower Bay region where conditions are classified as moderately good. Three regions had very poor Benthic IBI scores in 2010, these being the Rappahannock River, Mid Bay, and the Lower Western Shore regions. Overall, benthic community condition declined in 2010, compared to 2009. It is not possible to provide a score for the Elizabeth River Region until 2010 monitoring data becomes available later this year.
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