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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
Editable Vector Version (SVG)
High Resolution Raster Version (JPG)
Station Data
Samples for assessing benthic community (bottom habitat) were collected at approximately 300 sites in August and September 2006 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
Editable Vector Version (SVG) High Resolution Raster Version (JPG) Station Data
This map shows the Benthic Index of Biotic Integrity (Benthic IBI) values for the summer of 2006. 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. The majority of stations had degraded communities in 2006, with the degraded areas tending to be in the mid to lower reaches of the tributaries. Stations with relatively good benthic community health tended to be located in the mainstem Bay and Lower Eastern Shore (Tangier) region. Benthic community condition in 2006 was one of the worst since benthic community monitoring began in 1996. Benthic organisms could be responding to low dissolved oxygen conditions and abundance of suspended particles resulting from the June rain event. In the last few years, Benthic IBI values have decreased overall, suggesting a declining trend in benthic communities.
Samples for assessing the Benthic Index of Biotic Integrity (soft bottom community condition) were collected at approximately 300 sites in August and September 2006. 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
| Score (%) | |
| 0 20 40 60 80 100 |
| Upper Bay | |
| Lower Eastern Shore (Tangier) | |
| Lower Bay | |
| James River | |
| Overall Bay | |
| Upper Eastern Shore | |
| York River | |
| Upper Western Shore | |
| Rappahannock River | |
| Mid Bay | |
| Patuxent River | |
| Elizabeth River | |
| Lower Western Shore (MD) | |
| Patapsco and Back Rivers | |
| Potomac River | |
| Choptank River |
This figure ranks each region from best to worst for the indicator Benthic Index of Biotic Integrity (Benthic IBI). This Benthic IBI evaluates the health of the benthic community (soft-bottom only). Three regions of the Bay had a good overall Benthic IBI score in 2006, with all regions located in or adjacent to the mainstem Bay. Four regions had poor overall Benthic IBI scores. Once again, the Upper Bay has the highest score, the Patapsco and Back Rivers region was near the lowest, and all other regions were either poor or moderate. It was not possible to provide a score for the Elizabeth because the data was too variable.
Excel SpreadsheetTrends 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).
Editable Vector Version (SVG) Excel Spreadsheet