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Aquatic GrassesAquatic grasses, or submerged aquatic vegetation, are one of the most important habitats in Chesapeake Bay. Bay grasses provide critical habitat to key species such as blue crab and striped bass, and can improve water clarity.
Chesapeake Bay - Indicator Details:
Threshold Map
Editable Vector Version (SVG)
High Resolution Raster Version (JPG)
Station Data
Estimates of aquatic grasses cover are derived each year by VIMS using aerial surveys. The aquatic grasses score is determined as the area of aquatic grasses present in each of the 15 reporting regions as a percentage of the restoration goal. Each reporting region is assigned a score representing progress towards the goal.
Data Map
Editable Vector Version (SVG) High Resolution Raster Version (JPG) Station Data
This map shows the preliminary aquatic grass (submerged aquatic vegetation) distribution in 2008. While aquatic grasses fringe long sections of the shoreline, there are many areas of the Bay in which they no longer occur or have experienced a significant reduction in area. For example, aquatic grasses are absent in the Back, West, and Nanticoke Rivers and have very low coverage in many other areas. During 2008, many areas of the Bay, such as the Upper Bay, Lower Western Shore (MD), Rappahannock River, lower York River and Mobjack Bay experienced a significant increase in aquatic grasses distribution compared to 2007. Very few regions recorded a decline in aquatic grass distribution this year, those that did include the Choptank and Potomac Rivers. This assessment is based on aquatic grass survey data provided by VIMS. See http://www.vims.edu/bio/sav for more information.
Estimates of aquatic grasses cover are derived each year by VIMS using aerial surveys. Survey data was used to determine area of aquatic grass in each reporting region. Percent (%) difference in area between current and previous years was calculated.
Ranking
Comparison of Bay Health Index scores for 2010 (
) compared to (
)
| Score (%) | |
| 0 20 40 60 80 100 |
| Upper Bay | |
| Rappahannock River | |
| Upper Western Shore | |
| James River | |
| Lower Bay | |
| Potomac River | |
| Overall Bay | |
| Lower Eastern Shore (Tangier) | |
| Upper Eastern Shore | |
| York River | |
| Mid Bay | |
| Patuxent River | |
| Lower Western Shore (MD) | |
| Choptank River | |
| Patapsco and Back Rivers | 0 |
| Elizabeth River | No Growth Zone No Growth Zone |
This figure ranks each region from best to worst for aquatic grasses scores in 2008. The aquatic grasses score is determined as the area of aquatic grasses present as a percentage of the restoration goal. The Upper Western Shore and Upper Bay regions are closest to the restoration goal; in fact the Upper Bay region, at 92%, has almost reached the goal. With the continued decline of aquatic grasses in the Choptank River, it is now the lowest ranked region in the Bay, with the Patapsco and Back Rivers being second lowest. Overall, most regions are far from achieving their restoration goals. This assessment is based on aquatic grass survey data provided by VIMS. See http://www.vims.edu/bio/sav for more information.
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 SpreadsheetThreshold Levels
| Reporting Region | SAV restoration goal by reporting region (acres) |
| Upper Bay | 14,978 |
| Mid Bay | 18,436 |
| Lower Bay | 35,872 |
| Patuxent River | 1,954 |
| Potomac River | 21,203 |
| Rappahannock River | 2,534 |
| York River | 3,304 |
| James River | 2,629 |
| Elizabeth River | No Grow Zone |
| Upper Eastern Shore | 12,866 |
| Choptank River | 13,953 |
| Lower Eastern Shore (Tangier) | 57,651 |
| Patapsco-Back Rivers | 389 |
| Upper Western Shore | 3,661 |
| Lower Western Shore (MD) | 1,811 |
| Total | 191,241 |