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Browse History: Aquatic Grasses (2010)
Indicator Icon Aquatic Grasses

Aquatic 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:





  Indicator Selection Diagram


Threshold Map


This map shows progress of each reporting region towards meeting the aquatic grasses restoration goal. Overall progress towards the restoration goal decreased slightly for the second year in a row, due to decreases in the area of aquatic grasses in the Upper Western Shore, the Mid Bay, the Choptank River, and several other reporting regions. Aquatic grasses in the Upper Bay, Lower Bay, Potomac River, and Upper Eastern Shore regions remained steady this year. Increased aquatic grasses in the Rappahannock and James Rivers continue the increasing trend in these regions. This assessment is based on aquatic grass survey data provided by VIMS. See http://www.vims.edu/bio/sav for more information.

Creating this map
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


This map shows the preliminary aquatic grass (submerged aquatic vegetation) distribution in 2010. 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 2010, aquatic grasses decreased slightly in many regions. However, the main areas with aquatic grasses, the Susquehanna Flats and Tangier Sound can be seen on this map. There were also slight increases in the Rappahannock River, the James River, and the York River, continuing the recovery of those areas. This assessment is based on aquatic grass survey data provided by VIMS. See http://www.vims.edu/bio/sav for more information.

Understanding this map
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.

Ranking


Comparison of Bay Health Index scores for 2010 () compared to
()


Score Legend
 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

This figure ranks each region from best to worst for aquatic grasses scores in 2010. The aquatic grasses score is determined as the area of aquatic grasses present as a percentage of the restoration goal. The Upper Bay and Rappahannock River regions are closest to the restoration goal; the Rappahannock River aquatic grasses have increased dramatically over the past seven years. The Upper Western Shore aquatic grasses declined by 10% this year. The Patapsco and Back River and the Choptank River regions continue to be the lowest scoring regions. 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 Spreadsheet

Threshold Levels

Reporting Region SAV restoration goal by reporting region (acres)
Upper Bay14,978
Mid Bay18,436
Lower Bay35,872
Patuxent River1,954
Potomac River21,203
Rappahannock River2,534
York River

3,304

James River2,629
Elizabeth RiverNo Grow Zone
Upper Eastern Shore12,866
Choptank River13,953
Lower Eastern Shore (Tangier)57,651
Patapsco-Back Rivers389
Upper Western Shore3,661
Lower Western Shore (MD)1,811
Total191,241