The SAV ‘Navy’

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Murky waters in the Severn River ruin habitat for fish, crabs and waterfowl!

Just a generation or two ago, underwater grasses, the fabled submerged aquatic vegetation (SAV), were so plentiful that swimmers, boaters, sailors, fishermen and watermen viewed underwater grasses as a nuisance, even a hazard to navigation.

Yet during this same era fishermen, crabbers and oystermen all enjoyed bountiful harvests. One of the reasons for the thriving fishery were the thick beds of SAV that provided critical habitat for crabs, forage fish and other organisms that led up the food chain to the prized rockfish and perch. Stories abounded back then of being able to see 20 feet to the bottom of the river, to easily spot soft-shell crabs molting in the grasses.

Catching a ‘mess o’ crabs’ for a crab feast was an easy afternoon’s work. Little thought was given to the role SAV played in creating the thriving fishery of the Severn River.

Fast forward to today – a mix of pollution, poor water quality and human hubris virtually wiped out our SAV beds. Fish and crab stocks declined. How can we reverse this trend?


The SAV ‘Navy’

The Severn River Association, in partnership with the Maryland Department of Natural Resources, launched an effort to survey our SAV beds, identify species of grasses and map areas where the SAV is trying to return.

Thanks to a grant from the Maryland Department of Natural Resources and the Chesapeake Bay Program, SRA purchased monitoring equipment and created the program moniker, SAV ‘Navy,’ to describe our team of volunteer citizen scientists who help identify and monitor the underwater grasses.

Our volunteers kayak the length of the river to ground truth aerial surveys of SAV in the Severn River provided by the Virginia Institute of Marine Sciences and identify which species of grasses are in our waterway.

The volunteers also use GIS technology to pinpoint the grass beds and post the locations on charts. The charts enable the kayak teams to return to the same beds every year and monitor progress.

Through its monitoring efforts the SAV ‘Navy’ helps to raise public awareness of the critical value that underwater grasses hold:

  • Provide habitat for fish and crabs
  • Protect shorelines from erosion by absorbing the energy of powerboat wakes and storm-created waves, and,
  • Filter murky river water to create plumes of clear water, which is vital for the spread of more SAV because underwater grasses are like every other plant, they need sunlight to thrive.

With your support, we can continue to monitor and restore our SAV beds so they can provide habitat for fish and crabs, filter the water and protect our shorelines.


Severn River Association, Chesapeake Bay Program, Maryland Department of Natural Resources and the Virginia Institute of Marine Sciences


Program Goal

Restore and maintain the health of underwater grasses and increase understanding of how vital SAV is to the Severn River

Program Outcomes

  • Map areas where SAV is returning
  • Identify which species of SAV are in our river and creeks
  • Increase water clarity
  • Improve and habitat for forage fish and crabs
  • Provide erosion protection for river shorelines
  • Enhance underwater grass-related education and outreach.
7076 Bembe Beach Road | Suite 203 | Annapolis, Maryland 21403 | phone: 443-569-3556 | email: