2015 VIMS Chesapeake Bay Underwater Grass Survey

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An annual survey led by researchers at the Virginia Institute of Marine Science (VIMS) shows that the abundance of underwater grasses in Chesapeake Bay increased 21% between 2014 and 2015, from 75,835 acres to 91,621 acres.

VIMS tracks the abundance of underwater grasses as an indicator of Bay health for the Chesapeake Bay Program, the federal-state partnership established in 1983 to monitor and restore the Bay ecosystem.

The latest values are the highest ever recorded by VIMS aerial survey and surpass the partnership’s 2017 restoration target 2 years ahead of schedule.

VIMS researchers estimate the annual acreage of underwater Bay grasses through aerial surveys flown from late spring to early fall. Since 2013 the VIMS team has categorized abundance using 4 different salinity zones.

Underwater grass communities in the four zones respond differently to storms, drought, and other adverse growing conditions. Reporting grass abundance by salinity zone makes it easier for scientists to connect changes in grass communities with changes in growing conditions through time.

The increase of underwater grasses includes wild celery and other species in the fresher waters of the upper Bay, continued expansion of widgeon grass in the moderately salty waters of the mid-Bay, and a modest recovery of eelgrass in the very salty waters of the lower Bay.

Underwater bay grasses provide habitat and nursery grounds for fish and blue crabs, serve as food for animals such as turtles and waterfowl, clear the water by reducing wave action, absorb excess nutrients, and reduce shoreline erosion. They are also an excellent measure of the estuary’s overall condition because their health is closely linked to water quality.

Abundance by Region:

Elk River

In 2015, the grass beds in the Elk River surpassed the restoration target. Wild celery was the dominant species detected.

Choptank River

SAV abundance in the Choptank River increased 50% to 6,000 acres. The VIMS aerial survey also revealed a small, never-before-reported band of underwater grasses in the tidal freshwater portion of the river.


source: Virginia Institute of Marine Science

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