– Eleven square miles of coastal bays sea grasses have died off in the last two
years, according to a report by the Virginia Institute of Marine Sciences
institute reports that the coastal bays watershed has seen 38 percent of its
bay grasses disappear, dropping from 17,012 acres to 10,548 acres.
in Maryland’s coastal bays have declined by roughly 4,000 acres, while Virginia
lost about 2,500 acres, from 2004 to 2006.
preponderance of the bay grass losses occurred in Chincoteague Bay, previously
a local stronghold of the vegetation. Of the five coastal bays, the
southernmost body of water has long been considered the most pristine, with the
best water quality. Assawoman Bay lost 12 percent of its grasses and Sinepuxent
lost 10 percent.
only bay to show a gain was Isle of Wight Bay, which went up from 126 acres to
145, likely due to water quality improvements after the Perdue chicken plant
sewer outfall went offline.
grasses consume nutrients in the water, hold onto sediments, provide food for
ducks and geese, reduce shoreline erosion and provide safety to crabs, fish,
and shellfish. Every year, VIMS tallies coastal bays grasses by aerial survey.
grasses are prime indicator species of water quality as they are quite
sensitive to light levels. Light filtering into the bays can be reduced through
sediment run-off and algae blooms caused by high nutrients.
culprit in this die off is the combination of high temperatures and excess
nutrients, said Maryland Coastal Bays Program (MCBP) Outreach Coordinator Dave
increase in water temperatures can impact populations,” said Dave Blazer, MCBP
grasses like colder water and the coastal bays are at the southern edge of
their habitat. The grasses also need more light when the mercury climbs.
quality monitoring on both sides of the border reported high water temperatures
in 2005, with the bay grass beds appearing to thin out. Aerial surveys could
not confirm this, as planes were either prevented from flying by bad weather,
or the water was too cloudy.
influence of the excess nutrients is perhaps more alarming, particularly in
Chincoteague Bay, which is largely bordered by undeveloped land, and usually
suffers less nutrient loading.
is beginning to indicate that atmospheric deposition, and nutrients in
groundwater, which may have entered the water table decades ago, are having
more of an effect on the bays than previously thought. Failing septic systems,
point source discharges, and runoff also contribute to nutrient problems.
the first 15 years of the monitoring program, bay grasses increased, from 5,500
acres to 19,000. Beginning in 2001, however, the aquatic vegetation made little
progress, fluctuating between a slight decrease and a slight increase, until
the sudden plunge downward of the last two years.
water temperature appears to have been a major contributor to the recent
declines, the lack of any significant increase in bay grasses during the past
five years, coupled with degrading water quality trends, is certainly cause for
concern,” said John R. Griffin, Maryland Department of Natural Resources
MCBP officials called for greater environmental standards to curb the sudden
drop-off in the grasses.
needs to be done to reduce nutrient and sediment inputs into Chincoteague Bay,”
Blazer said. “We are hopeful that implementation of nutrient reduction
strategies will help reverse this recent declining trend and accelerate
progress towards our restoration goals.”
officials said the alarming news will be addressed shortly.
“The Coastal Bays
Policy Committee will be reviewing draft actions in June aimed at reversing the
trends in this area,” said Griffin.