The health of Maryland's coastal bays near Ocean City worsened slightly last year, according to the latest ecological report card. Driven by declines in the northernmost bays and in the southernmost bay reaching down into Virginia, the overall condition of the 175-square-mile watershed slipped from a C-plus in 2009 to a C in 2010, which advocates say needs improvement.

The annual report, produced by the University of Maryland Center for Environmental Science, provides a status check for the shallow embayments separating Assateague Island from the Worcester County mainland. Summer beachgoers flock there to boat and fish, and portions of the watershed have seen heavy development pressure over the years for vacation and retirement homes.  Their waters are a vital nursery area for summer flounder and other species.

Levels of dissolved oxygen in the water - needed for fish to breathe - were rated "generally moderate" except in Newport Bay, where declining water quality earned it a D-plus, the worst score of the five bays and river analyzed.  Nutrient pollution from farm runoff, development and septic leakage varied, with nitrogen levels relatively low in three bays and phosphorus readings moderate to poor in all but one.  Nutrient levels in the streams feeding into the bays were all relatively high, with phosphorus levels especially bad in the St. Martin's River and Newport Bay.

Sea grass growth and hard clam abundance on the bay bottoms were judged moderate to very poor everywhere but Sinepuxent Bay, which with a B grade was deemed the healthiest of the bays.

Dave Wilson, executive director of the Maryland Coastal Bays Program, said he thinks the northern bays are essentially "holding their own," despite what the report card characterizes as "slight" declines in some ecological indicators.  He attributes the dips in phosphorus in Assowoman Bay and the drop in hard clams in Isle of Wight Bay to unusually rainy weather washing more pollutants into the water.

More worrisome is the worsening condition of the southernmost bay, until lately considered one of the most pristine. Its health grade dropped to a C, from a B-minus in 2009.

"We're just continuing (to see) the decline of Chincoteague Bay, the jewel of our watershed," Wilson said. The reasons aren't clear, he added, because many of the farmers in that bay's watershed are practicing conservation.  But seagrass beds there have failed to rebound from a 2005 die-off, he noted, which may be a contributing factor.

This marks the 15th year of the coastal bays program, a partnership of local, state and federal governments aiming to preserve and restore the water bodies.   For more on the report card and the bays, go here.   

(Wild ponies on the shore of Sinepuxent Bay, 2010 Baltimore Sun photo by Karl Merton Ferron)