Seagrasses suffered major declines in 2015
Seagrass acreage decreased from 2014, with little to no bay grass documented above Ocean City Inlet. The 2015 abundance was better than 2013 (the lowest seagrass acreage in two decades) but elevated nutrients, high water temperatures, and prolific macroalgae (seaweeds) limited recovery. Water temperatures in some areas exceeded the seagrass temperature threshold of 30°C (86°F) over 600 hours (nearly 25 days) during the growing season.
Sinepuxent Bay seagrass acreage was equal to 2014, however Chincoteague Bay lost 1,000 acres. Chincoteague has lost nearly 9,000 acres of seagrass since 2001 (55% of its 2001 acreage), thus a decreased report card score from a B‒ to a C+.
Improvements seen in hard clams
Hard clam populations have been generally on the rise since the 2008 mechanical harvesting ban. Assawoman, Newport, and Chincoteague Bays were still substantially below historic densities while Isle of Wight and Sinepuxent Bays are approaching historic benchmarks. Even St. Martin River had an increase in density near the mouth of the river. Despite slight increases recently, the Chincoteague Bay population continued to struggle (<20% of goal) due to poor recruitment.
Phosphorus degradation continues
The greatest concern for the bays’ health is eutrophication resulting from high nutrient loading, especially phosphorus. Ninety-nine percent of sites do not meet the seagrass phosphorus threshold. Stricter requirements were established in 2016 to address this problem, by limiting the amount of phosphorus that can be applied to fields. High soil phosphorus is typically found on farms that have used biosolid waste or poultry litter as a crop nutrient over many years. This practice will be limited under the new requirements, but it will take time for reductions to be seen in bay phosphorus concentrations.