In late July 2012, researchers at the Virginia Institute of Marine Science (VIMS) reported blooms of algae forming so-called “red tides” or “mahogany tides” had appeared in summer 2012 two to three weeks earlier than normal and were covering a larger area than normal in VIMS-monitored waters in the York, James, Elizabeth, and Lafayette rivers; Mobjack Bay; and near the mouth of the Chesapeake Bay near the Hampton Roads Bridge Tunnel. The scientists attribute the early and more widespread blooms to abnormally high temperatures in summer 2012 and in the previous winter. The blooms, which can potentially be harmful to fisheries and to human health, are caused by Cochlodinium polykrikoides, a single-celled marine species in the algal group knonw as dinoflagellates. In order to help keep track of potentially harmful blooms by this or other algae species, VIMS requests anyone observes patches of water colored red or mahogany in coastal or marine areas to contact the toll-free Harmful Algal Bloom hotline at (888) 238-6154.
Source: VIMS researchers monitor “red tides” in local waters, Virginia Institute of Marine Science News Release, 7/27/12