Between April 23 and April 30, bloom events were recorded from the Chesapeake and Coastal Bays watersheds with the mahogany tide dinoflagellates Prorocentrum minimum, Karlodinium micrum and a cyanophyte (blue-green alga) Lyngbya. Several bloom events were in association with fish kill sites investigated by the Maryland Department of the Environment (MDE). Routine water quality monitoring of the Coastal Bays by Maryland Department of Natural Resources (DNR) also produced samples with low to moderate concentrations of the potentially toxic dinoflagellate Dinophysis acuminata. Warming temperatures and much needed rains have arrived this spring. Runoff from the recent storm events, however, will deliver a nutrient pulse to the Bays and their tributaries that will likely feed additional algal blooms throughout the spring season.

Prorocentrum minimum
Baltimore Harbor/Patapsco River - Blooms of P. minimum continue in the Baltimore Harbor region. On April 23rd water samples collected and analyzed by Maryland DNR collected from the Key Bridge area during routine water quality monitoring. Maryland DNR found average concentrations of P. minimum at 15,458 cells/ml. Another investigation at Bear Creek, tributary to the Patapsco River, revealed P. minimum at 40,454 cells/ml on April 26th.