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.

Karlodinium micrum
Main Channel of Chesapeake Bay During routine monitoring by the Maryland DNR water samples collected on April 24 off the mouth of the Patuxent River contained Karlodinium micrum at concentrations of 7,659 cells/ml. A bioassay of the sample by the University of Maryland Biotechnology Institute's Center of Marine Biotechnology (COMB) lab suggested the algae were capable of being toxic. No fish health events were found in association with the algae.