Mainstem Bay (IMAGE) Virginia Institute of Marine Science Caption The bloom of Alexandrium monilatum during late August 2015 extended well into the mainstem of Chesapeake Bay off the mouth of Mobjack Bay and the York River. Credit © W. Vogebein/VIMS. Usage Restrictions One-time use only License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.