Approximately 102 acres in Flanders Bay and 1,429 acres in Shinnecock Bay are affected.
The State Department of Environmental Conservation banned the harvest of shellfish and carnivorous gastropods from Flanders Bay in the Town of Riverhead and western Shinnecock Bay in the Town of Southampton on April 12.
The presence of the marine biotoxin that causes paralytic shellfish poisoning, saxitoxin, was detected in mussels collected in Meetinghouse Creek and Shinnecock Bay.