As Katama Bay oyster farms remain closed because of Vibrio illness tied to raw oysters, scientists are using the bay as a testing ground to understand more about the bacteria and how it interacts with oysters.

Katama Bay oyster farms will remain closed for another week following additional confirmed cases of Vibrio illness tied to the area, a state Department of Marine Fisheries official said Tuesday afternoon. Chris Schillaci told oyster farmers that handling is not the problem.

Katama Bay oyster farms have been closed for a week because of three cases of confirmed cases of Vibrio parahaemolyticus illness tied to consumption of raw oysters from the area, state officials announced Wednesday.

Katama Bay oyster farms in Edgartown were closed this week after two people who ate oysters from the bay contracted Vibrio parahaemolyticus (Vp).

The Massachusetts Department of Public Health and the Department of Fish and Game, Division of Marine Fisheries announced the closure Monday.

This month scientists from the Woods Hole Oceanographic Institution will descend on Edgartown with a sonar-equipped waverunner to map, in unprecedented resolution, the ever-shifting sands and currents of Katama Bay. While the bathymetry of the body of water, where change is a constant feature, is of special scientific interest to the Woods Hole scientists, the information is even more valuable for the surprising underwriter of the project: the U.S. Department of Defense.