Health officials are warning against swimming in a Shelter Island pond.

According to officials, Fresh Pond on Shelter Island contains a new cyanobacteria bloom, also known as blue-green algae.

The Suffolk Health Department says residents should avoid swimming or even wading in the water because the algae can cause health problems.

The blooms also are still present in Agawam Lake and Mill Pond in Southampton, Roth Pond at Stony Brook University, Laurel Lake in Laurel  and Maratooka Lake in Mattituck.