BELLPORT - Brown tide is popping up across the waters on Long Island's South Shore.

Researchers from Stony Brook University say the damaging tide has been spotted across much of the Great South Bay and Moriches Bay.

It has also been found in Shinnecock Bay and Quantuck Bay.

Experts say nitrogen pollution from septic tanks and fertilizers is to blame for the brown tide. It decimated the shellfish population when it first appeared on Long Island in 1985.

Marine science professor Chris Gobler says water temperature at around 75 degrees typically kills brown tide. Since it's been cool recently, he says it could stick around until mid-July.