An unwelcome and potentially hazardous sight has returned to Long Island waters.

Researchers at Stony Brook University say this is the 10th consecutive year that rust tide has appeared on Long Island. The algae has been found in both the Peconic and Shinnecock bays, and researchers say toxic levels of rust tide can kill marine life.

One Stony Brook professor says the rust tide will last until fall or when the water temperature drops below 60 degrees.