Northport Harbor in this aerial picture on July 1, 2019. Northport Harbor...

Northport Harbor in this aerial picture on July 1, 2019. Northport Harbor and Forge River were among the four locations rated poor this week due to algal blooms, low dissolved oxygen and water clarity. Credit: Newsday/John Keating

During the summer, a team of students and scientists led by Chris Gobler, professor of marine science at Stony Brook University and director of the New York State Center for Clean Water Technology, tests the water quality weekly at about 30 locations around Long Island. The result is the Long Island Water Quality Report, which aims to provide regular snapshots of ecosystem health, with an eye to how well the region's bays, harbors, rivers and inlets support robust fishing and shellfishing activity.

A good rating indicates clear water, adequate oxygen levels and no or low levels of algae or bacteria from human or animal waste, with levels of all parameters meeting or exceeding all state and federal water quality standards.

This week’s ratings are as follows:

GOOD: South Oyster Bay, Fire Island Inlet, western Great South Bay, Shinnecock Inlet, Mattituck Inlet, Little Peconic Bay, Great Peconic Bay

FAIR: Hempstead Harbor, Oyster Bay Harbor, Cold Spring Harbor, Huntington Harbor, Stony Brook Harbor, Port Jefferson Harbor, Mount Sinai Harbor, Hewlett Bay, Middle Bay, central Great South Bay, eastern Great South Bay, eastern Moriches Bay, Quantuck Bay, western Shinnecock Bay, mid-Shinnecock Bay, Peconic River, Sag Harbor, Three Mile Harbor

POOR: Northport Harbor, Forge River, central Moriches Bay, western Flanders Bay — Algal bloom, low dissolved oxygen, water clarity