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Brown Tide Chokes Western Shinnecock Bay

A destructive “brown tide” algae bloom has once again swept across western Shinnecock Bay, the Quogue Canal and eastern Moriches Bay, and this year’s occurrence appears to be approaching levels not seen since the devastating succession of blooms that nearly wiped out shellfish stocks in the 1980s and 1990s.

The brown tide began building in May, gradually staining the waters west of the Ponquogue Bridge a dingy brown. In recent weeks, the bloom has flourished, and densities of the algae cells may have already surpassed levels seen last year, the worst since the 1990s, according to scientists who have been observing the growing bloom.

“We’ve got a wickedly dense brown tide in Shinnecock Bay,” said Dr. Chris Gobler, a marine science professor at Stony Brook University and an expert on harmful algal blooms. “We’re seeing hundreds of thousands of cells per milliliter, on par with the really bad years. Last year, we got to two million parts per milliliter, and we’ll be doing testing this week—we’ll see if it’s over that this year. You can just see it, though. It’s thick.”

The brown tide blooms, which are not harmful to humans, first appeared in local waters in 1985, turning the waters of nearly every tidal bay and creek on the East End coffee brown. The density of the algae, which shellfish will not ingest as they do most other algae species, starved shellfish and cut off sunlight to aquatic plants. After several years of the choking brown tide blooms, the area’s once prodigious bay scallop populations finally collapsed in 1995 and have yet to return to even a shadow of their former abundance.

This year’s brown tide, appears just as concerns about another algae bloom—a “red tide,” for the reddish color of its individual cells—was fading out. The red tide organism, known as Alexandrium, has caused the closure of shellfish harvesting in all of western Shinnecock because the cells produce a biotoxin that can be harmful or even fatal to humans.

Dr. Gobler said the pattern in western Shinnecock has been that the brown tide will reach its peak in late June and early July, and then begin to wane, fading away in August as water temperatures reach into the mid- to upper-70 degree mark in the bay. In some years, it has returned in September as waters cooled again.

Regardless, the tide’s persistence in western Shinnecock Bay and eastern Moriches Bay, while largely absent from most other East End waters since 1995, is just another sign of the poor state of water quality in the bay.

“It’s sad to say, but this is business as usual for this water body,” Dr. Gobler lamented. “Since 2007, it’s been there every year. What’s special will be when it doesn’t occur.”

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