Thousands of dead fish found floating in the Hudson River suffocated, experts say

WHITE PLAINS, N.Y. – If you’ve spent time along or on the Hudson River in the past week, you may have witnessed a shocking – and smelly – phenomenon: thousands of dead fish stretching along the water.

The Atlantic menhaden, or “bunkers,” a coastal fish, use the Hudson estuary as a nursery.  

According to Riverkeeper, an environmental organization that watches the Hudson, the fish are succumbing to reduced levels of dissolved oxygen.

Basically, the fish are suffocating.

“We have to realize that all aquatic creatures require oxygen to breathe. The amount of oxygen that is present in a water body is an indicator of a body of water’s health,” said George Jackman, senior habitat restoration manager at Riverkeeper.

Many menhaden fish have washed up on the shores of the Piermont Pier. The die-off may be caused by the lowering of the oxygen level in the Hudson River.
Many menhaden fish have washed up on the shores of the Piermont Pier. The die-off may be caused by the lowering of the oxygen level in the Hudson River.

Hot, sunny days can cause the river to heat, Jackman said. The warmer water holds less oxygen. Low or no oxygen – called hypoxia and anoxia, respectively – are fed by large algal blooms from excess fertilizer and sewage runoff.

The large-scale die-off, Jackman said, is a sign that the river is out of balance.

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Sewage throws off oxygen levels. Natural cleansers, such as the oyster beds that once filled the area around New York Harbor, are all but wiped out.

When millions of menhaden swim into the estuary and consume the limited oxygen, “they will suffocate themselves,” Jackman said.

“The river is very fragile. … The bunker are showing us that there’s a problem,” he said.

Bob Walters, who retired last year as director of the Yonkers Science Barge, has seen the phenomenon before. “This is an extraordinarily large die-off,” Walters said. “It doesn’t happen every year, but it happens.”

Walters has been on, near and around the Hudson his whole life.

“I live 139 steps above the river,” the 72-year-old said. “I’m blessed.”

Because the menhaden is a “schooling fish” that swims in large numbers, the die-off looks dramatic, Walters said.

Walters said it’s not so easy to ascribe the die-off to a sign of a declining Hudson: “The river’s a complex system.” 

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Walters said the die-off is concentrated on the menhaden. “If I looked out my back door and saw perch, striped bass, sturgeon,” he said, he would be more worried. “It’s still terrible, but it’s not the demise of the river.”

Still, he said, it’s unpleasant – “the smell of the dying fish is so bad” – and alarming. “It’s a sad thing.” 

A request for comment from the state Department of Environmental Conservation was not returned.

Menhaden are a key part of the ecosystem, Jackman said. “They are the favorite forage of striped bass, even whales – that is why we are seeing so many whales in the (New York) harbor.” The footlong fish are harvested for fish oil capsules.

Jackman said the die-off fulfills a role in the life cycle. “I was at Piermont the other day,” he said, and saw birds “enjoying the bonanza of a menhaden buffet. It really doesn’t go to waste.” 

Follow Nancy Cutler on Twitter at @nancyrockland.

This article originally appeared on Rockland/Westchester Journal News: Thousands of fish suffocated in the Hudson River. Here’s why

source: yahoo.com