Warm-Water Fish Invade New York City’s Waters

Warm-Water Fish Invade New York City’s Waters

December 12, 2012 at 10:28 am

Carl Wills has been fishing in Long Island Sound for 58 years, and two months ago, for the first time in his life, he saw a sea turtle.


Fisherman on the boat Island Current. Photo by Henry Cass.

Working a night shift for a charter fishing company out of City Island in the Bronx, Wills, 61, was taking a moment to relax when the four-foot-wide turtle surfaced alongside the boat, the Island Current II.


“All of a sudden, this big thing comes out of the water and sticks its head up. What the hell?” says Wills, describing his reaction. “It was amazing to see that.”

Six species of sea turtle are found in U.S. waters, and they all usually dwell in the southeastern or Chesapeake Bay region. They are also not the only warm water animals to be living in Long Island Sound this fall.

Water temperatures in the Sound have been gradually rising for the past 30 years, a trend many area scientists attribute to global warming. Waters in the region around New York are warming faster than any other region in the country, and hit a record high this year on the eve of Hurricane Sandy. The trend threatens to destabilize a fragile marine ecosystem and the livelihoods of local fishermen already struggling to break even.

This year’s high water temperatures seem to be the result of an unusually warm winter persisting into the spring and summer months, according to scientists. They add that unseasonably high air temperatures are also coupled to the warming water.

The warming water in the region is disrupting traditional migration patterns, says Josh Kohut, an assistant professor in marine and coastal sciences at Rutgers.

“We’ve heard stories from guys out on the ocean that it’s just a really different ocean this year,” says Kohut.

Longer stays, new visitors

The waters around New York were already subject to some of the most dramatic annual temperate shifts, with ocean temperatures ranging from 40 degrees in the winter to 80 degrees in the summer. As a result, the region has always hosted some of the most migratory fish species on the planet.

And as hordes of fish clog New York’s waterways on their journeys north and south, Island Current customers drop their lines. Day trips get especially frenzied, with customers piling cold-adapted bluefish and warm-adapted sea robins up to their ankles.

Wills repairs houses on City Island during the day, skipping the fast-paced day fishing trips for the calmer night runs—his natural habitat. Night fishing is all about the long game. The slightest purr of a boat engine can startle a school, so one night a few weeks ago, the fishermen huddled inside their coats, watching their lines and murmuring fishing stories, flicking flaming cigarette butts into the salty night air.

The tranquility is broken when Wills gets hold of a recently-caught dogfish. The fish looks like a shark, and he grabs it by the tail and carries it around the small boat, his cigarette wagging between his stubbly gray beard, poking people with the creature and softly humming the “Jaws” theme music.

A warm-adapted species, dogfish are rarely caught this late in the fall, when they typically begin to migrate south. According to Kohut rising ocean warmth off the coast of New York are delaying the temperature triggers that prompt some fish migration. The trend has important consequences for local marine biodiversity.

“You would see a difference in the composition of species off our coast,” says Kohut. “I think there would be winners and losers.”

Who are the victors and the vanquished? Penny Howell, a fisheries biologist for the Connecticut Department of Energy and Environmental Protection has been studying 25 years of fishing catch reports for the Long Island Sound.

Howell found that warm-adapted species have grown in abundance in the Sound while cold-adapted species have declined. She notes, however, that the overall population and diversity of fish in the Sound has increased.

“We’re kind of gaining these mid-Atlantic species in slightly greater amounts and diversity than we’re losing the abundance of our usual cold-adapted species,” she says.

Howell adds that in a 25-year time frame her research showed a huge change in species diversity over just five years.

“Which was bigger than I thought it would be,” she says, considering the species that inhabit Long Island Sound are typically more resistant to temperature changes.

Debate over causes

Still, while scientists agree the warming trend is at least partly a result of human-induced global warming, they are quick to remind that they’re in uncharted territory. The science is young and the concrete, long-term consequences of the trend will only be understood through more research, they say.

Wills, like many other fishermen, doesn’t buy the climate change explanation.

“We never had a winter last year, so the water never got cold,” he says. “I don’t think it’s going to stay like that. We’ll have a cold winter and it’ll be back to normal, I hope.”

Warmer water holds less oxygen, meaning fish generally flee for cooler, more hospitable waters. The sea turtle wasn’t the only oddity Wills observed on the water two months ago. The bluefish his customers typically caught in droves that time of year were nowhere to be seen.

Earlier that summer, temperatures hit 80 degrees in Long Island Sound. Wills says cooler air made the water steam. Bunker fish floated to the surface, dead from the lack of oxygen.

Still, Wills is reluctant to blame global warming.

“I only see we had no winter this year, so strange fish are coming down. I might not see them again,” he says.

Instead, local fishermen are more worried about how shifting species migration could hurt their already struggling industry.

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