Jul 10 2014
A Slippery Search Transforms Students into Scientists
Photo credit: NYS DEC Hudson River Estuary Program
July 10, 2014
A Slippery Search Transforms Students into Scientists

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Environment

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High-pitched shrieks echoed through an otherwise silent marina in Gravesend Bay one overcast morning this past May.

In the thick of the commotion it was hard to tell just who was cheering louder: the six high school girls peering into a bucket, or their instructor, Melissa Carp.

Perched at the end of a floating dock, the students and teacher huddled together in a neon-colored mass, their orange life jackets shoulder-to-shoulder as they jostled for a closer look at the creature they’d plucked from the murky waters.

“I see it!” “There it is!” “Get over here, quick!”

From the excitement (and volume), one might think they’d caught something enormous, or even dangerous—a few of the grizzled old-timers polishing their boats looked over with a suspicious eye—but in reality, the critter they’d found was half the size of a spaghetti noodle and almost completely transparent.

Shake It Like You Mean It

“We worked so hard for that one little eel!” grins Dr. Chanda Bennett.

Bennett, who heads up the New York Aquarium’s education department, also leads programs like this one, a partnership between the Wildlife Conservation Society and the NYS Department of Environmental Conservation to monitor Brooklyn waters for the presence of juvenile American eels, also called glass eels.

Twice a week for the past three months, Bennett and her colleague Melissa Carp, an instructor at the New York Aquarium, have piled into a passenger van with a group of high school volunteers and headed out to a private 200-slip marina in Gravesend Bay,  less than two miles from Coney Island. This morning is their last trip of the season.

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WCS volunteers measure the pH of ocean water. Photo credit: Emily Manley via NYER.

When we arrived, the students tumbled out of the van, donned life jackets, and grabbed equipment: buckets, notebooks, and water testing kits. As they made their way to the dock, they were normal, rowdy teenagers—laughing, making jokes. But when they settled at their destination, they transformed into something more like scientists.

“Water temp?” “60 degrees.” “pH?” “7.8 I think, but the reading looks funny?” “Try it again just in case.” “Who’s measuring salinity?”

Once the baseline data was recorded in a thick blue binder, the students worked together to haul up the “eel mop,” a heavy, submerged trap that resembles a clump of weeds where eels can hide from predators. They placed it in a bucket and began to swirl it vigorously, hoping to dislodge any marine life. “Shake it like you mean it!” exclaimed Carp to a chorus of giggles.

The crew hauls up the eel mop on the side of the floating dock. Photo credit: Emily Manley via NYER.

The crew hauls up the eel mop on the side of the floating dock. Photo credit: Emily Manley via NYER.

When they lifted the mop, down fell snails, tiny shrimp-like crustaceans called amphipods, a few little crabs, and finally, the holy grail: a mysterious—and practically invisible— glass eel. Whoops rang out.

A Migratory Mystery

While most New Yorkers only know eel when it’s sliced atop their sushi rolls, the serpentine creatures can actually be found in many of our local waterways, including the Hudson River, the Bronx River, and a host of streams throughout the boroughs.

While most New Yorkers only know eel when it’s sliced atop their sushi rolls, the serpentine creatures can actually be found in many of our local waterways.

Eels are born in the Sargasso Sea, a patch of the Atlantic near the Bahamas. As they mature from larvae to glass eel, they hitch a ride north on the Gulf Stream, arriving in East Coast estuaries, like those in New York City, from February to late May. The eels swim up the tributaries and mature, spending upwards of 20 years in rivers before returning once again to the Sargasso Sea—this time to spawn and then die.

Sushi slices aside though, why should New Yorkers care about the elusive eel? For one thing, they’re an important component of a healthy freshwater system—the same one that brings us our drinking water. As a predator, they help regulate the population of other animals, and serve as a significant food source themselves for fish, mammals, turtles, and birds.

Eels also have an enormous economic impact. Last spring, the Boston Globe reports, the price of eels rocketed up to $2,600 a pound, primarily due to voracious overseas demand. In Maine, eels were a $39 million market in 2012, the second most valuable catch after lobster.

A tiny glass eel found in Brooklyn. Photo credit: Emily Manley via NYER.

A tiny glass eel found in Brooklyn. Photo credit: Emily Manley via NYER.

But in recent years eel populations everywhere have dwindled; there is even a bid to place them on the federal endangered species list. “The American eel is facing a range of challenges that are forcing their numbers to decline rapidly,” explains Bennett. Some of the causes, like habitat degradation or overharvesting, are well known. But there are other, more subtle possibilities, too: water pollution, dams, parasites, global warming.

With all that stands in their way between the Sargasso Sea and New York’s waterways, it seems a minor miracle that even a single eel could find one trap in Gravesend Bay. “They are little survivors,” agrees Carp. Which is why scientists in New York are turning to citizens for help.

Casting a Wide Net

“Eels present a great opportunity for people of all ages to study an incredible migratory animal,” explains Chris Bowser, Education Coordinator for the DEC. Since 2008, Bowser has led a citizen science project for the DEC’s Hudson River Estuary Program, a unique effort that engages a diverse group of New Yorkers, from high school students to retirees, in capturing data about eel migration.

Eels present a great opportunity for people of all ages to study an incredible migratory animal.

Each spring, teams of scientists, students, and community volunteers—many organized by local nonprofits like WCS—begin monitoring more than a dozen sites from Staten Island to Albany. They trap, count, weigh, and release juvenile eels, while also recording a range of environmental data for the DEC. The hope is that by gathering baseline information about eels—population numbers, health, and migration patterns—scientists can better understand how to save them.

According to Bowser, though, the program is not just about eels; it’s also about “building a constituency of citizen stewards who understand and enthusiastically support eel conservation.”

Recording data. Photo credit: Emily Manley via NYER.

Recording data. Photo credit: Emily Manley via NYER.

It seems to be working. In 2013, more than 500 volunteers helped capture (and release) some 100,000 juvenile eels. “I am really impressed at the work that groups like WCS, Rocking the Boat, the Bronx River Alliance, and the Hudson River Park Trust are doing to promote eel education in New York harbor,” Bowser states. “They are collecting data on an amazing animal, and turning students and other citizens into active conservationists.”

One is Enough

After returning the lone eel to the marina waters, the group moves on to the second monitoring site along the dock where they are less lucky: the mop contained “approximately one billion” snails and a most-docile pipefish, but no more eels. The students record their findings, and pack up the gear.

This is a great way to expose our urban youth to the abundant natural resources we have in the city.

Should we be worried about the low number of eels in Brooklyn waters? Bowser doesn’t think so, explaining that it’s just “easier to catch glass eels in tributaries where the water is channeled rather than the large volume of a bay or large river.”

Bennett doesn’t seem bothered by it either; on the contrary, she says, the program has provided an excellent way to engage borough volunteers. Bennett, aBrooklyn native herself, recalls how hard her parents worked when she was a child to find similar opportunities. “This is a great way to expose our urban youth to the abundant natural resources we have in the city.”

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Photo credit: Emily Manley via NYER

As we head back to the van, the group seems quieter, more contemplative. There is less joshing, more satisfied silence. We carefully maneuver down the wobbly floating dock, past the boaters preparing for a day on the water, and turn towards the van when a clear voice lifts from the center of the pack: “You know, it’s just so nice to find what you’re looking for.”

Photo credit: NYS DEC Hudson River Estuary Program