Eels born in the Sargasso Sea south and east of Bermuda are living in a creek just off Route 9G south of Rhinebeck. In fact, eels are living in streams up and down both banks of the Hudson River. How did they get here from the middle of the Atlantic Ocean? How long have they been here, and what exactly are eels doing in the Hudson River estuary? Student volunteers from the Kingston YMCA Farm Project waded into the Ender Kill on a warm afternoon in September to catch eels and collect data that will help answer some of these questions.
Led by YMCA education director Susan Hereth, the student volunteers are participating in an on-going mark-recapture study of eels conducted by state Department of Conservation. The DEC’s Hudson River Eel Project has been tracking eel populations over time at a number of Hudson River sites from Staten Island to Troy, including sites at Black Creek in Esopus and the Ender Kill in Staatsburg. The DEC monitors four sites on the Ender Kill each July, August, and September. Students work with the DEC to catch the eels, collect data on their weights and lengths, and then release them.
These eels begin their lives as tiny larva known as leptocephali. They hatch in the fecund waters of the Sargasso Sea and spend several months drifting along the Gulf Stream. As they meander with the current toward the continental shelf, these willow leaf-shaped larva metamorphose into miniature, translucent glass eels. Their bodies plumpen and grow rounder. As the year-old glass eels approach tidal estuaries along the seaboard, they transform once again into elvers. During this stage, they lose their see-through bodies, develop grey or green-brown pigments, and grow beyond several inches in length.
Some find their way to the Ender Kill or other tributaries along the Hudson River, where they spend most of their years living in muck and dining on crustaceans, caddisflies, minnows, and a variety of aquatic life.
American eels, Anguilla rostrata, are not an invasive species. For as long as anyone can remember, eels have lived in these waters. The Munsee, Lenape, and other indigenous people caught and ate shoxamèkw, the Lenape word for eel, during the spring and summer when they lived along the banks of the Mahicantuck, the river that flows both ways. Eels were a staple of the diet of many indigenous people throughout the Atlantic seacoast. The remains of indigenous fishing weirs and the eels they captured have been found as far south as Virginia and as far north as Ontario, Canada via the Saint. Lawrence River. Papers from the Massachusetts Bay Company also recorded how Wampanoag people shared eels with the Mayflower colonists and then taught the Europeans how to catch them by hand.
Nature is connected to everything
To catch eels in the Ender Kill, the DEC and Kingston YMCA team don chest waders, wear rubber gloves, and use a shock pole and hand nets. From the bridge overlooking the ribbon of water, I see nothing swimming about. The water is clear, but a brown muck coats the creek bed. Several pools are about two feet deep, but most places are no more than a trickle.
Clouds muddy the stream when two students armed with their nets and the DEC specialist shouldering an electric backpack attached to a shock pole enter the Ender Kill. With a netter on either side, the DEC specialist leads the way. Behind the team, Susan Hereth readies a bucket of stream water. When the electrified loop of the shock pole touches the water, a student scoops the area with the net and swiftly dumps the catch into Susan’s bucket. Shouts of “Eel!” and laughter fill the air. This is nothing like the meditative trout fishing I am used to.
Step by step, they work their way up both sides of the tiny creek. Attentiveness and speed are required because the mild shock wears off quickly. The team crosses a partially submerged log into deeper water. Hereth spied a rusty car jack and tossed it to the bank. In the murky pool, the netting becomes faster-paced. In half an hour, they have scoured a 20-foot beat. They emerge with smiles and bucket filled with treasures.
One of the eel anglers, Aleshanee Emanuel. sums up the work. “It is challenging. The eels are tiny and fast. I like this kind of science. Before, I never thought about eels – where they were born, why they come here, and when they go back. Working at the Kington Y Farm has opened my eyes to a lot.”
A second team of YMCA students and a DEC specialist have prepared a data collection station: a triple beam scale, a measuring board, a species ID book, and a log to record their data. The DEC specialist is busy attaching an aerator to a bucket of water and mixing clove oil and stream water in another bucket. Clove oil? I don’t know what is about to happen, but I’m sure something will.
The broad goal of the Kingston YMCA Farm Project is to empower youth. “The farm – our base for learning – teaches how nature is connected to everything,” Hereth tells me.
A bald eagle soars overhead. She calls it out, and the students identify its glinting white cap before it glides below the tree line and down toward the river. They resume their work.
DEC environmental educator Adian Mabey walks the students through the process of data collection. Each species captured must be positively identified and returned to the creek. Eels must be separated out and placed in the clove water to induce sleep. Once asleep, they will be measured and weighed. Eels over 25 centimeters will be scanned for a personal identification tag, and the information recorded. If no tag is found, one will be placed just inside the eel’s skin.
What’s on the bucket list
“All eels that are tagged also have their eye and pectoral fin measured,” Mabey explains. “This means if they are recaptured we can see any change in location, length, weight, eye and fin measurement from the last time they were caught. Overall, this gives us a better sense of the eel community in the creek and how eels at different life stages are using the Ender Kill as habitat.” The students total up the non-eel catch: nine pumpkinseed, one smallmouth bass (four inches long), two male spiny-cheeked crayfish (one with a missing claw), two mummichog, one banded killifish, three white sucker fish, three tessellated darters, and three green frogs. With each species, Adian pauses to show the students specific characteristics. The mummichog have upturned mouths that resemble a smile. The tessellated darter has fins to help it walk and swim.
By the time the bycatch has been logged, more than a dozen eels are fast asleep in the clove-oil water. One by one, the students take out the eels, measure, and weigh them. Some of the eels are yellow eels, the stage following elvers. Yellow eels have a distinctive yellow-green or olive-brown coloration. They are larger than elvers, several over ten centimeters. These yellow eels will spend another ten to 20 years living among us in the Hudson River estuary. One yellow eel measures 22 centimeters but is not long enough to tag. This one will return to the creek with the rest and spend another year maturing before it begins its transformation into its final stage, a silver eel.
Improving wildlife habitats
When their bodies are ready to reproduce, the eels metamorphose for a final time. “An eel becomes what it needs to be when the time is right,” writes Patrik Svennson in his 2019 bestseller, The Book of Eels. Silver eels turn grey or creamy white in color, lose their digestive tracts, and develop reproductive organs. Their pectoral fins enlarge for swimming, and their head grows in width between their eyes. At this time in their lives, silver eels journey back to the Sagrasso Sea to spawn and die. Curiously, the precise location of their spawning grounds remains unknown. “Eels are still a mystery, and mysteries are a rare find in this world,” remarks Hereth.
The Hudson River Eel Project has documented that American eel populations are on the rise after a precipitous decline at the end of the last century. More data is needed to help scientist understand the health of the eel population in the Hudson River. Climate change, land management planning, industrial and residential pollution, rising water temperatures, dams, and invasive species all play a part in the lives of eels, people, and hundreds of wildlife species living together in the Hudson River Valley.
This inter-relationship was one topic examined during the recent Cary Institute for Ecosystem Studies webinar workshop. The first of a three-part workshop, the event was free to the public.
In these workshops, Cary Institute experts explored the roles that each of us can play in improving wildlife habitats.
At the first workshop, the speakers discussed setting goals and making plans for wildlife management and provided tips on estimating wildlife populations. Like the eel study, gathering data is an important part of living with wildlife. Mike Fargione, manager of field research and outdoor programs at the Cary Institute, demonstrated how to set up a wildlife camera to capture images of the animals in your backyard, forest or field. He explained that knowing the species around us was critical if we are to plan correctly to live together with them, enhance their habitats, and reduce conflicts.
Julie Hart of the Dutchess County Land Conservancy outlined the importance of understanding how habitat changes positively affect some species while pressuring others. She explained how removing standing dead trees may reduce nesting sites for nuthatches who raise their young in tree cavities. Removing fallen dead trees may reduce various insect populations that help to decompose the trees but also serve as food for nuthatches. Consequently, a reduction in nuthatches reduces the feeding opportunities for hawks that prey on the birds.
The webinar workshop series continues at the Cary Institute with programs scheduled for October 7 and October 14.
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