Spring Series: April Means It’s Time To Study Eels

Apr 4, 2018

In what has become a rite of spring,  the Hannacroix eel net will be installed this afternoon in the Hannacroix Creek near the Albany/Greene County line. WAMC's Capital Region Bureau Chief Dave Lucas has the next story in our spring series.

Transparent baby eels, sometimes called "glass eels," are making their way up the Hudson River. Teams of scientists, students and community volunteers are waiting for them.

The count began a decade ago. Liz LoGuidice is an environmental educator who has been working with migratory eels for 20 years. She's a regular volunteer for the Hudson River Eel Project.   "The experience overall has just been absolutely fantastic, because we are able to get into the stream early in the season, which is very invigorating because the water is usually pretty cold and then find that there's all sorts of life in the stream even though in some cases the snow hasn't melted yet. Particularly these baby American Eels which are tiny transparent little wisps of a fish, yet they're very hearty and have traveled so far to reach the Hannacroix Creek. Even though I've been doing it for a lot of years, the wonder 0f pulling these baby eels out of the net never decreases."

These nearly transparent glass eels were born in the Atlantic's Sargasso Sea
Credit DEC

The Project is coordinated by the state Department of Environmental Conservation and partner agencies. Chris Bowser, DEC's Estuary Education Co-ordinator, says all of the river eels citizen-scientists are tracking were hatched somewhere in the Sargasso Sea...      "...roughly between Bermuda and Puerto Rico. So every eel along the East Coast was hatched there and then spent the first year of their life riding the gulfstream and other currents and getting scattered across the East Coast of North America, and some of them end up in the Hudson River.  But they don't just stop there at the mouth of the Hudson. They continue up the estuary, they continue up the tributaries, they continue up into the watershed, where many of them will mature for ten or twenty years. And finally, at the end of their life, they might be two or three feet long, and ten or twenty years old. They will head back to the ocean, they've got some sort of homing instinct, some sort of internal compass that leaves them back there to spawn once, and die."

Tracey Testo is a program coordinator for the environment and natural resource program area with Cornell Cooperative Extension of Columbia and Greene County.   "The Hannacroix Creek is one of the upper streams on the Hudson River that we sample for young eel migration. Our net is special in that we can only sample every day at low tide.  So we look at the tide charts for Hudson and other areas close by and get an idea of when it will be most safe to access the stream."

When the tide is right, DEC staff, volunteers and others haul their equipment to the stream, including a very long mesh net... "...it's called a fyke net. And that acts as a tunnel to focus the eels in through the net. So we install that with rebar, which you have to pound into the stream bed bottom to hold the net secure. We also tie it along the shore just to stabilize it a little bit more. We've found over the years that the eels like to travel upstream close to a bank, so through some trial and error we discovered which banks they prefer on the Hannacroix Creek."

Volunteers check the fyke net daily, count and weigh the captured eels, record the data and release the eels upstream. Bowser points out the migratory American eel has been in decline over much of its range since the 1970s.   

"For thousands of years,  many people in many cultures have loved to eat eels.  And because of that, we see a story that we see with other species, where we love something so much that we deplete their stocks. And so, scientists and fisherfolk alike noted in the 70’s and 80’s that eel numbers were going down, and that was a cause of great concern.  So the Atlantic States Marine Fisheries Commission set up monitoring protocols so that every state from Florida to Maine could keep an eye on how many of these juvenile glass eels were coming in from the ocean every year. It’s sort of meant as basically taking the vital signs of the eel population.

Well, those protocols were set up and some of us at the Department of Environmental Conservation said ‘You know, we could model these protocols and make them appropriate for citizen-science, for trained volunteers, for high-school students and college interns and watershed groups. They could be helping to collect this data, helping to collect these vital signs on different tributaries of the Hudson River Estuary, and so that’s one of the main reasons  why we got this program started, was to collect those vital signs, but also to get those volunteers engaged in the river in a very new and different way. Not just sort of a one-time field trip to the river, or not just a recreational activity, but something that combined field work and science and discovery, all in a wonderful package known as the juvenile American Eel. "

The DEC has more than a dozen eel-monitoring sites.

LoGuidice says the volunteers enjoy the springtime ritual of catching, counting, weighing and releasing eels.   "It's a sure-fired cure for cabin fever, just being out in the early spring. The whole community that is involved with eel conservation, it's a hearty crew, they have a good sense of humor and they really care about all sort of aspects of water, waterways and the creatures that live in the water. And it's also the sense of helping these creatures to continue on their migration and to celebrate the fact that the Hudson River is a living system that is home to all these fish that really connect us to the world. They are not just our fish, They are the global trust that we all are responsible for stewarding, and being an eel volunteer is part of that stewardship for me."

Waders and equipment are provided by the DEC Hudson River Estuary Program.  DEC provides training for new eelers; newbies work with established volunteers to gain experience checking the net. Again, Bowser.   "On April 21st we're going to be celebrating World Fish Migration Day. This is a series of events that's going on all over the globe on that day. And on Saturday April 21st we'll be at the FallKill Creek in Poughkeepsie, New York at around noon, doing some special events, we'll be sampling for eels, we'll have some displays set up. So folks can actually see these eels and help us count and help us do monitoring. And that takes place right at the Upper Landing Park by the Mid-Hudson Children's Museum."

Officials say there's always a need for more volunteers.  Download NYS DEC's Eel Project Volunteer Flyer (PDF, 340 KB)