Tag Archives: American eel

The American eel: Tale of a champion migrator

The American eel spawns and hatches in the ocean waters of the Sargasso Sea, near Bermuda, about 2 million square miles of warm water in the North Atlantic.


Map of Sargasso Sea in relation to NYS, USFWS

The larvae of this snake-like fish drift with the currents for about a year to find homes throughout their huge range, from Greenland to Venezuela. Many eels migrate north and make it all the way to Lake Ontario.

A champion migrator if I’ve ever seen one.

Eels go through a very complicated maturation process that usually takes them from oceanic waters to freshwater and then back to the ocean for spawning. Some eels remain in saltwater or estuaries like the Chesapeake Bay their entire lives.

If you need a reason to conserve these amazing marathon swimmers, then here are some pretty unique behaviors to keep in mind. Eels can absorb oxygen through their skin and gills, allowing them to travel over land, particularly wet grass or mud (so cool!). Eels also can cover their entire bodies with a mucous layer, making them nearly impossible to capture by hand.

Historically, eels were abundant in Lake Ontario with over 1 million documented annually migrating upstream at the Moses-Saunders Hydropower Dam on the St. Lawrence River. In 2001, there was a huge drop to 944 migrants. Numbers have increased in the last decade, but are still below 50,000, leaving biologists looking for answers.

The extreme population decline may have been fueled by the 1970s demand for yellow and silver life stages of the American eel. Harvest can be especially detrimental because of the eel’s slow and complex maturation process, but the definite cause of the decline is still not clear.

American eels no longer have access to much of their historical habitat because dams and other obstructions in rivers block their migration and prevent them from accessing all available habitat. Localized population declines are also attributed to mortality in hydropower plant turbines, degradation of current habitat, and overharvest.

Addressing these threats to the American eel and its conservation is a multifaceted approach which includes research and monitoring to increase eel access to former habitat and understand the mysterious spawning migration, as well as reducing anthropogenic mortality.

Organizations including the U.S. Fish and Wildlife Service, Canadian Department of Fisheries and Oceans, New York State Department of Conservation, the Ontario Ministry of Natural Resources and Forests, the Quebec Ministry of Forests, Wildlife, and Parks, the New York Power Authority, Hydro Quebec, and Ontario Power Generation have targeted projects to develop methods to safely pass eel around hydro dams on large rivers.

Within New York State, our field office has partnered to track eel migration in the St. Lawrence River. Eels are tagged with acoustic tags in the Bay of Quinte (on the north shore of Lake Ontario). They then travel downstream along the St. Lawrence River and can be tracked with receivers located at the Iroquois Dam, about 80 miles downriver. That migration usually takes place in late summer or early fall when the eels are maturing from their yellow form to a beautifully elegant silver mature stage.

EelMapIWCD2 (1)

Documented eel movements at the Iroquois Dam in NYS, USFWS

In collaboration with other natural resource agencies, the Service continues to work to mitigate adverse impacts to eels. These measures are specified during the licensing or relicensing of hydropower projects by the Federal Energy Regulatory Commision and can include the addition of facilities like eel ladders to safely pass eels upstream, screens to keep eels out of turbines, passageways to guide them downstream, or shutting turbines down at night when silver eels migrate.


Service biologists collecting eel receivers on the St. Lawrence River, USFWS

Eel ladders, which are designed specifically for this species, allow eels to swim over barriers using an ascending ramp. Eel migration is monitored at various areas both upstream and downstream to help understand and optimize eel passage inland and to the ocean.

Other conservation actions include restrictions on eel harvest by the United States and by the federal and provincial governments in Canada.

The U.S. Fish and Wildlife Service continues to work with partners to better understand and conserve this remarkable species. The more informed we can be about the species around us, the better we are able to makes conscious choices to conserve and protect wildlife and the ecosystems in which we all live.


Yield of Streams: If you remove it, they will come

Little feet tread through slushy April snow and approach the railing, peering over the edge of the bridge into the cold, flowing water of the Shawsheen River in eastern Massachusetts.

“I see one!”

They counted them 1,2,3.

The Joshi family children shouted out numbers as silver blue blurs glided through the dark water.

“We counted 95,” recalled Andover resident Jon Honea. He explained that this meant that as many as 425 passed by when volunteers weren’t watching.

They were counting river herring­­ – alewives and blueback herring, two closely related species of migratory fish that hadn’t been seen in the river for nearly two centuries.

And while river herring are no Shoeless Joe Jackson, their homecoming to the Shawsheen points to the success of the recent removal of the Balmoral and Marland Place Dams.

“All you have to do is make space,” said Honea, member of the Andover Conservation Commission and an environmental science professor at Emerson College.

Tracking the herring’s return to the Shawsheen River was a community affair, drawing over 250 volunteers. Residents from the Atria assisted living facility – whose residence was threatened by increased flood risk from the dam – joined the fun, alongside Andover high school students and dedicated families like the Joshi family, who counted multiple times every week.

“The removal of these two dams not only increases the resiliency of the Town of Andover, but reconnects the community to the river by restoring lost recreational opportunities and natural ecological processes upon which we all rely,” explained Bill Bennett, a U.S. Fish and Wildlife Service biologist.

Not only were these dams a public safety hazard – heightening flood risk and threatening paddlers – they also blocked the travels of migratory fish throughout the river.

Dams prevent rivers from flowing naturally, impairing water quality and interrupting natural stream processes that both people and wildlife populations rely on.

Partners and volunteers have already documented a steady reappearance of river herring in the Shawsheen, but other wildlife such as American shad and American eel are also expected to arrive.

These removals opened up 4.1 miles of the river and restored 16 acres of wildlife habitat, allowing these fish to reach spawning grounds that are critical for their survival.

Though these smaller fish aren’t coveted by anglers, they are eaten by other wildlife such as larger game fish – like striped bass – shorebirds, raptors and river otters.

Snapping turtles and great blue heron have also been observed enjoying the free-flowing state of the lower Shawsheen River, below the remaining Ballardvale Dam.

Jane Cairns of the Andover Historical Society explained the rich history of the Shawsheen River, mentioning that the Marland Place Dam supported mill operations in the town, even powering a site that at one point supplied gunpowder to George Washington’s Continental Army.

She, like Honea, is also a member of the Shawsheen Greenway, an organization focused on making the Shawsheen River corridor a vital recreational, cultural, transportation, and educational resource for the entire community and region.

“We’ve been reminded, as many other communities have before us, that a clean and healthy, free-flowing river is a significant asset for the town, and can provide a boost to both our recreational and business resources,” Cairns said.

Nick Wildman, a restoration specialist from the Massachusetts Department Fish & Game, has been involved with these removals since 2009. He called the projects a “public investment for public benefit,” adding that the dam removals along the Shawsheen River represent a resurgence of the place that rivers have in our lives.

It doesn’t end there. Though public safety and stewardship of the river and fisheries were paramount to community leaders, fewer dams are a home run for experienced paddlers, who no longer have to transport their boats around the dams on land.

“The newly opened stretches of the river are quite beautiful and exciting,” Honea said. “There are long stretches with just forest on either side and several newly accessible drops, including a couple very exciting rapids.”

“These projects are not possible without strong partnerships between the federal, state, and local communities,” Bennett said.

Some of these partners embarked on a celebratory paddling trip in May to explore the newly free-flowing Shawsheen River.

Three canoes set out on the river. Eric Hutchins of National Oceanic and Atmospheric Administration and Bill Bennett of the Service in one, Nick Nelson of Interfluve – a national firm focused on river restoration – and his son in another, and Andover’s Conservation Commissioners, Jon Honea and Floyd Greenwood, in the third boat.

While paddling, Hutchins and Nelson noticed a gizzard shad also exploring the newly restored river.

“Rivers are the lifeblood of our nation and their stewardship is of the utmost importance,” Bennett said.

The town sees it the same way.

“The Town of Andover is very excited about the removal of the dams – many people see this as the start of a real renaissance of the Shawsheen,” said Bob Douglas, conservation director for the Town of Andover. “Our residents are looking forward to being able to paddle the unbridled Shawsheen from the Ballardvale mill district, through the center of town, all the way to the mighty Merrimack.”

Heavy machinery at hogansburg dam

Removing Hogansburg dam = Restoring nature and culture in Upstate NY

Check out the rapid changes to the St. Regis River even after just removing the west side of Hogansburg Hydroelectric Dam. Photo courtesy of Tony David

Check out the rapid changes to the St. Regis River even after just removing the west side of Hogansburg Hydroelectric Dam. More like a river, less like a lake! Photo courtesy of Tony David.

Justin Dalaba

Today you’re hearing from Justin Dalaba, our new outreach coordinator for the New York Field Office. He graduated this summer from St. Lawrence University with a bachelor of science in conservation biology. Welcome Justin!

Near the mouth of the St. Regis River in Franklin County, New York, are the final remnants of the Hogansburg Hydroelectric Dam.

The 330-foot-long dam blocked migrating fish and hindered a way of life for over 85 years. The dam neighbors the Saint Regis Mohawk reservation, also known as Akwesasne, and is part of the Tribe’s decades old boundary claim. Talk among stakeholders about decommissioning the Hogansburg Hydroelectric Project, owned by Brookfield Renewable Energy, began in the early stages of Federal Energy Regulatory Commission, aka FERC, relicensing nearly five years ago.

Here’s what you should know:

    1. Hogansburg is the first hydroelectric dam in New York State to be fully removed. Plus, the Saint Regis Mohawk Tribe is the first Tribe in the U.S. to remove a FERC-licensed hydroelectric dam!
      Hogansburg Dam has been the site for various mills and dams since 1762, with the initial construction of the Hogansburg Hydroelectric Dam we know today in 1929. The project underwent a thorough review in 2015, when FERC needed to begin the project’s relicensing process. For Brookfield, relicensing would mean costly mechanical and environmental work. Our agency, along with the New York State Department of Environmental Conservation, Trout Unlimited, and Saint Regis Mohawk Tribe, offered an alternative—decommission the dam in disrepair. The Tribe took the lead, ultimately returning project lands to the Mohawk people. FERC issued a decommissioning order in June 2016, followed two months later by removal that is now near completion.
    2. The removal of Hogansburg Dam has reconnected nearly 275 miles of main stem and tributary habitat for migratory fish. Removing Hogansburg Dam, the first dam on the St. Regis River, will re-establish the river’s direct connection to the St. Lawrence River. For nearly a century, the dam has blocked this important stream habitat to fish migrating from the St. Lawrence River within the St. Regis watershed. The key fish that will benefit from removal of the dam include the American eel (Anguilla rostrata), lake sturgeon (Acipenser fulvescens), Atlantic salmon (Salmo salar), and walleye (Sander vitreus).

      juvenile lake sturgeon

      Juvenile lake sturgeon, one of the species expected to benefit from the dam removal.
      Credit: Justin Dalaba, USFWS

    3. Removing Hogansburg Dam restores historic territory that has shaped the Mohawk peoples’ way of life.
      The Mohawk people of Akwesasne have a deeply rooted history in a subsistence lifestyle including hunting and fishing along the expansive network of rivers connecting the St. Lawrence River to the Adirondacks. This was changed when early settlers reshaped the network of tributaries for natural resource and hydroelectric power exploitation.With funding from a variety of private and federal sources, the Saint Regis Mohawk Tribe was able to have a direct hand in the Hogansburg Dam removal and studying pre and post removal conditions. Decommissioning of the Hogansburg Project means the repatriation of land to the Tribe surrounding the river. Saint Regis Mohawk Tribe will continue working with other stakeholders to study changes following the dam removal.

      Heavy machinery at hogansburg dam

      Let the heavy machinery have at it! Photo courtesy of Tony David.

    4. This removed dam does not mean lost power.
      The poorly functioning Hogansburg Dam provided a miniscule amount of the power supplied for New York (if you want to be exact, 0.00058%). While the project could power 74 households per year in total, it was in need of significant resources to run, repair and upgrade the facility. In comparison, the much larger Moses-Saunders Power Dam on the St. Lawrence River matches Hogansburg’s annual power output roughly every 30 minutes. The Moses-Saunders Power Dam produces more than enough electricity to light a city the size of Washington, D.C.!
    5. The removal of Hogansburg Dam is a stepping-stone toward future conservation.
      While removing this dam does not restore the entire landscape, it is an important starting point toward meeting migratory fish restoration goals and restoring land for the Tribe. This is an opportunity for scientists, including our agency and the U.S. Geological Survey, to work with the Saint Regis Mohawk Tribe to monitor the success of the dam removal and future habitat enhancement.

Stephen Patch, senior fish & wildlife biologist at the New York Field Office, stands among the final remnants of the Hogansburg Dam. Steve has been an integral part of the dam removal. Credit: Anne Secord, USFWS.