The Outside Story: American eels on the move in fall | Weekend magazine
Cool fall temperatures signal many changes. Among the less visible, but the most incredible, is the migration of the American eel.
Somewhere right now, at the bottom of a lake, pond or river, an American eel is about to leave the home it has known for three, 13, or maybe even 30 years. . Her yellowish skin turned silver, her eyes and nostrils widened to absorb more sights and smells, her body became strong with muscle and fat. She’s ready to go.
A few hours after sunset, she will begin her journey of more than 1,000 miles over rain-swollen rivers to the ocean. She will travel against the tide, returning to the hot, grassy oceanic whirlpool known as the Sargasso Sea. There, among millions of her fellows, she will mate, release millions of eggs and die.
Scientists have yet to document the spawning phenomenon of the American eel, which takes place somewhere in or around the Sargasso Sea. Exactly where one of the world’s great mysteries remains. The researchers tried to tag the eels, to follow the larvae, to search the sea with nets, all without success. What they do know is that eel larvae float near the ocean surface, somewhere between Bermuda and the Azores, and are washed away by currents, including the Gulf Stream.
More than a year after the silver eel left her home one fall night, her young will undergo a metamorphosis, from drifting larvae to tiny “glass eels” capable of swimming. As they approach the coast, perhaps smelling the earth – a smell of the forest beyond – they move upstream, now transforming as they become “yellow” eels. Some will stay in bays and estuaries while others will continue, riding high tides on darker nights, moving up rivers in spring and summer to distant lakes, ponds and reservoirs.
American eels are believed to occupy the widest range of habitats of any fish in the world. They extend along the coasts of the Atlantic, the Gulf and the Caribbean, from Labrador to Venezuela. Historically, the species lived throughout Maine, New Hampshire, Vermont, and most of New York State, including Lake Ontario, but Niagara Falls prevented them from reaching Lake Erie and the Upper Great Lakes. They live in salt water and cool, fast and still, hot and cold. Unlike salmon and other anadromous fish, they are not loyal to the particular habitat from which their parent comes. The eels that travel the farthest are usually females.
During the day, they burrow in the mud, wallow in the sand, hide among aquatic plants, and hide behind rocks and fallen trees to avoid predation from eagles, ospreys, loons and otters. . They wait until night to eat, feeding on a wide variety of worms, insects, clams, crayfish, frogs and fish.
Eels are also food for humans. A 5,000-year-old eel dam on the Sebasticook River in Maine suggests a long history of fishing in the area, and eels remain important to the Wabanaki people today. Eel recipes can be found in New England cookbooks from the 19th and 20th centuries. Today, in some places, yellow eels are fished with baited traps and (usually accidentally) caught by anglers. In the rivers of Maine, there is a net fishery for young elvers and elvers, which are shipped to Asia and raised in aquaculture ponds, only to be sold as kabayaki and unagi.
Although eels continue to live in most of their historic range, their abundance has declined. Their habitat has been destroyed and polluted, the ocean currents they depend on are shifting due to warming temperatures, and dams are blocking their migration. Turbines in hydroelectric dams are particularly lethal to eels moving downstream.
Pressure from fishing, lack of safe passage to dams, and reduced abundance in much of the eel’s range have led to petitions to the US Fish and Wildlife Service to consider legal protections for the American eel. In 2007 and 2015, the agency found that listing in the Endangered Species Act was not warranted, although since then the Atlantic States Marine Fisheries Commission has determined that the eel population America remained depleted, with persistent downward trends being “a cause for concern”. The International Union for the Conservation of Nature includes the American eel on the “Red List” of endangered species.
American eels are less common than they once were, but they remain widespread. Among the many gifts exchanged between the northeastern forests and the sea, the eel is worthy of attention, especially now, as it glides downstream, silvery in the darkness of the autumn night.
Catherine Schmitt is a science writer and author of “The President’s Salmon: Restoring the King of Fish and its Home Waters”. The Outside Story is attributed and edited by Northern Woodlands magazine and sponsored by the Wellborn Ecology Fund of the New Hampshire Charitable Foundation.