As daylight lengthens and tidal waters around New York Harbor begin to warm, an incredible aquatic voyage is underway, one that is unlike any other in the animal kingdom. Can you feel the excitement?
Thousands if not millions of juvenile American eels are about to enter the bay after swimming more than a thousand miles for about a year from the Sargasso Sea, two million square miles of warm water in the North Atlantic between the West Indies and the Azores, to reach the East Coast to water bodies like New York Harbor. The juvenile eels leave Sargasso Sea as transparent larvae, less than two inches long. By the time they reach the coast, the little eels have grown to about 2 to 3 inches long and are known as glass eels.
This is part of an amazing life history. In the fall, adult eels (those that have generally lived more than 20 to 40 years and are about four feet long) migrate vast distances from the east and western Atlantic Ocean to spawn in the Sargasso Sea. This mysterious large area of warm, clear, clam water in the North Atlantic is the only sea with no shore and no fixed boundaries. Historically, ship captains tried to keep away from the Sargasso. They referred to the place as the “Horse Latitudes,” because the general calm conditions would often maroon ships for some time making the captain and crew run out of fresh water and causing people to jettison livestock over the side to lighten the ship to get sailing again.
Yet, it’s the only place in the world where the American eel reproduces. In Europe and North Africa, the same eel is known as the European eel.
It must be an amazing sight to see, even more amazing because no one has ever witnessed eels spawning in the Sargasso Sea. It’s one of the great natural mysterious of all time.
Adult eels from all over their range from Europe, North Africa, Iceland, Canada, Mexico and the United States come together to reproduce by the millions. They will travel hundreds of miles to somewhere specific in a vast patch of the Sargasso Sea, covered with drifting and floating sargassum weed, a bright gold plant that resembles seaweed, to spawn and release large numbers of eggs - the next generation; and then pass away. This mighty excursion is a one-way trip for adult eels.
The American eel is a catadromous fish, meaning it spends most of its life in freshwater or estuarine environments, but will swim to the ocean as an adult to reproduce and die. The eels leave it to future generations to carry on the existence of the species.
A mysterious strategy that must be working for juvenile eels are still entering New York Harbor every spring, as they have for countless years. Fisheries biologists, Kenneth Able and Michael Fahay, write in their book, The First Year in the Life of Estuarine Fishes in the Middle Atlantic Bight, that young eels will drift in the ocean for up to a year, during which time the Gulf Stream and other ocean currents transport the tiny eels northward away from the Sargasso Sea where they were born over six months ago. Sometime starting in February the young eels leave the ocean currents and swim fast and furious towards the coast. Glass eels are strong swimmers and as currents take them close to the continental shelf and coastal waters, they will swim toward the coast to seek out estuaries. Sometime in the spring, the little glass eels enter New York Harbor and will spread out. Some will stay in brackish water, while others will swim up small creeks and large rivers in freshwater systems, including the Hudson River, the Raritan River, the Navesink River and their tributaries.
Without any chart or navigational aid the little transparent fish, which look as clear as glass with tiny black eyes, small mouths, and red gills, generally swim into New York Harbor during a flood tide when ocean waters flow toward the shore, moving little eels rapidly inward and up into bays, tidal rivers and creeks. Once glass eels are here, they develop into elvers, which are gray to green-brown eels that are more than 4 inches in length. For the next several decades the little eels will call New York Harbor and surrounding waters home. With luck, the eels will grow longer and bigger, discover how to escape predation and will learn how to forage at night on a variety of food including small fish, fish eggs, worms, insects, clams, and dead animal matter.
At one time, the American eel population in New York Harbor and along the East Coast supported a healthy commercial and recreational fishery. According to the Atlantic States Marine Fisheries Commission, from the 1970s to the mid-1980s, commercial landings of American eel ranged from 2.5 to 3.6 million pounds. “Landings dropped to 1.6 million pounds in 1987 and have remained at low levels, ranging from 1.5 million to 700,000 pounds since then.” Recreational harvest of American eel has also been on the decline along the East Coast. Peak harvest was in 1985 at 160,000 eels, but in 2009 (the last year the Marine Recreational Information Program collected recreational data on American eel) the harvest was only around 6,000. Chat with any “old salt” around New York Harbor and they will tell you the same stories of when eels in the 1970s were crawling all over the place and how fishermen would easily harvest them for bait.
Today, while the American eel still inhabits about 75 percent of its historic range in the United States and Canada, they continue to face numerous threats to their long-term survival from overfishing, chemical contaminants and water quality, climate change, habitat loss from the construction of dams, and the increase of nonnative parasites that might be impacting their ability to swim.
To help protect the American eel population, a petition was filed in 2010 with the U.S. Fish & Wildlife Service to list the American eel as threatened under the Endangered Species Act (ESA). On October 7, 2015, the U.S. Fish and Wildlife Service announced that the American eel population is stable and does not need protection under the ESA. Instead, federal authorities recommended to states that they work to maintain healthy habitats and improve river passage for migrating eels, and continue to monitor local eel populations.
In New York State, work continues to learn more about the American eel. The New York State Department of Environmental Conservation has been monitoring eel numbers in upstate tributaries of the Hudson River since 2008 as part of the agency’s American Eel Research Project. In 2012, the program added Richmond Creek in Staten Island as a sample site.
Together with the NYSDEC Hudson River Estuary Program and the Hudson River National Estuarine Research Reserve, in partnership with the Water Resources Institute at Cornell University, the project brings together scientists, students, and local residents to collect glass eels using specialized nets, called fyke nets, and traps on Hudson River tributaries each spring. The juvenile fish are counted, weighed, and released, and other environmental data is recorded. At the end of each season the data is amassed and sent to government officials for review. Find out more about this wonderful project here: http://www.dec.ny.gov/lands/49580.html