American Eel

Anguilla rostrata

Last updated: October 3, 2022
Verified by: AZ Animals Staff

Don't eat raw eel! Their blood is poisonous to humans when consumed raw.

American Eel Scientific Classification

Kingdom
Animalia
Phylum
Chordata
Class
Actinopterygii
Order
Anguilliformes
Family
Anguillidae
Genus
Anguilla
Scientific Name
Anguilla rostrata

Read our Complete Guide to Classification of Animals.

American Eel Conservation Status

American Eel Locations

American Eel Locations

American Eel Facts

Prey
insect larvae, fish, molluscs, bivalves, crustaceans, insects, worms, frogs, plants
Name Of Young
Leptocephalus, glass eel, elver, yellow eel
Group Behavior
  • Solitary
Fun Fact
Don't eat raw eel! Their blood is poisonous to humans when consumed raw.
Estimated Population Size
700,000
Biggest Threat
Human activity
Most Distinctive Feature
Long, snakelike body
Other Name(s)
Atlantic eel, black eel, Boston eel, bronze eel, common eel, freshwater eel, green eel, little eel, river eel, silver eel, slippery eel, snakefish
Gestation Period
Unknown
Litter Size
750 eggs
Habitat
Freshwater, estuaries, Atlantic Ocean, Sargasso Sea
Predators
Fish, bad eagles, seagulls, large waterfowl
Diet
Omnivore
Common Name
American Eel
Number Of Species
1
Location
East coast of North America
Group
Solitary

American Eel Physical Characteristics

Color
  • Brown
  • Yellow
  • White
  • Green
  • Dark Brown
  • Silver
  • Light Grey
  • Dark Grey
Skin Type
Scales
Lifespan
15-20 years
Weight
Up to 17 pounds
Length
Up to 4 feet
Age of Sexual Maturity
1-4 years
Age of Weaning
Immediately after birth
Venomous
No
Aggression
Low

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View all of the American Eel images!



The American Eel is the only eel found in North America. Don’t confuse it with a water snake! It does have a long and thin body like a snake, but it is actually a fish. American Eels look slimy because they are covered in a layer of mucus. This slippery layer helps prevent infections from parasites, allows them to slip through small spaces easily, and helps them escape a predator’s grip.

5 American Eel Facts

  • American Eels live in freshwater for most of their lives, but when they get old enough, they make a long journey to the Sargasso Sea in the Atlantic Ocean to spawn.
  • American Eels die after mating.
  • A female American Eel can lay up to 4 million eggs.
  • Never eat an American Eel raw! Their uncooked blood is poisonous to humans.
  • The oldest American Eel ever found was about 43 years old.

American Eel Classification and Scientific Name

The scientific name of the American Eel is Anguilla rostrata. However, it also has many regional colloquial names including snakefish, Atlantic eel, Boston eel, black eel, bronze eel, common eel, freshwater eel, green eel, little eel, river eel, silver eel, or slippery eel.

The American Eel is in the order called Anguilliformes, which encompasses all eels. There are eight suborders of eels as well as 19 families and 111 genera under the order of Anguilliformes. Overall, there are around 800 species of eels worldwide.

The American Eel is in the family Anguillidae which includes other freshwater eels like the European eel, the Japanese eel, and the New Zealand longfin eel. There are 19 existing species of Anguillidae today.

American Eel Appearance

The American Eel goes through five distinct phases of life once it has hatched from an egg. Each phase has a different name and appearance.

1. Leptocephali

This is the first stage of life for the American Eel. These tiny larvae are fully transparent and less than 5 millimeters long. They are essentially flat with a pointy head. They have tiny teeth that point forward from their body. These teeth fall off as they get older. You can see their simple organs through their transparent body. They grow at a rate of .21-.38 millimeters each day.



2. Glass Eel

After about 200 days, the leptocephali grow into a glass eel. This happens when the leptocephali are between 55 and 65 centimeters long. They are still transparent but have a more recognizable eel shape. This phase encompasses the full stage of changing between leptocephali and the next, pigmented phase of life. Glass eels are often around 3 inches long.

3. Elver

Once the glass eel has grown enough, it starts to get dark pigmentation. At this stage, there is no difference between males and females. Elvers are between 4 and 6 inches long.

4. Yellow Eel

American Eels are still sexually immature in this phase. They have a yellowish color and a white, cream, or light yellow underside. Yellow eels living in freshwater tend to grow larger than those in estuaries, which are where saltwater and freshwater mix together. They live the majority of their lives in this stage. A yellow eel is considered to be any eel that is over 6 inches long. Once the eel is 3-5 years old, they also grow small scales.

5. Silver Eel

When the eel reaches sexual maturity, it turns grey with white or cream on the underside. Their pectoral fins get bigger, their eyes get larger and they get more fatty than ever before. This prepares them for their great migration to the ocean to spawn. In this phase, they can be up to four feet long and weigh up to 17 pounds. Females are often larger than males. Females are also more lightly colored. Experts believe the changes in color and physiology help the eels survive in the ocean. In the yellow eel phase, they are more adapted to survive in freshwater and estuaries.

American eel
The long, sleek body of the American eel can be up to four feet long.

IrinaK/Shutterstock.com

American Eel Distribution, Population, and Habitat

In 2002, the Atlantic States Marine Fisheries Commission (ASMFC) estimated that there may be as few as 700,000 American Eels in the wild. Experts estimate that their population declined a lot in the 1980s and 1990s, but that they have been stable in the 2000s. However, they also say that there may not be enough recent studies that focus on American Eels to determine their current population levels. The American eel’s conservation status is endangered, which means that the species could become extinct soon.

The American Eel is found all along the Atlantic Coast of North America and islands large and small surrounding it. They are found in Greenland, on the entire East Coast of Canada and the United States, and down into the Gulf of Mexico all the way down to Panama. They are also found throughout the West Indies as far south as Trinidad.

Their habitat changes throughout their life cycle. They are born in the Sargasso Sea, a special area off the east coast of the US where four ocean currents circulate, creating a unique area. From there, they spend up to a year traveling to freshwater and estuaries.

Once they are there, they hide in branches and shelters towards the bottom of the water. They can live in rivers, lakes, and streams. However, they can also live in ocean bays, estuaries, and the ocean itself.

If an area becomes less desirable, an eel can travel through small waterways or even wet grass to find a better location. American Eels may stay in freshwater in the winters and then travel to brackish water like an estuary or bay to feed in spring and summer.

American Eel Predator and Prey

American Eels have a different diet depending on which phase of life they are in. In all phases of life, they are mostly nocturnal and eat at night. They have a great sense of smell and use that to find their meals. They are technically omnivorous but mostly eat other animals in whatever aquatic environment they are in.

1. Leptocephali

It is not fully known what leptocephali eat. Some experts believe that they eat marine snow, which is waste that falls from the top of the ocean to the bottom. They may also eat fecal matter and other small particles in the ocean.

2. Glass Eels & Elvers

Glass eels and elvers may eat small insects or insect larvae.

3. Yellow Eels

Yellow eels eat other animals in their marine environment which may include other fish, snails, mussels, or frogs. They also eat plants. What they prefer to eat depends on their size. Smaller yellow eels eat insects and smaller prey. Larger eels eat fish and larger prey.

4. Silver Eels

Silver eels do not eat. They make their journey to spawn and die shortly after.

American Eel Predators

The largest predator of the American Eel is likely humans. While eel is not a hugely popular dish in American cuisine, in other countries, like England, Japan, and Korea, it is a highly desirable food. Because of this, American Eels are caught in many life stages. When they are caught as glass eels they are often sent to other places, where they are then grown until they are large enough to be eaten.

In general, large fish likely eat American Eels in their smaller phases. Predators include largemouth bass and striped bass, who may feed on American eels in the elver stage, or as small yellow eels. Larger yellow eels have been known to eat glass eels. Bald eagles, seagulls, and other birds that eat fish are other predators. Rainbow snakes, also known as eel mocassins, feed almost exclusively on American eels.

Another threat to the American Eel is habitat reduction or changes. Constructions of dams can inhibit their travel back to the Sargasso Sea for reproduction. Dredging of rivers and lakes can affect the habitat and food sources available. Otherwise, while they are a rather hearty species that can survive in a variety of temperatures and habitats, they are more sensitive to contaminants like heavy metals in the water. They have a higher fat content than some other fish species, so the toxins can accumulate in their bodies more, affecting their life cycle.

American Eel Reproduction and Lifespan

American Eels can live up to 40 years. They can also live for as few as 5. They live longer if they spend time in freshwater as an adult.

Once they get to the silver eel stage, they travel back to the Sargasso Sea where they were born. Female American Eels lay up to 4 million floating eggs. Then males come close to females and release sperm. However, no one has ever observed eel reproduction in the wild or found any species of freshwater eels’ breeding grounds. The only information scientists have about it is based on lab observations.

American Eel in Fishing and Cooking

If you remember one fact about American Eels, it should be this one: never eat raw eel! The blood is poisonous to humans when raw. When eel is cooked, it is no longer toxic. Their blood contains a toxin that causes extreme muscle cramping, including the body’s most important muscle: the heart.

Eels are very popular in Japanese cuisine. If you’ve ever had an unagi sushi roll, you’ve had eel! Japan consumes 70% of the world’s annual catch of eels. Kabayaki is another Japanese preparation of eel in which the fish is marinated in sweet soy sauce and broiled on a grill. Another popular Japanese eel dish is unadon, a bowl with rice topped with kabayaki.

Eel dishes, like jangeo-gui, or grilled eel, are also popular in Korean culture. Several regions of Vietnam have different styles of eel soup as a delicacy.

Eels are also popular in European countries. Jellied eels became a popular dish in England during the 1700s. In Belgium, eels are eaten in a green herb sauce with bread to dip in it. Additionally, smoked eel is eaten in many European countries like Germany and Poland.

Elvers used to be a cheap meal for fishermen. However, as eel populations of different species have declined worldwide, they are now an expensive delicacy. In Spain, a dish called angulas consists of elvers sauteed in olive oil with garlic and chili pepper. This dish can run up to $100 for a small serving these days.

It is interesting to note that Jewish people who keep kosher do not eat eel. In the Old Testament, it says that it is OK to eat fish in general, but that eel are an abomination and should not be eaten.

In addition to being caught for food, they are also caught to be used as bait for other fish.

What Does Eel Taste Like?

Freshwater eels have a soft, flaky texture. Many people say they taste a bit like crab, with a sweet aftertaste. However, others say it tastes more like squid. Some people feel that eel is bland, but when it is prepared with herbs, spices, or sauces, others think it tastes great.

Eel Nutrition Facts

100 grams of eel contains:

  • 236 calories
  • 15 grams of fat including:
    • 3 grams of saturated fat
    • 9.2 grams of monounsaturated fat
    • 1.2 grams of polyunsaturated far
    • 838 milligrams of omega-3
    • 251 milligrams of omega-6
  • 23.7 grams of protein
  • 0 grams of carbohydrates

Fishing American Eels

One of the reasons for the decline of the American Eel is fishing. Greenpeace has the American Eel on its “seafood red list,” due to the fact that they believe the majority of American Eels available in stores are not acquired with sustainable practices. Each state in the US has different rules about fishing eels. The rules may include size restrictions, when the eels can be caught, and restrictions on how many you can catch in one day. For example, in Massachusetts, you may only catch eels longer than 9 inches, and you can only take home 25 per day.

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About the Author

I'm a freelance writer who has been working in the field of content creation and digital marketing for more than seven years. My favorite topics to write about include health, animals, fitness, and nutrition, though as a professional content provider and ghostwriter, I can easily write about pretty much anything! I love all animals and have been some form of vegetarian or vegan for over 10 years. My favorite animals are cats, dogs, and chickens, especially my own cat, Tula.
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American Eel

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Sources
  1. US Fish and Wildlife Service, Available here: https://www.fws.gov/species/american-eel-anguilla
  2. Canadian Wildlife Federation, Available here: https://www.hww.ca/en/wildlife/fish-amphibians-and-reptiles/american-eel.html
  3. NY Department of Environmental Conservation, Available here: https://www.dec.ny.gov/docs/remediation_hudson_pdf/hrlpk3eel.pdf
  4. Maryland Sea Grant College, Available here: https://www.mdsg.umd.edu/onthebay-blog/american-eels-population-fishery-and-poaching#:~:text=These%20are%20typically%20yellow%20eels,eels'%20status%20%E2%80%9Cdepleted.%E2%80%9D
  5. Mississippi State Univeresity, Available here: https://www.cfr.msstate.edu/wildlife/fisheries/pdf/AmericanEel.pdf
  6. Florida Fish and Wildlife, Available here: https://myfwc.com/research/freshwater/species-assessments/american-eels/faq/#:~:text=Reported%20landings%20of%20American%20eels,landings%20reported%20for%20southern%20states.
  7. National Park Service, Available here: https://www.nps.gov/lowe/learn/nature/americaneel.htm
  8. Connecticut Dept. of the Environment, Available here: https://portal.ct.gov/DEEP/Fishing/Freshwater/Freshwater-Fishes-of-Connecticut/American-Eel#:~:text=Small%20(3%2Dinch)%20juveniles,Size.
  9. Sustainable Fisheries, Available here: https://sustainablefisheries-uw.org/american-eel-endangered/

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