European Eel

European Eel

European Eel – Introduction

The European Eel (Anguilla Anguilla) is a snake-shaped fish of which the females can grow to more than 1 meter and the males a maximum of 50 cm. This migratory fish belongs to the family Anguillidae. You can find this animal in the Atlantic Ocean, Northern Africa (Morocco), Mediterranean Sea, Black Sea, Baltic Sea, all of Europe to the north of Norway. The European Eel is also called a ray-finned fish. Its color varies from brown to grayish. This eel likes to stay in water plains with a muddy bottom.

An eel that grows in freshwater is also called ‘red eel’ and has a black to green-brown back and a white belly. In fact, the color of the glass eel changes color continuously until it is finally a silver eel and full-grown. The adult eel that returns to the sea is also called ‘silver eel’ and has silvery-white sides and larger eyes. Eels that are close to adulthood take on a yellowish color. This eel is therefore in the penultimate phase to return to the sea and to spawn there.

After their 6,000 km swim from their birthplace in saltwater (Usually in the Sargasso Sea) to their home in freshwater, they metamorphose into glass eels. The animals reach maturity after 5 to 12 years, with the females reaching maturity later than the males. If the area in which they are located has no migration potential, they can easily become decades old.

For those who are interested, I have also written an article about the American Eel.

Glass Eels on the River Bed
Glass Eels on the River Bed

Depending on food availability, the eels continue to migrate upstream, up to hundreds of kilometers inland.

During the day, the eels hide between water plants, stones, hollow banks, or burrow themselves. The eel does the digging in the soil with a
corkscrew-shaped movement, tail first. At night they start to hunt. It is, therefore, better to fish for eel in twilight or at night. Their prey consists mainly of aquatic invertebrates such as small fish, water lice (Asellus aquatics), and carrion shrimp (Mysidae). They mainly hunt macrofauna, mosquito larvae, mosquito pupae, bivalves such as zebra mussels and the exotic clams, amphipods, and other small invertebrates.

Some say the eels are corpse eaters but that is absolutely not true! The eel does eat dead carrion but only fresh dead carrion. His food consists of what was mentioned above. It is also recommended to go fishing for eel with small lobsters.

Later (end of summer until beginning winter), the eels swim 6000 km back to the sea where they spawn at a great depth (100 – 200 m). They usually arrive there in October. During this trip, they make use of the ocean currents. The migration takes several months and the eels survive on their own fat reserves. After spawning, the parent animals die.

The larvae of the eel thus originate in the Sargasso Sea (or in its periphery). Their appearance resembles a willow leaf and is flattened. A little later they migrate to continental plateaus where they transform into glass eels (metamorphosis). The moment that these glass eels then move further from the salt to the freshwater depends on the water temperature. They are then between 1 and 3 years old. The migration takes place mainly at night and at high tide. They then move on via the inland flood current. With a favorable flood current, the glass eels cover a distance of 2.5 km per hour.

Larva of the Eel (Leptocephalus)
The larva of the Eel (Leptocephalus)

Eel is mainly fished for human consumption and is therefore also commercially important. Unfortunately, the eel is under serious threat and that is why this fish is on the International Red List of Threatened Animals by IUCN, the International Union for Conservation of Nature. The eel stock may still recover but will take a very long time due to the long generation time and low stock of parent stock. There could even be a total ban on eel fishing. It is even recommended to start breeding eels to prevent extinction. That is why many eels are released in streams, ponds, and lakes that have no outflow to the sea. In this way, these eels continue to breed in captivity.

There are also more and more built obstacles that make migration more difficult and here and there lead to the loss of beautiful habitats for the eel. Dams in particular are a major problem.

European Eel – Some eel species

Red Eels (Anguilla Anguilla)
Red Eels (Anguilla Anguilla)
Silver Eel (Anguilla Anguilla)
Silver Eel (Anguilla Anguilla)
American Eel
American Eel (Anguilla rostrata)
Clown Snake Eel (Ophichtus Bonaparti)
Clown Snake Eel (Ophichtus Bonaparti)
European Conger Eel (Conger Conger)
European Conger Eel (Conger Conger)
Moray eel in the Maldives (Muraenidae)
Moray eel in the Maldives (Muraenidae)
Electric eel at the New England (Gymnotidae)
Electric eel at the New England (Gymnotidae)
Spotted Garden Eel (Congridae)
Spotted Garden Eel (Congridae)
Greyface Moray Eel (Muraenidae)
Greyface Moray Eel (Muraenidae)
Giant Mottled Eel (Anguillidae)
Giant Mottled Eel (Anguillidae)

European Eel – External characteristics of the eel

Eels look like serpents and have very slimy skin. There is only a dorsal fin that extends to the tip of the tail to connect there with the anal fin. These fish do not have pectoral fins.

They have a wedge-shaped head that is pointed and flattened upwards. It is also noticeable that the lower jaw is longer than the upper jaw. Unlike the conger eel where the upper jaw is longer than the lower jaw.

Their tiny gill openings that they can close keep the gills moist long enough if they decide to make migratory movements across the land.

Furthermore, the eel has 2 pairs of nostrils. At the front on the tip of the nose and then also just under the eyes where the water can leave the nose again.

By sight, you could say that the eel has no scales, but they are indeed present but in the deeper layers of the skin. Their smooth, slimy skin makes them difficult to handle. Many fishermen can confirm this. When they land in the grass, they can quickly run away with their wild twisting movements.

Eel in the food chain

I do not know how eel is prepared and/or consumed in other parts of the world or countries, but in Belgium, the recipe “Eel in the Green” is much in demand. In the Netherlands people prefer “Smoked Eel“. The eel must be skinned for the Belgian dish and the eel is simply smoked at the Dutch dish. It is also partly because of this popularity for eating eel that this species is threatened by extinction.

But eating eel or other types of predatory fish, the Flemish government in Belgium does not advise people to do so. Since these fish live in the vicinity of polluted bottom sludge, they also ingest toxic substances. PCBs (Polychlorinated biphenyl), heavy metals (such as lead), and pesticides are often found in these animals. Some eels also eat contaminated other fish. Some substances can even be carcinogenic.

It is therefore very important not to eat your own catch and it is recommended to only eat farmed eels or eels from waters other than the major rivers. Normally packaged eel should state whether it is farmed or wild eel and which country it comes from. Even with fresh fish, you also have the right to ask where the eel was caught; the fisherman is obliged to say this when asked about it. There is strict action against companies that violate the rules.

Often the young glass eels are caught for further cultivation in aquaculture until they reach maturity and can be consumed. Glass eels are considered a delicacy mainly in Spain and the south of France. Most eels are eaten in Europe, China, and Japan.

Eating healthy eel, on the other hand, is considered by scientists to be good for the brain, heart and blood vessels. The healthy omega 3 fatty acids ensure that. Be careful with the cholesterol. Smoking eel is also not recommended because the fatty acids then become saturated.

The senses of the eel

There is only one sense in the eel that arouses excellently and that is its sense of smell. In contrast to the terrible hearing and sight. This sense of smell is especially useful during the growth phase of the eel: from glass eels to red eels to silver eels. Their sense of smell rivals a dog’s sense of smell. They are also believed to use it to socialize. Silver eels then use their sense of smell to detect the salinity in the seawater when they migrate to spawn.

How can eel be fished?

As mentioned before, the eel is only really active in the twilight and during the night. But there are also fishermen who say that it is better not to fish at a full moon because they believe that this would reduce the activity of the eel. True or False? They like to stay at sheltered places, weirs, and other water inlets where the water is rich in oxygen. In my place (Belgium) and in the Netherlands the eel is not active from November to March.

The bait used must be fresh to stimulate the eel’s sense of smell. Examples include maggots, meatballs, roach, cheese, and luncheon meat.

Eel farming

In order to prevent the extinction of the eel, it is, therefore, necessary to breed them. In Japan, they have been actively involved in this for their own Japanese eel since 1974. This is done on a very small laboratory scale. Yet eel larvae are born there every Friday. For this purpose, Japanese scientists have developed a special artificial food for the eel larvae.

Japanese Eel (Anguilla japonica)
Japanese Eel (Anguilla japonica)

No one has ever seen the birth of an eel, so it is not known what the larvae eat. Therefore, the exact artificial food is sought further. Once that is in place, the eel can be farmed commercially from start to finish. Unfortunately, there is no financial support for such specialized studies in most countries.

In 2007 France and Denmark launched their breeding program, but it appears to be unsuccessful there.

Enemies of the eel

In fact, the eel has only 3 serious enemies and they are the heron, the cormorant, and … the human.

Cormorant (Phalacrocorax carbo)
Cormorant (Phalacrocorax carbo)
Grey Heron (Ardeidae)
Grey Heron (Ardeidae)
Fisherman (Homo sapien) with eel catch
Fisherman (Homo sapien) with eel catch

Finally

Hopefully, you learned something from reading this article. As always, you can ask me questions, send me additional information, or request more information below. Thank you for your attention.

For those who are interested, I have also written an article about the American Eel.

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