Thursday, November 22, 2012

American Eel

Anguilla rostrata
Well, it's Turkey Day here in the United States, but we've already talked about the two different Turkey species. So why not learn about one of the other critters that made an appearance at the very first Thanksgiving? Yup. Eels.

American Eels are a very common fish that have been commercially harvested for hundreds of years. Though we don't eat them too often in the States, they are still consumed across the pond in Europe. You'll find them in the Atlantic Ocean, though they often spend their early years hanging out in nearby rivers and streams.

American Eels have a complex aging process that contains 6 distinct phases and can take up to 10 years. The whole shebang starts with the external fertilization of the eggs, which are laid out in the middle of the ocean. A single female can release 30 million eggs during spawning! It is assumed that the adults die after spawning, but this is unconfirmed.

The eggs hatch after only a week, and the second life phase begins- Leptocephali. These larval eels are very transparent looking, and spend most of their life phase being carried by the currents towards to coast. This journey can take as long as 12 months! Once there, they shift to yet another phase, the "Glass Eel." At this point they are still transparent, but they look more like eels, having the distinctive elongated bodies (but the lack of skin color still gives them some camouflage).

The final three phases in American Eel life all relate in part to their coloration. Stage 4, "Elver" is where they finally start to gain skin pigmentation. Oftentimes the Elvers will move to freshwater, and will continue to grow there before reaching the fifth, "Yellow" stage. At yellow they finally have a distinct sex, and have more color in their skin. Their final stage, "Silver," is when they are finally considered sexually mature adults and are strong enough to return to the open ocean. They may not return to spawn until they are 25 years old!

Unfortunately, because they have no many life phases, in so many locations, they face a number of conservation threats. Construction of dams and other structures have caused habitat obstruction, and over-fishing and pollution are additional concerns.

IUCN Status : Not Listed
Location : Atlantic Ocean
Size : Length up to 4ft (1.2m)
Classification : Phylum : Chordata -- Class : Actinopterygii -- Order : Anguilliformes
Family : Anguillidae -- Genus : Anguilla -- Species : A. rostrata

3 comments:

  1. I wouldn't want to meet an eel when I'm swimming, but this is good to know. I wasn't aware they ate eels in Europe. That's interesting.

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  2. Fishing in Dubai Your place is valuable for me. Thanks!…

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  3. thanks for sharing.

    ReplyDelete

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