Its body is covered in a slimy mucus layer and its coloration ranges from olive-brown to yellowish on the belly. They live in freshwater but migrate to the sea to spawn. Specifically, they are born in the Sargasso Sea, then drift thousands of kilometers across the ocean to European rivers, where they spend most of their lives growing and maturing. After up to 20 years, they return to the Sargasso Sea to reproduce, and then, die. Over the past few decades, European eel populations have declined significantly due to overfishing, habitat loss, pollution, and barriers like dams.

https://doi.org/10.1038/s41598-017-07650-6, August 03, 2017

Author: Laia García Casanova