Catadromous
Embed This Widget
Add the script tag and a data attribute to embed this widget.
<script src="https://cdn.jsdelivr.net/npm/fishfyi-embed@1/dist/embed.min.js" defer></script>
<div data-fishfyi="glossary" data-slug="catadromous"></div>Embed via iframe for maximum compatibility.
<iframe src="https://fishfyi.com/iframe/glossary/catadromous/" width="420" height="400" frameborder="0" style="border:0;border-radius:10px;max-width:100%" loading="lazy"></iframe>Paste this URL in WordPress, Medium, or any oEmbed-compatible platform.
https://fishfyi.com/glossary/catadromous/Add a dynamic SVG badge to your README or docs.
[](https://fishfyi.com/glossary/catadromous/)Use the native HTML custom element.
<script src="https://cdn.jsdelivr.net/npm/fishfyi-embed@1/dist/embed.min.js" defer></script>
<fishfyi-glossary slug="catadromous"></fishfyi-glossary>Definition
Describing fish that live in freshwater but migrate to the ocean to spawn, the opposite of anadromous. The European eel is the best-known catadromous species.
Ausführliche Erklärung
European eels (Anguilla anguilla) live in freshwater rivers for up to 20 years before undergoing a dramatic metamorphosis: eyes enlarge, skin silveries, and the gut degenerates as the eel prepares for a 6,000 km migration to the Sargasso Sea. The entire reproductive cycle of the European eel has never been directly observed — eggs, larvae, and spawning adults in the wild remain undocumented. Glass eel and elver stages migrate upstream from the sea in spring. Critically Endangered due to habitat loss, parasites, and barriers to migration, European eel populations have declined by over 90% since the 1980s.