From DW Documentary.

Calico crayfish originate from North America, where people often use them as fishing bait. Nobody knows for sure just how they made it all the way to Germany, but it’s possible they were brought to Europe by Canadian soldiers stationed in Karlsruhe, where they began spreading non-stop.

They started off in ponds and small bodies of water in South-Western Germany. But now, 30 years after they first got here, they’ve been spotted hundreds of kilometers upriver. They can’t really outcompete larger predators, but in places with little competition, they’ve been hard to stop. Crayfish reproduce incredibly fast – a single female cay lay hundreds of eggs, leaving locals, scientists and conservationists scrambling for ways to stop its quick spread and preserve their local ecosystems.

#documentary #dwdocumentary #dwdocs
______

DW Documentary gives you knowledge beyond the headlines. Watch top documentaries from German broadcasters and international production companies. Meet intriguing people, travel to distant lands, get a look behind the complexities of daily life and build a deeper understanding of current affairs and global events. Subscribe and explore the world around you with DW Documentary.

Subscribe to: ‬
⮞ DW Documentary (English): https://www.youtube.com/@DWDocumentary
⮞ DW Documental (Spanish): https://www.youtube.com/@DWDocumental
⮞ DW Documentary وثائقية دي دبليو (Arabic): https://www.youtube.com/@DWDocarabia
⮞ DW Documentary हिन्दी (Hindi): https://www.youtube.com/@DWDochindi
⮞ DW Dokumenter (Indonesian): https://www.youtube.com/@DWDokumenter
⮞ DW Doku (German): https://www.youtube.com/@DWDoku

For more visit: http://www.dw.com/en/tv/docfilm/s-3610
Follow DW Documentary on Instagram: https://www.instagram.com/dwdocumentary/
Follow DW Documental on Facebook: https://www.facebook.com/dwdocumental

We kindly ask viewers to read and stick to the DW netiquette policy on our channel: https://p.dw.com/p/MF1G