UK Crayfish vs. Invasive Crayfish: What You Need to Know.
1. Native UK Crayfish (White-Clawed Crayfish)
Species: The white-clawed crayfish (Austropotamobius pallipes) is the only native freshwater crayfish in the UK.
Habitat: It inhabits clean, flowing rivers, streams, and lakes.
Appearance: White-clawed crayfish have a pale underside and distinctive white claws.
Threats: Unfortunately, they face multiple threats, including habitat loss, pollution, and competition from invasive species.
Disease: They are susceptible to crayfish plague, a lethal disease carried by invasive crayfish.
2. Invasive Crayfish (Signal Crayfish)
Species: The signal crayfish (Pacifastacus leniusculus) was introduced from the US in the 1970s for commercial purposes (restaurants and food shops).
Spread: Accidental and intentional releases led to their rapid establishment in the wild across the UK and continental Europe.
Characteristics:
High Reproduction: Signal crayfish produce numerous offspring.
Diet: They are omnivorous, consuming detritus, aquatic plants, invertebrates, and even other crayfish.
Burrowing: Their extensive burrowing erodes river banks.
Threats to Native Species:
Competition: Signal crayfish outcompete native white-clawed crayfish over time.
Crayfish Plague: They carry a disease lethal to native crayfish.
Pollution: White-clawed crayfish populations have declined significantly due to pollution.
Control Measures:
Trapping: Baited traps are used to catch and remove signal crayfish.
Humanely Destroy: If you accidentally catch a signal crayfish, bring it ashore or into the boat for humane destruction. Do not take it home alive.
Biosecurity: Prevent transfer between waters by practicing good biosecurity (e.g., cleaning equipment, boats, and clothing).
Remember, responsible actions can help protect our native crayfish and maintain the delicate balance of our aquatic ecosystems! 🦐🌊
For more information, visit the GB Non-Native Species Sectariat website.
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