Rare crayfish back in wild after drought rescue

A close-up scene of a person carefully measuring a small, dark brown crayfish. The individual is holding the crayfish in one hand while using calipers with the other hand to determine its length. The measurement is being conducted over a yellow plastic bucket that contains water. The setting appears to be outdoors, as the background includes green foliage and natural ground elements.Image source, Environment Agency
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The rescued crayfish have been released back into the wild

  • Published

Endangered crayfish rescued from a drying watercourse have been released back into the wild.

More than 30 white-clawed crayfish, including 21 egg-carrying females, were removed from a beck in Burley in Wharfedale, West Yorkshire, in July because they were struggling due to the drought.

The adults, along with 30 juveniles that hatched during quarantine, have now been released into a tributary of the River Wharfe.

Tim Selway, a biodiversity specialist and crayfish expert at the Environment Agency, said: "We're hoping this population will breed and support the long-term future of the species."

According to the agency, the species is the UK's only native freshwater crayfish. The crustaceans play an important role in keeping waterways clean and as a source of food for other native species.

White-clawed crayfish used to be common across Yorkshire, but have lost out to the larger, more aggressive American signal crayfish.

The Wharfe catchment has long-established and extensive populations of the invasive signal crayfish, which puts the native species at risk.

A small crayfish in a shallow, clear body of water. The crayfish is slightly off-center and appears to be either resting or moving across the rocky bottom. The water is transparent enough to reveal a mix of brown and tan stones beneath, along with some greenish algae or aquatic plant matter.Image source, Environment Agency
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About 60 eggs hatched in quarantine, the Environment Agency said

The previously unknown population of white-clawed crayfish in Burley was reported by local resident Scott Davies, who noticed the crustaceans in distress.

He alerted the Environment Agency, whose fisheries team carried out an emergency rescue of 32 adults and quarantined them at York Gate Gardens, near Leeds.

About 30 more juveniles are being kept in quarantine until they grow large enough to be released.

Two pairs of hands engaged in a close-up activity involving a piece of burlap fabric held over a yellow container. The hands on the left are gently holding the fabric in place, while the hands on the right are carefully examining juvenile crayfish. The yellow container beneath contains a small amount of water.Image source, Environment Agency
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The Environment Agency released 30 juveniles, together with 32 adult crayfish

Mr Selway said: "This location has been chosen as it is already a known safe site for native crayfish in the Wharfe, as a barrier in the river prevents the invasive American signal crayfish from reaching them.

"Finding this unknown population was great news, and this will help to support native crayfish conservation work in Yorkshire."

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