'Hairy crab' threat to Scottish fish
An invasive crab species discovered in a Scottish river could have a "devastating impact" on salmon and trout if it spreads, experts warn.
The remains of a Chinese Mitten Crab - also known as "hairy crab" - were found in the Clyde in June.
Scientists have warned the crabs will eat fish eggs if they spread to areas where trout and salmon spawn.
The Mitten is classed as one of the top 100 worst alien species and threatens biodiversity.
It preys and on native species and causes severe structural damage to riverbanks.
The crustaceans are native to East Asia and were first recorded in the River Thames in 1935.
Dr David Morritt, an expert at the School of Biological Sciences at Royal Holloway, University of London, said: "The occurrence of these Chinese mitten crabs in a Scottish river could have a devastating impact on the famous salmon and trout fishing rivers should they manage to reach parts of the catchments where these fish spawn."
Chinese mitten crabs are named after the furry mats covering their claws.
They spend most of their life in freshwater but return to salt water to breed and travel well on land.
The remains of the mitten crab were found in the Clyde on 23 June.
Concerns have also extended to the River Tweed with anyone spotting the crabs there being asked to report it immediately.
Nick Yonge of the Tweed Foundation said they could cause major damage.
"It is very bad news - they are quite large, they are about the size of a dinner plate and they live in sea water and fresh water and they can migrate really very long distances," he said.
"If they were on the Tweed, which thank heavens they are not, they could easily migrate the whole way up the river system.
"They can cross land as well so they pretty much go wherever they want and they are big scavengers so they pretty much eat whatever they want as well."