ArabiaWeather - The first trap to catch Chinese mitten crabs was installed in Britain as the numbers of this strange species increased. Mitten crabs, which first appeared in the UK in 1935, have recently appeared in several areas of Britain, including London and Cambridgeshire, and have even made their way into gardens in the south-west of the capital, embankments in Whittlesey, and country gardens in Peterborough.
This type of crab, known for its furry claws, is believed to have moved from eastern China to Europe and North America via sediment accumulated at the bases of cargo ships. It is also believed that the Chinese mitten crab settled in the River Thames in 1973, and has spread further afield since then. Then, like the rivers Tyne, Humber, Medway, Wharfe, Ouse, Tamar and Dee.
Since 2016, the species - named after its furry claws - has been classified as 'widespread' across the UK and according to the Natural History Museum's 'Mitten Crab Watch' initiative, more than 800 reports have been recorded so far. ; Which indicates the spread of this creature throughout the United Kingdom, and the interactive map showed that crab sightings have been confirmed in various areas of Britain, including London, Newcastle, Manchester, Swansea, Glasgow and Brighton.
It can be distinguished from the crab by its body color, which ranges from gray-green to dark brown, and the thick, brown fur on its white-tipped claws.
Dr. Paul Clarke, an expert in the field of Chinese mitten crabs and a researcher in the Department of Life Sciences at the Natural History Museum, in an interview with Mail Online, pointed out that the increasing numbers of Chinese mitten crabs are due to their very unique life cycle.
After their migration to the riverbed, adult females have the ability to produce three eggs each mating season, and the number of eggs in each hatching process can range between 500,000 and one million eggs , and this is the number of larvae that separate from them and hatch in the river mouth and of course, Not all of these larvae will develop into small crabs capable of returning to the stream again, and Dr. Clark noted that once this species becomes established, it becomes increasingly difficult to control its spread.
The first permanent Chinese mitten crab trap has been installed at Pode Hole in collaboration with Lincolnshire Wildlife Trust, Welland and Deepings Internal Drainage Board and the Natural History Museum.
Mick Henfrey, who works on the Welland and Deepings Inland Drainage Board, built the trap and the Welland Board donated around £8,000 to set up the device. The trap was installed on August 31, and so far they have not caught any Chinese crab. Dr. Clark suggests this may be due to the warm weather , but he is not sure.
The trap works similar to a letterbox, trapping the mitten crabs inside until they are extracted and transported to do their studies. Based on Dr. Clarke's estimates, if he drove to the Chelsea Embankment in London, he might be able to catch about 50 to 100 baby crabs in an hour.
Dr Clark says Chinese mitten crabs have “very few natural enemies” , perhaps a few exotic creatures and some birds, but he doubts this will reduce their numbers.
When asked if Chinese mitten crabs pose a threat to native crab species, Dr. Clark replied:
“Yes, they feed on native species in and out of the water.”
“We were very concerned about its effect on fish eggs, and we fed them some of the fish eggs, and they did not hesitate to eat it.”
“There may be a negative impact on biodiversity in the Thames and other areas, but it is difficult to verify at the moment.”
At present, it is not known specifically what Chinese mitten crabs feed on, and Dr Clark noted that crabs caught in the trap will be frozen and preserved for analysis, which could help to understand their feeding pattern.
He stressed that no glove crabs will be released again in the region. He added:
“There is a possibility that over the coming years we can reduce the impact of these crabs in this aquatic community.”
The Natural History Museum confirmed that mitten crabs can reach sizes up to the size of a dinner plate, and Dr. Clark noted that he had a mitten crab with a body width of 85 mm (8.5 cm), which indicates their large size.
The giant Chinese mitten crab poses an environmental challenge to Britain, and confronting it requires joint efforts by government, researchers and the public, and a good understanding of its impact on the conservation of Britain's biodiversity and environment.
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