The UK has asked people to report any sightings of Chinese Mitten Crabs. This invasive species is of great concern, and its population is believed to be increasing.
The Chinese mitten crabs are native East Asian crustaceans named after their brown furry claws that resemble mittens. Their body color can range from greenish brown to dark brown. They usually grow to 8 centimeters in length, and their legs are twice as long.
The crabs have spread all over the world in the last century. They are now an invasive species, even in Europe and North America. Crabs are usually found in freshwater habitats such as rivers and canals.
The Chinese mitten crabs are capable of causing environmental damage by digging into riverbeds, blocking waterways, and damaging fisheries gear with their sharp nails. They could also eat fish eggs and compete with native species to get resources.
Since 1935, the species has spread throughout the UK’s waters. Recently, a large number of crabs have been seen in Cambridgeshire.
The Natural History Museum runs “Mitten Crab Watch,” an initiative that encourages members of the public to submit sightings. The UK Department for Food, Agriculture and Rural Affairs encourages people to report sightings, as this can help track crab populations and prevent the spread of eggs.
The Chinese mitten crab on the Thames riverbank
The number of mitten crabs is increasing because their life cycle is unusual. Mail Online reported that Paul Clark from the Natural History Museum said this. Clark noted that each spawning could produce up to 1 million eggs.
The Natural History Museum, Welland and Deepings Internal Drainage Board, and Lincolnshire Wildlife Trust installed the first permanent Chinese Mitten Crab Trap in Pode Hole in Lincolnshire in August.
Are Chinese mitten crabs edible?
Chinese mitten crabs can be eaten. They are popular in China as a seasonal treat in the fall. They are usually steamed and served whole with vinegar. A box of eight crabs can cost up to 2700 yuan.
According to food writer Fuschia Dunlop, “the pale, velvety flesh of the crabs is delicious, but the shells hold the real treasures – the golden, voluptuous sperm of the males, and the bright, orange roe from the females, spread out lazily on top of a custardy mass of meat.”
In 2008, Clark and his co-workers published a report in which they concluded that “the mitten crab population is large enough to sustain an artisanal fishery.” The Report stated that this could lead to a reduction in the number of mitten crabs caught and bring additional financial benefits to local fishermen.
There have been concerns about the possibility of lung flukes in the mitten crabs found in the Thames Estuary. However, a study conducted in 2005 showed that these parasites were not present. Clark’s team found high levels of vibrio parahaemolyticus in Thames crabs. They warned that “consumption, particularly of the product raw or lightly fried, may pose a health risk to public”.
Crabs can accumulate dioxins, polychlorinated biphenyls (PCBs), and other pollutants in their body. Clark’s Report found high levels of these chemicals in Thames crabs but concluded that harvesting mitten crabs for culinary purposes is not discouraged.
Wood says that Bordeaux wines will continue to improve with climate change and as these weather patterns become commonplace. However, there is likely to come a point when the conditions are too hot and dry for grapes to thrive. Wood says, “we can’t know from this analysis when the failure point will occur.”
The terroir concept is supported by the chemical signature of Malbec wine
He says that vineyards will also be increasingly affected by extreme weather events such as wildfires, flooding, and hailstorms. These could destroy entire harvests.
Wood, who conducted the study, believes that other vineyards in the world that grow similar grape varietals, like Cabernet Sauvignon and Merlot, should also benefit.
He says that winemakers can use these findings to improve their wines. For example, they could irrigate the soil in winter and trim the foliage of vines to reduce the shading of grapes. They could also increase drainage or erect rain covers in the event of a wet, humid summer.