YouTuber Barny Dillarstone Films Invasive Species in London's River Thames

Key facts

• YouTuber Barny Dillarstone dropped cameras into the River Thames and its adjacent dock systems in Central London.
• The River Thames is a tidal river, making it murky and a difficult place to film due to constant sediment movement.
• Dillarstone previously dropped cameras in the Indo-Pacific region.
• He filmed a freshwater mussel jetting water, which it does for reproduction, feeding, and waste removal.
• He found signal crayfish, an invasive species first introduced to Europe in the 1960s after being bred on farms for restaurants as a delicacy.
• Signal crayfish burrow deep into riverbanks, causing erosion and collapse, and outcompete native species like the white-clawed crayfish.
• During daytime filming, he captured pikes, a barbel, river chub, silverfish, perch, and an enormous Thames carp.
• At night, he glimpsed a Chinese mitten crab, a furry, clawed crustacean from Asia that is silently eroding riverbanks and outcompeting native species.
• He eventually recorded a large barbel up close, confirming that infrared cameras are discreet enough to film big freshwater fish at night.
• Dillarstone plans to continue discovering the secrets of big rivers.