Blood-sucking vampire fish flooded many rivers in England

The swimmer was urgently alerted after a meter-long number of rocky grouper with sharp teeth reached a record on many rivers in England.

According to the Mirror, rocky grouper can attack humans on hunger, and the species is growing rapidly throughout the UK. The number of rocky grouper is recorded at a record level on the Great Ouse, Trent, Derwent and Wear rivers.

Sardines can attack humans when hungry.(Photo: Stian Alexander).

Sardines are also known as vampire fish because they kill other fish by clinging to themselves and sucking on their prey. Web sites specializing in outdoor swimming in the UK are recommending that members who regularly swim in rivers and lakes should be alert to rocky fish when diving deep.

Rocky grouper is a prehistoric fish that has existed on Earth for 360 million years. They have wide palate with strong suction force and sharp teeth arranged in many rings. The number of stalactites has decreased sharply after humans built many dams, preventing them from swimming upstream to lay eggs. The female grouper lays about 170,000 eggs per breeding season.

Rocky grouper reaches a record number on the Great Ouse River.(Photo: Hot Global News).

According to Mark Owen, an administrator at the Angling Trust, the pathways allow grouper and other fish such as eel, freshwater salmon and salmon to swim through the dam and grow in numbers."The return of grouper shows the quality of the water is improving , " Owen said.

For species like rocky grouper, migration plays an important role because migration helps them breed, feed and complete their life cycle. Measures for relocating dams and creating passageways for fish make the route from the sea to the upstream of rivers become faster and easier. The project not only benefits the fish that live in the river during the life cycle but also migrates between the river and the sea.

Stone grouper has existed on Earth since prehistoric times.(Photo: The Huffington Post).

"By increasing investment, English rivers have become cleanest for 20 years. It is through a decade-long effort to improve water quality," said Sarah Chare, head of the Fisheries Department British school, said.

As a protected species in the UK, rocky grouper plays a very important role in treating nutrients in rivers and providing food for other fish. This strange-shaped creature was once considered a luxury dish for British, Viking and Roman kings and queens. It is suggested that King Henry I of England died in 1135 after eating too many rocky grouper.