After over 200 years, the prehistoric lamprey fish, also known as the sea lamprey, has been spotted in English rivers. The last time it was seen was in 1800, and while it was not yet considered extinct, it was classified as extremely rare and endangered by the English environmental agency. For environmentalists, this is good news, but for avid river swimmers, it may be a frightening development. Lampreys are eel-like fish that have inhabited the earth for hundreds of millions of years. They are often referred to as living fossils because they lived long before the dinosaurs. The largest European subgenus of lampreys, the sea lamprey, can grow up to a meter long and has a circular mouth with sharp teeth that it uses to bite into other fish and suck their blood. Despite their appearance, lampreys require very clean water to survive.
The industrial revolution and the resulting water pollution caused a dramatic decline in lamprey populations. Additionally, newly constructed water barriers such as mills or dams made it difficult for them to swim upstream to spawn. The British environmental agency has been working to improve the living conditions of lampreys for several years by removing obstacles in their path to spawning grounds or building special lamprey ladders. These ladders allow the fish to move slowly but surely upstream using their suction mouths. It is now estimated that there are three species of lampreys that have resettled in British rivers, one of which lives permanently in freshwater, while the other two species mostly live in the sea but swim upstream to spawn. Even in the Baltic Sea, lampreys have been spotted again. However, a comprehensive return of lampreys to European waters is still unlikely, as they are still considered extremely rare and endangered.
The increased sightings of lampreys show that international efforts to protect the environment are having an impact. The return of these prehistoric fish is due to improved water quality, according to the British environmental agency. While this is good news for the environment, it may be a cause for concern for those who enjoy swimming in rivers. Nevertheless, the return of lampreys is a positive development and a sign that conservation efforts are making a difference.
