Where have the Thames eels gone?The Thames River at one point was full of eels. The eels originate from the Sargasso Sea, and then migrate to European rivers like the Thames. They spend 20 years in the rivers before returning to the Sargasso Sea to spawn and eventually die.
Scientist regularly trapped 1,500 or more Thames eels in yearly studies. But last year, only 50 eels were caught. The eel population, according to the scientists, has dropped 98% in the last 5 years.
The migrating eels are either not coming to the Thames anymore, or are not surviving once they arrive. Scientists are not sure which, but either way the absence of the eels could have a disastrous effect on other species that depend on them as food.The Thames Estuary was considered a “biological dead zone” in the 1960s, but has made a comeback. It now supports over 120 species of fish, 350 species of invertebrates, plus hundreds of thousands of migrating wildfowl each year. The North Sea fishery depends upon the estuary as an important nursery ground for many species.
Knocking out the eels from the food chain might start a chain reaction with other species. In fact, when the Thames estuary was first coming back to life in the 1960s, it was the eels that were first to re-colonize the waters.
To explain the eels’ disappearance, scientists are looking at possible changes in oceanic currents, man-made structures such as dams, and perhaps the presence of diseases and parasites.
