Stop fishing to help European eel

The European eel has always been a popular food fish, but it is now threatened with extinction. That is why assemblages of small transparent, glass-like snakes are closely monitored. Meanwhile, the number of glass eels on European coasts has fallen so sharply that the International Council for the Exploration of the Seas (ICES) has recommended a complete moratorium on eel hunting for the first time.

European eel (Anguilla anguilla) makes an impressive journey in its life path: from its place of birth in the Sargasso Sea in the Atlantic Ocean, fish larvae migrate more than 5,000 km with the Gulf Stream to the European coasts. Meanwhile they have evolved into tiny transparent glass snakes, the animals reaching estuaries. Many of them continue their journey there upstream in fresh water. Years later they returned to the sea and the Sargasso Sea, as the silver eel is called, to lay eggs and die.

The eel population has decreased dramatically

But this migration, along with hunting small eels in particular, has brought the fish to the brink of extinction. Migration barriers such as hydroelectric power stations and dams make it difficult for snakes to reach their habitats and spawning grounds. As a result, the European eel is now listed as Critically Endangered by the International Union for Conservation of Nature (IUCN). This classification is based on regular controls of glass eel stocks at more than 50 sites along European coasts. They show that their number has steadily decreased, especially since the beginning of the eighties. In 2011, eel stocks reached an all-time low and have stagnated at that level ever since.

For conservationists and fisheries scientists, there is a warning sign: “If the number of young fish remains at a low level over a longer period of time, this is a sign of an insufficient number of parent animals or of unfavorable environmental conditions,” explains Reynolds Haanel. , President of the Thunen Institute for the Environment of Fisheries in Bremerhaven. If the glass eel has shrunk, this indicates that very few full-grown eels have started migrating into the Sargasso Sea and have survived. However, if they are absent, the population is unlikely to recover.

It is recommended to stop – also to reposition

In response to declining eel numbers, the International Council for the Exploration of the Sea (ICES) some time ago recommended that eel fishing and other potentially harmful effects on the river and marine environment be reduced as much as possible. Now the council has stressed this again: in its fishing recommendations for 2022, it is clear for the first time that it supports a complete halt to eel hunting in all habitats. This recommendation is based on the continuing decline in the incidence of juvenile eels. In 2020, its population in the North Sea region was only 0.9 percent compared to values ​​in the 1960s and 1970s. In the rest of Europe the ratio is 7.1.

“This development does not allow for any further conclusion and the recommendation is only logical, even if it is belated,” comments Hanel. He also considered the recommendation of the International Fish Farming Council to include removal of glass eels as a basis for aquaculture and their transfer to lakes and rivers, as positive. This implementation, which is practiced in many places, is aimed at replenishing local stocks in lakes and rivers. Unlike salmon, which can be incubated artificially, this does not add any animals to the total population. In addition, some of these snakes die when they are moved from the coast to inland waters and the risk of developing diseases and parasites increases, Handel explains. So it’s doubtful if this was an ancestor’s protection measure.

However, it remains to be seen if and how the current recommendation from the International Council for the Exploration of the Sea will be implemented. This is because marine waters are already the responsibility of the European Union under the Common Fisheries Policy, but inland fisheries are a matter of the federal states. So it is still not clear if we can agree on comprehensive protection for this threatened species.

Source: Johann Heinrich von Thunen Institute, Federal Research Institute for Rural Areas, Forestry and Fisheries; ICES publication, doi: 10.17895/ices.advice.7752

© natur.de – Nadia Podebrigar