New eel habitat makes Copenhagen Harbor the world’s first eel sanctuary

WWF Denmark and public entity By & Havn now take a big step towards eel conservation in Denmark by creating more eel habitat in Copenhagen Harbor for this critically endangered species. Combined with existing initiatives, this will make the harbor the world’s first eel sanctuary. WWF Denmark also recommends a complete ban on eel fishing in all of Denmark as well as restoration of destroyed eel habitat.

© Jonas Lysholdt Ejderskov, WWF Denmark

The number of young eels—so-called glass eels—that enter Danish waters via ocean currents is down to 0.6 percent compared to the 1980 levels. Hence, the European eel is now on international nature conservation organization IUCN’s Red List of critically threatened species.

Together with By & Havn, the public entity responsible for development of Copenhagen Harbor, WWF Denmark want to turn this development around. The parties now lay out eel pebbles at former dockland area Teglholm in the southern part of Copenhagen Harbor. More specifically, 800 tons of pebbles with a diameter of 16 to 32 millimeters are placed on the bottom of the harbor.

The project aims to create more habitat for juvenile European eels that need hiding places such as cavities until they grow older and bigger. In addition, 200 old brick pipes are placed in the harbor so adult eels can also find shelter.

“It is a fantastic day for juvenile eels below the surface. They get more high-quality habitat and thus better surroundings to grow bigger and get more robust. We expect this initiative to strengthen the eel population locally, and time will tell whether these eels will stay in the harbor or migrate further into the Baltic Sea,” says Dr. Henrike Semmler Le, Senior Specialist, Ocean and Fisheries at WWF Denmark.

© Jonas Lysholdt Ejderskov, WWF Denmark

WWF Denmark’s biologists and other experts have chosen the former dockland area for this project since, no eelgrass is present here—as opposed to most of the port of Copenhagen. The large amount of eel pebbles come from gravel pits, ensuring that stones are neither rough nor sharp so the eels can use their special digging technique.

Copenhagen Harbor becomes the world’s first eel sanctuary

WWF and By & Havn have already established 80 so-called fish kindergartens, also known as biohuts, in different parts of the harbor. The purpose is to establish more habitats for juvenile and small fish. This initiative has inspired others—including companies—to follow and to deploy an additional 120 fish kindergartens in the harbor, making Copenhagen Harbor the world-record owner.

The combination of the existing initiatives, the ongoing commercial fishing ban in Copenhagen Harbor, and the 800 tons of pebbles and 200 brick pipes now make Copenhagen Harbor the world’s first eel sanctuary which excites By & Havn:

“We have come a long way with the transition of the harbor, but we want to do more so we can increase biodiversity in the future. We are excited about this project and hope to strengthen the eel population. Meanwhile, we investigate how to create new habitats for the other animals and plants present in the harbor. An eel sanctuary is something completely new. No one else has done anything on such a scale before. That we are proud of. The initiative comes at a time where the need to protect eels is greater than ever before,” says Anne Skovbro, CEO at By & Havn.

Need to combine new habitat with ban on eel fishing and nature restoration

According to Dr. Henrike Semmler Le from WWF Denmark, this new eel habitat is not enough when trying to reverse the negative development of the European eel. She calls for a complete ban on eel fishing throughout Denmark combined with the restoration of destroyed habitats.

“The European eel is critically endangered both in Denmark and the rest of Europe. Hence, there is a high risk that it will become extinct. It is very concerning that it is still allowed to fish and sell eel. A total ban on eel fishing both on a national and European level—both commercial and recreational—is necessary if we are to turn the direction and restore the stock. Ireland has banned eel fishing all year around and we should do the same in Denmark,” she says.

According to WWF Denmark, Danish commercial and recreational fishers caught around 300 tons of eels per year in recent years. Other reasons for the loss of eels include human-made destruction of eel habitat by extracting pebbles from the seabed and draining wetlands where the species live.