Fehmarnbelt contains a rich variety of fish species. As part of the environmental surveys for the fixed link across Fehmarnbelt, no fewer than 58 different species have been recorded. This is substantially more than biologists had expected to find.

A rich fish life
Herring and sprat are common in the open seas while the coastal waters are dominated by adult cod, young whiting, a variety of flatfish as well as sea scorpion, goldsinny and eelpout.

The belt also functions as a migration route and for spawning by a number of species including lumpfish, herring and garfish which spawn in shallow waters in spring. This also applies to migratory silver eels which pass through the belt in autumn and cod, which gather in deep waters during the winter.

Gillnets and trawl hauls
To keep track of the abundant fish life, monthly surveys are conducted using e.g. the so-called multi-mesh gillnets.

"These are 60 metre long gillnets with 12 different sizes of mesh to ensure that we catch a wide cross-section of fish," explains Senior Advisor Jens-Peter Müller from the Fish Ecology Laboratory in Elsinore. “We use them in shallow water whereas in deep water we typically use the trawl drag."

In addition, fish migration, spawning areas and nursery areas are charted by tagging experiments, hydro-acoustic measurements, video surveys and the collection of eggs and larvae by so-called bongo nets. Through tagging and the recapture of eel, for example, it is possible to establish the eel’s main migration routes.

Closely monitoring the food chain
The many different fish species each have their particular place in the food chain. Some play an important role as a food basis for birds in the area's winter resting sites and for regulating the lower layers of the food chain. These issues are being examined closely by the project's biologists.

"We're working to obtain an overview of the current situation so we can assess the impact of a Fehmarnbelt fixed link on fish life," says Jens-Peter Müller.