Image: European Commission / FIS
When artificial is beneficial
Friday, June 02, 2023, 07:00 (GMT + 9)
Much to the fishers’ dismay, cod populations in the Baltic Sea have been decreasing since the 1990s. The reasons are many, including habitat degradation. The same decade also saw the start of a potential solution to habitat loss. It was then that the German Research Institute for Agriculture and Fisheries of Mecklenburg-Western Pomerania (the Landesforschungsanstalt für Landwirtschaft und Fischerei Mecklenburg-Vorpommern, or LFA) launched a study looking into the technical feasibility of artificial reefs and their potential benefits for local fisheries. The results were promising. Today, there are two artificial reefs that were built thanks to EU funding.
Source: riff-nienhagen./ Wiki / FIS
Artificial reefs improve the Baltic ecosystem
The main objective of the reef project was to establish the feasibility of artificial reefs as attractive fishing areas. Thanks to EU funding, two artificial reefs were built in the Baltic Sea, at Nienhagen (4 ha in area, 1.5 km off the coast at depths of 11 to 12 m) and Rosenort (1.2 ha, 2 km off the coast at depths of 6 m). Both reefs consist of natural rocks and various underwater structures made of concrete reef cones, tetrapods and concrete rings. In addition, mesh fabrics and lines act as substrates on which seaweed and mussels can grow.
Source: riff-nienhagen -->
The two reefs provide large-scale artificial underwater habitats that create shelter, feeding and rest zones for the fish species present in the area. Ongoing scientific research has shown that the fishing value of the sea areas around the reefs has increased, but more reefs need to be built to achieve measurable benefits for local fisheries.
Artificial reefs to support local fisheries in the Baltic
These are the only reef projects of their kind in the Baltic Sea to have provided data over such a long period of time. The structures in the water column give the reefs very high biodiversity in comparison to the sandy or marly substrates that surround them. They are especially advantageous for young cod, which have a better chance of survival and – according to observations from tagging experiments – return to the same area when they are older.
The reefs also have an impact beyond their boundaries. Over the years, young fish have spread across a large area around each of them. Researchers have found more than 30 different species in total, some of which are rare.
"It is quite impressive to observe large schools of juvenile cod, gobies or sand eels on a dive between the reef elements," said Gerd-Michael Arndt from the Mecklenburg-Vorpommern Research Center.
The EU contribution has been essential for the feasibility study and building the first reefs. Thanks to the good results, Fraunhofer Institute for Graphical Data Processing in Rostock will take over from the Landesforschungsanstalt to continue the maintenance and research in the the reef areas. To expand their knowledge on how reef areas influence the marine environment, the Fraunhofer Institute researchers are looking into building an ocean technology centre and more reefs. They also plan to look into aquaculture opportunities in and around the reef structures.
Source: European Commission