EAA Germany (Deutscher Angelfischerverband) has recently published an article entitled “No healthy waters, without fish”. A research project, led by the University of Koblenz, has shown how fish from the Nister River in Germany clean their waters and significantly contribute to the water quality.
20 years ago, local people sounded the alarm because of the dramatic
deterioration in the ecological condition. Since then, the Nister working group
Nister) has brought stakeholders from administration, recreational
fisheries, and science to one table. The causes of the algae growth were
investigated under the scientific supervision of the University of Koblenz and
strategies for saving the Nister River fish populations were put in place.
the main issue concerns the massive development of algae that pollute waters.
They invade the bottom of water, which deteriorates the living conditions of
fish and shellfish according to Carola Winkelmann, an aquatic ecologist from
the University of Koblenz. Hence, the reduction of the fish stocks in the Nister
River influences the development of algae and water pollution. For example,
certain species of fish, such as the common nase, feed exclusively on algae. They
act like a cleaning crew that keeps down the amount of algae. The most important discovery of this project is
that fish can improve their habitat for themselves and other groups of species by repelling algae in the water. Fish
thus provide ecosystem services of extraordinary value contributing to
healthier water bodies.
quality is also increasing rapidly due to cormorant hunting. Indeed,
as cormorants reduce fish stocks, water quality decreases consequently. A study
regarding the influence of cormorants on fish stocks reveals that water quality
increases if the number of cormorants decreases. “After targeted protection
measures, the condition of the fish population has improved significantly in
recent years. The decisive factor was the intensive deterrence of cormorants,
as these had significantly reduced the fish population in the Nister and have
thus allowed the massive growth of algae. Today the algae are repelled. From
the Stein-Wingert bridge, visitors can see large schools of fish swimming their
courses on the gravelly ground” – says Manfred Fetthauer, the president of
successful rescue project was awarded the DWA Water Development Award by the
Water Industry in March 2023. “We are very happy that we can support this
lighthouse project with its important research on the influence of cormorant
predation on fish stocks. We very much hope that the display board will help to
improve understanding of the problem," says Florian Stein from the
German Anglers' Association DAFV.
to the article : here
Germany and all EAA members around the EU are deeply involved in such
restoration projects. For more information, you can find the report of
an event organized by the Recreational Fisheries Forum in the European
Parliament on the upcoming Nature Restoration Law and the need to secure the
continued presence of anglers in protected nature zones.
Image credit to DAFV