The Atlantic salmon (Salmo salar) is one of the migratory fish species that has been proposed for inclusion in the CMS appendices. | Photo: Pixabay
In her statement to the SMC, the river researcher makes a clear case for adding further species to the list, as she argues that the sharp decline in migratory fish populations has so far been significantly underestimated, overlooked or ignored at both political and institutional levels. There is a need to catch up not only for species in South America, Asia and Africa, but also in Europe. For example, Atlantic salmon, allis shad, common nase and river lamprey have been proposed for inclusion in the CMS appendices.
“Migratory fish have had a weak lobby so far, even though they are umbrella species for diverse species communities and habitats – and thus also for their rich ecosystem services, which are important for us humans too,” says Sonja Jähnig. Interest groups from inland navigation, energy generation, industry and agriculture are often more influential than conservationists, yet at the same time there are also conflicts of interest between these user groups.
In Europe, there is not a lack of knowledge but a lack of implementation when it comes to more sustainable river management: the scientific evidence exists, but river systems remain heavily fragmented by migration barriers, e.g. dams for water storage and hydropower generation. The latter may be renewable, but it is not environmentally friendly. The global expansion of hydropower is in fundamental conflict with the protection of migratory fish species: “Dams fragment river systems and interrupt key migration corridors. Altered flow, temperature and sediment regimes mean that important environmental stimuli for the reproduction and development of these species are absent.”
According to Sonja Jähnig, effective strategies primarily involve the removal of key barriers, the protection of river sections that still flow freely, the reconnection of floodplains and side channels to the rivers, and the restoration of natural flow and temperature regimes.
Read the complete article of the SMC on the topic (in German) >
More on the topic
Protection gap for migratory freshwater fishes in the CMS I IGB
IUCN Red List: One quarter of freshwater animals at risk of extinction I IGB
