Protecting threatened river fish against predation

2026-07-22

Freshwater ecosystems are heavily impacted by human activities and climate change. Overall, at least 37% of Europe's freshwater fishes are threatened at a continental scale, and 39% are threatened at the EU level. This is one of the highest threat levels of any major taxonomic group (DG. Environment, 2011). Many species of river fish are in a very poor conservation status and even those that are protected by eg. the Habitats Directive, are not regularly monitored and documentation of the population trend and status is often lacking. A recent great increase in predation pressure has further increased pressure on river fish, even in healthy, restored or least-impacted areas. In the EU, predation may be the main reason for widespread loss of populations of Habitats Directive listed grayling (Thymallus thymallus). There is a genuine and widespread concern among managers and stakeholders regarding protection of wild populations of river fish, as grayling, from unsustainable predation pressure. The conflicts involving fish protection and predation have been intense in most member states for decades and despite protective measures, including culling (Birds Directive article 9-derogations), the conflicts have remained intense. ProtectFish aim to investigate the monitoring and protective measures of Habitat Directive-listed river fish species, answering Area A of the call. We will develop and test protective actions, using cormorants (Phalocorax carbo sinensis) and grayling as a case. Small- and large scale field experiments will be conducted to measure the effect of relieving cormorant predation pressure on fish populations. We will examine the background for the conflicts, by estimating the current population status of cormorants and grayling in EU as well as quantify the culling of cormorants. The results of ProtectFish will directly aid to achievement of EU Biodiversity Strategy, Natura 2000 and the WFD as well as improved adaptive nature management on local levels.

Denmark, Germany, Austria, Czechia, Sweden, Italy, Belgium, Poland

2026-02-15