Europe is confronting a contentious debate over how to manage the rapidly growing population of great cormorants, a fish-eating bird whose numbers have surged in recent decades after nearing extinction in the mid-20th century. The species’ recovery, celebrated by conservationists, has generated significant concern among fishers in several European Union countries, who argue that the birds’ feeding habits threaten fish stocks and livelihoods.

In May 2026, nine EU member states—Croatia, the Czech Republic, Estonia, Finland, Latvia, Poland, Romania, Slovakia, and Sweden—submitted a request to the European Commission seeking a relaxation of protection measures established in 1979. These countries called for action to maintain cormorant populations at what they described as "ecologically and economically acceptable levels."

Representatives of fishing communities expressed frustration over the situation. Peter Bozik of the Slovak Fishing Club described the birds as a major problem, stating their presence at wintering sites can rapidly deplete fish populations in unfrozen waters. Pavel Vrana, an ichthyologist affiliated with the Czech Fishing Union, characterized the impact of large cormorant flocks as akin to a "chainsaw massacre," noting that the birds not only consume fish but also injure or stress them to the point of reducing reproductive success. Similarly, Grigore Stefan of the Murighiol Fishermen’s Association in Romania’s Danube Delta reported substantial annual fish losses attributed to cormorants.

Historically, European authorities subjected cormorant colonies to systematic eradication efforts using fire brigades and even military intervention, reducing their numbers to a few thousand breeding pairs by the early 1960s. However, the granting of protected status and changes in fish populations have allowed cormorant numbers to rebound dramatically. Estimates put the current European population at approximately two million birds.

Experts point to several factors behind the species’ resurgence. Zdenek Vermouzek, from the Czech Society for Ornithology, said overfishing in parts of the Baltic Sea has diminished large predatory fish, effectively leaving cormorants to fill the ecological niche left vacant. Additionally, habitat management practices in central Europe—including the removal of natural fish shelters and the design of ponds with steep banks—have made fish more vulnerable to predation. The lack of natural predators for cormorants further facilitates their population growth, according to Romania’s General Association of Hunters and Sport Fishermen.

Stakeholders largely agree that migratory cormorants traveling in large flocks inflict the most significant damage, while resident populations remain relatively stable. Nonetheless, approaches to mitigation diverge sharply. Pavel Vrana advocates for reproductive control by applying oil to cormorant eggs, a practice that prevents embryos from breathing and curbs population growth at nesting sites. He argues that intervention must focus on reproduction areas despite the unpleasant nature of such methods.

Conservationists caution against broad population control measures, endorsing only targeted deterrent shootings allowed under current EU exceptions to protect sensitive fish habitats during critical periods. Jozef Ridzon, an ornithologist with SOS/Birdlife Slovakia, emphasizes the importance of identifying specific areas for protection rather than pursuing a uniform approach, warning that generalized culling efforts are likely to fail.

Vermouzek also notes the logistical challenges of large-scale interventions, pointing out that cormorants exhibit adaptive nesting behaviors that complicate control attempts. He suggests habitat management changes, such as reducing river clearing to provide fish with natural refuges, as a more sustainable solution.

While both fishers and conservationists recognize that human activities have contributed to the present imbalance, their perspectives on remedies differ. Fishers call for active management to correct ecological disruptions, whereas environmentalists advocate for more natural regulatory mechanisms. Vrana encapsulated this divide by stating that, although human error caused the problem, humans must now take responsibility to restore balance rather than rely solely on nature’s uncertain course.