Invasive Bighead Carp Confirmed in Finnish Waters for First Time
Finland has recorded its first confirmed sightings of the invasive bighead carp (Hypophthalmichthys nobilis), a species native to large rivers in China, following discoveries in Loviisa and the Kymi River in July 2025. The Natural Resources Institute Finland (Luke) confirmed the species through genetic analysis in July 2026, resolving initial uncertainty over the fish’s identity.
The first specimen, measuring over 90 centimetres in length and weighing more than seven kilograms, was caught in a fisherman’s trap off the coast of Loviisa. Researchers initially examined its external features—such as the absence of an adipose fin, low-set eyes, and a large head—before genetic testing provided definitive confirmation (Helsingin Sanomat). A second bighead carp was later filmed swimming upstream in the Kymi River fishway, raising concerns about the species’ potential spread.
Luke states that the bighead carp has been widely used in aquaculture across Asia, North America, and Europe, with escapees establishing invasive populations in natural waters. While the species is not currently classified as harmful within the European Union, it poses risks due to its rapid growth, high reproductive rate, and ability to tolerate Finland’s winter conditions. Senior researcher Sanna Kuningas notes that in North America, the bighead carp has become a disruptive invasive species, particularly along the Mississippi River, where it competes with native fish for resources (Yle).
The discovery follows previous observations of the species in neighbouring Sweden and Estonia, with Luke suggesting that the Finnish specimens are likely escapees from aquaculture. The Kymi River sighting is particularly notable, as it indicates the fish’s ability to navigate upstream, potentially facilitating further spread.
