This innovative, nature-based initiative aims to support the restoration of the Danube floodplains through sustainable fish farming, focusing on indigenous species to help restore the local aquatic ecosystem.
Where Croatia, Serbia and Hungary meet, the Danube River flows through one of Europe’s richest wetland ecosystems. Yet beneath its lush surface, nature is under pressure: native fish populations are declining, invasive species are spreading, and the river's natural connection with its floodplains has been disrupted.
To help restore this vital ecosystem, the Horizon Europe Mission Ocean project DaWetRest (Danube Wetlands Restoration) has launched Croatia’s first green hatchery in Velika Gorica. Opened on 31 March, the hatchery is a key step toward reviving the Danube’s biodiversity.
With a capacity to breed 1,200 to 1,500 kilogrammes of native fish annually, the hatchery will release young fish into Danube side channels to support the recovery of natural populations in areas where they’ve vanished. The initiative directly supports the Mission Ocean and Water’s objective of restoring 25,000 km of free-flowing rivers by 2030, in line with the EU’s biodiversity strategy.
A nature-powered system
What makes the hatchery ‘green’ is its environmentally responsible design. It runs on solar energy and heat pumps, uses durable, natural building materials, and avoids chemicals in the farming process.
Most importantly, it breeds only native fish species, those essential to the Danube’s ecological balance. By cultivating and periodically restocking these native species, the system aims to help restore natural habitats and foster broader biodiversity – particularly through food chains that include species such as piscivorous birds. By reinforcing native fish populations, especially predators, this nature-based solution aims not only to support natural reproduction but also to curb the spread of non-native species.
More than conservation: a community effort
This innovative solution goes further than just revitalising ecosystems. “This project isn’t just about restoring nature – it’s about supporting people,” says Professor Hrvoje Mikulčić from the University of Zagreb, Faculty of Mechanical Engineering and Naval Architecture, a project partner and the hatchery’s creator. Managed by the Odra Sports Fishing Association, a local group with roots dating back to 1956, the hatchery serves as a model small business that strengthens the local economy.
Under Croatian law, fishing associations are required to repopulate the waters they manage. By breeding fish themselves, Odra avoids the cost of purchasing stock – and can even sell fish to other associations along the Danube. Thanks to the hatchery’s renewable energy setup, operating costs are also kept low.
The benefits extend beyond fisheries. Healthy wetlands attract birdlife, opening up ecotourism opportunities like birdwatching, further boosting local income and engagement with nature.
Scaling up for broader impact
The hatchery has already inspired replication. A private investor in Croatia has committed to building a second facility – ten times larger – based on the same sustainable model. It’s a sign that this local solution could scale up to address ecological challenges across Europe.
‘The green hatchery is just one piece of the puzzle,’ says Mikulčić. ‘But it’s a big step forward. It’s not just about fish – it’s about a more sustainable way of living.’
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