A national cornerstone in Romanian freshwater aquaculture
This article was featured in Eurofish Magazine 3 2025.
Founded in 1941, the Research and Development Station for Fisheries (Stat,iunea de Cercetare-Dezvoltare pentru Piscicultura˘) in Nucet, Romania, has established itself as a vital institution in the field of freshwater aquaculture and fisheries research.
Over more than eight decades of continuous operation, the Research and Development Station for Fisheries has played a central role in shaping Romania’s aquaculture development through applied research, genetic selection, artificial reproduction, and technical support for fish farmers. Today, under the leadership of Director Miora Costache, the station remains the only national-level institution fully dedicated to freshwater fish reproduction and research, safeguarding a legacy of innovation, scientific knowledge, and participatory collaboration with producers.
Critical support to the fish farming industry
Nucet’s institutional mission focuses on applied research in aquaculture technologies, genetic improvement of freshwater species, and dissemination of knowledge to support the Romanian fish farming sector. The station maintains the country‘s only live gene bank for freshwater species, which enables it to carry out artificial reproduction of key fish species and ensure the availability of genetically sound breeding stock. It also serves as a demonstration and pilot centre where innovative technologies are tested, refined, and adapted to farmers’ conditions.
A core function of the station is to support Romanian fish farmers by providing fish fry and fingerlings, mainly of carp and Chinese carp species, as well as expertise in pond management, breeding strategies, and environmental monitoring. In recent years, its activities have increasingly focused on resilience, adapting aquaculture to climate change, and developing genetic lines that can tolerate higher temperatures, lower oxygen levels, and that are resistant to disease. Nino Marica explains that there are endemic fish species that are naturally resistant to higher temperatures and lower oxygen levels such as crucian carp and tench. There is already a natural hybrid between crucian carp and common carp and researchers at Nucet are looking at creating hybrids that combine the good eating qualities of carp with the resilience of other species.
Sustainability and resilience are focal points for research
The research programmes conducted at Nucet cover a range of topics, but two priority areas stand out: polyculture and integrated multi-trophic systems, and genetic selection under changing environmental conditions. One of the station’s key research directions involves the development of sustainable pond aquaculture using species polyculture, particularly combinations of common carp, silver carp, grass carp, bighead carp, and paddlefish (Polyodon spathula). These integrated systems aim to replicate ecological balance by using species with complementary feeding behaviours. For example, grass carp feed on aquatic vegetation, while silver carp filter phytoplankton. This strategy maximises pond productivity without relying on expensive feed inputs and contributes to nutrient recycling.
The second major area of research is selective breeding for climate resilience. Through government-funded programmes, Nucet has begun selecting common carp strains that can tolerate higher water temperatures and low dissolved oxygen. In controlled trials, fish exposed to such conditions were monitored, and those demonstrating adaptation were selected as future broodstock. The aim is to establish new carp lines with both environmental tolerance and strong growth performance.
Reproduction infrastructure and genetic conservation
The station operates a state-of-the-art artificial reproduction facility, including recirculating aquaculture systems (RAS) with controlled temperature and lighting. This enables Nucet to begin breeding activities earlier in the season, extending the production cycle and allowing fingerlings to reach market size within a single summer. In typical years, Nucet produces around 300 million fish larvae and 70 to 100 tonnes of one-year-old fry. These are distributed to fish farms throughout Romania, which often prefer larger juveniles to reduce losses from bird predation and environmental stress. Large juveniles of 200 g can grow to 2-3 kg in one season from April to October. Today Nucet is the only Romanian institution breeding fish for on growing by inducing the broodstock, although some farms produce carp juveniles through natural spawning. In addition to carp species, the station breeds paddlefish, pike, pike-perch, European catfish, and various ornamental species including goldfish and koi. It uses a mix of natural and artificial reproduction methods, depending on the species. For instance, Chinese carp are often bred using circular tanks that simulate riverine conditions, allowing fish to spawn more naturally. A fundamental asset of the station is its live gene bank, which preserves the biological material of Romanian freshwater fish. This includes three strains of common carp—Ineu, Frăsinet, and Ropșa—each adapted to specific climatic zones. These genetic resources underpin the national capacity for restocking, adaptation, and resilience.
Close collaboration with farmers
Nucet plays a hands-on role in supporting fish farmers, especially those operating in extensive and semi-intensive systems. Through its participatory approach, the station works directly with producers to design stocking strategies, determine pond carrying capacity, and select appropriate species combinations. It also collaborates on feed formulations, water quality monitoring, and health assessments. Farmers are involved throughout the research and demonstration cycle. They participate in experimental stocking trials, observe feeding practices, and receive training in disease management and production planning. This collaboration helps bridge the gap between scientific research and on-farm implementation. It also ensures that the station’s outputs remain relevant to real-world constraints, such as low investment capacity, bird predation, water scarcity, and limited technical staff in rural fish farms. Nucet is often asked what value research brings to the farmer. Ms Costache emphasises that the benefits are both tangible and systemic: higher yields, lower mortality, improved environmental conditions, and access to improved seed stock. She also notes that farmers involved in research projects are often more committed and open to innovation, contributing to sectoral modernisation.
Eng. Nino Marica, Researcher, Research and Development Station for
Fisheries Nucet
Climate change impacts force the institute to adapt
Climate change has profoundly affected aquaculture in Romania, especially in pond-based systems. Rising temperatures, prolonged droughts, and increased day-night temperature fluctuations have made fish reproduction and growth more unpredictable. According to Nucet’s data, the average water temperature has increased by 1.2–1.5°C since the 1990s, with growing frequency of extreme events. The warming water caused by climate change also has a beneficial effect in that it extends the growing season. The natural productivity of the ponds is a little higher and the fish feed (and can be fed) and grow for a longer period of time. On the other hand, eng. Nino Marica, a researcher at Nucet, says the difference in water temperature between day and night are wider and more frequent than five years ago. These fluctuations negatively affect the maturation of the gonads and thereby the reproduction process. These changes have forced the station to adapt. For example, reproduction is increasingly carried out in controlled environments to counteract environmental variability. In some cases, reproduction is advanced by two months, allowing larvae to be stocked early and take full advantage of the spring productivity peak. The station is also piloting new systems such as floating cages in reservoirs, especially in areas where pond aquaculture is no longer viable due to water shortages. Floating cages allow more control over feeding, predator exclusion, and harvesting. They also offer a dual-use model, combining extensive stocking of grass carp in the wider lake with intensive production in cages.
Currently, the station occupies approximately 150 hectares, down from over 1,000 hectares before the sector was privatised in the 1990s. Despite this reduction, it maintains a complex infrastructure including incubation halls, research ponds, floating cage modules, water chemistry labs, genetics labs, and experimental units for polyculture and climate adaptation. The station employs 52 staff members, of whom 16 are full-time researchers. The others are aquaculture technicians and support staff, many with hands-on experience in fish handling and farm operations. This practical orientation is a key asset of the institution, enabling it to maintain tight feedback loops between research, demonstration, and dissemination.
Structural challenges to aquaculture call for initiatives at all levels
Despite its central role, the Nucet station—and Romanian aquaculture more broadly—faces several structural challenges. These include low remuneration in the sector, difficulty in attracting young specialists, lack of subsidies for fish farms, and increasing exposure to market and climate-related risks. The location of fish farms near villages or small towns and remote from big cities is also why the sector faces challenges finding young and educated workers. The war in Ukraine has also led to rising input costs, especially for feed and energy, and among the most burning issues is that of predation by birds and fish-eating animals. A dedicated aquaculture law has been adopted in Romania but has been sent back pending constitutional clarification. When implemented, it is expected to clarify ownership rights over water bodies, facilitate investment, and provide stable support for research institutions. The law could open the door to a stronger framework for innovation, conservation, and sector growth. Dr Costache thinks that the new law will finance a programme of aquaculture research which will benefit institutions like hers enabling them to develop and collaborate more closely with institutions in other parts of Europe. Nucet also maintains long-standing collaborations with universities and research institutes, including the University of Agronomic Sciences and Veterinary Medicine in Bucharest and the Grigore Antipa Marine Research Institute in Constanța. These partnerships extend to international cooperation, including exchanges and joint projects with institutions in Turkey, China, and Georgia.
Juvenile silver carp being transferred into a pond for on growing before being supplied to the industry. Farmers prefer to introduce bigger fish into their ponds as losses from predation are smaller.
Invaluable service for the aquaculture sector
The Research and Development Station for Fisheries Nucet is a cornerstone of Romanian aquaculture science. It combines historical expertise, biological heritage, and practical innovation to serve the country‘s freshwater fish farmers. As the sector faces increasing pressure from climate change and economic uncertainty, Nucet‘s role becomes more important than ever. Through its commitment to research, training, and collaboration, the station provides a rare model of how public institutions can support sustainable aquaculture development grounded in science, tradition, and adaptation.
