European Aquaculture Conference Held in Ljubljana: 2,522 Attendees Focus on Farming Resilience Under Climate Change

A four-day conference organized by the European Aquaculture Society was held in Ljubljana this year, bringing together 2,522 researchers, industry representatives and other aquaculture professionals to discuss the theme "aquaculture in a changing world."

Jurica Jug-Dujaković, biotechnology lead at MJD Advisory and Development, was the first plenary speaker to take the stage. Drawing on decades of aquaculture experience, he examined in his presentation which species and farming systems are more likely to adapt to climate change, and what actions farmers, scientists and other industry participants can take now to make production more resilient.

Introducing the topic of sustainability, Jug-Dujaković cited the United Nations' 1987 definition of sustainable development: "meeting the needs of the present without compromising the ability of future generations to meet their own needs." He called the definition "quite poetic" but noted that it focuses strongly on the environment, while economic, social and energy sustainability also need to be considered. On top of this, climate change adds a layer of uncertainty: will species and production systems considered sustainable today still perform well under changed conditions?

According to his overview, climate change can directly affect the physiology and health of farmed animals, and can also have indirect effects by influencing the availability of aquafeed ingredients. Adaptation may therefore involve many parts of the value chain, from genetic improvement and species diversification to changes in production systems.

On adaptation of production systems, Jug-Dujaković said: "Fish farming in ponds and wetlands is very close to sustainable, but very far from climate-proof." Falling water levels can mean higher water temperatures and less dissolved oxygen, while shallower ponds expose fish to predatory birds. Some farmers are already responding: dividing large ponds into smaller units, excavating deeper areas, and installing electrical infrastructure so that aeration can be carried out when temperatures rise.

He also described hybrid approaches, including systems that raise juvenile fish at higher density in tanks next to ponds—tanks that are sometimes covered with tents or kept indoors. After solids are removed from the wastewater, the water flows from the tanks into the ponds, which act as natural biofilters, and the water then returns to the tanks. He cited examples of this approach in Türkiye and Croatia.

Turning to other systems, he explained that traditional flow-through farms face different problems. They depend on large volumes of water to maintain water quality and are therefore vulnerable when water availability declines. "Some farmers have already added some components of recirculating aquaculture systems to flow-through systems, creating partial flow-through or hybrid systems," Jug-Dujaković said. He cited the example of Hungary, where adding mechanical and biological filtration allows part of the water on farms to be recirculated.

For cage farming, Jug-Dujaković said there is relatively little research specifically on how such systems can be made more resilient to climate change. He believes more robust equipment is needed, along with species that can tolerate changes in water quality, especially temperature. He also suggested that selective breeding has historically focused on producing faster-growing fish, but breeding priorities also need to evolve, increasingly toward tolerance of environmental stressors.