Climate change is gradually changing the conditions of fish farming in the Czech Republic. Rising summer water temperatures will be deadly for some species in the coming decades. Globally, fish production is growing at a rate of about 4% per year. Increasing demand, with stagnant catches from classic ponds, is to ensure or replace breeding in specialized production systems in the Czech Republic, says Jan Mareš from the Department of Zoology, Fisheries, Hydrobiology, and Beekeeping of Faculty of AgriSciences at Mendel University in Brno. This applies in particular to rainbow trout, ie fish that require cold and clean water. Researchers will study the new production systems in detail.
In the conditions of the Czech Republic, fish farming has for several centuries been predominantly focused on traditional pond production. “However, it is often limited by the non-productive functions of ponds, the amount of water, the temperature in the summer, and the occurrence of various predators. In the future, there is a risk of a reduction in the production of freshwater fish in pond farming,” describes Mareš.
Individual fish farms are already looking for new ways. The classic production systems include farms that rely on sufficient quality water to flow in throughout the year. These are standard concrete tanks, most often flow gutters. However, the future is focused on systems using recirculated water, including aquaponics, in the research of which Mendel University in Brno also participates. “The reason is to minimize dependence on a year-round source of quality water. In addition to tanks for fish farming, such systems also have sections for water purification, disinfection, and quality treatment,” said Mareš.
Researchers from several institutions, including MENDELU, will now focus on promoting and introducing safe and healthy farms to produce rainbow trout. The breeding of salmonid fish, especially rainbow trout, in the Czech Republic is at the level of up to 1,000 tons per year. Thanks to the new project, the researchers will verify the suitability of the selection of rainbow trout of various origins for specific breeding conditions. They will deal with the selection of lines resistant to diseases that are potentially threatened in a given breed.
“We will look for optimization methods to detect such dangers in a timely manner and use appropriate preventive intervention. This can be, for example, disinfection of the inflow water with ozone, application of table salt to the water, influencing fish resistance by suitable addition to feed mixtures, “said Mareš. According to him, this is not the addition of antibiotics but targeted probiotics even as supplements in human nutrition.
Experts will also prepare a manual for breeders, which will enable the detection of risk points in a specific breed and eliminate them in time. The project entitled Globalization, Modern Technologies, and Climate Change as Sources of New Opportunities and Threats for Salmon Fish Farming (2021-2025) was supported by the National Agency for Agricultural Research. In addition to MENDELU, several institutions participate in it. The coordinator is the Institute of Vertebrate Biology of the Czech Academy of Sciences.
Source: Mendel University in Brno