One of the obstacles to the artificial breeding and market utilization of domestic freshwater, protected predatory fish is the high specific production cost. One of its main factors is the high price of sea fishmeal, which provides a source of animal protein for animal feed. Researchers at the Balaton Limnological Institute of the ELKH Centre for Ecological Research investigated whether mussel meal extracted from invasive mussel species (Dreissena), which are abundant in Lake Balaton, could be suitable as a substitute for declining quality fishmeal. The basic research project implemented as part of the Hungarian Fisheries Management Operational Program under the measure “Encouraging innovation in aquaculture”, funded by a grant of nearly HUF 129.5 million, has shown that mussel meal provides adequate food for freshwater predators.

As part of the project “Production of fish feed from organic mussel with innovative technology”, researchers developed a technology for separating mussel meat and mussel shell in a laboratory, and modelled compound feed made from mussel meal was used in experiments to feed wels catfish. Experiments have shown that feed containing mussel meal, which replaces fishmeal, has been shown to be effective in terms of both the growth and meat quality of catfish fed with it.

Researchers have also developed artificial housing conditions for mussel involved in fish feed and established a so-called recirculated algae and mussel farming system (REALKAR). In this, an algal strain with favorable physiological properties, which is favored by the mussel and has been successfully bred, also utilizes the mussel’s metabolites. The mussel bed algae system has also proven to be suitable as a biological filter for purifying the fish farm effluent and recycling the useful materials contained in it.

The objectives of the project – the assembly of the elements of the algae-mussel-fish recirculation system and the description of its operating parameters, as well as the use of mussel meal as a protein source in the feed of growing catfish – have been fully achieved. The results have been presented by researchers in the framework of national and international conferences and the studies are being published in international journals.

Based on these results, the researchers developed an applied research plan for utilization, and they are looking for additional grant sources for its implementation. Refinement of results and detailed elaboration of technology are necessary for its utilization. Researchers are confident that with the support of decision-makers, it will be possible to create an economically useful feed ingredient from domestic sources that can be used in fish farming, together with the technology that produces it.

Further information: Dr. Csilla Balogh, technical director (balogh.csilla@ecolres.hu)