Off-flavors in fish and water mold cause significant economic losses to fish farming globally. The Natural Resources Institute Finland (Luke) and VTT have developed capture solutions based on chemically treated fiber materials to address these challenges in fish farming.
Unpleasant off-flavors can accumulate in fish and reduce the market value and consumer interest in fish products. Managing off-flavors is key to the profitability of sustainable fish production both in Finland and globally.
Water mold is also a common problem in fish farms both in Finland and globally. In salmonid farming, water mold has been estimated to cause production losses of up to 10% per year through all stages of production. Water mold is also a threat to endangered fish stocks maintained in aquaculture farms.
"We have developed promising capture solutions to address the problems of off-flavors and water mold in aquaculture. Our solutions can have a significant impact on the profitability of the industry," says Jani Lehto, Director of Luke's Bioeconomy and Environment Unit.
"These new cellulose-based capture materials will capture water mold spores and off-flavor compounds from the water, preventing them from accumulating in the fish," tells Hannes Orelma, Research Team Leader at VTT.
Encouraging results from trials
The capture of off-flavor compounds was studied at Luke's Laukaa experimental aquaculture facility. The concentrations of 14 off-flavor compounds were tested in a recirculating aquaculture environment, where part of the water was recirculated through a fiber material.
The chemically treated fiber material accumulated up to 1,000 times higher concentrations of off-flavor compounds compared to those in untreated water. After the treatment, the concentrations of off-flavors in the fish remained below the sensory thresholds.
"This is a very interesting result, as no new solutions have been introduced in recent years to reduce off-flavors in recirculating aquaculture systems," says Luke’s Research Manager and Senior Scientist Petra Lindholm-Lehto, who was responsible for the design and implementation of the experiments and measurements at Luke.
At Luke's Enonkoski aquaculture facility, a fiber material developed specifically for the capture of water mold spores was tested. The use of the fiber material significantly reduced the amount of mold spores in the water compared to a culture tank without the material.
"Not enough is yet known about the behavior of the water mold and studying it in fish farming is challenging. Previously used treatments have proven to be unsafe or ineffective. The method we have developed is based on the use of harmless capture material and therefore the results of our experiments are interesting," says Lindholm-Lehto.
Patents sought for capture solutions
Patent applications have been filed for both innovations developed by Luke and VTT.
"Our results are encouraging and show that these solutions have a lot of potential. Our next steps are to continue development of both technical solutions in commercial-scale farms and to move forward with commercialization. We look forward to hearing from companies and operators who would like to develop these solutions further with us!" says Jani Lehto.
Luke's Laukaa experimental aquaculture facility (Picture: Jussi Judin / Luke)
