Recently Nordic Aqua had to cull 2,000 tonnes of salmon due to off-flavour issues at its RAS in China
Unpleasant off-flavours can accumulate in fish – especially in RAS farms – and reduce their market value, while water mould is also a common problem in fish farms globally. In salmonid farming, water mould has been estimated to cause production losses of up to 10 percent per year through all stages of production.
"We have developed promising capture solutions to address the problems of off-flavours and water mould in aquaculture. Our solutions can have a significant impact on the profitability of the industry," said Jani Lehto, director of Luke's Bioeconomy and Environment Unit, in a press release.
"These new cellulose-based capture materials will capture water mould spores and off-flavour compounds from the water, preventing them from accumulating in the fish," added Hannes Orelma, Research Team Leader at VTT.
Encouraging trials
The capture of off-flavour compounds was studied at Luke's experimental aquaculture facility in Laukaa. The concentrations of 14 off-flavour compounds were tested in a recirculating aquaculture environment, where part of the water was recirculated through a fibre material.
The chemically treated fibre material accumulated up to 1,000 times higher concentrations of off-flavour compounds compared to those in untreated water. After the treatment, the concentrations of off-flavours 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-flavours in recirculating aquaculture systems," said 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 fibre material developed specifically for the capture of water mould spores was tested. The use of the fibre material significantly reduced the amount of mould spores in the water compared to a culture tank without the material.
"Not enough is yet known about the behaviour of the water mould 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," said Lindholm-Lehto.
Patents sought
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 commercialisation. We look forward to hearing from companies and operators who would like to develop these solutions further with us!" Lehto concludes.
