GEOSMIN MANAGEMENT KUTERRA

In 2021-22, Kuterra engaged in a significant project to manage geosmin, an off-flavor compound, in its recirculating aquaculture systems (RAS), which are essential for land-based fish farming. Kuterra has been raising land-based salmon in British Columbia since 2013 and prides itself on high-quality, sustainably reared fish. However, one of the persistent challenges in closed aquaculture systems is the occurrence of off-flavors like geosmin, which are absorbed by fish, resulting in a less desirable taste that requires costly 'purging' before the fish can be marketed.

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The project focused on addressing the geosmin levels which were initially managed by adjusting the makeup water units (MUW) within the systems. Traditional approaches such as increased water changes and ozone additions proved ineffective, as geosmin levels continued to exceed the acceptable limit of 5ng/L. Consequently, Kuterra adopted an innovative approach by implementing the RAS-Right bacteria developed by BluePlanet, designed to enhance nitrification and manage off-flavor compounds effectively.

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BluePlanet's approach centered around Active Microbiome Management using RAS-Right bacteria, which not only targeted the geosmin but also ensured the maintenance of essential populations of nitrifying bacteria. This method involved continuously multiplying bacteria in a bioreactor grow tank and dosing them into the biofilter at regular intervals. This strategy aimed to improve the overall microbial environment of the RAS, ensuring optimal water quality and maintaining the health of the fish. The results were successful, with geosmin levels consistently maintained below the threshold, thereby avoiding the need for extended purging periods and reducing the costs associated with water makeup and treatment. The project not only enhanced the product quality but also reinforced Kuterra’s commitment to sustainable aquaculture practices.

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