Delar av vattenbruksforskninger sker i Andalsvågen, Norge
Photo: Evan Durland


Research project
Inactive research
Project period
2018 - 2022
Project owner

Short description

Integrated multi-trophic aquaculture, or IMTA, is a term which describes aquaculture systems that cultivate extractive organisms, such as mussels and seaweed, in conjunction with a ‘fed’ species such as salmon. In these systems, waste products from the fish farm, can be re-captured by filter feeders and primary producers to simultaneously reduce effluent load and improve the growth of the associated crops. Although sound in concept, few commercial examples of IMTA can be found in use and the assimilation efficiency of extractive species in open ocean environments remains unclear. We are currently working in collaboration with a Norwegian salmon company, Akvafuture, near Brønnøysund, Norway to investigate how to optimize IMTA deployments with their farms and quantifying nutrient uptake by filter feeders and kelp in these systems.

Participating researchers:

Evan Durland
Göran Nylund

One of the key ways in which seaweed farms can be directly integrated with existing aquaculture operations is through IMTA systems.  The ability of extractive organisms, such as mussels and kelp, to reduce the effluent from salmon farms while simultaneously converting metabolic wastes to harvestable biomass makes these systems an attractive alternative to monoculture farms.  Linking nutrient transfer between trophic levels is straightforward in theory, but challenging in real open ocean farm environments.  We are working in collaboration with a Norwegian company farming salmon in semi-enclosed systems near Brønnøysund, Norway to optimize IMTA methods in their fjords.  Our projects focus on numerous aspects of the co-culture of salmon, mussels, tunicates and kelp including:

  • Harmonizing production schedules to maximize nutrient uptake
  • Strategizing deployment based on currents and tidal exchange
  • Quantifying nutrient assimilation of extractive organisms
  • Microbiome interactions between trophic levels