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Evaluating ecological impacts of seaweeds in integrated multi-trophic aquaculture (IMTA)



Seaweeds are an integral part of the Integrated Multi-Trophic Aquaculture (IMTA) system, where multiple species are grown in close proximity to each other to help reduce the environmental impact of a finfish site. Beyond their ability to extract and convert nutrients from finfish waste (bioremediation), these species can promote economic resilience whereby farmers are able to diversify their products and improve the overall ecological sustainability of the site. Current IMTA research is exploring many native species of seaweeds that may be grown on farm sites, however, concurrent research is required to evaluate potential habitat and ecological impacts of seaweed farming on neighbouring natural seaweed populations.

It is possible that the culture of seaweeds on an IMTA site could affect the structure and function of adjacent near-shore communities by changing nutrient concentrations, or through the release of offspring (propagules) thereby affecting plankton communities or natural seaweed diversity and abundance. Seaweed within an IMTA site may also attract other organisms to the area and alter the habitat for local species.

Within this project one (or more) local seaweed species will be incorporated into an IMTA system in Kyuquot Sound, British Columbia. The ecological impact and interactions of this culture on the near-shore and adjacent habitats of native seaweeds will be evaluated. Additionally, the impact on associated invertebrate and fish species, and overall bioremediation capabilities will be determined, both in the immediate area of the farm and on adjacent near-shore habitats. The information gained through this project will help to better inform siting decisions and regulations for IMTA and the aquaculture industry. Results will also contribute to a greater understanding of the complex relationships between cultured species and the native environment.

This project supports the environmental performance objective of the Aquaculture Collaborative Research and Development Program (ACRDP), pertaining to the 2013-14 national ACRDP priority to evaluate the environmental impact of aquaculture on the environment through the increase of the knowledge and understanding of how aquaculture finfish operations interact with the environment.

Program Name

Aquaculture Collaborative Research and Development Program (ACRDP)


2013 - 2014


Pacific: Vancouver Island West Coast

Principal Investigator(s)

Hannah Stewart

Collaborative Partner(s)

Kyuquot SEAFoods Ltd.

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