Impacts of shellfish aquaculture on marine vegetation



Marine vegetation, such as seagrass and seaweeds, form the foundation of many nearshore ecosystems and are considered critical habitat for many ecologically and economically important species. Shellfish aquaculture has the potential to impact marine vegetation in a variety of ways: via waste particles smothering vegetation; increasing water clarity affecting light penetration (thereby enhancing growth of marine vegetation); and eutrophication (fuelling growth of epiphytes which compete with the seagrasses). The range of effects of shellfish culture on marine vegetation can be complex; however, our understanding of the interactions between them is limited. Determining the impact that shellfish farms may have on marine vegetation has been identified as a priority research area in the Pacific Region.

Baynes Sound, British Columbia is an area of intensive shellfish aquaculture and is therefore an ideal location for this research. In addition, data on the oceanography, plankton and benthic communities in Baynes Sound have been collected for several years. This project will evaluate changes in marine vegetation and associated communities by measuring the relative biomass of each trophic level (grazing, predatory, invertebrates and fish) along a gradient of effects from intensive shellfish aquaculture. This approach will provide a quick assessment of ecosystem-level effects that may be induced from shellfish aquaculture activities.

Project results will provide aquaculture managers with information that will help with decision making to establish appropriate carrying capacity for shellfish tenures, as well as to develop management plans with the goal of reducing environmental impacts from shellfish aquaculture.





Program Name

Program for Aquaculture Regulatory Research (PARR)


2012 - 2014


Pacific: Vancouver Island West Coast

Principal Investigator(s)

Hannah Stewart
Research Scientist, Fisheries and Oceans Canada, West Vancouver Laboratory, Pacific Region
Tel.: (604) 666-6659

Team Member(s)

Terri Sutherland and Beth Piercey, (DFO West Vancouver - Pacific Region)

Collaborative Partner(s)

Steve Katz - NOAA - Channel Island National Marine Sanctuary, California