Pathogen Depletion by Cultured Mussels: Investigating the Further Benefits of Integrated Multitrophic Aquaculture

Description

One of the methods currently being considered in the evolution of aquaculture in Canada is a practice known as integrated multi-trophic aquaculture (IMTA). The underlying principle behind the IMTA concept is one of re-cycling of nutrients for more profitability and sustainability. In essence, the IMTA practice combines, in the right proportions, the cultivation of fed aquaculture species (e.g. finfish) with organic extractive aquaculture species (e.g. filter feeders, deposit feeders) and inorganic extractive aquaculture species (e.g. seaweed) for a balanced ecosystem management approach that takes into consideration site performance specificity, operational limits, and food safety guidelines and regulations.

When different organisms are combined, either intentionally or unintentionally, the possibility exists for biological interactions to occur. In commercial aquaculture situations, these negative interactions could be expressed in the form of disease transfer or parasites and this has been the concern of several countries (i.e. Norway, Scotland) in their adoption of IMTA principles. However, we need to recognize from the outset that there is no such thing as a monoculture. There will always be other organisms attracted to food sources and as a result, the issue is not about the presence of an organism, but what is the critical threshold when it could be either a problem or an asset to the operation. The IMTA research to-date has demonstrated that adding the blue mussel (Mytilus edulis) to a salmon operation will increase the profitability of the site. In addition, there is some new research that is showing that there may be benefits to fish health by adding mussels to the site. Studies are beginning to emerge that suggest mussels may have the ability to destroy ISA virus (Skar and Mortensen 2007; unpublished data from the proponents of this study).

The goal of this project is to determine the ability of mussels to affect the occurrence and titre levels of various fish pathogens in their environment, and compare the utility of diagnostic techniques to detect low levels of virus.

Program Name

Aquaculture Collaborative Research and Development Program (ACRDP)

Year(s)

2007 to 2008

Ecoregion(s)

Atlantic: Gulf of St. Lawrence, St. Lawrence Estuary

Principal Investigator(s)

Shawn Robinson
Email: Shawn.Robinson@dfo-mpo.gc.ca