One of the world's leading teams developing open-ocean integrated aquaculture is showing that sea farmers can successfully grow finfish, shellfish and seaweed together.
Aquaculture operations, more commonly known as fish farms, are at
an environmental and economic crossroad. Monocultures of finfish, shellfish
or seaweed in coastal waters are showing their limitations in different
parts of the world, in a way very similar to monoculture practices on
"We need to combine fed aquaculture (finfish) with extractive inorganic aquaculture (seaweed) and extractive organic aquaculture (shellfish) to balance each other, so that the nutrients from the salmon farms are converted into other crops that have a value," says Dr. Thierry Chopin, the principal investigator who is working with the federal government's Department of Fisheries and Oceans (DFO) on one of the world's leading projects on open-ocean, pre-industrial-sized, integrated aquaculture.
The mussel taste test
Dr. Shawn Robinson, a co-investigator from DFO on the AquaNet integrated aquaculture project, wondered if blue mussels grown alongside salmon would taste fishy. The answer is critical to the commercial viability of polyculture - the practice of growing more than one species at the same location. In this case, mussel and kelp were grown alongside salmon.
"We performed scientifically designed taste tests with mussel connoisseurs. They couldn't distinguish our polycultured mussels from mussels from other sites," says Dr. Robinson.
In partnership with the Canadian Food Inspection Agency, the food safety component of the project is ensuring that the polycultured mussels and kelp do not pick up the therapeutants used in salmon farming. Two years of data show that they don't accumulate these chemicals and are safe to eat.
Launched in 2001, this "polyculture" project is located in the Bay of Fundy, near St. Andrews, New Brunswick, at commercial salmon farms operated by Heritage Salmon Inc., a partner in the Aquanet-funded research project. To create the polyculture operation, Dr. Chopin's team built on the existing infrastructure to integrate kelp and blue mussel production into the salmon farms.
"For me, one of the biggest advantages of this research with AquaNet is the multidisciplinary aspect at the scale of a commercial salmon operation," says Dr. Chopin, a professor of marine biology at the University of New Brunswick. "It was through AquaNet that I was able to put together a team of biologists, economists, social scientists, government regulators and industry partners."
The results are providing important insights into polyculture's potential. Additional nutrients from the salmon operation stimulated a 46 percent increase in the growth of kelp at the salmon farm, compared to kelp at a reference site. Similarly, the polyculture site's blue mussel growth was up to 100 percent greater than at reference sites, and the mussels reached commercial size faster.
"We now have enough data to say that polyculture makes sense biologically," says Dr. Chopin, noting that to date the project has trained nine graduate students in world-class polyculture research. "What we now need to show is that it makes economic and social sense."
An economics student and a social-science student are working to do just that. Starting in the summer of 2003, with the support of the Atlantic Canada Opportunity Agency, they are studying the market and acceptability potentials of integrated aquaculture.
The AquaNet project also involves partnerships with two key Canadian companies involved in the development of seaweed products, Acadian Seaplants Limited and Ocean Nutrition Canada. Although there are as yet no commercial kelp harvesting operations in Canada, the industrial partners hope that this will change. They are helping to analyse the kelp grown at the polyculture site, comparing it with kelp from reference sites. The goal is to target profitable niche markets such as nutraceuticals, sea vegetables and feed ingredients for other aquacultured organisms.
The mission of AquaNet, Canada's Network of Centres of Excellence for aquaculture, is to foster a sustainable aquaculture sector in Canada through high-quality research and education. Established in 1999, AquaNet is a collaborative research network involving universities, industry, government and non-government organizations.