Raising Fish in Canada to meet Growing Demand

By Rosie Schwartz, RD, FDC

Over the past decade, Canadians have been eating more and more seafood- both finfish and shellfish. It’s not surprising, though, when you consider the mounting scientific evidence pointing to an assortment of health benefits for those who include it on the menu on a regular basis.

Don’t think of it as just being brain food or heart-healthy. Research is showing it provides a wide assortment of advantages for your health. Besides a long list of nutrients, it supplies antioxidants and anti-inflammatory compounds as well.

It’s also a fast food. Seafood can be cooked in a flash. What has become known as the Canadian Fisheries rule is that fish should be cooked no more than 10 minutes per inch thickness.

But there’s a catch to the increasing popularity.

Seafood consumption is surging globally and as this demand rises, traditional capture fisheries cannot meet the needs. As a result, aquaculture, the farming of fish, shellfish and marine plants, is starting to play an increasing role in supplying the world with seafood.

While the practice of aquaculture has grown significantly over the past few decades, its history goes back thousands of years to ancient Rome and to an even earlier time in China. In Canada, the farming of aquatic species, like Atlantic salmon, brook trout and oysters, began in the 1800s.

A growing variety of aquacultural products

Currently, though, the variety of species now commercially cultivated in Canada has grown to approximately 45 different kinds of finfish, shellfish and marine algae. Arctic char, sablefish, salmon including Atlantic and Chinook varieties, sturgeon (and its roe), tilapia and trout are among the finfish while clams, mussels, oysters, both Atlantic and Pacific, and scallops are examples of the shellfish being farmed. As for marine plants, Canadian farms are cultivating various species of kelp, moss and seaweed in the Atlantic provinces. Marine algae farming is yet another segment of the industry.

Aquaculture takes place in diverse settings, among them salt-water or marine environments, freshwater lakes and rivers and land-based ponds or tanks. Fish farming can be found in every province and in the Yukon. The choice of setting depends on a number of factors including the species being raised, what the environment is, such as marine or freshwater, and the actual conditions where the farming is taking place.

Environmental impact initiatives

As aquacultural practices have expanded, there have been concerns about their impact on the environment. But the industry has been working towards ways to optimize aquaculture production while decreasing the environmental impact of this type of farming.

One solution is called Integrated Multi-Trophic Aquaculture (IMTA). Instead of growing only one species, or what is called monoculture, and focusing primarily on the needs of that species, IMTA instead farms a combination of different types of species together where each benefits from growing together.

Think of it almost like aquacultural recycling. One example of IMTA is where finfish are grown together with mussels and sea cucumbers alongside seaweeds. The leftover feed, fish wastes and by-products from the finfish are used by mussels and sea cucumbers alongside seaweeds for growth. This type of farming mirrors natural ecosystems where a variety of species grow together with beneficial results.

An added benefit of IMTA for fish farmers is that some species such as mussels and sea cucumbers can ingest various microbes that cause diseases in finfish.

There are also other initiatives underway where the water containing fish waste is being turned into a valuable resource as it’s not just being used to produce clean water but also yields fertilizers for agriculture along with biogas, a mixture of gases that is a renewable energy source.

In British Columbia, at a First Nation’s tilapia farm, instead of simply getting rid of the fish waste in nearby lagoons as was done previously, the biogas produced is now being used to heat the water for the fish in place of gas and wood chips.

Another initiative involves the Manitoba-based Myera Group  and their fertilizer production. They have been working to reduce the environmental impact of aquaculture in a unique way. They have been developing the technology to use the water containing the fish waste as a fertilizer during the summer growing season to grow a highly nutritious wild rice. This rice has been historically harvested by Indigenous people as traditional medicine and food source.

To use the fish waste all year round, Myera is using an indoor setting to produce a specific algae strain. They have been collaborating with scientists and traditional healers to use this algae as a traditional medicine to address the vision loss that is associated with diabetes and is extremely prevalent in Indigenous communities.

There’s no doubt that as environmental issues continue to arise, aquaculture practices are indeed evolving to both meet the greater demand for food while, at the same time, creating sustainable methods.