As wild fish stocks are being harvested to capacity and global demand for seafood continues to grow, some sectors are espousing that land-based salmon farms are the answer. At present, most land-based farms operate for smolt production. So how economically viable is it to raise salmon on land through harvest size? And what are the implications?
The International Salmon Farmers Association (ISFA) sought to “facilitate the dialogue” with its global report released in October, The Evolution of Land-based Atlantic Salmon Farms.
According to the report, it appears that the odds are stacked against land-based salmon farming. “This report shows that farming Atlantic salmon in their natural environment — the ocean — is the responsible way to farm. Until that changes, we will do what we do best: use the marine and freshwater resources in the most efficient and considered way, in both marine and land-based systems, to help feed the world,” said ISFA president, Trond Davidsen.
Challenges that were identified were related to energy, fish welfare, water and land use, and socio-economic realities. Pictographs effectively illustrated the significant amount of energy and natural resources it takes to raise salmon on land compared to its natural environment.
Land-based farms mimic the natural environment conditions such as flow, temperature and oxygen, necessitating high consumption of energy. To circumvent high cost of power consumption, a study suggested choosing sites with cheap power and located close to key markets. Savings in power consumption, however, will not reduce its carbon footprint.
For land-based Atlantic salmon farms to be profitable, the report suggests farmers have to raise fish at much higher densities than in marine systems. Two of the key indicators that salmon in land-based systems may not be thriving are precocious maturation and decreased or subnormal growth rates. Raising an all-female salmon population may be the solution to precocious maturation.
There is also the challenge of pathogens contaminating a land-based system. Once this happens, notes the report, it is virtually impossible to remove the pathogen unless the system is depopulated and all the biological filters are disinfected.
Water and land use
The report stressed the amount of water and land used to raise salmon on land. Growing 75,000 tons of salmon in a 99-percent RAS system would require 4.16 billion liters of water just to fill the tanks.
Meanwhile, it said that to move Canada’s current production to a land-based system would require 136 square kilometers of land, which could fit 28,000 Canadian football fields.
A land-based indoor salmon farm is more than three times as expensive to operate as a traditional ocean salmon farm, according to a study by the Freshwater Institute and Norwegian research organization, SINTEF. “This could ultimately have a negative effect on the sector’s contribution to the global economy as well as tax contributions in respective countries, provinces and communities,” the report said.
ISFA said it “will continue to collaborate with researchers, governments and ENGOs to understand the socio-economic and environmental realities of land-based fish farming systems, both the opportunities and limitations, to advance the technology and apply it on a case-by-case, species by-species basis as technology advances.”
Some land-based proponents acknowledged the challenges cited in the report, but wondered whether some facts and figures were skewed to exaggerate the situation.
“We all know that there are certain limitations in land-based RAS production. That said, the sea sites have a certain threshold in production capacity and, in my opinion, the large increases in production on the sea is on the wane. Therefore, I do believe that the market is ready for a limited introduction of production on land. We will therefore see some major investments in this market in the years to come,” said an industry stakeholder.
— Ruby Gonzalez