Rethinking salmonoid supplies with land-based farming

Article 1/3: What is a Recirculating Aquaculture System (RAS)?

As global demand for salmonoids continues to rise, and coastal fish farms face mounting pressures, salmon processors face challenges around supply consistency, product quality, and sustainability pressures. The exciting industry sector in the aquaculture industry is gaining traction and could offer a compelling solution. Land-based salmonoid farming using recirculating aquaculture systems, though still in its infancy, represents a fundamental shift in how we can approach fish production and processing.

Land-based aquaculture has been around for millennia; there is evidence of carp being farmed in China as early as 1500 B.C. Since then, the industry has proven its value as a way for communities to achieve self-sufficiency in fish products. The last 100 years have seen rapid development of the industry with the introduction of granulated fish food in the 1950s, and the invention of lightweight, hardwearing materials such as fiberglass and plastic tubes to use in cages and tanks. As technology changes so does the possibility of what is now possible in aquaculture.

A solution to a strained industry?

In theory, land-based fish farms would allow multiple fish species to be bred anywhere in the world, regardless of proximity to oceans and seas, dramatically reducing transportation times and costs. While local energy costs, water availability, and market access must be carefully evaluated, the potential to revolutionize supply chains is undeniable. Even accounting for these variables, the reduction in travel distances from farm to processor, the reduced risk of lice and disease common in coastal-based operations, and the high-quality of end products being seen in land-based farms, represent significant operational advantages.

Understanding the current technologies: RAS & FTS

Two technologies lie at the heart of modern land-based aquaculture; Flow-through systems (FTS) and Recirculating aquaculture systems (RAS).

First in the industry was FTS (also known as Raceway) which relies on water continuously flowing through raceways and tanks - this has been used in farming freshwater species including trout, catfish and tilapia land-based trout farming, as well as juvenile marine species of salmon, sea bass and sea bream. FTS requires a constant water supply, which is why they are often built on diverted riverways or springs to utilize the nature drop of the river to provide continuous flow to provide oxygen and self-cleaning of the tracks or tanks. Traditional FTS designs can struggle with heavy effluent accumulation on tank floors, increasing disease risk and compromising fish health.

Early commercial RAS aquaculture was seen in Europe during the 1980s and 1990s. They are now used to produce both fresh and marine species including trout, shrimp, turbot, and salmon. Unlike FTS, RAS creates a closed-loop environment with sophisticated water treatment and recirculation capabilities, which means they can reuse the same water again and again, dramatically reducing freshwater intake.

In a RAS water temperature and current flows can be regulated to keep fish growth steady. The farming method can minimize disease and enable the removal of virtually all waste and minimize pollutant discharge of water through recycling. The RAS closed-loop system improves biosecurity and containment, which reduces exposure to external parasites and pathogens; tank isolation can also limit spread. However, RAS farms still face internal disease risks, and biosecurity must be actively managed.

In the 1970s Norway floated what was regarded as the first coastal salmon farm. Large floating cages made it easy to feed the fish and kept predators out. Coastal-cage farms have minimal control of their environment; changing ocean temperatures, lice and disease can affect the health, growth and mortality rate of the fish. In recent years, coastal farms have made headlines with high fish losses and damage to natural ecosystems.

The distinctions between the technologies demonstrate how RAS fisheries could offer farmers and processors an entirely different level of control. Understanding the technologies is the first step to answering the big question for producers and processors: what can the latest developments in RAS aquaculture mean at an operational level?

In the next article, we'll explore how RAS technology can address supply chain challenges, improve yields, and create quality end-products by integrating directly with processing facilities. Translating into tangible benefits in the high-growth market for salmon.

Share this page:

Login to get full access

Enter password to continue