Salmon farming methods and operations

How will global warming affect our salmon farming industry?

  • Salmon farming requires water temperatures of 8 – 14 degrees Celsius. Recently water temperatures in Hobart ranged from 11 to 15 degrees, and there have been large fish losses during heat spikes, most recently in the Tamar River. Global warming means that our ocean temperatures are rising quite rapidly, and will continue to rise, which will make current salmon farming marginal at best within a few years.
  • Worldwide, the salmon industry is exploring moving to colder deep ocean areas. But there is a much greater effort towards raising salmon ashore in huge tanks, using water that is filtered and recycled with fish waste removed and used for agricultural fertiliser. Tasmania is falling rapidly behind.

How does industrial open-pen salmon farming work?

Salmon production takes about 3 years. Hatching occurs in controlled freshwater environments, usually on land, and when the salmon are about a year old, they are transported to seawater pens. They reach a harvestable size after 12-18 months, then they are killed and prepared for sale.

What do they feed the salmon?

Farmed Atlantic salmon are fed pellets of fish feed. The Food and Agriculture Organisation of the United Nations states that:

Several protein supplements such as high-quality fishmeal, plant protein products (soybean meal, corn gluten meal, canola meal, pea meal), animal by-product meal (poultry by-product meal, meat meal, blood meal, hydrolyzed feather meal) and crustacean meal (krill, shrimp, crab) are used in salmon feed formulation . . . Several feed additives are added to salmon feeds to enhance growth, flesh pigmentation, physical properties, digestibility, osmoregulation, palatability and preservation of the feed. Several carotenoids, including synthetic astaxanthin and canthaxanthin, and certain natural supplements such as yeast (e.g. Phaffia rhodozyma), algae (e.g. Hematococcus pluvialis) and crustacean products (e.g. krill and shrimp) are used to impart an attractive pink-red colour to the salmon flesh. . . . Antioxidants such as ethoxyquin are added to fishmeal and fish oil to increase their stability. (FAO Aquaculture Feed and Fertilizer Resources Information System. Downloaded 15 May 2023)

This introduces several problems:

  • Poultry by-product meal is the ground up waste from intensive farming, including beaks and feathers, and may contain residual medications such as antibiotics used to manage sickness and promote growth in hens. This is a possibility even if there are no antibiotics added during the salmon farming itself. For more information on antibiotics, see our Food Quality page.
  • Ethoxyquin is banned as a food additive in Europe. For more information on this, see our Food Quality page.
  • Most importantly, krill are an absolutely vital part of the food chain in Antarctica, and are being ruthlessly exploited by commercial fishing operations, including those that service the industrial salmon farming industry. This threatens the very existence of all animal life higher up the food chain, from small fish, and penguins, through to whales. (see “We thought we’d saved the whales. Were we wrong?” Amanda Hooton, Sydney Morning Herald Good Weekend, 13 May 2023)

Surely fish farming on land would be too expensive, just as contaminating, or just too impractical?

  • Any potential contamination from closed-loop fish farming can be strictly monitored. The main effluent from a fish farm is faeces – and that’s a good agricultural fertiliser which is easily marketed.
  • The set-up costs of closed-loop fish farming ashore are considerable. However, the costs of running the installations is far less than the cost of maintaining fish pens that require towing, cleaning, repairing and protecting from weather.
  • Land based operations are intrinsically safer for staff, and cause less stress and harm to salmon stock.
  • Is salmon farming on land viable? The Tasmanian industry says no, but does not provide any evidence for their exaggerated cost and energy claims. Here is a simple analysis of the current situation, showing how land-based aquaculture is increasing around the world (4 pages, PDF). Here is a report of the development of a $750 m RAS facility in Saudi Arabia -the Saudi kingdom plans to produce 600,000 tons a year by 2030.

Surely fish farming out at sea would be too expensive, and incredibly difficult and dangerous?

  • Scandinavian producers have developed ways of farming fish in deep, stormy ocean waters. There are no shortage of industry leaders overseas for Tasmanian fish farmers to follow.
  • NOFF is neutral on the economics of such methods when it comes to the smaller Tasmanian enterprises, but we suspect that moving onshore would be more economically viable.

Does the technology exist to move on-shore or off-shore?

Yes. The past decade has seen huge investment overseas in developing RAS (recirculating aquaculture systems – land-based fish farming) – even in Dubai, hardly the coldest place in the World. One of the largest RAS facilities in the USA converts the waste to fertiliser for their own enormous hydroponics farm producing two million kilos of salad greens a year. The Saudi government plans to produce 600,000 tons a year in land-based RAS facilities – mostly for export.

The Tasmanian industry claims to have RAS systems, but this applies only to about half of their hatcheries, and all their salmon are matured in open pen setups at sea.

There is a risk that overseas operators, or overseas owners, will establish land-based facilities on the Australian mainland, close to their main markets, and Tasmania will not be able to compete.

And now that all the Tasmanian companies are overseas owned, what is to stop them using our hard-earned environmental reputation and branding to market products farmed and processed overseas?