Is fish farming a growing industry?

More than one half of all fish consumed by humans has been farmed, and Finnish people also eat more farmed than wild-caught fish. Is fish farming sustainable, and what does its future look like?

The most common species farmed in Finland is the rainbow trout, in addition to which common whitefish, brown trout, Arctic char and other species are also farmed to some extent. The outlook for the industry is good, as there is a growing demand for fish. Finnish fish farms face competition from imported fish, however.

Pollution causing eutrophication from fish farms has cast a long shadow over fish farming. It may have a high impact locally, even if fish farming only accounts for around one per cent of all nutrient emissions in Finland.

The harms can be reduced by technical means and by selecting suitable sites for farms. The methods to be selected depend on whether the fish are kept offshore in cages, or in purpose-built ponds inland. In land-based fish farming, the water can be treated and circulated back into the pond. This reduces nutrient emissions to one fifth, or even one tenth, of that generated by conventional fish farming.

Nutrients are also cycled at offshore farms if, for instance, the fish are reared on feed made from Baltic herring caught in the sea. This does not eliminate local harms, however, which can be reduced by keeping fish farms away from sensitive areas. In the future, offshore fish farms will increasingly be located in the outer archipelago, or even in open sea areas. This means that sturdier cages will be needed to endure rough seas and currents. Structures of this type are already in use in other countries.

Fish farming is subject to permits referred to in the Environmental Protection Act and the Water Act, which enables the authorities to influence the locations of farms and regulate the pollution they generate.