The FAO believes that we cannot afford to plough up more land for agriculture and we need to derive more protein from the sea. There is a growing realisation, greatly promoted by the United Nations Food and Agriculture Organization (FAO), that we have to start producing much more protein to sustain a growing world population. For Atlantic salmon, the situation is even more desperate.

In 2005, a group of scientists studying the survival prognosis for Pacific salmon concluded that 23% of all salmon stocks in the world were at moderate or high risk of complete extinction. This is partly because it is central to the “food web” (now that we understand the importance of biodiversity and the interdependence of species, this term has replaced the more familiar “food chain”) and partly because of a complicated life cycle that depends on both marine and inland habitat. Complex as the problem of survival is for most fish, few species are faced with as many difficulties as salmon. Our greatest assaults on the environment are visible in salmon. Most of what we do on land ends up impacting the ocean, but with salmon we are able to see that connection more clearly.

That is because anadromous fish – fish that live part of their life in freshwater lakes and rivers and part of it in the sea – offer a clear connection between marine and terrestrial ecology. The salmon, though it belongs only to the northern hemisphere, has always been a kind of barometer for the planet’s health.

Fishing planet money farming