Will there be enough fish to go around? Not if we follow healthy eating guidelines

That’s the two portions for this week sorted then. EPA

Will there be enough fish to go around? Not if we follow healthy eating guidelines

That’s the two portions for this week sorted then. EPA

Globally, we still catch enough fish to eat – just about. But numbers of fish caught from the sea haven’t kept up with human population growth and unsustainable fish farms have filled the gap. So why are we still being encouraged to eat more fish?

The health benefits are clear: fish protein is typically low in saturated fats and high in nutrients and essential fatty acids. UK and US food standards agencies recommend eating two portions of fish per week, while Australia, New Zealand and Estonia advocate two or three servings per week and Greece five or six.

Yet as our recent research has shown these health recommendations must be set against a backdrop of declining global fish stocks and food security concerns. While in the UK fish constitutes just one choice of animal protein among many, one billion people throughout the world rely upon it as their primary source of animal protein and our global fisheries are in crisis.

Healthy living, 1930s style. British Trawlers Federation

Some fisheries do exist that successfully balance production and sustainability, but many more are under increasing pressure from over-exploitation, destructive fishing practises like trawling and dredging, pollution or other factors. As the world’s population continues to expand these pressures are likely to intensify, not decrease.

Over the past 50 years fisheries have rapidly expanded and today fish is one of the world’s most globalised commodities. The UK is typical: the fish you buy in supermarkets comes from all over the world. Cod and haddock are sourced from Iceland and Norway, while much of our tuna comes from the Indian Ocean, South-East Asia and West Africa. Shrimp and prawns are sourced from Asia, Iceland and Canada. The UK also exports fish – mainly mackerel, herring and farmed salmon – to the EU, the US and Russia, although far less than it imports.

Fish and chips

For a nation surrounded by the sea, the British have never been especially ardent lovers of fish. Before the advent of freezers and swift transport networks you could understand why; fish spoils rapidly unless salted or smoked. However, railways built in the mid-19th century provided reliable transport to inland markets for the first time and helped drive the expansion of industrial fisheries around the UK. Subsequently, the British developed a taste for fish, although mainly when covered in batter and deep-fried.

Cod: best in batter. Niall Carson/PA

National recording of landings and fishing effort began in the 1880s and help us chart the development of the UK’s fisheries. Fuelled by steam power and ice, accessible fishing grounds expanded to the Arctic, North America and Africa during the early 20th century and the total catch grew rapidly. However the formation of exclusive economic zones in the late 1970s forced a return to home grounds and it became ever more apparent that fish had been over exploited and stocks were seriously depleted.

Government records show that landings of fish by UK vessels peaked in 1913 at 1.27m tonnes and declined throughout the remainder of the 20th century. Today, a significant proportion of UK vessels land their fish abroad, but even accounting for these ships domestic production is still half what it was a century ago.

This can be partly attributed to a loss of European markets during and after the war, and restriction of traditional fishing grounds from the 1970s, but many fish stocks are also at historically low levels. During this period, the UK population has also increased and to keep up with demand as well as diversify our fish supply, greater and greater quantities of fish are sourced from other nations’ waters. Clearly, fish supply is not merely a domestic issue and policies that support increased consumption at the national level must also strive to adopt a more global outlook.

For example, the quantity of domestic fish available (through landings and aquaculture) per person in the UK plummeted throughout the 20th century, with overall supplies only kept stable by imports. But even despite this declining supply UK consumers still eat less fish than the recommended two portions (280 g) per week, which is fortunate really, since only twice in the past 120 years have supplies been sufficient to meet this aspiration. If demand should rise further, either through population growth or changes in consumer preference, it is likely that even more extra fish will have to be sourced from other nations.

Increased imports are not necessarily an indication of unsustainability, but they do demonstrate the potential for developed nations to mask domestic shortfalls in wild fish. This experience is not just restricted to the UK: Europe imports around 55% of the fish it consumes; last year the US imported 91% of its fish.

Global total wild fish capture and aquaculture production in million tonnes. FishStat

While developed countries are able to mask domestic declines, this is not the case in societies that rely upon fish as their major source of protein. Global wild fish landings plateaued at 85-95m tonnes during the 1990s. However, when human population growth is taken into account, wild fish availability per person has been in decline since 1970.

Global fish supplies have only been stabilised by increasing aquaculture production, which is currently exceeding the pace of human population growth. Yet fish farms come with associated environmental costs of habitat loss, pollution, introduced species, pests and diseases, which will need to be addressed if aquaculture production is to keep up with future population growth.

Though aquaculture has so far prevented a downturn in global fish supplies, many developed nations continue to aspire to consume more fish than they produce. Until demand is balanced with sustainable methods of production governments should consider carefully the global social and environmental implications of national policies that promote greater fish consumption.