At a glance
The Food and Agriculture Organisation currently estimates that 70 per cent of all worldwide fish stocks are either fully exploited or depleted. Indeed, if current trends continue, it’s thought that fish stocks may only last for another 50 years.

This isn’t an issue restricted to a few overfished regions; it’s estimated that edible fish are endangered in nearly all of the world’s fishing areas. And neither is it restricted to a few select species; fish of all kinds are under threat: swordfish, herring, skate, haddock, anchovies – they’ve all reached alarming levels of depletion in certain parts of the world.

We’re taking more fish out of the sea than ever before, using more technologically advanced methods: huge, floating factories stay at sea for months at a time, tracking schools of fish with sonar and processing their huge catches instantly using on-board freezing and canning facilities.

What is the impact?
Bigger trawls, using huge nets with small mesh sizes have led to the problem of by-catch, where other marine life is caught and then discarded. The most well-known example is of dolphins and porpoises being caught up in trawls for tuna, but sharks face a similar problem and there are other alarming statistics being generated: for every tonne of prawns that’s caught, it’s estimated that three tonnes of other fish are killed and thrown away.

If one species dwindles, those further up the food chain also suffer. Intensive fishing for krill in the Antarctic Ocean is now widespread, but we have no idea of how this will affect the whales, seals and penguins relying on it as a food source.

The necessity of allowing nature to replenish fish stocks is crucial – not just from an ecological perspective, but for our own survival. Fish plays a crucial part in our diets; on average we consumed 16.2kg each in 2002.

We also depend on fish economically, with 200 million people earning at least some part of their income from fishing and related activities. Coastal communities often rely on a good daily catch for their livelihoods, and the devastation of fisheries will in turn devastate local economies – the most notable example being the collapse of cod stocks in Newfoundland.

What measures are being taken?
It would be wrong to say that the world is standing by and doing nothing about the problem. Ever since the first overfishing conference in London back in 1936, all manner of international agreements have been put in place in order to try and safeguard our fisheries.

Much work has been by the UN, including their Convention on the Law of the Sea and programmes of action to protect the marine environment. Regional Sea Conventions and Regional Fishery Bodies continue to work to protect specific regions of the world against overfishing. But all these good intentions are powerless if the rules cannot be enforced and illegal catches are allowed to continue.

What can we do to help?
As consumers, we have a collective responsibility to reduce our demand for fish that are under threat.  Firstly, look for the Marine Stewardship Council’s ecolabel on packaging; this indicates that the fish therein is the product of environmentally responsible fisheries management.

With oceans being cleared at twice the rate of the forests, it's certainly worth us all taking a moment to think when we buy fish, and exercise a little consumer choice to help combat the serious problem of overfishing.