For some time now, the world's oceans and the people who fish them have been a constant source of bad environmental news. Cod is effectively an endangered species now; every year, thousands of dolphins are drowned and fatally injured by Spanish sea-bass trawlers in the Channel; dredging for oysters and scallops is destroying vast areas of coral reef; huge tuna farms are wrecking the Mediterranean Sea. And when environmentalists aren't pointing fingers at the fishermen, they're pointing them at globalisation and the supermarkets.
Now marine biologists have warned that our seafood is in terminal decline. According to research published in Science last November, stocks of all of the fish, prawns, crabs and lobsters that we currently eat will collapse before 2050. Or at least, that's how the media reported it.
However, the scientist who led the study has told Geographical that the main thrust of his research has been buried beneath the shrill headlines. While the danger to our seafood supply is real enough, says Boris Worm, assistant professor of marine conservation biology at Dalhousie University, Canada, there is a more serious point: that the way in which we manage the oceans is not only threatening the survival of individual species, it's upsetting the delicate balance of marine communities and, in doing so, causing the collapse of entire ecosystems.
Indeed, the evidence is mounting: research published in October has shown that the number of ecosystems where all higher forms of life are extinct, so-called dead zones, has increased from 150 to 200 in the past two years. These include a zone in the Baltic Sea that now has an area of 120,000 square kilometres--about half the size of the UK.
The point that many reports failed to highlight, says Worm, is that we have to revolutionise the way our marine resources are managed, changing the focus from stocks and quotas to biodiversity and ecosystem protection. And in order to do that, we have to change the way the debate about our marine resources is conducted in the public domain and at policy level.
Around 7,500 years ago, retreating glaciers and subsequent sea-level rise created what's known today as the Wadden Sea, a 13,500-square-kilometre area of the North Sea off the coasts of Denmark, Germany and the Netherlands.
During the first 5,000 years or so of its existence, the sea's waters teemed with life: cod, haddock, rays and herring as well as an array of cetaceans, including right whales, grey whales, harbour porpoises and bottlenose dolphins. On the seabed, rich expanses of oyster banks, sea moss stands, mussel beds, sand-coral reefs and seagrass meadows provided food and shelter to all manner of creatures, including pipefishes, sticklebacks, sponges, sea anemones, worms, whelks and sea urchins.
The freshwater rivers, brackish estuaries and coastal lagoons that fed the sea were also brimming with life, including vast numbers of salmon, sea trout and sturgeon. And the peatlands, bogs, salt marshes and mud flats on the coast supported millions of waterfowl, seabirds and shore birds, including such fantastic species as the Dalmatian pelican, white-tailed eagle and the greater flamingo.
This diversity thrived until around 2,000 years ago, when human pressure began to tell. According to research by Heike Lotze, professor of marine ecology at Dalhousie University, Canada, some of the larger whales and birds disappeared more than 500 years ago. And by the late 19th century, populations of most of the small whales, seals, birds, large fish and oysters were severely reduced, leading to the collapse of several traditional fisheries, including haddock, ray, salmon, sturgeon and shad.
The Wadden Sea is one of 12 coastal ecosystems whose histories were analysed in the Science paper. Although they stretched from the northern Adriatic to the Gulf of St Lawrence and from San Francisco Bay to Moreton Bay in Australia, in each case, the story was the same: human interference had led to a decline in the health and productivity of the ecosystem, increasingly so during the past 150 years. …