Wild oysters are now “functionally extinct” in many places where they were once plentiful.
More than 85 per cent of their reefs have been lost through overfishing, a study says.
The decline of the mollusc is so severe that three-quarters of the world’s remaining stock can be found in only five locations in North America.
And in once famous harvesting sites such as Britain’s Essex coast, the Wadden Sea off the Netherlands and Narragansett Bay, off Rhode Island, only 1 per cent of reefs remain.
If nothing is done to protect remaining wild oysters, they could disappear within a generation, says Dr Michael Beck of the University of California, Santa Cruz.
Dr Beck led a team of marine biologists who examined 144 former strongholds of the creatures in 40 regions around the world. The overall condition of the various species is poor, concludes the largest ever investigation into wild oyster stocks, published in the journal BioScience.
Their loss is important since they play a vital role in filtering impurities from sea water, supporting fish populations and preventing coastal erosion.
The oil spill in the Gulf of Mexico hit the one place in the world native oyster catches had stayed at historical levels. The disaster destroyed as much as half of the most productive reefs, Beck estimates. “Oyster reefs are at less than 10 per cent of their prior abundance in most bays (70 per cent) and eco-regions (63 per cent),” reads his study.
“They are functionally extinct, in that they lack any significant ecosystem role and remain at less than 1 per cent of prior abundances – in many bays (37 per cent) and eco-regions (28 per cent), particularly in North America, Australia and Europe.”
The fate of wild oysters is starkly apparent when weighed against their role in history. During the time of the Roman Empire, they were abundant enough to keep the English Channel crystal clear. As recently as the late Victorian era, they were thought of as a staple food of the working class.