Oyster reefs once thrived along Europe's coasts – now they're gone
Oysters once formed vast reefs along much of Europe's coastline – but these ecosystems were destroyed over a century ago, new research shows.
Åsa Strand, oyster expert at IVL
"The presence of oysters creates favourable conditions for many other organisms, and was thus beneficial for biodiversity. Moreover, oysters played an important role in stabilising shorelines, circulating nutrients and filtering water", says Åsa Strand, researcher and oyster expert at IVL Swedish Environmental Research Institute, who participated in a major research study that has now published its results in the journal Nature Sustainability.
Because of their economic and cultural significance, oysters have featured in historical documents such as newspapers, books, travel diaries, records and charts, as well as in early scientific studies. In the study, information from 225 different historical sources published over the course of almost 400 years was compiled.
The study shows that in the 18th and 19th centuries, European flat oysters formed large reefs along the coasts of Europe. The researchers found evidence of oyster reefs from Norway to the Mediterranean, and that the reefs covered at least 1.7 million hectares, an area larger than Northern Ireland.
"Oysters are still present in these waters but they are dispersed, and the reefs they formed are gone. Nowadays we often think of our seabed as a flat, muddy expanse, but in the past many places were a three-dimensional landscape of complex living oyster reefs", says Ruth Thurstan, researcher at the University of Exeter.
Oyster reefs develop slowly in the wild, but destroying them through overfishing went relatively quickly, the study shows. Today only a fraction of the oysters that once existed in European waters remain, and the reefs are almost completely gone. But it is not too late to do something about the disappearing oyster reefs. Restoration projects are underway across Europe – but efforts need to be scaled up.
"Although oyster numbers in Sweden declined over the same period as in Europe, we have a unique situation today with a ban on destructive fishing methods and the absence of parasites that cause problems for oysters in other areas. This means that Sweden has one of the largest oyster populations and the highest oyster densities in Europe, and can serve as a reference area for restoration", says Åsa Strand.
Read the article in Nature Sustainability: Records reveal the vast historical extent of European oyster reef ecosystems
External link, opens in new window.
The study was partly funded by the European Research Council, and the research was led by the University of Exeter and the University of Edinburgh.
For more information, contact:
Åsa Strand, asa.strand@ivl.se, tel. +46 (0)10-788 66 05