European Coastlines Once Lined with Oyster Reefs, Says New Study

Berlin, 3 Oct (ONA) --- European coastlines were once lined with oyster reefs, stretching from Norway to the Mediterranean, according to a new scientific study published today.

The study, written by 30 European researchers from various scientific institutes, said the reefs would have covered at least 1.7 million hectares.

It said the oyster reefs were destroyed over 100 years ago, mainly from overfishing, leading to a flattening of the seabed.

One of the study's authors, Ruth Thurstan, said that in the past, many parts of the seabed "were a three-dimensional landscape with complex living reefs - now completely gone from our collective memory."

Oyster reefs are formed very slowly, with layers of new oysters forming on the dead shells of their predecessors, explained another of the study's authors, Philine zu Ermgassen.

The complex ecosystems provide habitats for many other animals and, according to the German Alfred-Wegener-Institut, are ecologically as important as coral reefs.

The study, published in the Nature Sustainability journal, said that the oysters stabilise the coastline and filter water, with a single oyster able to filter up to 200 litres per day.

Reduced water quality, sediment deposits and the introduction of pathogens into the environment have led to European oysters becoming virtually extinct across large parts of their original habitat, it added.

Although European oysters can still be found in some places, they usually live individually in the sea and only very rarely form clumps, banks or reefs, the study said.

The researchers recommend that restoration projects for oyster reefs, such as one in the North Sea off the German island of Borkum, should be intensified.

Historical records have previously documented the existence of oysters along Europe's coast, suggesting that the largest concentration of European oyster reefs was in the southern part of the North Sea.

--- Ends/Khalid