Oysters in danger of extinction

By Astrid Madsen - 14 Feb 2011 15:1:1 GMT
Oysters in danger of extinction

Over the past century 85% of oyster reefs have been lost globally, and in most bays 90% of them are functionally extinct. That's according to a study published in the journal Bioscience by a team of American marine scientists.

This is not only bad news for those who like to eat the mollusks, it's also worrying for the world's ecosystems. Oysters filter harmful pollutants and clear up the muddy waters they inhabit, all of which is quite important to keep bays clean of suspended solids and nitrates. As ''ecosystem engineers'' oyster reefs also help protect our shorelines from erosion and storms and provide a habitat - and food source - for fish, crabs and birds, among others.

Oysters are in fact not only threatened by external factors such as alterations in freshwater flow but also by decades of over harvesting, which in the case of trawling has led to sedimentation. Damage continues to be made by oysters being harvested without considering the impact it has on the reefs, and by the introduction of non-native species to replace native ones despite this practice being linked with an increased risk of disease. Oysters are, perhaps unsurprisingly, quite resilient and as such the vast majority of the reefs affected were significantly damaged not by one but by multiple causes.

The researchers point to some of the work being carried out worldwide on protecting and restoring/recovering reefs, highlighting that much can still be done, especially with regards to how restoration is perceived, including the notions that reefs are navigation hazards.

But little has actually been done to successfully protect oyster populations, and most reefs continue to be over harvested. This is in large part due to many stakeholders not believing this to be a major problem and to the perception that replacing native species with non-natives species is a successful strategy. Still, the researchers say that habitats can be successfully recovered - for all of those oyster lovers out there, let's hope they're right!