85% of all oyster reefs worldwide have been destroyed, with 75% of all the remaining reefs in poor condition.
Where they were
Oyster Reefs used to be a common occurrence throughout the world, but due to harvesting and degradation of the population there are now few left. Oyster Reefs used to be located all around the world, especially around the Americas
Why they were destroyed
Oyster reefs have been destroyed for centuries, mainly by dredging. Dredging is the process whereby the seabed is practically just scooped up, stripping the oysters from their reefs. This has happened to the extent that 85% of oyster reefs have been exploited. The main cause of this disappearance is over fishing. Other reasons include disease, degraded habitat and pollution.
Where they are now
The current oyster reef situation is very poor but there are still some oyster reefs in good condition, especially in the Gulf of Mexico. There are also patches around southern Australia, New Zealand, West Europe and around the Americas.