The Extinction of Oysters

oysters filter water

Oysters are filter feeders that filter water naturally as they feed.

Yes, you read that right. According to a recent study of oyster habitats around the world, these mollusks are disappearing, and 85 percent of their reefs have been lost due to over-harvesting and disease. Most of the remaining oysters in the world can be found in five locations in North America.

The study involved an international team of researchers led by Michael Beck of the Nature Conservancy and the University of California, Santa Cruz. They examined the condition of oyster reefs in 40 ecoregions and found that they are at less than 10 percent of their prior abundance in most places.

While they are not officially extinct, the researchers claim that they are “functionally extinct”, meaning they lack any significant ecosystem role. What does that mean for us? Well, besides the fact that they provide food and employment to people living in coastal areas, oysters are important to ecosystems because they are some of nature’s best water filters. Known as “filter feeders”, they consume harmful pollutants while feeding. As we have mentioned before, an adult oyster can filter up to 60 gallons of water a day, which is more than most reverse osmosis filters can do. In addition to the mollusks, themselves, oyster reefs are also constructed to naturally purify contaminated waters.

In order to avoid complete extinction, any reefs with less than 10 percent of former abundance should close to further harvesting until the numbers rise again.