Oysters May Be Functionally Extinct Throughout Much of the World

empty oyster shell photo

Photo credit: Abi Skipp/Creative Commons
Oysters play an important role in their native ecosystems by filtering impurities from the water. In addition to this, they provide an important source of income for the fishermen that harvest them.

But worldwide, oyster populations are declining. The problem, a recent study shows, is that as much as 85 percent of their reefs worldwide have been destroyed.Based on work started in 2009, a team of researchers from the Nature conservancy and the University of California, Santa Cruz, have published a comprehensive study of the world's shellfish populations in BioScience, the journal of the American Institute of Biological Sciences.

oyster farm photo

Most of the oysters people eat are not wild caught, but grown to market size in farms, like this one. Photo credit: L'eau Bleue/Creative Commons

According to the study, the situation is even more grim than that initial number indicates. In 70 percent of bays and 63 percent of eco regions, oyster reefs are at 10 percent of their former abundance. What remains of the population exists in just five locations, all in North America.

The authors explained:

[Oysters] are functionally extinct—in that they lack any significant ecosystem role and remain at less than one percent of prior abundances in many bays (37 percent) and ecoregions (28 percent)—particularly in North America, Australia, and Europe.

In most places, trawling and dredging projects that damage a portion of a reef. What remains is left vulnerable to other environmental stresses.

Any reef with less than 10 percent of their former abundance, the authors suggest, should be closed to harvesting until the populations can rebuild themselves.

Read more about oysters:
85% of World's Oyster Reefs Already Gone, Many Functionally Extinct
UK Oysters Could Be Tapped to Generate Electricity
Saving the Oyster, and the Bay: Shell Recycling Program Replenishes Endangered Oyster Population

Oysters May Be Functionally Extinct Throughout Much of the World

Related Content on Treehugger.com