February 3, 2011

Oyster Populations On The Decline

Experts are calling for some reefs to be closed to oyster harvesting based on research that they claim has revealed that the global population of the mollusk species is declining rapidly.

An international team of investigators, led by Michael Beck, a Senior Scientist with the Nature Conservancy and a Research Associate at the University of California, Santa Cruz, examined oyster reefs in 144 bays across 44 different ecoregions, according to an American Institute of Biological Sciences (AIBS) press release dated February 3.

They discovered that "over-exploitation" of the oyster, which is viewed by many as a culinary delicacy, as resulted in the loss of at least 85% of their reefs, and that three-fourths of the world's remaining population of wild oysters can be found in just five different North American locations, the press release also reported.

"Oyster fisheries there are probably the last opportunity to achieve large-scale oyster reef conservation and sustainable fisheries," Beck and his coauthors write. Oysters provide important ecosystem services, such as water filtration, as well as food for people," the AIBS said.

The study, which has been published in the AIBS journal BioScience, also reported that the oyster is "functionally extinct"--meaning that less than one percent of their previous population remains--in 37% of bays and 28% of ecoregions studies.

The study did not include oyster reefs in parts of South Africa and Asia, however.

According to an AFP article published Thursday, "The authors recommended that any reefs with less than 10 percent of their former abundance be closed to further harvesting until the oysters can build up their numbers again."

Oysters are typically harvested simply by gathering them from their beds, but in some cases--especially in deeper waters--tools such as rakes or tongs are required. The mollusks are scraped off the reefs, piled together and collected.

They can be prepared in any number of different ways, including raw, baked, fried, steamed, stewed, or pickled, and are valued not only for their taste, but also as a good source of iron, zinc, and vitamin B12.


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