May 21st, 2009 · No Comments

From Green Right Now Reports

A new report released today by The Nature Conservancy says 85 percent of oyster reefs have been lost worldwide and they are now the most severely impacted marine habitat on the planet.

“We’re seeing an unprecedented and alarming decline in the condition of oyster reefs, a critically important habitat in the world’s bays and estuaries,” Mike Beck, senior marine scientist at The Nature Conservancy and lead author of the report, said in a statement. “However, realistic and cost-effective solutions within conservation and coastal restoration programs, along with policy and reef management improvements, provide hope for the survival of shellfish.”

The Nature Conservancy said the report is the first comprehensive global analysis of the state of shellfish. It was written by scientists across five continents, from conservation organizations as well as academic and research institutions. The report was released today at the International Marine Conservation Congress in Washington, DC.

In addition to being a culinary favorite and a long-standing staple in seafood restaurants around the globe, The Nature Conservancy said oysters provide benefits to humans in less obvious ways. They act as natural water filters and improve water quality, provide food and habitat for fish, crabs and birds, and serve as natural coastal buffers that help to protect shorelines and keep coastal marshes intact, an important factor in protecting communities against storm surges and sea-level rise.

A number of conditions threaten oysters around the globe, according to the report:

• In the majority of individual bays around the world, there has been a greater than 90 percent loss of oyster reef habitat and in some areas, the loss of oyster reef habitat exceeds 99 percent.  Globally, 85 percent of oyster reefs have been completely lost.
• Reefs are functionally extinct in many areas, particularly in North America, Australia and Europe, and no are no longer able to provide any ecosystem benefits to people.
• Most of the world’s remaining wild capture of oysters comes from only five regions on the east coast of North America, and in most of these regions, oyster reefs are in poor condition or worse.

The report says the driving forces behind the decline of oyster reefs include destructive fishing practices, coastal over-development, and associated effects of upstream activities such as altered river flows, dams, poorly managed agriculture and poor water quality. Many of these threats have been around for decades and even centuries, but today there are two main issues that impede oyster recovery efforts.

According to the report, the first is a widespread lack of awareness that shellfish habitats are in trouble. In nearly all cases, shellfish are managed as fisheries, meaning they are viewed solely as a commodity but are not valued for the intrinsic role they play in keeping marine ecosystems healthy and intact. The second challenge is the common perception that as native shellfish decline, non-native shellfish can act as an ecologically suitable replacement. But previous introductions of non-native oysters and other shellfish into new areas have spread disease and have had other negative impacts on the surrounding environment.

The report lays out specific recommendations drawn from examples around the world, such as the need to elevate native, wild oyster reefs as a priority for habitat management and conservation, carry out large-scale restoration programs, and make better use of protected area policies for shellfish protection.

“We want to raise awareness that the world’s remnant oyster reefs and populations are important, since they may in fact represent some of the last examples of reef habitat produced by a particular species of oyster,” Christine Crawford, a scientist with the Tasmanian Aquaculture and Fisheries Institute at the University of Tasmania in Australia and a co-author of the report, said in a statement. “We have an opportunity to conserve such reefs in Australia and elsewhere with the results of this assessment.”