One of the biggest problems for the Chesapeake Bay oyster is that too many people expect too much from the filter-feeding bivalve.

Watermen want to harvest them to make a living; biologists want their reefs, which serve as habitat for a host of other species; and cleanup advocates want a return of their water-filtering abilities.

"This is the image I have," said Bill Eichbaum, vice-president of the World Wildlife Fund. "I've got one oyster. Some people want me to take that one oyster and make it be an economic force. Others want to make it be an ecological force. It's impossible, even it you multiply them by a million."

Eichbaum chairs the Maryland Oyster Advisory Commission, which was created by the General Assembly in 2007 to find an approach for both the ecological restoration of oysters in the Bay and a revitalization of the oyster industry.

In its recently released report, the commission said the best way to achieve both goals was to separate them. It called for setting aside large sanctuary areas to allow for the ecological recovery of oysters, while commercial harvests increasingly come from aquaculture.

Today's depleted oyster population cannot rebound to levels that would provide ecological values while also supporting harvests, the report concluded.

"If we want to get more oysters, if we want to get more people working, if we want to get Maryland oysters back in the marketplace as a quality brand, we cannot do it based on a wild fishery," Eichbaum said. "We have demonstrated that for the past 20 years."

The Maryland Department of Natural Resources will consider its recommendations as it updates the state's oyster management plan this spring.

Oyster populations in the Bay are at a fraction of their historic level because of disease, overfishing and loss of habitat. Maryland's portion of the Bay was once filled with thousands of boats and harvesters; there are only a few hundred working the six-month season today.

Rebuilding the state's once-robust oyster industry would mostly take place "through the development of sustainably-managed aquaculture," the commission's report said. That would also allow the growing of oysters year-round, rather than just providing oysters to the market during a few months of the year.

That follows the global trend. Nearly 95 percent of the oysters harvested worldwide are grown in some form of aquaculture. Research funded by the National Oceanic and Atmospheric Administration's Chesapeake Bay Office in recent years showed that growing sterile native oysters in aquaculture can be economically viable in the Bay, and an increasing portion of the Virginia harvest comes from aquaculture.

But to make that transition, the report said the state needs to revise laws that inhibit private cultivation of shellfish in the Bay and its tributaries. It also cited the need to create a streamlined permit process to encourage production.

The report said the state must create a strategy that includes education, training and startup funding to help watermen make a transition to aquaculture.

In many respects, the commission's recommendations are in line with those stemming from a five year, 1,500-page Environmental Impact Statement released last fall that examined oyster management options in the Chesapeake, including the potential use of nonnative oysters. That report also called for separating ecological restoration goals from commercial goals by switching commercial production to aquaculture and having a moratorium on wild harvests.

The Maryland commission-which evaluated only the use of native oysters-stopped short of calling for a moratorium, but said that what fishery remained in public areas should be managed much differently.

Instead of limiting the harvest through daily catch limits during the oyster season, it called for establishing a maximum number of oysters that could be sustainably harvested each year, based on annual population and habitat surveys.

When it comes to restoration, the report has a simple message: Think big. Rather than restoration projects measured in a handful of acres, it said projects should encompass entire river systems.

"We are talking about major area closures," said Donald Boesch, president of the University of Maryland Center for Environmental Science, who is a member of the commission's ecological workgroup. "Not just temporary, but indefinite."

Those sanctuaries would be designed to conserve the remaining oysters and reefs, and would in some places be large enough to link low-salinity areas, where survival is high but reproduction is poor, and high-salinity areas, where survival is poor but reproduction is more successful.

The sanctuaries would be permanent to promote the development of disease resistance by protecting "survivor" oysters, and restoration efforts should be focused in those areas.

But the price tag is also huge. The commission in 2007 estimated that it would cost $40 million annually for at least 10 years to support oyster recovery and the transition from a wild fishery. That figure is in line with cost estimates in the oyster environmental impact statement.

But that's also more in a single year than has been spent Baywide in the past 15 years.

Boesch acknowledged that it was unlikely the state would have that much money for oyster restoration. But, he said, it was important that political leaders realize that restoring oysters-even in a single tributary-would require significantly more money than has been spent in the past.

"This is not doable with just fairly small investments, even if we continue this over a fairly long period of time," he said. "It would take a ramping up of efforts to make a difference."

Much of the money is needed to build and rehabilitate habitat. Many of the existing oyster bars have, with the absence of oysters, deteriorated over time or been buried with sediment. Oyster shells for restoration projects are also becoming more difficult to obtain.

The report also warned that a key element of any oyster strategy is to improve enforcement.

It noted that the ranks of the state's Natural Resource Police have declined 40 percent in the last 17 years, contributing to the "rampant theft of oysters" throughout state waters.

"Currently, there is no single factor more important to the future of ecologic restoration and aquaculture than to address and dramatically reduce the ongoing illegal oyster harvesting activities," the report said.

It suggested that fines be increased, and that resource police be empowered to seize vessels involved in illegal harvesting within protected areas.

Establishing larger sanctuaries would also help discourage poaching, Eichbaum said. With the current patchwork of small sanctuaries, it is often difficult to determine whether a boat is operating within a reserve. "If you have it all closed, if it looks like they're oystering, then they're probably illegal," he said.

Grappling with the future of the Bay's oyster population has been the subject of many studies and committees over the years, but Eichbaum said there is "a very clear sense that everybody recognizes that we cannot tinker the way we did in the past."

Still, even with the major changes recommended in the report, recovery will likely be measured in decades, not years, he said. "if we succeeded in two decades," Eichbaum said. "it would be a great accomplishment for the state and the Bay."