Pregnant blue crabs that survive a gauntlet of crab pots, scrapes, trotlines and dredges will now get a bigger break as they prepare to launch their eggs into the water.

The Virginia Marine Resource Commission in May voted to greatly expand its deepwater spawning sanctuary for blue crabs, the Bay’s most valuable fishery.

The action, which places all areas more than 30 feet deep in Virginia’s portion of the Bay off-limits during the summer, is expected to protect up to 75 percent of the spawning females that live long enough to make it to the sanctuary.

“It’s a very large area, and it protects an enormous percentage of the sponge crabs,” said Jack Travelstead, fisheries director for the commission. “I think we are going to see some very significant things come about as a result of it.”

The new sanctuary will ban any crab fishing in the bulk of the state’s portion of the Bay — nearly 950 square miles — from June 1 through Sept. 15, when females travel toward the mouth of the Chesapeake to spawn. It increased by a third the amount of protected area for crabs. Previously existing sanctuaries at the mouth of the Bay and in areas more than 35 feet deep had been aimed at protecting 40–50 percent of the spawning females.

The expansion helps the state meet the Baywide goal of reducing fishing pressure by 15 percent. In that role, it is doubly helpful. It not only reduces fishing-related mortality, but by focusing on protecting the spawning stock, the action results in more larvae being released, potentially leading to greater production.

Rom Lipcius, a blue crab researcher at the Virginia Institute of Marine Science, estimates that while the sanctuary reduced the overall blue crab exploitation by only 6 percent, it can help increase crab abundance — the ultimate goal — by 15 to 20 percent.

The expansion also suggests growing interest in sanctuaries as an alternative to traditional methods of reducing blue crab mortality, which have focused on restricting the sizes of crabs harvested, the types of gear used and when harvesting can take place. Those regulations are often complex because the crab’s many life stages are fished at different times, in different places, with different types of gear.

By contrast, the sanctuary is an “off-limits” zone that is easy to enforce. In less than two hours, a plane can fly the entire sanctuary and spot any buoy marking an out-of-bounds crab pot. No violations were observed all of last year.

And, while different groups of watermen often contend they are disproportionately affected by a particular rule, the sanctuary is generally considered to affect everyone more or less equally.

Also, because no harvesting of any type is allowed, it prevents non-target crabs from being inadvertently harmed, Travelstead said. For example, some research shows that if “sponge” crabs — females with a developed sack of eggs — are taken out of the water, they often die after being returned to the Bay. And even if the crab survives the trauma, the eggs frequently do not.

“So you can put limits on sponge crabs, but if they are still being brought to the surface, the regulations may not be having the full effect that is intended,” Travelstead said. “One nice thing about the sanctuary is there is no gear in that area. Those crabs never come out of the water.”

Virginia began experimenting with a blue crab spawning sanctuary decades ago when it established an area near the mouth of the Bay as a safe haven for female blue crabs. The females, after migrating up the Bay and its tributaries to mate, return to the mouth of the Bay to hatch larvae from their eggs into saltier water, from where they are carried into the coastal ocean. Months later, a postlarval stage returns to the Chesapeake and settles in shallow areas, mainly grass beds.

The initial sanctuary was expanded with a protected area on the Eastern Shore side of the Bay’s mouth in 1994. Together, the two areas protected about 195 square miles.

But research by Lipcius and his colleagues at VIMS, Rochelle Seitz and Buck Stockhausen, showed that most female crabs didn’t make it to the mouth of the Bay until late summer, and the small size of the sanctuary was protecting only a fraction of the spawners.

Nor was it stemming a decline in the crab population. From 1992 through 2000, VIMS surveys indicated the spawning stock biomass — a measure of the size of the spawning population — declined by 80 percent.

The problem, according to Lipcius, wasn’t that the sanctuary was a bad idea — it was just too small. His research showed that during the summer, deep areas had higher abundances of adult females moving toward the mouth of the Bay, while adult males, juvenile males and juvenile females were most dense in habitats shallower than about 40 feet.

Although crabbers historically had not targeted deepwater areas during the summer, that was beginning to change in the mid-1990s, as crab populations declined elsewhere.

As a result, Lipcius in 2000 proposed — and the VMRC approved — setting aside a deepwater corridor that would selectively protect adult females en route to the spawning grounds, while the remainder of the stock would remain available to crabbers. Altogether, that placed about 660 square miles off-limits.

Protecting the spawning crabs is particularly important, Lipcius said, because many marine species around the world have been overharvested when they are targeted in spawning areas where species typically congregate.

But, Lipcius cautioned, the sanctuary cannot do the job alone: The potential number of spawners has already declined substantially because of harvests by the time they reach the protected area.

“They basically have to run a gauntlet before they get down to the spawning sanctuary,” Lipcius said. “That is why the spawning sanctuary is only a foundation. It protects them once they get to the spawning ground.”

Further, the sanctuary only protects one life stage — the spawning females. By curbing pressure there, it could shift fishing pressure onto other life stages, he cautioned. “You have to protect them both inside the spawning ground as well as outside the spawning grounds where they are maturing,” Lipcius said.

While that job can be done with traditional regulations, part of it might also be accomplished by sanctuaries. This year, as an alternative to expanding the deepwater sanctuary, Lipcius had proposed a series of four shallow water sanctuaries in rivers. Those would be connected to the existing deepwater sanctuary via a migratory corridor that would also be off-limits to harvesting.

The idea was to protect a portion of the blue crab population during its entire life cycle by setting aside some of the underwater grass beds and mud flats where juveniles and adults spend much of their lives.

While the deepwater sanctuary expansion drew little complaint at the May VMRC meeting, the alternate idea of setting aside shallow areas — where many watermen were actively harvesting — drew much stiffer opposition. “We shouldn’t have to pay for his experiment,” one waterman told the commission, which rejected the idea.

Still, Travelstead called shallow water sanctuaries “the next generation of the concept of sanctuaries.” The problem is that — unlike the deepwater sanctuary, which is seen as affecting everyone equally — targeting a specific creek will disproportionately affect local watermen. Further, a good sanctuary also has high-quality habitat, something that also makes it a hotspot for crabbing.

“You are not going to put some barren mud bottom in the sanctuary where it probably is not going to be as productive,” he said.

Because of the wide array of additional regulations that have gone into effect in the past two years, Travelstead said it was unlikely the commission would reconsider the shallow water extensions anytime soon.

But that doesn’t mean the idea is dead. Tangier Island watermen have expressed interest in the concept, and Lipcius plans to work with them, and the commission, to see if an experimental area can be set aside. If that happens, he wants to further experiment with the release of hatchery-reared crabs into grass beds to see if they can help bolster the population. “You don’t want to release them into an area where they are going to be caught,” Lipcius noted.

In addition, he is exploring the potential of eventually expanding the sanctuary into Maryland.

Right now, scientists and managers agree that is not practical for a variety of reasons. Virginia’s deepwater spawning sanctuary is only in place during the summer. At that time of year, many of the deep water areas in Maryland suffer from anoxia — or lack of oxygen — so those areas can’t be used by crabs. Female crabs do move down the Bay from Maryland in the fall and spring, but they are not protected in Virginia’s deep waters at those times.

“For Maryland to declare a mid-Bay sanctuary in the summer doesn’t accomplish anything,” said Bill Goldsborough, a fisheries scientist with the Chesapeake Bay Foundation. What would be useful, he said, would be a year-round migration corridor in the deep portion of the Bay, something the CBF had proposed in 1995. “We continue to think that something like that would be helpful,” he said.

But that would require action not only by Maryland, but also Virginia which would have to restrict its winter dredge harvest. “It would become compelling for Maryland to take similar action if Virginia were to extend the corridor sanctuary into the fall and spring,” Goldsborough said.

Anson “Tuck” Hines, a biologist with the Smithsonian Environmental Research Center in Edgewater, MD, agreed a that migratory corridor in Maryland would be useful, but said it may not have to be set in place all year. Recent research suggests that the bulk of the migration in Maryland appears to take place in the fall.

But scientists don’t have enough information — yet — to know just when and where a sanctuary would be effective if it were extended across state lines.

Hines, working with Tom Wolcott, a professor at North Carolina State University, has begun placing computer chips in captured crabs and releasing them into the Bay. The chips provide data about both the crabs’ movement and water conditions they encounter.

Ultimately, the information may provide clues about the migratory paths used by crabs and when they use them. That, in turn, may help to develop more effective Baywide sanctuaries.

If such work results in a potential Maryland sanctuary, Travelstead said the VMRC would consider revising its rules to make it work.

“If there were things that would have to be done down here to accommodate something up there, certainly we would take a look at that,” Travelstead said. “We would be very interested in having Maryland take a look at that and adopt some type of sanctuary in their portion of the Bay. At the same time, we recognize that each state has to design measures that they think are best for its fishery.”

But scientists and managers agree that further sanctuaries are not imminent. Fisheries managers and watermen alike have both indicated that regulations have changed so much in recent years that they want no further changes in the near future.

Hines said expanded sanctuaries could someday make life easier for regulators and watermen alike.

He and others caution that sanctuaries alone would likely never replace crab management. But if sanctuaries can eventually provide a foundation for protecting all life stages, it could turn out to be good not only for crabs, but for crabbers, because it may allow some of the more onerous, or complex, regulations to be removed or relaxed.

“A large component of management could be done by sanctuaries and I think that would leave a lot of area to be fished, and in so doing it would leave people freer to fish without such an array of complex regulations,” Hines said.