Maryland Marine Notes: September-December 2000 Sidebar

Volume 18, Numbers 5-6 • September-December 2000

Sanctuary in the Lower Bay

In June 2000 the Virginia Marine Resources Commission established a 660-square-mile sanctuary that reaches from the Maryland-Virginia line down to an area already protected by previously established sanctuaries. All waters in this area deeper than 35 feet will be off limits to crabbers during the summer, from June 1 to September 15.

These summer months are key for crabs. As the weather warms, female crabs emerge from their winter's rest in the mud and begin to move down the Bay to spawn.

According to Rom Lipcius of the Virginia Institute of Marine Science (VIMS), the females "dribble down" during much of the period from June to September, but twice a year a veritable migration occurs – once in spring, known as the spring peeler run, and again in the fall.

The spring run occurs in May or early June, Lipcius says, when females molt and mate and move down toward the Bay mouth. The fall run occurs largely in September. Females that do not spawn by mid-December will hold eggs and sperm and spawn the next spring, around May, says Lipcius.

Once spawned, blue crab larvae drift like orphans toward the open sea. Fortunately for both watermen and Bay seafood lovers, they return, carried back into the Bay by low-lying high-salinity waters. Once in the Bay they will take their chances not only against an army of predators but also against commercial and recreational crabbers. Now, thanks to the new sanctuary, at least those spawning females that take to deeper waters will have nothing to fear from human predators from June through mid-September in the deeper waters of Virginia's portion of the Bay.

This approach toward conservation has appealed to both watermen and resource managers – to watermen because few pot for crabs in the deeper waters in warm weather, and managers because the sanctuary will prevent fishing pressure from moving into the middle of the Bay even when prices are high and crabs scarce.

"It is important to close off some areas before fishing pressure moves in," says Josef Idoine of the National Marine Fisheries Service, "instead of trying to close off an area already in heavy use."

According to Lipcius, who has closely monitored crab stocks in that region, the deep waters provide a significant site for spawning, and the added sanctuary should help protect some 40 percent of spawning females. "Our recent work has shown that spawning tends to reach from the Rappahannock River down to the mouth of the Bay," Lipcius says. "Spawning appears to move from the upper parts of this region [near the Rappahannock] early in the summer to near the Bay mouth by September." According to Lipcius, until the crab sanctuary was expanded, important parts of the spawning area were not protected, especially the upper part, near the Rappahannock River, during the critical June period.

Most researchers agree that a similar sanctuary would not make sense in Maryland, because of the Bay's bathymetry and a serious lack of oxygen in summer, as well as the general migratory patterns of crabs. Other adaptations of the sanctuary concept could make sense – for example, at other times of the year, perhaps at different depths. "We expect both Maryland and Virginia to take actions to conserve blue crab stocks," says Lipcius, "but we don't expect them to always take the same actions."

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