Bay Journal

Maryland looking at Virginia’s oyster management method

VMRC’s repletion expert warns that rotational harvest is no silver bullet

  • By Timothy B. Wheeler on November 13, 2016
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A waterman harvests oysters from the Nansemond River. The use of power equipment to haul up oysters is limited, with areas opened to “hand-scrape” and dredging on a rotating basis every two or three years. (Dave Harp)

As Maryland watermen seek to shake up their state’s management of the Chesapeake Bay oyster fishery, they’re looking south, where landings in Virginia’s public fishery last year were six times what they were a decade ago.

Maryland’s wild harvest has actually surpassed Virginia’s in the last four years, as it enjoyed a similar boom. With a strong tradition of private oyster farming, Virginia gets more bivalves from leased bottom areas than from its public fishery.

But it’s the way that the Old Dominion manages its public fishery, rather than the overall result, that has drawn the interest of its northern neighbors.

Virginia regulates the harvest on much of its public oyster grounds on a rotating basis. Oyster reefs are opened to boats using power gear — dredges or smaller, motor-driven “hand scrapes” — only once every two or three years, and then for just a portion of the October through May harvest season. The schedule is staggered so some reefs in every part of the Bay are open at any one time.

To hear Jim Wesson tell it, the state more or less backed into its rotational harvest system about a decade ago, as managers tried to keep watermen from rapidly depleting reefs that had just been restocked with oyster shells.

Wesson is the long-time chief of oyster conservation and replenishment for the Virginia Marine Resources Commission. A former waterman, Wesson has a Ph.D. in wildlife ecology and more than two decades of experience in oyster management. With Maryland watermen expressing an interest in trying rotational harvest in their end of the Bay, that state’s officials recently invited the Virginian to brief Maryland’s oyster advisory commission on rotational harvest.

“It started in the Rappahannock (River), in an area where we did a major restoration,” Wesson recalled in an interview. The area was initially closed to harvest, to give juvenile oysters, or spat, a chance to grow to market size after they had settled on reefs.

That normally takes three years. But back then, the oyster diseases MSX and Dermo were rampant in the Bay and killing bivalves before they could be harvested. With landings seriously depressed, watermen lobbied successfully to open part of the restored area so they could take what was there before it died.

Once those reefs were depleted, Wesson said, watermen began to press to open the rest. Worried that the restoration would be short-lived if that happened, VMRC officials negotiated with watermen to divide the lower Rappahannock into six regions, and to open two areas a year in different parts of the river.

“They wanted to get in the lower areas so bad they were willing to go with rotation,” Wesson said. “If we had started from scratch, it would not have taken off.”

When reefs are closed for two to three years at a time, Wesson explained, oysters have time to spawn, and their young can grow without being hurt by constant harvest pressure. Even though watermen are supposed to throw back any oysters smaller than 3 inches, they’re often lost for good as the reef itself is torn up by the heavy metal dredging gear.

By forcing watermen to wait, the rotational harvest not only prevented the rapid depletion of oyster reefs, it resulted in a bigger overall catch, Wesson said.

“You get more bushels than if (they were) harvested every year,” he said. But to realize those rewards, he noted, “you’ve got to put up with some pain.”

Since then, rotational harvest has been extended to the York River and Mobjack Bay, to the Great Wicomico River and to Tangier and Pocomoke sounds. Meanwhile, Wesson said, the major threat to the survival of the Bay’s oysters — and to the viability of the oyster industry — has shifted. The diseases have abated; now, he said, the main challenge is harvest pressure itself.

“We have to control the harvest,” Wesson said, “in order to keep something out there for the watermen to harvest down the road.”

Virginia watermen have accepted it, for the most part. “I think overall, it’s been successful,” said J. C. Hudgins, acting president of the Virginia Waterman’s Association. “There’s so much pressure on the oyster resource now, two or three boats work an area for 30 days, they clean it up pretty good. It takes three years to grow back.”

Other areas in Virginia’s portion of the Bay are open on a yearly basis to hand tonging, the traditional scissors-like rakes on long wooden shafts that watermen with strong backs have used since the Civil War to muscle oysters from the depths. But Wesson said that the hand-operated gear is so inefficient that watermen wielding it give up on working reefs once the oysters thin out to a certain point.

The motorized gear, though, is so effective that watermen can still catch their limit even when the marketable bivalves are widely dispersed. Any surviving adult oysters left can be so far apart that they have trouble connecting to reproduce. The gear also wreaks havoc on young bivalves, Wesson said, tearing up the reefs by breaking up and scattering the shells on which they’re growing.

That’s an unpopular view among watermen in both states, who insist that “working a reef” is vital to maintaining a healthy oyster population. Like a farmer plowing a field, they say, dredging turns oyster shells over and knocks off potentially smothering silt. But Wesson called that “an old wives’ tale” not borne out by the evidence. Surveys in Virginia have found, he said, that after watermen work a reef for just one month with hand scrapes to get the large, market-size oysters, 90 percent of the spat, or newly settled baby oysters, are destroyed.

“It’s pretty clear that working the bottom hurts; it doesn’t help,” he said. “They are not farmers; they are harvesters.”

Wesson’s views on oyster sanctuaries proved more to the liking of Maryland’s watermen, who want to be allowed to work in some of their state’s extensive network of areas closed to harvesting. To them, the rotational system sounds like the proverbial win-win.

“Really, it’s better than a sanctuary,” argued Robert T. Brown, president of the Maryland Watermen’s Association. Leaving the reefs alone for a while means the oysters perform the ecological role for which the sanctuaries were established, Brown said, filtering water and providing habitat for other fish. But then by allowing harvests every few years — maybe even four or five, he suggested — watermen can collect the older oysters on the reefs, which he contended are bound to get infected by disease and die if left in the water.

Wesson said it’s unclear what, if any, benefit oysters enjoy in sanctuaries beyond being spared from harvesting. Surveys have found that the reefs in Virginia’s sanctuaries have no more oysters or better spat set than those nearby that are regularly harvested, he said.

Even so, the Virginia shellfish manager said he wouldn’t support eliminating his state’s sanctuaries, which tend to be smaller than Maryland’s. They’re natural monitors, he said, for the impacts of disease and harvest on the overall oyster stock.

“They’re canaries in the coal mine,” he said. “You need them there to know what’s going on.”

Virginia’s rotational harvest system could still use some tweaking, Wesson said. The Tangier and Pocomoke areas are open every two years instead of three, and the landings from that region have plummeted of late. He’s proposed lengthening their rotation to three years, but watermen have successfully resisted that. Meanwhile, the James River, home of Virginia’s most productive oyster grounds, is open every year, and the hand-scrape harvest there is expected to be down this season.

Even with rotational harvest, Wesson said, the fishery is showing signs of stress. The rebound in oyster stocks that came as diseases abated has brought a resurgence in the number of watermen seeking to harvest the bounty. So many, in fact, that they’re having a hard time catching enough lately to make a living. The VMRC has responded by trying to reduce the number of oyster harvest licenses.

Maryland has seen a similar surge in its oyster industry, but the state’s oyster advisory commission is talking about opening sanctuaries to harvest rather than controlling the amount of harvest pressure.

To Marylanders considering emulating Virginia’s rotational harvest system, Wesson offered some cautionary advice.

First, he said, the reefs put in rotation need to get a dependable spat set of new baby oysters, or there won’t be a new crop to harvest every few years. That’s more likely to happen in the saltier waters in Virginia, he pointed out — in Maryland’s lower salinity water, good natural reproduction occurs less frequently.

Another key, he said, is ensuring that the shells on the reefs remain in good condition. That, he said, is his big concern for the future of the public oyster fishery in the Bay.

Oysters create shell as they grow, and their shells provide the foundation for succeeding generations, as initially free-swimming oyster larvae need hard surfaces on which to settle. But Wesson said the Bay is suffering a net loss in reef habitat — they disintegrate naturally over time, and their destruction is hastened by being repeatedly raked over by harvesters.

The VMRC gets $2 million a year from the General Assembly to replenish reefs where the shell stocks have been worn down by harvest pressure. But Wesson said that’s nowhere near enough — the VMRC this year was only able to pay for dredging up or buying enough shell from oyster-packing houses to replenish about one third of the 1,500 acres of reefs in need of rebuilding.

“We don’t have enough oysters creating enough shells to replace what’s lost,” he warned. “We are always losing shell, and if we don’t put shell back, then we cannot maintain any stability in our oyster beds, and we’ll lose them all.”

About Timothy B. Wheeler
Timothy B. Wheeler is managing editor and project writer for the Bay Journal. He has more than two decades of experience covering the environment for The Baltimore Sun and other media outlets. .(JavaScript must be enabled to view this email address).
Read more articles by Timothy B. Wheeler

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