Walk with Us Through the Decline of Chesapeake Bays Native Oyster and the Rise of Its Alien Cousin
Times of Virginica
Our native oysters are in a world of trouble. The byproducts of our habitation of Chesapeake Country have made the Bay a tough place for oysters to live. At the same time, our appetite for oysters has outgobbled the resource. Now few and weak, the Bays remaining oysters are dying of infection by the microscopic oyster predators dermo and MSX.
In finding ways to keep Crassostrea virginica alive, weve pushed the limits of human ingenuity. Scientists and entrepreneurs have tried hundreds of variations on seed, seed-planting and reef building. Even turning Baltimores hallowed Memorial Stadium into oyster reefs hasnt turned the tide.
|photo courtesy of PaynterLab of University of Maryland Center for Environmental Science
A restored reef of native Chesapeake oysters.
For perspective, the Chesapeake Bay Foundation scores the Bays health on a scale of 100 each year, measuring against the pristine standards recorded by Captain John Smith on his explorations of some 400 years ago. Since the first year of scoring in 1998 the oyster fishery has suffered a stagnant score of two.
Marylands oyster harvest peaks at 15 million bushels. Some 32,000 Marylanders earn their livings in the oyster industry. The conservation-minded cull law setting a size limit on catches is passed.
2,559,112 bushels of native oysters harvested from Chesapeake Bay.
Disease delivers a shock, dropping harvests to 1,481,942 bushels, a 28-percent decline from the previous season.
The last season to top one million bushels, with 1,557,091 harvested. Two thousand to 3,000 oystermen still work the waters.
The oyster harvest hits a record low: 70,618 bushels.
Chesapeake Bays oyster harvest bottoms out with 53,000 bushels. The disastrous season sees record high infections and, between dermo and MSX, a range of infection between 88 and 94 percent of Bay oyster sites.
Maryland Department of Natural Resources Shellfish Division projects this seasons harvest at a mere 15,000 bushels
Only 279 oystermen are active, down from 437 last season and 1,293 in 2001
Over the past decade, oyster processing plants have diminished from 30 to three.
The future for at least four years out is very bleak, says DNR shellfish expert Chris Judy. Drought from 1999 to 2002 incubated disease with warmer, saltier waters. The rains of 2003, though fortuitous for some sites, were not enough to turn the tide. Much more rain is needed if new spat sets the industrys hope for recovery are to thrive.
University of Marylands Horn Point hatchery aims to counter failing natural production, with farm-raised spat dispersed to corners of the Bay with low disease pressure. Recently established sanctuaries give new oysters the time and space to grow.
More hope comes from new disease-resistant native oyster strains, DEBY and CROSBreed, bred under supervision of the Virginia Institute of Marine Science. Successes in Virginia tributaries have spurred the Army Corps of Engineers to plan spreading millions more of the disease-resistant DEBY strain oysters throughout the Chesapeake with hopes of reestablishing self-sustaining reefs. Most will probably die of disease, but survivors may anchor revival.
- O Oysters, come and walk with us!
The Walrus did beseech.
A pleasant walk, a pleasant talk,
Along the briny beach.
f rom Lewis Carrolls poem The Walrus and the Carpenter
in Through the Looking-Glass
Longer than memory has Americas eastern oyster, Crassostrea virginica, flourished in Chesapeake Bay. Asian cousin Crassostrea ariakensis is a newcomer thats barely touched these waters. In less time than weve known ariakensis name, that balance could reverse.
Virginia and Maryland, the Bays oyster states, are nowadays sounding a lot like Lewis Carrolls walrus in wooing ariakensis.
Will we will be lured (and devoured) like the young oysters in Carrolls poem if we pin our hopes for restoring oysters and oystering in Chesapeake Bay on a foreign oyster, Crassostrea ariakensis, the Suminoe or Asian oyster?
Only time will tell.
|photo courtesy Virginia Institute of Marine Science
Ariakensis oysters, at top, outgrew natives, at bottom, in Virginia trials.
So as the plot thickens like a rich oyster stew, we bring you the Bay times of those oyster cousins.
The Thickening Plot
Debate over Crassostrea ariakensis seesaws pro and con. In this century, Virginia scientists at the Marine Resources Commission and boosters at the Seafood Council, as well as some Maryland and Virginia watermen, have supported Asian oysters as the most promising solution for revitalizing the industry. Ariakensis grows more than twice as fast as the native Chesapeake Bay oyster, and it is resistant to dermo and MSX, diseases that have ravaged native oysters.
Now ariakensis also has powerful Maryland friends, with Gov. Robert Ehrlich on its side and the states Department of Natural Resources stirring the pot.
But other scientists and environmentalists remain skeptical about how non-native oysters might behave in the wild, worrying that the alien species could overtake Bay and coastal waters. Topping that worry is concern about what will become of the years of effort and the millions of dollars spent to restore native oyster reefs in the Chesapeake Bay.
The middle road, espoused by the National Academy of Science, has been to keep those aliens caged until theyve been better studied. But year by year, native harvests drop and pressure builds to reoyster Chesapeake Bay by any means possible.
Ariakensis is a wide-ranging native species in the Far East, where it has also been aquacultured. The oyster originally inhabited the Ariake Bay in Japan, from which it takes its name. But the species died off there between 1925 and 1940, a mass mortality attributed to a rapid rise of water temperature and salinity.
In Chesapeake Bay, temperature and salinity both run the gamut. Salinities range from ocean-salty 28 parts per million at the mouth of the Bay in Virginia to nearly fresh up high in the Bay and its tributaries. Keep salinity in mind, because it turns up again in full-salt 30 parts per million coastal waters.
Another Asian oyster, Crassostrea gigas was introduced in the Bay back in the 1960s. Gigas is the oyster that repopulated the Pacific Northwest coast, but it did not thrive in low-salinity Chesapeake beds.
Virginias Marine Resources Commission first considers introducing another Asian oyster, ariakensis, to the Bay. At the time, Virginia Institute of Marine Science professor Roger Mann said the worst-case scenario is that these animals will spawn, spread up and down the Bay and displace the native oysters. We are up against the wall here. But we are in the situation of potentially having to take a risk here.
Alien oysters on trial throughout our region are produced at Virginia Institute of Marine Science to be aquacultured in trays or mesh bags, not seeded in free-water oyster beds. Theyre also genetically engineered to be non-reproducing.
The Virginia Legislature directs the Virginia Institute of Marine Science to begin a study of non-native oyster species for possible introduction to the Chesapeake Bay. First studies confirm that gigas is not the species for Chesapeake Bay.
Seeking another candidate, researchers at Virginia Institute of Marine Science begin to produce sterile ariakensis for controlled studies.
In the short term, ariakensis is considered as an annual crop to be farmed and harvested in plots of Chesapeake waters. In the long term, its talked of as partner, if not a successor, to virginica.
Virginia Institute of Marine Science releases data showing that gigas has poor commercial potential. But ariakensis shows promise, and Virginia Marine Resources Commission the equivalent of the fisheries branch of the Maryland Department of Natural Resources approves the Institutes marketability proposal for this oyster.
2000 ~ Steps toward testing Ariakensis
Chesapeake Bay Program approves Virginia Institute of Marine Sciences marketability proposal to test ariakensis.
Virginia Seafood Council asks permission to test 6,000 ariakensis deployed in floating cages at six open-water sites.
|photo courtesy of University of Maryland Center for Estuarine Studeis
Mountains of cleaned oyster shells at the Horn Point facility await seeding and replanting.
Virginia Marine Resources Commission approves Virginia Seafood Council request for in-water tests.
Limited tests begin; Virginia aquaculturists grow sterile ariakensis seed oysters in Virginia waters.
Chesapeake 2000 Agreement commits to increasing native oysters tenfold by 2010
The watershed partnership of the states Virginia, Maryland, Pennsylvania, the District of Columbia, the Chesapeake Bay Commission and the U.S. Environmental Protection Agency signed historic agreements in 1983 and 1987, establishing the Chesapeake Bay Program partnership to protect and restore the Chesapeake Bays ecosystem.
Now, they reaffirm their partnership, committing to achieve by 2010 a tenfold increase in native oysters in the Chesapeake Bay, based upon a 1994 baseline. By 2002, they agree to develop and implement a strategy to achieve this increase by using sanctuaries, aquaculture, continued research into oyster diseases and developing disease-resistant oysters plus other management approaches.
2001 ~ Score a big one for Ariakensis
Asian test oysters in Virginia rivers grow to market size nearly twice as fast as native oysters, thrilling Virginia watermen and fueling debate among state and federal agencies over introducing the foreign species to Bay.
In nine months, said Jim Wesson, who directs oyster restoration for the Virginia Marine Resources Commission, every one of the ariakensis had reached market size with no mortality, while the virginica that survived and a great many were dead are still not at market size.
Lose two for Ariakensis
Maryland Department of Natural Resources advises against introduction fearing unforeseen consequences.
No matter how impressive the results, Chesapeake Bay Foundation says there can be more to ariakensis than meets the eye. Advising caution in a December Position Paper, the Foundation calls for substantial scientifically validated information about the ecological risks and benefits. Also seeks independent review by the National Academy of Sciences.
Stay the native oyster course
In December, the Federal Agencies Committee of the Chesapeake Bay Program asks the Bay Partners to stay the course with the oyster strategy to which we committed in the Chesapeake 2000 Agreement. The Committee asks the partners to oppose introducing ariakensis unless environmental and economic evaluations show low risk. The fear is that introduction may worsen disease problems and detract from funds and efforts of the Chesapeake 2000 commitment to a tenfold increase in native oysters.
Encouraged by big, fat, healthy oysters after testing 6,000 ariakensis at six sites, the Virginia Marine Resources Commission approves the Virginia Seafood Councils request for continued testing. In an upsized trial, 60,000 neutered oysters are planted at 13 sites from the James River, up the Potomac on the Western Shore and up to Pocomoke Sound on the Eastern Shore. These oysters will have to pass the more difficult real-world test of growing on Bay bottoms rather than in floating cages. The councils members, seafood packers and processors, offer to pay for the experiment.
Help! National Academy of Sciences called in
The Chesapeake Bay Commission calls on the independent academy of the nations top scientists to convene an expert panel to consider ariakensis and set future guidelines.
The Virginia General Assembly votes to establish a commercial aquaculture industry for the production of genetically sterile crassostrea ariakensis.
But the Assembly also votes to keep ariakensis out of the Bay for now.
At the same time, Virginia gives scientists three years to find fault with the fast-growing, disease-resistant Asian.
If such research fails to prove, within three years, that the Crassostrea ariakensis will be harmful, House Joint Resolution 164 concluded, the General Assembly suggests the introduction of the reproductive disease-resistant Crassostrea ariakensis into the public waters of the Commonwealth.
National Academy of Sciences agrees to review the ariakensis issue.
The Maryland General Assembly approves research on ariakensis
Federal agencies including NOAA, EPA and U.S. Fish and Wildlife Service and state agencies from Maryland and Virginia announce a project to examine the ecological and socio-economic risks and benefits of open-water aquaculture. In other words, theyre looking at direct introduction of ariakensis into Chesapeake Bay.
Virginias director of oyster restoration for the Virginia Marine Resource Commission says the Suminoe oyster offers the best chance for oyster populations in the bay to rebuild.
Rob Brumbaugh, Chesapeake Bay Foundation fisheries expert says, anyone who thinks these Asian oysters are going to be some type of silver bullet is going to be sorely disappointed. Were just not at the point where we should give up on our native oyster.
The partners of the Chesapeake Bay Program follow through on the Chesapeake 2000 Agreement committing to increasing native oysters tenfold by 2010. They release their Draft Chesapeake Bay Comprehensive Oyster Management Plan for rebuilding native oyster populations and improving oyster management. Its steps are managing around disease; establishing sanctuaries; coordinating among oyster partners; and developing a database to track oyster restoration projects.
|photo courtesy of Virginia Institute of Marine Science
Until doubts are alayed, all Ariekensis experiments are kept in floating cages to keep the aliens from comingling with natives.
Virginia Seafood Commission proposes a privately funded trial to cultivate one million ariakensis in 10 locations to determine their economic potential.
Meanwhile, North Carolina considers using Asian oysters to recoup its own loss of native oysters, planning a two-year test of a half-million genetically sterilized oysters, both Pacific (bred from the Japanese gigas oyster) and ariakensis.
2003, January to February
Virginia Marine Resources Commission approves the Seafood Commissions privately funded trial of one million ariakensis.
With the numbers used [in previous research], they didnt have enough to sell them, says Virginia Marine Resources Commissions Wesson.
Approval now rests with the U.S. Army Corps of Engineers (see April) though the U.S. Fish and Wildlife Service also hopes to stop the trial.
Not so fast!
But Chesapeake Bay Program halts the trial until National Academy of Sciences recommendations are published and incorporated into the trial (see August).
2003, April to May
Army Corps of Engineers requires more stringent conditions on Virginias planned introduction of one million ariakensis oysters. The big worry is the possibility that the alien species might bolt and reproduce in the Bay.
Agreeing to wait for National Academy of Sciences study, the Virginia Seafood Council postpones its request for a state permit to dump one million non-native oysters in Virginia waters.
Virginia processors accuse Maryland of sabotaging the project with federal agencies.
Something needs to be done, and it needs to be done now.
Gov. Robert Ehrlich takes an aggressive step, by pushing the Army Corps of Engineers to make an environmental assessment of seeding the Chesapeake Bay with Asian oysters
announces his administration will pursue the feasibility of introducing the Asian oyster into the Bay.
Ariakensis wins funding in Maryland
NOAA National Sea Grant Program commits funding for two ariakensis studies by the University of Maryland to help bolster native Eastern oysters, which have been ravaged by disease. The two-year study will expose non-native species to predators commonly found on Chesapeake Bay oyster bars. But the aliens will be quarantined in a controlled lab setting.
Rebounding from rejection earlier in the year, Virginia Seafood Council submits a substantial revision of its one million-oyster test
Chesapeake Bay Foundation endorses the revised proposal by the Virginia Seafood Council to plant one million sterile Asian oysters in Bay and coastal waters.
We think there may be a real commercial potential for growing sterile oysters in an aquaculture situation, says Charles Epes, of the Foundations turnabout.
We had some concerns last year, being sure that proper safeguards were in place to ensure that theres no chance of inadvertent introduction of fertile oysters. Now controls are put in place to as much as humanly possible avoid reproducing non-native oysters in the Bay.
The one million are triploid oysters, which are bred by the Virginia Institute of Marine Science to contain three chromosomes, thus rendering the bivalves sterile. They are also tested to prove that theyre disease free.
2003, August ~ Slow and steady
After a year of study, the National Academy of Sciences National Research Council releases its report, recommending a cautious go-slow approach to introduction of non-native Asian oysters. Foreign oysters are not a quick fix for Chesapeake Bay, they conclude, urging at least five years additional research before allowing breeding aliens into the Bay. Whats more, the Academy reports surprise that no federal regulatory approval is required, leaving new species introductions up to the states. Still, the Academy says that aquaculture of sterile oysters may help our ailing oyster industry.
The Chesapeake Bay Program watershed partners praise the study, sharing concern over possible rogue introduction of the Suminoe oyster.
Trouble brews in North Carolina
Much of the first batch of ariakensis die in the North Carolina test. Fearing a disease, researchers destroy the rest.
Virginia floats nearly one million sterile ariakensis. The trial will last through 2005, with regular sampling. A parallel trial also runs with a sterile, disease-tolerant strain of our native oyster virginica to compare its performance to that of ariakensis.
Maryland Board of Public Works including Gov. Ehrlich and Comptroller William Donald Schaefer gives the go ahead to plant 3,000 caged sterile ariakensis (along with an equal number of native oysters) in Severn River as well as the Choptank and Patuxent. Anne Arundel County environmental officials worry about what unforeseen troubles ariakensis at Severn might lead to.
Army Corps of Engineers must approve trial (see February, 2004).
One million dollars for one million ariakensis
Nearly one million federal dollars are promised to support Virginias one-million ariakensis test with cosponsoring Virginia Seafood Council. NOAAs Chesapeake Bay Fisheries Research Program makes the award to Virginias Center for Innovative Technology.
Ariakensis shows its Achilles heel
A parasite protozoan of a genus previously unknown in the region, Bonamia, is found in ariakensis that died in North Carolina.
Unanticipated problems like this are why testing is so important. Whether Bay ariakensis will be vulnerable remains to be seen. Salinity in North Carolinas Bogue Sound is 30 parts per million; Chesapeake Bay salinity ranges from 28 at its mouth to less than 10 in many oyster-growing regions of Bay.
This doesnt seem to be an issue of C. ariakensis introducing an exotic disease to the native oyster, its an issue of a local parasite causing problems in C. ariakensis, says Eugene Burreson, the Virginia Institute of Marine Science researcher who identified it.
$1 million is dedicated by Maryland for research on fast-growing ariakensis as Marylands DNR plans to test its own ariakensis stock before years end.
2004 , January
High salinity is blamed for loss of ariakensis to parasites off North Carolina coast.
High salinity also made ariakensis vulnerable in its native waters as well as in France. With lower salinity levels, Maryland may have better luck.
The Virginia Institute of Marine Sciences experiments on the newly discovered parasite, Bonamia, to learn if it will thrive in lower-salinity waters like in Chesapeake Bay.
The U.S. Army Corps of Engineers joins with Maryland and Virginia in a multi-year study to analyze the environmental impact of Proposed Introduction of the Oyster Species, Crassostrea Ariakensis, Into the Tidal Waters of Maryland and Virginia.
Public hearings begin on establishing naturalized, reproducing, and self-sustaining population of this oyster species. In other words, were talking about free-breeding ariakensis in Chesapeake Bay.
Join the debate in Annapolis at 7pm Monday, January 26, at Radisson Hotel, 210 Holiday Court, Annapolis; free: 410/224-3150.
As ariakensis is evaluated, the Corps pledges to continue native oyster restoration efforts throughout Chesapeake Bay.
First ariakensis trials in the Maryland Bay.University of Maryland Center will run side-by-side tests of 1,300 virginica and 1,300 ariakensis in cages at three spots: the Severn River at the Naval Academy, the Patuxent River and the Choptank River.
The project is permitted, but were still working on some conditions with the Army Corps of Engineers, says principal investigator Kennedy Paynter.
We feel real good about this study, if its conducted with all the safeguards, for it will teach us some things we desperately need to know, says Chesapeake Bay Foundations Bill Goldsborough.
Gov. Ehrlichs target for planting breeding ariakensis in Chesapeake Bay.
Endpoint for Virginias one-million ariakensis trial.
Year set by Chesapeake Bay Program in 2000 for increasing tenfold the native oyster populations in Chesapeake Bay from its 1994 base.
written and compiled by Sandra Martin, M.L. Faunce and Mark Burns
Dermo and MSX have together ravaged the Chesapeakes native oyster population. Both diseases thrive in waters with high salinity and temperatures above 68 degrees Fahrenheit.
Dermo has festered in the Gulf of Mexico since about 1950 and appeared in the Bay as early as 1954. In the late 1980s, the disease hit the Chesapeake in force. Because southern strains of oysters have been subjected to Dermo for so long, these oysters may have developed natural immunities that Bay stocks, which are terribly susceptible, do not have.
MSX (multinucleted sphere x) has proliferated rapidly along the East Coast since 1957, when it was first documented in Delaware Bay. Two years later it invaded the lower Chesapeake; now the parasitic disease ranges from Maine to Florida.
to the top