Charting a New Course for Oysters in the Chesapeake Bay
By Lori L. Rossbach
Having a viable oyster population in the Bay will have resounding effects on Maryland’s economy—the seafood industry, tourism, restaurants, packing houses, shipping. Envision a Bay full of oysters, our natural filtration system working, once again, to capacity. Imagine how blue crabs and striped bass will benefit from feeding and hiding habitats within thriving reef structures and submerged aquatic vegetation beds.
The challenge of restoring oysters for economic purposes forces us to examine difficult and costly issues related to water quality—how we dispose of waste, be it sewage, industry emissions, or run-off. Fisheries and water quality go hand in hand and we’ve learned that conservation is less costly than restoration, and prevention less taxing than crisis management. Change is in the wind. This is a pivotal year for oyster restoration, and all indicators show that Maryland is poised to move in new directions to revitalize its oyster industry and by default, the health of the Chesapeake Bay.
“Things are coming together like the perfect storm,” says Tom O’Connell, assistant director with Maryland Department of Natural Resources Fisheries Service, speaking of the impending Draft Environmental Impact Statement (EIS) due out next month by the State of Maryland, Commonwealth of Virginia, and U.S. Army Corps of Engineers. The EIS will provide a scientific foundation to set forth recommendations for the future course of oyster restoration in the Chesapeake Bay.
“Oyster management is transitioning into something more economically sustainable, as we develop a new comprehensive plan. With new science we move forward. We are confident we can do a better job and revitalize the industry,” says O’Connell. “Right now 60-80% of the harvest is from the state program, subsidized from the government. The government has a clear role to restore for ecological reasons, but when it comes to industry, the government’s primary role is to prevent overfishing. The Maryland Oyster Advisory Commission suggests that efforts to support the harvest should largely be funded by the industry.
Private Aquaculture
“Every major producing area in the world has transitioned to private aquaculture; this change is upon us. There is opportunity for watermen to get engaged,” says O’Connell.
“If you look around the world, there are very, very few places still reliant on a hunter-gatherer shellfish fishery harvest. Most places are almost exclusively dependent on aquaculture to meet demand,” says Rich Takacs, habitat restoration and native oyster specialist with the National Oceanic and Atmospheric Administration’s (NOAA) Chesapeake Office.
“Aquaculture needs to increase. It’s clear when you look at all the world’s fisheries. People need to recognize it is not the magic bullet, but one of the tools in the tool box. Does is need to take a bigger role? Yes. Are there things changing to facilitate that? Yes,” Takacs said.
One of the components of change includes the creation of the state’s second oyster hatchery at the Morgan State University Estuarine Research Center in St. Leonard, where a $470,000 federal grant will be used to develop a prototype that watermen, interested in private oyster aquaculture, could emulate.
“There are overlying goals to address a lack of availability of larvae and/or spat oysters and for waterman to get engaged in commercial grow-out operations,” says Takacs. “The focus is far more on aquaculture or small scale production by watermen, then for a restoration component.”
“Maryland has been based on a public fisheries for so long; we are still fairly new at this,” says Karl Roscher, aquaculture coordinator with the Maryland State Department of Agriculture. There are currently six private oyster farms in Maryland, from which about 500,000 oysters were grown and harvested last year, and sold to regional restaurants and packing houses at a cost of about 50 cents per oyster, Roscher said. “Right now we’re getting a better harvest off bottom, in floats, but that is a reflection of more oysters being grown that way.”
“Oysters are growing really well in floats. They are off the bottom, where there is less silt, an increased food supply, and more oxygen. They grow to market size in two years versus three years for oysters on the bottom,” says O’Connell.
“It may be that they are more tolerant of disease when they are getting better oxygen, food, etc.,” says O’Connell. “It raises the question: When we rehabilitate the reefs, should we bring them up higher?”
Native Oyster Restoration
“The government’s role is to develop, restore, and manage the oyster population to reestablish ecological functionality; oysters are critical to the health of the Chesapeake Bay,” says O’Connell.
“So far, there is no silver bullet for dealing with disease issues in the native oyster. Our biggest chance, our greatest hope for native oyster recovery is natural disease resistance, and that will take time to evolve. Perhaps 100 or more years. Maybe never, there is great uncertainty,” says O’Connell. “We may have to accept the fact that we will experience significant die offs before we see rebound.”
Since 2000, Maryland has planted over 1 billion oysters, rehabilitated over 900 acres of oyster reefs, and established 22 new sanctuaries. Despite disease pressure and poor water quality, current data suggest over 200 million of those oysters have gotten a foothold and are growing. While restoration work has been concentrated in areas of low salinity, where disease pressures are lower, oysters need high salinity levels to spawn. “In 2008 we will begin to take the best management practices we have established while restoring oysters in low salinity waters, and move that knowledge to areas of higher salinity,” says Stephan Abel, executive director of Oyster Recovery Partnership. “We need to restore a spawning population of oysters in the Chesapeake Bay.”
Current best management practices include the rehabilitation of bars by removing silt and topping the bars with a layer of shell, and then planting disease-free hatchery grown spat (tiny baby oysters).
With limited shell supply, Maryland has been testing alternative substrates for oyster reef restoration, including concrete rubble and stone. “In the right location, if it’s hard, oysters will set on it. From rubble to stone to concrete forms, we have enough data to show that it all works,” said Takacs. “All of them have performed adequately, so what it comes down to is availability and cost factor. Dredged shell is still the cheapest, but not currently accessible. Take away availability of shell, we are forced to look at alternatives.”
According to the Oyster Advisory Commission’s 2007 Interim Report released in January, planting a 6-inch layer of dredged and reclaimed oyster shell costs $14K per acre, compared to about $40K per acre for slag, concrete, or stone.
“We are currently in the stages of planning what projects we will implement,” says O’Connell. “One thought is ‘proof of concept’ restoration projects. For example, begin to identify the most productive bars, protect them, rehabilitate them, and understand why they are productive. Productive means the reef is self-sustaining, the habitat quality is high, the bar has multiple sizes of oysters growing.
“We are evaluating a moratorium in the EIS, and further harvest resistance may be needed, but a moratorium alone won’t restore oysters,” O’Connell says. “We need to address disease issues and water quality in concert with restoration.”
“Oysters are filtering more and more silt, or trying to filter out silt,” says O’Connell. “Then there are issues of dissolved oxygen. Oyster reefs are more susceptible during summer months. Oysters are only so tolerant of low oxygen levels. Reefs in deeper waters are more susceptible to mortality. Water quality goes hand in hand with oyster recovery.
“With regard to land-based management decisions, from local government all the way up to state government, every time a development is approved, a shopping center, etc., at some level we have made a decision that that ‘deal’ is more valuable than water quality and the aquatic resources that live in the Bay,” says O’Connell. “Land-based management and fisheries must go hand in hand.”
Nonnative Considerations
The nonnative Asian oyster species, Crassostrea ariakensis, is currently under consideration for introduction into tidal waters of the Bay. Showing disease resistance and marketability, could this alternative revitalize Maryland’s seafood industry in as little as 10-20 years? Will the Bay’s water quality improve by having more oysters in it?
“Worldwide, non-native oysters have been utilized for over 100 years—on the West Coast and in France they are dependent upon nonnative oysters. It is not a new idea,” says O’Connell. “It seems to be more of a concern here in the Chesapeake. A lot of people relate a non-native to an invasive, thinking it will take over the Bay.”
“The issue about introducing new diseases is really low. There are protocols that minimize the risk of introducing new diseases,” says O’Connell.
O’Connell explains that international protocol prohibits the direct introduction of an imported nonnative marine species, as done in the Delaware Bay in the 1960s which many believe introduced the MSX oyster disease. Instead, imported nonnative oysters must be placed in a closed, quarantine system and induced to spawn. The offspring are then removed and placed in a separate quarantine tank. They are tested for all known diseases before introduction. According to O’Connell, the Asian oyster under consideration have been maintained in accordance with these protocols, and new diseases are not of concern.
“What can we achieve with the native oyster? If it’s a long time frame, is the public willing to wait that long? If it’s going to require a significant investment of government funding, is the public willing to make the investment in the face of great uncertainty? If so, it seems prudent to stick with native oysters. If the outlook for native oysters is bleak, is the public willing to take a risk with the nonnative Asian oyster? It may be possible to achieve significant and self-sustainable increases in oyster abundance within 10-20 years with a nonnative Asian oyster that has similar population characteristics that the Bay’s native oyster had prior to becoming highly susceptible to dermo and MSX diseases”, says O’Connell. “The big question is, if we are restoring for ecological functionality, do we want to accept the unknown risk of nonnative oysters? If we go forward with the introduction, it is an irreversible action.”
This is a significant public policy decision, says O’Connell. The public will be provided an opportunity to comment on the Draft EIS that is scheduled for release in late May. There will be a 60-day public comment period, with public meetings scheduled in both Maryland and Virginia. The final EIS to include the states’ preferred oyster restoration alternative is scheduled for October.