Some recent media attention about oyster culture and restoration in the Chesapea

Question

Some recent media attention about oyster culture and restoration in the Chesapeake Bay and other coastal areas intrigued some environmentally minded citizens in Chincoteague Island, VA. They're now contemplating starting commercial oyster aquaculture in their own water body, Chincoteague Bay. The success of a certain existing Chincoteague Island commercial oyster operation may have been a motivating factor. They have asked you, as an objective environmental expert from outside the area, to help them decide whether it makes sense environmentally to do so. (Whether it makes sense economically is another question for another time.) They want to know, briefly:

a. The links between oysters, environmental quality and human health

b. Chincoteague Bay's current environmental quality, and in the potential near-term future

c. Your recommendations, based on a & b

Some notes to guide you:

Please cite your information sources.

Explanation / Answer

a).After having a quick look on what oysters are...this is the link..

1. Over-fishing:

Like many examples of marine organisms, over-harvesting can not only diminish current

population size but also restrict future generations of organisms from having the critical mass

necessary to restore sustainable populations. For over one hundred years, large quantities of

oysters were removed from New York harbor and its surrounding estuaries with little regulation

(comparisons should be made to other fishing models including tuna, swordfish and salmon -

management techniques, policy, fishing methods and business models are available for

contrast/comparison in future lessons). Traditionally, when oysters are harvested with large metal

rakes or by dredging, the reef integrity is compromised. Once oysters were sold and consumed,

the shells were ground for industrial or fill materials instead of being returned to the water. As a

result of these practices, historic oyster reefs are no longer in abundance and reproducing oysters

have few locals to thrive in a community.

2. Dredging:

To compound the problem, as ships increased in size, the dredging of channels became more and

more prevalent, causing even more destruction to oyster habitats . This continues to be a problem

today.

3. Pollution:

Although water quality is improving, the absence of oysters as filtration agents, compounded by

many years of pollution, have limited growth/reproductive rates in current oyster populations.

PCBs, dense oily pollutants used by electric companies as an insulation material, are

concentrated in the bottom sediments of the Hudson River. The issue of cleaning up this material

is currently being debated and will have profound impact on the future of the river. As more land

is cleared to accommodate growing human populations, urban sprawl, and expanding industries,

the threat of increased non-point source pollution from run-off is of great concern.

4. Disease:

The variables which influence the spread of disease of among oysters are not clear. MSX and

Dermo, two protozoan parasites which crippled Chesapeake's oyster fisheries, seem to thrive now

that there is an imbalance in the ecosystem. Increased spread of disease occurred in many areas ofChesapeake Bay when oyster men deplete populations in a given area and then unsuspectingly

import infected oysters to replenish the population. Local disease-resistant oysters were often

harvested when they reached market size, compounding the problem.

Scientists feel that the fishing industries have greatly mismanaged oyster populations and have

caused an ecological imbalance in eastern estuaries. Several studies have indicated that

sustainable oyster populations can only be restored by creating permanent reef sanctuaries. Reef

sanctuaries are three-dimensional structures composed of deposited oyster shells (a limiting

factor in some projects) which rise at least one half the distance of the water depth off a hard

bottom. Sanctuary reefs are best placed in historic oyster reef sites for several reasons, including

optimal currents, salinity, and estuary floor composition. These sites are either still occupied by

some remaining reef or can be identified on old navigation charts. Projects that spread oyster

shells over a wide area have been much less successful. In addition to the advantages vertical

reefs provide they increase fecundity. Since oysters reproduce by external fertilization, a close

proximity of adults is critical to ensure high fertilization rates during spawning. Since larvae start

out free-swimming, sanctuaries can serve the entire region by seeding surrounding reefs outside

the sanctuary boundaries. Growing oysters to seed sanctuary reefs serves as a brood stock to

replenish populations of this keystone species.

b).Chincoteague Bay WRAS Project:

The Chincoteague Bay Watershed is in the

Atlantic Ocean drainage area, which includes

the Mid-Atlantic Coastal Bays in Maryland

and Virginia. The Chincoteague Bay watershed in Worcester County, Maryland Location is the focus for this WRAS

project. The Chincoteague Bay watershed

prioritized in the Maryland Clean Water Action Plan in two ways. Regarding restoration

needs, the Chincoteague Bay watershed is a

Category 1 watershed for restoration, which

recognizes the presence of water quality impairments that need improvement. Regarding

protection of existing natural resources, the

Chincoteague Bay watershed is a Selected Category 3 watershed, which is the State

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