Bill Goldsborough/John Page WilliamsCCA/MD Anglers’ Night Out
March 31, 2015
Restoring the “Coral Reefs” of the Chesapeake
“The abundance of oysters is incredible. There are whole banks of them so that the ships must avoid them…” - Francis Louis Michel, 1701
“Chesapiooc”Great Shellfish Bay
Oysters are communal animals
Reef section showing vertical growth(Bureau of Commercial Fisheries 1964)
The introduction of the oyster dredge in 1810
Laws prohibiting dredging: VA – 1811MD - 1820
“…well-grounded apprehensions are entertained
of the utter extinction of oysters
in the state.”
Darling Oyster CompanyHampton, Virginia, circa 1900Harper’s Weekly
March 1, 1884
Post-Civil WarLegalization of dredging led to an Oyster Boom and the “Oyster Wars”
“We have wasted our inheritance by improvidence and mismanagement and blind confidence.”- Dr. William Brooks, JHU, 1891
“Today destruction of the oyster’s prime habitat in the Chesapeake, the natural, self-renewing upthrusting oyster reefs, is nearing completion. When they are gone it will have taken somewhat less than two centuries to destroy some 6,000 to 7,000 years of nature’s works.”- Dr. William J. Hargis, VIMS, 1999
Oyster harvest peaked in 1884 and has declined since
2 hrs.
In the 1980s scientists determined: •only 1% of oysters were left in the Bay•oysters are critical to the ecosystem
One oyster can filter 50 gallons per day
BBA
Typical MD oysterbar with 1 or 2oysters per squaremeter and heavysiltation
Restored bar with >50oysters per sq. meterand oysters outgrowingsiltation:•more than ten times
the # of organisms•more than twenty
times the N-removal
Increasing oyster density from 2/m² (typical density on harvest bars) to 50/m² (target restoration density) increases the fertilization rate tenfold
Restored tributary reef networks designed to maximize spawning and export larvae to other bars
UMD larval transport model simulation
Day 1: restored reefs in Harris Creek spawn
Day 15: larvae have spread miles with the tide
Day 27: bars where spat have attached
“Three-dimensional reefs, standing substantially above the bottom, are essential for oyster reproductive success, for predator protection and to create habitat for other organisms.”- Chesapeake Research Consortium report, 1999
HealthySystem
EutrophicSystem
Minimal Nutrient Inputs
Excessive Nutrient Inputs
Water Quality Limitation
Low oxygen in deep water and vertical clearance rules mean only a narrow band of vertical reefs can support oysters
Reef Substrate
“The lack of suitable oyster habitat is the principal impediment to… recovery. As it takes decades to create an oyster bar naturally, engineering replacement habitat with artificial structures… seems to represent a viable alternative.”- Dr. Brian Rothschild, UMD, 1994
Concrete “Reef Balls” for re-creating vertical relief
Cost per reef ball = $182.288 vol. hrs @ $22.55= 180.40
Total = $362.68
over 5 years, 1213 reef balls with 6.8 million spat and 21.9 million spat-on-shell were planted on 8 acres
Cook’s Point Sanctuary,Choptank River, MD
May 6, 2014Tangier Sound reef ball retrieved and examined after 11 years in the water
www.cbf.org/reefballvideo
Final ProgrammaticEnvironmental Impact Statement
for Oyster Restoration in Chesapeake BayIncluding the Use of a Native and/or
Nonnative Oyster
Six-year EIS rejects the Asian oyster & endorses native oyster restoration
President’s Executive Order calls for focused effort to restore self-sustaining networks of reefs.
2009 – a turning point year
Lafayette
Piankatank
Harris Creek
Lynnhaven
Tred Avon
Little Choptank
MD adopts a targeted plan
Harris Creek targeted tributary oyster restoration:user conflicts with alternative material for reefs
“UPDATE: Watermen Protest Md. Oyster Project in Dorchester County”WBOC-TV 16, Delmarva's News Leader – May 01, 2014
Little Choptank River targeted tributary oyster restoration:Dispute over fossil shell
What can you do?
1. Spread the word about oysters to friends and neighbors
2. Share your support for oyster restoration by writing letters to local papers or state officials
3. Volunteer for oyster programs at CBF oyster center in Shady Side
4. Become an oyster gardener5. Help recycle oyster shells
Conclusions3-D oyster reefs, once common in Chesapeake Bay, were a key part of the estuarine system, very much like the coral reefs of the tropicsThe Bay’s 3-D reefs were destroyed historicallyBay users have grown accustomed to a flat Bay, but vertical relief should be part of oyster restorationReef balls are a viable option for 3-D reefs:
Oysters appear to grow better than on the surrounding bottom
Spat-set reef balls provide suitable reef habitat for fish