Oysters: A Great Little Bivalve

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Oysters A Great Little Bivalve
Crassostrea virginica
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The Chesapeake Bay

• Name Origin
• Major Pollutants
• nutrients
• sediment
• toxins
• bacteria

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Oh how those babies grow
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Geographic Range
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Geographic Range

• The eastern oyster is native to the East coast of
  Canada and the United States, Gulf of Mexico, and
  Caribbean and as far south as the North coast of
  South America.

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History of Oysters

• Used to be 3-D structures
• Now mostly flat
• Used to be as high as the ceiling at low tide
• see the tips at high tide
• John Smith could see 60ft. down into the
  Baynavigational hazard

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Oyster Tonging up until 1800s

• Not too destructive
• inefficient
• hard
• couldnt go deep

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Oyster Dredging
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Results

• 99 decline in 400 years
• Dredges ripped up 10,000 year old reefs
• Overharvest
• Disease
• Diminished water quality
• No habitat

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• 1912 postcard from Portsmouth
• (1 years worth of shells)

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Shells Used For

• Paving
• Ground for chicken feed and fertilizer
• Make island bridges
• Should have been put back into water

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The Life of an Oyster
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Fecundity vs. Size
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Fecundity vs. SizeNumber of eggs in ONE SUMMER
Imagine if they got to be the size of dinner
plates how many babies theyd have!!!!!!
mostly boys
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Virginia Oyster Landings (1884-2005)1,000s of
bushels
Non-native oyster with MSX introduced
90 death
4000
3000
Dermo outbreak
2000
1000
500
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Ecological ValueFiltration and Food Production

• Sediment
• Nutrients
• Algae
• Toxins
• Bacteria

CLEAN WATER
BIODEPOSITION-feces or pseudofeces in
sedimentfood for benthos/worms
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Oyster Reef Biodiversity

• Pile of shells
• Nooks and crannies
• Create 3X surface of flat mud
• Attract larger organisms coming to feed

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Foodbut not on protected reefs

• People eat as adults, lots of things feed on larva

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Oyster Restoration

• Construct shell bases on historic sites (over 120
  now)
• Transplant disease resistant oysters to serve as
  brood stock
• Reefs designated as sanctuaries
• Research ongoing

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Lynnhaven River Community Oyster Contributions
Transplanted Oysters