Application of selective breeding to oyster restoration: A ... · Photo by L. Degremont Two...

Application of selective breeding to oyster restoration: A unique strategy of genetic “rehabilitation”

in the Chesapeake Bay

S. K. Allen Jr. and L. DegremontAquaculture Genetics and Breeding Technology Center

Virginia Institute of Marine Science

Photo by L. DegremontDo n

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• desperate

• foolproof

• foolhardy

• hijacked

• default


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Forces of selection onChesapeake Bay oyster populations

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Fisheries selectionFisheries selection

Genetic rehabilitation?Genetic rehabilitation?

Natural selectionNatural selection

MSX Dermo

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Baylor Survey: oyster groundsBaylor Survey: oyster grounds

1892 survey of most productive oyster

grounds in Virginia

Yield of oysters from the Bay, nearly 8

million bushels/ year

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Age class structure

Fecundity

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Natural selectionNatural selection

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Age class structure

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barriers to gene flow?

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Age class structure

Fecundity

fish out

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Do not

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or au

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Age class structure

Fecundity

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fish out


retain

resistance

Artificial selectionArtificial selection

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Genetic Genetic

rehabilitation?rehabilitation?


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Recommendations: Release / genetic rehabilitation strategy

• Limit release to restricted embayments

• Assess release strategies with use of

molecular markers

• Use multiple releases in one system

• Use more than one system

• Use multiple stocks among systems

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the hijacking


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XB line

DBY line

tetraploid

6th generation DBY line

two years old

80% survival

10x increase in seed orders

4XDXB x CDBY: triploid DR aquaculture strain

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RESTORATION vs. AQUACULTURERESTORATION vs. AQUACULTURE

base population

aquaculture and domestication

diminished diversity

“wild-type” genotypes

natural populations

maintain genetic variation

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Photo by L. Degremont

Two complementary approaches to selection for disease resistance using C. virginica

Line (variety) development

Family selection

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9 lines

7 replicates

4 sites


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Kinsale

York River

WachapreagueChesapeake

Bay

Atlantic

Ocean

Lynnhaven


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Kinsale

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YOBOY

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CDBY

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AXB 04 CAMX

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MBC 04 XDBLA

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York River

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Broad bay

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Burton's Bay

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~10 ppt ~18 ppt

~28 ppt ~32 ppt

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Family selection

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>1600 replicates of 200 oysters each

>300,000 single oysters

50 families/ year

8 replicates

2 sites

Family selection

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MODUS OPERANDI: Disease resistant varieties

VIMS hatchery

also hold brood stock

for distribution

commercial

hatchery

lines and families for

field tests, selection

lines

families

oyster restoration

commercial aquaculture

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Disease resistant varieties on restored reefs

Restoration hijacked the aquaculture lines

Do not

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withou

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or au

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IDEAL vs. REALITYIDEAL vs. REALITY

base population

“wild-type” genotypes

natural populations

maintain genetic variation

wild stocks

mixture of DR strains

locally adapted

all the above

Do not

disse

minate

withou

t auth

or au

thoriz

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Thanks to Tommy Leggett for pants


ot dis

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Banquet. n. From the Celtic ban (or bread) and

quetta (to lead on or tease).

A ritual of proffering small amounts of bread or

food for the purpose of exciting the palette.

Especially popular in northwest regions of Europe.

Do not

disse

minate

withou

t auth

or au

thoriz

ation

Application of selective breeding to oyster restoration: A ... · Photo by L. Degremont Two...

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