Pinctada Pearl Oysters ( Pinctada spp.) Midway Atoll (Northwestern Hawaiian...
Transcript of Pinctada Pearl Oysters ( Pinctada spp.) Midway Atoll (Northwestern Hawaiian...
8/15/2012
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Pearl Oysters (Pinctada) of
Midway Atoll (Northwestern
Hawaiian Islands)
Kristin McCully, Don Potts
Ecology and Evolutionary Biology Department
University of California, Santa Cruz
Western Society of Malacologists Meeting
June 2012
Pearl Oysters (Pinctada spp.)
• Economically important industry
• Important filter feeders
• Ecosystem indicators
– Heavy metals
– Nutrients
Gametes Larvae Recruits Juveniles Adults
Pearl Oysters of Hawaii
Pinctada radiata
• Small (up to 10 cm)
• Extensive beds in
Pearl Harbor, Oahu
• Die-off in mid-1800s due to
sedimentation
Pinctada margaritifera
• Much larger (up to 30 cm)
• Extensive beds at Pearl and
Hermes Atoll until 1920s
• USFWS and PMNM
interested in restoration
Photos courtesy of Bishop Museum in Walther (1997)
http://sanctuaries.noaa.gov/science/condition/pmnm/images/fig1_lg.jpg
Hawaiian Archipelago
Midway Atoll
(Wada and Tëmkin 2008,
Hwang et al. 2007,
Mavuti et al. 2005)
Sites of aquaculture of P. margaritifera
P. margaritifera
Black-lipped Pearl Oyster Pinctada margaritifera (Linnaeus 1756)
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Overall Questions
• What is the current spatial distribution of
pearl oysters (and other large bivalves)?
• How might managers restore the
population?
• What are their demographic rates?
– Recruitment
– Growth
– Survival
Midway Atoll
Distribution: Habitats
N
NW
Deep
S
SE
E
SWBased on: NOAA.
2003. Draft atlas of
the shallow-water
benthic habitats of the
NWHI.
Legend
Forereef
Backreef
Patch reef
Sand
Distribution: Survey SitesLegend
2009 2011 Habitat
Backreef
Forereef
Patch reef
Sand
n = 108 surveys
Baggy pen shell
Streptopinna saccata
Cliff oyster Spondylus violacescens
Black-lipped pearl oyster
Pinctada margaritifera
Jewel oyster
Chama iostoma
Distribution: P. margaritifera
500 m
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0
1
2
3
4
5
6
7
8
Spondylus Chama Streptopinna
Ave
rage
Nu
mb
er
of
Biv
alv
es
pe
r 1
00
sq
m (
±S
E)
Species
Fore Back Patch Sand
Distribution: Other Bivalves
Habitat:
Restoration?
Spat
collector
Recruitment: Methods Predation on P. margaritifera
• Highest risk of mortality as juveniles
• Escape size 80-100 mm (Crossland 1957 in Gervis and Sims 1992)
• Potential predators (Gervis and Sims 1992)
– Fish
– Octopus
– Predatory gastropods
– Sea stars
– Crabs
Juvenile Growth, Survival, & Predation
Site: WB
No Mesh Large Mesh
X 4 tiles X 4 tiles
X 3
juveniles
X 3
juveniles
PP
WB
Site: PP
No Mesh Large Mesh
X 4 tiles X 4 tiles
X 3
juveniles
X 3
juveniles
Juvenile Survival & Predation: Results
0%
10%
20%
30%
40%
50%
60%
70%
Open Closed
Pe
rce
nt
Su
rviv
al fo
r 3
8 d
ay
s (±
SE
)
Cage Status
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Adult Growth and Survival
500 m
Molecular Species Identification: Methods
• Very hard to identify Pinctada
species morphologically
(particularly juveniles)
• Collected about 100 juveniles at
Midway
• Variety of coloration, location,
size, dates collected, methods
of preservation
• Marker: ITS1 between nuclear
rDNA genes (Yu and Chu 2006
Biochemical Systematics and Ecology)
18S 5.8SITS1
Pinctada Phylogeny
Cunha et al. (2011) Marine Biotech
Photo courtesy of Bishop Museum, Honolulu in
Walther 1997
Phylogeny
• Midway samples
– Definitely not P.
margaritifera
– Likely P.
maculata
• Working on
sequencing
mitochondrial
cytochrome
oxidase I (cox1)
marker
Pteria penguin
P. albina1
P. albina2
P. chemnitzi1
P. chemnitzi2
P. fucata1
P.f. martensi1
P.f. martensi2
P. fucata2
P. fucata3
P. imbricata
P. martensi
0.05 substitutions/site
99/99/97/100
85/82/75/73
66/66/60/98
ML/MP/NJ/BPP
P. margaritifera2
P. maxima
P. margaritifera1
P. margaritifera3
P. margaritifera4
P. maculata1
P. maculata2
P. maculata3
18 Midway samples
P. nigra
Model: Goals
• To determine most important data to collect
in the Hawaiian archipelago
• To establish priority life stages and
demographic processes for managers
• To estimate probable impacts of
management options, including restoration
Model: Life Cycle Diagram
Gametes Larvae Recruits Juveniles Adults
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Male
Large
Adults
Model: Life Cycle Diagram
Juveniles
Female
Large
Adults
Male
Small
Adults
Time Step:
1 year
Female
Small
Adults
Model: Transition Matrix
FROM
1 2m 2f 3m 3f
TO
1 s1(1-g1) 0 f2s0 0 f3s0
2m s1g1(1-sx2) s2(1-g2)(1-sx2) 0 0 0
2f s1g1sx2 s2(1-g2)sx2 s2(1-g2) 0 0
3m 0 s2g2(1-sx3) 0 s3(1-sx3) 0
3f 0 s2g2sx3 s2g2 s3sx3 s3
Model: Vital Rates
Description VR
Probability of survival
s0
s1
s2
s3
Probability of growth transitiong1
g2
Fecundity of femalesf2
f3
Probability of becoming femalesx2
sx3
Conclusions and Next Steps
• P. margaritifera is very rare at Midway, but is
most common on patch reefs in central lagoon
• Other bivalves are more common on forereef
• Very difficult to restore P. margaritifera, given
biology and regulatory climate
• Next steps:
– Confirm species identity of recruits
– Use molecular techniques to check species
identity of pearl oysters in Main Hawaiian Islands
– Further develop and analyze mathematical model
Acknowledgments: Funding
• Mitsubishi Corporation Global Coral Reef
Conservation Program
• U.S. Fish and Wildlife Service
• Midway Atoll National Wildlife Refuge
• Friends of Long Marine Lab
• UCSC Center for the Dynamics and Evolution of the
Land-Sea Interface (CDELSI)
• DoD National Defense Science and Engineering
(NDSEG) Fellowship
• UCSC NSF GK-12 grant SCWIBLES
Acknowledgments: People
• Advisor: Don Potts
• Proposal committee:
Laurel Fox
Tim Tinker
Maria Haws (UHawaii)
• Statistics help: Pete Raimondi
• Labmates:
Wendy Cover, Anne Warner,
Helen O’Brien, Rachel Fabian
• Lab volunteer: Ryan Harry
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Acknowledgments: Midway Team
• Field assistants:
– Kate Schoenrock
– Jamie Barlow
• Field volunteers:
– Jessica Lee
– Mitsubishi
volunteers
(2008-11)
• John Klavitter &
Matt Brown
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