Coral Culture for Reef Rehabilitation

1
Coral Culture for Reef Rehabilitation
Laurie J. Raymundo1 and Aileen P.
Maypa2 1Silliman University Marine Laboratory,
Dumaguete City, Philippines 2Project Seahorse,
Cebu City, Philippines
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Study Rationale

• Reef health and productivity continue to
  decline, with few
• management options available
• Coral transplantation using broken fragments or
  whole
• colonies is the major method of coral
  reintroduction
• This method may be unsuitable for certain growth
  forms
• can result in additional reef stress or
  colony mortality
• Coral culture using seeded larvae may supply
  colonies
• suitable for transplantation

3
Study Objectives

• To evaluate using larvae from the
• brooding coral Pocillopora
• damicornis to grow a trans-
• plantable population via
• Comparing settlement and early
• survival of lab vs. field-settled larvae

• Determining the optimum size at which to
  transplant
• lab-reared colonies and
• Examining fusion between juveniles to enhance
  growth
• and survival of lab-reared colonies.

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Methods
1) Comparing settlement success early survival
in lab vs. field larvae were collected from
ripe adults in lab tanks settled simultaneously
on limestone tiles in lab aquaria and on bare
reef substrate
2) Determining optimum transplant size colonies
reared in lab aquaria from seeded larvae grown to
four size classes lt3 mm, 3.1-6 mm, 6.1-10 mm,
10.1-29 mm max. diam.
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Methods, cont.
3) To evaluate effects of fusion on juvenile
growth survival larvae from 3 parents settled
separately, reared in lab aquaria and allowed to
fuse as they contacted neighbors. Growth
survival monitored in 3 populations for 6 mo
a) colonies grown from individual larvae
(individuals) b) colonies from fusion of 2
previously separate colonies or settled
larvae (fused pairs) c) colonies from gt2
previously sep- arate colonies or larvae
(fused groups)
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Results

• Lab vs. Field Settlement Early Survival
• Settlement success lab aquaria mean59.4
  17.6 gtgt reef substrate mean24.3 11.1 (ANOVA
  df1 F7.09 p0.02)

• First-week mortality lab aquaria mean12.4
  6.1
• ltlt reef substrate mean57.7 33.7 (ANOVA
  df1
• F6.972 p0.02)
• Mean growth rate in aquaria 1.54 mm mo-1 to 6
  mo

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Results, cont.

• 2) Determining optimum transplant size
• Significant size-related mortality among
  size-classes
• 1-yr survival
• 0 of lt3 mm size class
• 2 of 3-6 mm size class
• 12 of 6.1-10 mm size class
• 48 of 10.1-29 mm size class
• Colony shrinkage in larger colonies during1st 3
  mo
• post-transplant possible stress response
• Spawning in transplants from largest size class
  2 yr
• post-transplant colonies 2 ½ years old

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Post-transplant survival and growth in juveniles
of 4 size cohorts (N80/cohort Mean /- SE)
 
 
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Results, cont.

• 3) Effects of fusion on colony survival growth
• Fusion enhanced
• survival (Logistic
• Regression
• df1 F12.106
• p0.0006), but no
• difference between
• fused pair and fused
• group survival

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• Growth rate differences
• between groups increased
• as group size increased
• (ANOVA df2, F8.35
• plt0.001) fusing colonies
• budded more. Budding rate
• was constant growth
• curve slopes were similar
• (ANCOVA Fused StateAge
• interaction p0.57), so no
• other intrinsic advantage to
• growth aside from higher
• polyp number.

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• Transition matrix data
• growth transitions in
• unfused colonies none
• reached largest size class
• in 6 mo stasis increased
• with time
• (B) transitions in fused
• colonies faster growth
• stasis rate was constant
• Est. time to reproductive
• size of A

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Conclusions Management Issues

• Higher success with lab settlement, early
  rearing vs. direct
• field seeding. 5 out of 2,070 field-seeded
  larvae survived
• to 2 y. 70-80 survival to 6 mo in aquaria
  trials.
• High mortality in colonies lt 10mm when
  transplanted
• gt 10mm max. diam. recommended minimum size to
• transplant.
• Fusion facilitated rapid growth, survival
  could decrease
• lab rearing time time to reproductive size
• This approach applicable to brooding species
  culturing
• broadcasters requires incorporation of
  fertilization phase

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• Culture can supply coral for reef rehab
  (potentially) the
• aquarium trade reduced impacts from
  fragmenting /or
• collecting wild colonies
• A caveat Laws protecting corals must be
  reevaluated
• before culture can be developed in the
  Philippines
• Further research required re species-specific
  responses to
• culture. Grow-out phase in ocean nursery may
  allow
• community involvement
• Management must be based on sound science
  options for
• rehab developed through rigorous experimental
  research

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Acknowledgements

• C. D. Harvell, Cornell University
• National Science Foundation
• Silliman University Marine Laboratory
• May and Jasper Maypa