Population structure of Acropora

[antonio ortiz]

Dear all:

I wondered to received more information about the biological status of 
acroporids species, principally about the population dynamic of Acropora 
palmata.  I'm doing some research on this area and at that moment I'm 
collecting information about the population size using different mechanism, 
number of parent colonies (standing colonies), number and size of fragments 
or loose colonies generate by hurricane Georges.  Also, I have information 
of fragment transport (previously tagged) during hurricane Georges. High 
survival of fragments (>70% ) after one year suggested that fragmentation is 
an efficient mechanism to increase the population densities of these specie. 
  However, because asexuality is associated with both lowered genetic 
variation and lowered evolutionary potential the next step of my research is 
to estimate the genetic structure of the population.

I suggest that understanding the asexual and sexual reproduction of 
individual coral species and the interrelationship between these phenomena 
is vital to proposed management programs for coral specie/population 
conservation. The maintenance of sufficient levels of genetic variation  is 
the main objective of genetic management because is crucial for the 
maintenance of a species' evolutionary potential.  Given the importance of 
genetic variation for the long-term survival of coral populations, methods 
and guidelines to measured genetic variation need to be developed . I would 
suggest some strategies to management these populations based on the concept 
of managing the effective size of a population.  It was suggested that the 
larger the effective size, the smaller the rate of genetic loss.  In ideal 
populations (i.e., populations that follow the Hardy-Weinberg model) the 
effective size equals the population size.  However, due to the high 
probabilities of asexually derived colonies within Acropora populations, the 
effective population (Ne) may expected to be low than the population size 
(N).

For a moment I'm going to use DNA fingerprinting as proposed by Mary A. 
Coffroth to estimate the contributions of sexual and asexual reproduction to 
the population structure.  But, how a made my sample collection is another 
story and I will appreciate any recommendation.  Depending on sites/reef 
Acropora palmata usually form an aggregate patch separate by other discrete 
patch or colonies are widely disperse along the reef.  Those patch may be 
expected to be compose by one or few genotypes.  The method used to collect 
the sample need to fit both case.

If you have any information or recommendation please send me at the 
following direction:
Antonio L. Ortiz
University of Puerto Rico
Department of Marine Science
Magueyes Island
P.O. Box 408
Lajas P.R. 00667
Or by Email: alortiz9 at hotmail.com

I will appreciate your contribution.
Thanks,

Antonio

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