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The Ecology of Juvenile Hawaiian Corals

I studied coral recruitment, growth and community
development in Kaneohe Bay, Oahu, Hawaii. In one
experiment, I investigated coral recruitment at 7 sites, in
3 consecutive years. Coral community development was
followed for up to 3 y. Hollow concrete blocks were used
as experimental substrata. The smallest recruits which I
detected were 1 mm in diameter.
variability in recruitment was observed both between
sites and between surfaces of the blocks. Temporal
variability in recruitment patterns between years was also
recorded. After 3 mo immersion, Pocillopora damicornis, a
brooding species, was-the most abundant coral. Another
brooding species, Cyphastrea ocellina, and the ahermatype,
Culicia cf. tenella were also detected. Two spawning.
species, Montipora verrucosa and Porites compressa were not
detected until after 6 mo immersion. Over 3 y, the
relative abundance of Pocillopora damicornis declined at
most sites and the relative abundance of Porites compressa
increased. Montipora verrucosa recruits remained uncommon.
The distribution of hermatypic corals on the blocks
also changed with time. Initially recruits were most
abundant on interior top surfaces after 3 y, they were most
common on outer surfaces of the blocks.
Inter- and intraspecific differences in growth were
recorded. pocillopora damicornis attained the largest colony sizes. Growth rates varied considerably between
sites. Successful recruitment was highest after 3 y
immersion, at sites where corals grew most rapidly.
In the second set of experiments, I measured invisible
recruitment sensu wallace (1983) and investigated the
effects of urchin and fish grazing on coral recruitment.
Montipora verrucosa was the most common recruit after 3 mo
immersion. Fish and urchin grazing significantly affected
the abundance of M. verrucosa but not that of Porites
compressa or Pocillopora damicornis.
After 3 mo immersion, the maximum size attained by P.
damicornis was greater than P. compressa or M. verrucosa
which had similar colony diameters and number of polyps.
However, during the next 5 mo P. compressa grew more
rapidly than M. verrucosa. The different growth rates of
these species explains why P. compressa increased, and M.
verrucosa decreased in relative abundance.
Interspecific differences in larval size at
settlement, the time taken to deposit a skeleton, and postsettlement
growth strategies, all influence recruitment
success. / Thesis (Ph. D.)--University of Hawaii at Manoa, 1993. Includes bibliographical references (leaves 240-252)

Identiferoai:union.ndltd.org:UHAWAII/oai:scholarspace.manoa.hawaii.edu:10125/15320
Date01 May 1993
CreatorsFitzhardinge, Rachel C
PublisherUniversity of Hawai'i, Honolulu
Source SetsUniversity of Hawaii at Manoa Libraries
Languageen-US
Detected LanguageEnglish
TypeThesis, Text
Format264 pages
RightsAll UHM dissertations and theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission from the copyright owner.

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