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|Title:||Interactions between trophic levels on coral reefs: Scleractinian corals and corallivorous butterflyfishes in Hawaii|
|Authors:||Cox, Evelyn Fenton|
|LC Subject Headings:||Coral reef biology.|
|Publisher:||The University of New Mexico|
|Citation:||Cox, Evelyn Fenton. Interactions between trophic levels on coral reefs: Scleractinian corals and corallivorous butterflyfishes in Hawaii. Albuquerque: The University of New Mexico, 1991.|
|Abstract:||Resource use by coral feeding butterflyfishes (Family|
Chaetotondidae) was studied at 6 geographic sites in the
Hawaiian Islands. There was little diet overlap between the
specialist species, Chaetodon unimaculatus and the
generalist species, Chaetodon multicinctus, C. ornatissimus,
and C. trifasciatus. Although there was high diet overlap
between the generalist species, C. multicinctus showed a
strong feeding preference for the coral Pocillopora
meandrina. Chaetodon ornatissimus fed on corals roughly in
proportion to their abundance, and C. trifasciatus, contrary
to laboratory feeding preferences for pocilloporids and
montiporids, fed on Porites spp. in the field. The
specialist, C. unimaculatus, preferred Montipora spp. at all
sites, and there was a trend towards a relationship between
C. unimaculatus densities and coral cover of Montipora spp.
There was no correlation between overall butterflyfish
densities and coral cover at these sites. Butterflyfishes used non-overlapping feeding ranges
intra-specifically, but showed high inter-specific overlap.
Chaetodon multicinctus, the smallest bodied species, used
the smallest areas and showed the most aggressive
interactions against conspecifics and other butterflyfishes.
The effects of grazing by butterflyfishes on coral was
investigated with the Hawaiian coral Montipora verrucosa.
M. verrucosa colonies, protected from the butterflyfishes
with wide mesh cages, were compared to their clonemates
exposed to predation. Although reproductive output was
highly variable among clones, gamete weight per unit surface
area of grazed clonemates was signficantly greater than
their ungrazed clonemate. Ramets protected from
butterflyfishes, however, had twice the linear growth as
grazed ramets. These results corroborate the predictions of
Williams (1975) Strawberry-Coral Model for the allocation of
resources to reproduction in clonal organisms.
Photosynthetic and respiratory rates were measured in a
laboratory respirometry setup. Respiration rates and
maximum photosynthetic capacity were the same for grazed and
ungrazed clonemates. Parameters for light saturation curves
for photosynthesis for clonemates were not significantly
different, suggesting that energy available from the
symbiotic zooxanthallae in protected clonemates was used to
fuel rapid growth and in grazed clonemates to repair tissues
and increase sexual reproduction.
|Description:||Thesis (Ph. D.)--University of New Mexico, 1991.|
Includes bibliographical references (leaves -123).
|Rights:||Copyright Evelyn Fenton Cox|
|Appears in Collections:||Kaneohe Bay Research|
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