Coral propagation for aquarium specimens.
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Date
2001
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Abstract
Coral reefs are being destroyed and degraded by natural and anthropogenic
processes. Live corals are becoming increasingly popular as marine aquarium
specimens, in both the commercial and private sectors, leading to the degradation of
coral reefs. This often has serious economic implications for the fishing, aquarium and
tourist industries. It is clear that there is a need for the management and protection of
these fragile ecosystems. The artificial propagation of coral is desirable as it will
alleviate the demand for wild coral specimens, and will also provide a stock for the
rehabilitation of damaged reefs. Although corals are being propagated worldwide by
hobbyists, reports on their work are mainly anecdotal and there is little in the scientific
literature on the specific requirements for optimal growth rates and survival in suitable
coral species. This study thus focused on developing techniques to propagate a range
of appropriate coral species and to promote their optimal growth.
The results revealed that different morphological groups of scleractinian corals
require specialised techniques of fragmentation and attachment to ensure survival.
The corals were broken using a hammer and chisel. Attachment techniques varied
from the use of superglue (which is widely used in the United States), to thermoplastic
glue. The mean mortality using superglue was 73% (n=120, ±0.167), using epoxy,
62% (n=120, ±0.127) and with thermoplastic glue it was 11% (n=120, ±0.108)
Superglue was extremely difficult to work with and proved ineffective, especially when
attempting to glue uneven surfaces. Certain species did not survive using this
adhesive due to exposure of the coral to air. The most effective method of rapid
attachment was the use of thermoplastic glue that set rapidly underwater. The use of
electrolysis to promote the attachment of coral nubbins was tested as an alternative to
the various adhesives. This method increased the survival of the nubbins and
eliminated exposure to air. It has proven suitable for both coral propagation and in situ
reef rehabilitation.
Growth experiments revealed that the manipulation of current flow, light and
the addition of different feeds had different effects on the growth rates of selected
candidate species. A suite of optima was thus developed for each species. The
majority of species grew best in a bi-directional current flow, with yeast as feed, under
actinic blue light. An experiment that combined the optimal current flow, feed and light
conditions, revealed that the majority of species grew best under mixed light with
yeast as feed.
The trade in corals is sensitive in terms of their handling, transportation and
CITES (Convention on International Trade in Endangered Species) status. Having
established the viability of their propagation, consideration was given to appropriate
regulatory and marketing procedures to accommodate this sensitivity of the cultivated
material.
Description
Thesis (M.Sc.)-University of Natal, Durban, 2001.
Keywords
Coral industry and trade., Coral reef conservation., Coral reefs and islands., Theses--Marine biology.