Early work on the reproductive seasonality of corals in the Red Sea suggested that corals
exhibit temporal reproductive isolation, unlike on the Great Barrier Reef where many
species spawn in synchrony. More recent work has however shown high synchrony in the
maturity of gametes in Acropora species, suggesting multi-specific spawning is likely to
occur in the Red Sea. In this thesis I investigate the patterns of coral reproduction in the
central Red Sea. The spawning season in the central Red Sea lasts four months, from
April to July and spawning occurs on nights around the full moon. During this period
Acropora species show a peak of spawning in April, with some species spawning again
in May. The level of synchrony, quantified with a spawning synchrony index, is
comparable to other locations where multi-specific spawning has been reported.
Observations over two consecutive years show that the synchrony of spawning was lower
in spring 2012 than in spring 2011, and thus that spawning patterns are variable from one
year to the other. Coral settlement patterns on artificial substrata confirmed a main
spawning season in the spring but also supported reproductive data suggesting that some
Porites spawn in October-November. Settlement was studied over 2.5 years on a reef,
which had suffered recently from high mortality after a local bleaching event. Settlement
appeared low but post-bleaching studies from other locations indicated similar
abundances and showed that recruits generally did not increase until 5 years after the
bleaching event. Abundance of juvenile corals however started to increase significantly
three years after the bleaching. Successful recruitment, although low suggests that the
coral assemblage on the affected reef will most likely recover as long as it is not affected
by another disturbance.
Date of Award | Dec 2013 |
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Original language | English (US) |
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Awarding Institution | - Biological, Environmental Sciences and Engineering
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Supervisor | Michael Berumen (Supervisor) |
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- scleractinia
- coral reef
- reproduction
- synchronous spawning
- Recovery
- larval settlement