CORDIO Status Report 2002.pdf

Table 1.
Percentage of live corals at selected reef sites.
Location Depth Pre-bleaching 1999–2000 2001–2002
(m) (Percentage of live coral) (Percentage of live coral) (Percentage of live coral)
Bar reef 0– 3 78.5% overall Nearly 100% mortality 2 Several new colonies recorded but
in 1993–1994 2
too sparse to estimate percent
cover
Bar reef 7– 8 Nearly 100% mortality 14
Kandakuliya 0– 5 22 1 Small colonies were Corals smothered by Halimeda
present 2
Hikkaduwa
Nature Reserve 0– 4 47.2 2 7 2 12
Hikkaduwa, South
of Nature Reserve 7–13 Not estimated Percent cover of live 17
corals was not measured
Rumassala 1– 5 45 5 19.6 4 Better recovery at 4–5 m depth.
Live coral cover not estimated
Weligama 0– 2 92 2 28 2 54
31.04 3
Sources: 1 Öhman and Rajasuriya 1993; 2 Rajasuriya and Karunarathna 2000; 3 Fairoze, Cumaranatunge and Amarasinghe 2000; 4 Rajasuriya (unpublished
report); 5 Rajasuriya et al. 1998b
highly variable depending on many factors. McCook
(2001) cites previous studies (Lapointe, 1997; McCook,
1999) where it has been shown that algae can overgrow
corals and lead to a phase-shift from a coral dominated
habitat to an algal community as a result of reef degradation
due to natural causes or eutrophication combined with
overfishing. Factors such as over fishing and pollution
are problems on Sri Lankan reefs although it is not known
whether such factors contribute to increased growth of
algae that has been observed on many reef habitats.
In addition to filamentous algae there appear to be an
increase in calcareous alga such as Halimeda and most of
the dead corals are covered by crustose algae (encrustrating
coralline algae). Crustose algae help to bind the reef
and prevent erosion of the reef structure (Fabricius &
De’ath, 2001). They cite research carried out by Morse
et al. (1988), Heyward and Negri (1999) that indicate
that crustose algae induce settlement of reef organisms
including hard corals.
Management of human activities is the single most
important aspect in the recovery of coral reefs.
Threats from human activities such as coral mining
in the sea, destructive fishing methods and uncontrolled
resource extraction continue to be chronic problems and
difficult to control (Rajasuriya et al., 1995; Rajasuriya et
al., 2000; Spalding, 2001). Recently the government of
Sri Lanka banned the use of coral lime for buildings
constructed by the government (Rajasuriya & Premaratne,
2000). However this has not prevented or reduced
illegal coral mining in the southern coastal belt. Coral
miners are arrested occasionally in the southern coast
but are released with minimal fines. There are no recent
known instances where the law against coral mining has
been implemented in the east coast where this practice is
rampant, for example in Passikudah and Kalkudah. In
Sri Lanka it is well known that there is partiality in
applying the laws and that politicians interfere in the
legal processes whenever people are arrested for illegal
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