Status of Coral Reefs of the World 2000

Status of Coral Reefs of the World: 2000
The coral reef of Ouenefou is highly degraded and coral communities on the northern
slope once started near the beaches and descended gently to the outer slope. Acropora
corals have been completely destroyed and loose rubble covers the whole surface.
Exploratory dives showed 25% living coral cover of Favia, Favites, plus Pocillopora and
Seriatopora, with approximately 70% dead coral. The destruction was extensive and
caused by dynamite smashing of the branching corals, but leaving some large soft corals,
Fungia corals and giant clams. At another site on the outer slope, living coral cover was
around 30%, with 25% algae and 60% dead coral. Fish diversity was low and all were very
small, although there were many butterflyfishes. A permanent transect was established at
12m depth where there was 80% dead coral and rubble, with a few living Porites,
Pocillopora and Fungia.
Madagascar
Reefs stretch over more than 1000km of the west coast from Toliara (Tulear) in the South to
Antsiranana in the North with some breaks near Mahajanga. Reefs are only present between
Antalaha and Toamasina on the east coast. Ten stations in 5 sites were established in the
north: Tanikely and Dzamandjar in the northwest (Nosy-Be region); and Fouplointe, Nosy-
Antafana and Antanambe on the east coast. Coral cover on the outer slopes was high:
50.9% at Dzamandjar; 68.3% at Tanikely; 85.7% at Nosy-Antafana; 83% at Antanambe; and
lower at Foulpointe, 35%. There was evidence of deterioration on the reef flats with lower
coral cover: 27% at Nosy-Antafana; 28.7% at Antanambe; 47% at Foulpointe; but higher on
Nosy-Tanikely with 65.7%. The reef at Dzamandjar experiences higher anthropogenic
pressures from industrial pollution (sugar refinery), intensive coral mining, domestic
pollution from many hotels, no sewage treatment for the town of Dzamandjar, and overfishing.
There was, however, relatively high coral cover of 42% in 1998 with many soft
corals. Foulpointe reef is highly degraded, with large-scale collection of corals for sale to
tourists and as building material. The reef flat is heavily sedimented with the remaining
corals buried in sand, because the southern pass has been blocked and sediment build up
has reduced the depth of the lagoon to 2m. Nosy-Antafana is in the Mananara-North
Biosphere Reserve with water sports (spearfishing, diving, etc.) banned on the outer slope.
Fishing for invertebrates, net and hook and line fishing appear to have few impacts on the
outer slope with high coral cover. In 1998, cover was 46% on the reef flat, but it was lower
(27%) in 1999, with coral regeneration evident around many dead coral colonies which had
mostly died and were covered with algae lawns, although they remained fixed in place.
On the reef flat of Ifaty (South Toliara) in 1999, there was 25.3% coral cover (13.5%
Acropora and 11.8% non-Acropora), and high cover of abiotic (sand, mud, rock) forms,
(69.6%) mainly dead corals and rubble, and 4.7% algae. Monitoring in February 2000
showed an increase in algae cover (26.6%) due to the proliferation of macro-algae (14.8%),
mainly standing algae such as Turbinaria, Sargassum and Halimeda. Also there was a small
increase in live coral cover (28.8%). On the Ifaty outer slope, there were almost equal
amounts of Acropora (20.1%) and non-Acropora (20.6%) in the 40.7% cover, and nonliving
cover of 52.5% in 1999. In 2000, there was a small increase in live coral (41.9%) with
the appearance of many scattered juvenile colonies.
On the Great Barrier Reef of Toliara, exploratory snorkelling showed a relatively high living
coral to dead coral ratio, and often 10% soft coral cover. Transect data showed the
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