Download - Coral Reef Status in 2009 Maldives Reefs
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N.J. Quinn and H.N.J. Quinn and H. ZahirZahir
Marine Research Centre, MaleMarine Research Centre, Male
Republic of MaldivesRepublic of Maldives
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y The Maldives ~1192
islands with a 300 km2
land mass
y Exclusive economic zone
of 859,000 km2
y Within atoll lagoon and
reef areas ~21,300 km2
y
The 26 atolls lie along anorth-south axis between
7o N to 0.4oS and from
72o- 73o E. longitude in
the central part of the
Chagos Maldives Laccadive ridge in the
central Indian Ocean
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Reef Check survey techniques were used to monitor a suite of
biological indicators of coral reef health from a geographically
diverse set of lagoon, shallow reefs from northern Haa Dhaalu to
Addu atoll, south of the equator.
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The Marine Research Centres National Coral Reef Monitoring
Survey data provided an historical record, along with other outside
agency studies, for assessing the recovery of Maldivian coral reefs to
natural disasters in the past 12 years.
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The unprecedented coral bleaching in 1997 - 1998 around the world
including the Maldives, resulted in extensive mortality to scleractinian,
reef building corals.
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y Coral cover on Haa Dhaalu atoll was nearly 0% after the 1998
bleaching event.
y Subsequent reef recovery was slow with coral cover only
achieving 3-5% in 2005.
y However, since 2005, coral cover has been rapid.
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0
10
20
30
40
50
60
70
1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010
%C
oralCo
Hondaafushi
Finey
Hirimaradhoo
Coral cover on the northern reefs of Haa Dhaalu atoll was
nearly 0% after the 1998 bleaching event.
Subsequent reef recovery was slow with coral cover only
achieving 3 - 5% in 2005.
Since 2005, coral cover has been rapid.
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HaaHaa DhaaluDhaalu AtollAtoll
y In 2009, coral cover ranged from 14%-29%.
y
This was collectively the lowest coral cover for all the atolls surveyed.
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0
10
20
30
40
50
60
Hon'daafushi Finey Hirimaradhoo
%C
oralCover
3 m
10 m
Hondaafushi & Finey had higher coral cover at 10m than at 3m
Hondaafushi coral cover -50%, Finey coral cover 21%
At Hirimaradhoo because zooanthid was dominating the reef,
hard coral cover was the least of the Haa Dhaalu sites with only
14% cover at 3 m and 0.6% at 10 m
2009
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North and South Male Atoll
0
10
20
30
40
50
60
70
1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010
%C
oralCover
Boduban'dos
Udhafushi
aniyafushi
nboodhoofinolhu
Udhafushi was the outer reef slope of a faru in the center of North
Male atoll. From the post bleaching coral cover of 1.3% in 1998, the
site recovered slowly to 2.9% in 2002
Enboodhoofinolhu had the lowest live coral cover in NCRMS in
2009. The reef has been used for sand mining for several decades.
Coral cover at Bodubandos
after the 1998 bleaching was
2% . Coral cover increased
6.9% in 2002.Subsequent to the 2002
survey construction of a
harbour for the Bandos
Resort occurred adjacent to
the survey site. Despite the
nearby harbor the coral
cover increased to 41% in
2009. This is a remarkable
recovery!!
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0
10
20
30
40
50
60
70
1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010
%C
oral
Fesdhoo
Velidhoo
Maayafushi
Dega Giri
Kandholhudhoo
Ari Atoll
The shallow reefs of Fesdhoo, Maayafushi, Velidhooexhibited
exceptional resilience.
In 2005,most ofthese reefs hadcoralcover lessthan 11%.
Afterthebleaching event Fesdhooquickly recoveredto 10%coralcover in 2000.By 2005 it had over 30%coralcover.In 2009, itwas
amongthemost luxuriant reefs surveyedwith about 65%coral
cover.
Velidhooreef also demonstrated remarkable recovery from about
11% in 2005to 50% in 2009.
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After the sampling in 2005 the hotel atAfter the sampling in 2005 the hotel at MaayafushiMaayafushi reef hadreef had
expanded constructing water bungalows over the reef flat and withinexpanded constructing water bungalows over the reef flat and within
100 m of the reef edge.100 m of the reef edge.
It does not appear that the sedimentation associated with theIt does not appear that the sedimentation associated with theconstruction of the bungalows greatly thwarted the recruitment ofconstruction of the bungalows greatly thwarted the recruitment of
new corals by either smothering new recruits or covering suitablenew corals by either smothering new recruits or covering suitable
substrate with silt rendering then unsuitable for settlement.substrate with silt rendering then unsuitable for settlement.
Much of the recovery in these sites is due to successful recruitmentMuch of the recovery in these sites is due to successful recruitment
and growth of primarilyand growth of primarily acroporidacroporid colonies and to lesser extentcolonies and to lesser extent
pocilliporidpocilliporid colonies.colonies.
MaayafushiMaayafushi reef also had good recovery from 6% in 2005 to 31%reef also had good recovery from 6% in 2005 to 31%
coral cover in 2009.coral cover in 2009.
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Kandholhudhoo is a picnic island with beautiful beaches naturally
replenished by a diverse, healthy coral reef which surrounds the island
Kandholhudho reef
showing some
physical damage and
partial mortality to
tabulate Acropora
and intact tabulate
Acropora colonies,
March 2009.
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Addu Atoll
Addu atoll were subjected to the 1998 bleaching event, but had
the greatest recovery of live coral cover in sites distant from
anthropogenic influences. After the 1998 bleaching, the reefs at Addu atoll still had some
living coral.
1
199 1998 1999 1 8 9 1
%
CoralCove
GanVillingili
Hithadhoo
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The Vilingili reef had about 4% coral cover in 1998
increasing to 13% in 2002.
In 2009, the coral cover had increased to 55% in spite of its
proximity of the development of resort water bungalows and
beach restoration efforts.
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Recently killed coral was observed at Vilingili reef, but
only covered 0.3% of the substrate in the two transect
lines.
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Large colonies ofPorites lobata were common at Vilingili reef, May
2009.
Porities are slow growing corals
Indicate continuous coral community over the past several decades.
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A member of the MRC coral reef monitoring team conducting a survey
along four 20 m transects at Hithadhoo reef, Addu atoll in May 2009
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Assessing the recovery of the reefs in the Maldives is like the story
of three blind men each describing an elephant by touching the
trunk, leg or tail.
There is considerable variation among reefs and among habitats
within reefs.
This variation is a function of the wide latitudinal range of the atolls,
the structure of the atolls and chance.
These factors create considerable variation in the abiotic factors
that influence reef development and, therefore, considerable
variation among reefs.
The recovery of most of the reefs surveyed during the past decadeis remarkable and suggests the question:
Where were the new recruits coming from????
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Increasing sea water temperatures still threaten coral reefs.
Coral bleaching occurred in July2010.
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Reef restoration activities are an important way to enhanceReef restoration activities are an important way to enhancecoral recovery near areas used by human visitorscoral recovery near areas used by human visitors
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A detailed study of currents around the Maldives would help to
determine the larval dispersal for both invertebrate and reef fish
stocks.
This information is necessary to better understand and manage
these larval source communities.
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AcknowledgementsAcknowledgements
MRC Director ShihamA d a m i s g r a t e f u l l y
acknowledged for his
e nc ou ra ge me nt a n d
hospitality to N.J. Quinn
N. Thoufeeq, H. Amir, and
Y. Rilwan assisted in the
data collection and data
entry. B.L. Kojis assisted
with the reef surveytraining . Their assistance
and good cheer helpedexpedite the expeditions.
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Captain Shareef and crew of the M.V. Mohara, Captain Anwar ofM.V.
Gaaviya and Captain Adam of M.V. Noah provided the safe and
comfortable logistical platform for our field trips.
NJQ is grateful to the US State Department for the Senior Fulbright
Fellowship.
AcknowledgementsAcknowledgements