The impact of bleaching 2010 in the Andaman Sea and the management to mitigate the impact

Presented by Niphon Phongsuwan Phuket Marine Biological Center, Department of Marine and Coastal Resources Long-term monitoring on coral reefs since 1986 Manta-tow survey Line intercept transect : 100 m permanent transect year Andaman Sea Gulf of Thailand 1991 Very extensive bleaching – moderate mortality 1995 Very extensive bleaching – moderate mortality

1998 Moderate bleaching – low mortality Very extensive bleaching – high mortality 2003 Moderate bleaching – very low mortality 2005 Minor bleaching – no impact 2007 Minor bleaching – no impact 2010 Very extensive bleaching – very high Very extensive bleaching – low mortality to high mortality Monthly mean SST recorded in the Phuket area 33

32

31

30

29 o 28 30.34 C 27 Bleaching 26 threshold temperature (degree celsius) (degree temperature 25

24

23 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec month average 1991 1995 1998 2010 non-bleaching Fraction (%) of normal and bleached in May-June 2010

Phuket Khai-nok

Koh Laem Panwa Lone Koh Koh Ao Yongkasem Hae Aeo Ao Tonsai

Ao Siam Racha-E-1 normal Ao ราชา Bleach Plabpla Racha-E-2 The impact varied widely from place to place depending on

• the structure of coral communities • The intensity of current / waves shattering the reef structure

Surin Islands impact in 1991 & 1995 • not much impact in the area where water flow is good (in blue circle) • high impact in the area where water is stagnant (red circle)

SW-monsoon wind Most of ( spp.) began to die after only 1 month of bleaching Response of corals to temperature rising is very variable • some can resist to bleaching while some are very susceptible Genetically different ?? (genetic character of coral / zooxanthellae)

Symbiodinium Clade D (zooxanthellae) are diverse and occurred frequently in hosts from the northeastern Indian Ocean Very susceptible group Fast growing/high metabolic

Acropora spp. Porites rus Hydnophora rigida

Pavona clavus Merulina ampliata Montipora sp. Pectinia spp. Very few species of Acropora show moderate resistance to bleaching

Acropora valida

Acropora divaricata Acropora secale Diploastrea heliopora The most resistant group •

Heliopora coerulea

Pavona decussata Porites lutea on shallow reef flat was more resistant to bleaching than those colonies on reef slope due to corals on shallow zone have adapted/acclimatized to high temperature. west of Payu Island west of Similan Island

Coral reefs in the sheltered coves on the western aspects of islands in Andaman are sometimes influenced by internal waves which bring up cold water, leading to variable and on average lower sea temperatures. As a result, the impact of coral bleaching was not as severe and mortality was less than on coral reefs located on other aspects of the islands. SST duringอุณหภ มู 2009บิ ริเวณเกาะภ-เู ก2010ต็ 2551-2553 at Phuket

34 33.5 33 32.5 32 31.5

ส 31 ย

ี 30.5 ซ

เ 30 29.5

ล 29 ซ

เ 28.5 า 28 ศ 27.5 ง 27 อ 26.5 26 25.5 25 24.5 24 1/1/09 15/2/09 1/4/09 16/5/09 30/6/09 14/8/09 28/9/09 10/1/10 25/2/10 11/4/10 19/5/10 7/7/10 6/8/10 5/9/10

วันที่ Sea temperature started to drop to 29 – 30 oC (nearly normal climatic state) at the end of June (orange arrow) Some corals can tolerate high temperature for a period of time. They are gradually gaining symbiotic algae when temperature drops to normal Porites lutea which forms the main structure of coral reefs, was the first group transforming back to brown indicating its slow recovery.

Approximately 50-80% of the Porites lutea survived the bleaching event

A. clathrata

A. formosa

A. danai

Acropora species either branching or table shape used to be dominant but after the A. hyacinthus bleaching event they became the rarest species in all areas surveyed. • Coral larvae settlement were already found during late 2010 survey The damage that occurred to the coral reefs during the 2010 bleaching event will definitely take different lengths of time to recover in each location The bleaching event in 1991 and 1995 was fairly disastrous but not nearly as severe as the event in 2010.

After 1991 & 1995 bleaching, the coral reefs took a minimum 5 years to recover to a similar condition without any disturbance from humans. In some areas there was some improvement over pre-bleaching conditions, but the structure of coral community was different from prior to the event % Live coral cover at site A, Surin Island

60

50

40 Bleaching 1991 total Live Coral Cover 30 Acropora 1995 Porites rus 20 2010

10

0 19902533 19932536 19982541 20002543 Aprเมย.2553- Decธค. 2553- 2010 2010 Change of coral species structure over time Survey sites in Surin the Andaman Sea

approx. 100 Similan permanent transect sites Phuket (50 sites Phiphi surveyed in 2010) Andaman Rok Sea

Adang-Rawi Surin Islands

Live coral cover

Before bleaching

After bleaching Phuket Islands

Live coral cover

Before bleaching

After bleaching Adang-Rawi Islands

Live coral cover

Before bleaching

After bleaching Bleaching severity in 2010

Very high impact (mortality > 70%)

moderate impact (mortality ~ 50%)

Very low impact (mortality < 10%) In summary ….What happened after 2010 coral bleaching?

• Many of coral reefs have transformed from being in a healthy state to a very poor condition

• Those corals which survived would adapt to high temperature in future ??!!??

• Coral community (biodiversity) changed ??!!

70

60

50 Ko Hae 40 Ko Lone 30 Ko Aeo no. of spcies 20 Ao Patong 10 Ko Racha 0 Jan- Jan- Jan- Jan- Jan- Jan- Jan- Jan- Jan- Jan- Jan- 2 per. Mov. Avg. (Ao 90 92 94 96 98 00 02 04 06 08 10 Patong) 2 per. Mov. Avg. (Ko 70 Hae) 2 per. Mov. Avg. (Ko 60 Aeo) 2 per. Mov. Avg. (Ko 50 Racha) 40

30 Ao Tonsai no. of species 20 Ao Yongkasem 10 Ao Lolana 0 2 per. Mov. Avg. (Ao Jan- Jan- Jan- Jan- Jan- Jan- Jan- Jan- Jan- Jan- Jan- Lolana) 90 92 94 96 98 00 02 04 06 08 10 2 per. Mov. Avg. (Ao Yongkasem) 70 2 per. Mov. Avg. (Ao 60 Tonsai)

50

40 Park front

30 Ao Mayai

no. of species 20 Ao Tao 10 Ao Mai-ngam 0 2 per. Mov. Avg. Jan- Jan- Jan- Jan- Jan- Jan- Jan- Jan- Jan- Jan- Jan- (Ao Mayai) 90 92 94 96 98 00 02 04 06 08 10 2 per. Mov. Avg. (Ao Tao) 2 per. Mov. Avg. (Park front) 2 per. Mov. Avg. (Ao Mai-ngam)

Management to mitigate the impact and accelerate recovery

Short term activities • Rapid surveying the impact of coral bleaching and identifying the locations of resilient reefs. • Closing down some areas completely without allowing for any human activities or use. Some coral reef areas will require strict protection, such as some areas in national parks that have significant impacts from tourism – for examples, reefs with shallow areas where people are able to stand. • Building the knowledge and understanding of residents, tourists, business operators, and anyone who benefits from coral reefs in order to increase knowledge of coral bleaching situation and its impacts. A PR campaign has been created aimed at encouraging diving business owners to be environmental friendly. Medium and long-term activities

• Decreasing the impact from tourism activities affecting the reefs by establishing proper zoning for levels of use and types of diving activity, and creating suitable rules for anyone benefit from coral reefs. • Creating and enforcing strict development and management plans in order to decrease sediment runoff from the shore. Measures should also be put into place for controlling top-soil turn over and for preventing soil erosion • Preventing fishery activities that lead to coral reef damage, in particular, the smuggling of ornamental and food fishes in coral reefs in national park boundaries and other marine protected areas. Programs should be put into place to monitor fishing activities and regulations should be strictly enforced. • Building a new diving area or supplemental artificial reefs in a suitable location to reduce the usage of coral reefs. • Conducting researches in order to understand the natural process of reef recovery, the obstruction of reef recovery and the mechanisms to accelerate reef recovery Thank you