December 7th, 2011 class

Outline
1. Review of dangers facing coral reefs (bleaching!).
2. How to stop bleaching (?).
3. Red coral in the Mediterranean.
4. The importance of fish and mangroves to coral reefs.
5. Community conservation in the Philippines.
6. Conclusions.
Part 1 - Review of dangers facing coral reefs (bleaching!)
Dangers facing coral reefs
Global warming is raising the temperature of the ocean; this kills corals - “coral bleaching”.
Also, as the oceans become more acidic, it is more difficult for corals to make their skeletons.
Perhaps 90% of coral reefs will be dead by 2050.

Crown-of-thorns starfish outbreaks

Dynamite and cyanide fishing

Coral bleaching: Images from Phuket, Thailand 2010
Background
Corals (and many other coral reef invertebrates) are in symbiosis with Symbiodinium (zooxanthellae).
This symbiosis allows these invertebrates to live in nutrient-deficient sub-tropical and tropical waters.
Algal-animal symbioses are a successful strategy that has been repeated many times in evolution.
Weak point
Despite the success of this symbiosis, it has one very serious weak point:

Symbiodinium are very sensitive to low and high temperatures.

<18°C, and >30°C.
Coral bleaching
When temperatures are abnormal for the holobiont, stress occurs.
With this stress, thylakoids in Symbiodinium begin to break down; the symbiont begins to poison the host.
Corals lose their symbionts, either through cell-death, or by expelling them.
Hosts turn white = coral bleaching.

Predicting coral bleaching
The NOAA (USA) has spent much time on predicting bleaching.
Can now predict bleaching very accurately.
These tools available for free on the internet.
Vocabulary
SST=sea surface temperature
DHW=degree heating weeks
Daily max=expected average maximum SST for a certain day
MMM=maximum monthly mean, average temperature of the hottest month
SST anomolies
Observed SST – daily max SST
Can be used to see what location is hotter than usual.
Coral bleaching HotSpot
Predicts what areas have thermal stress that can cause/contribute to coral bleaching.
HotSpot=observed SST - MMM
Degree heating week (DHW)
However, it is not just anomolies and hotspots that cause coral bleaching.
The total stress from the past weeks is important. One hot day does not kill most coral!
DHW=0.5*(sum of previous 24 HotSpot reports), where HotSpots <1.0°C are not counted.
Example: 1 week of 2°C higher than normal = 2 weeks of 1°C higher than normal.
DHW >8.0 usually can cause coral death.
Thailand’s situation
Very high DHW on both sides of the Malaysian Peninsula.
Made worse by no cold temperatures last winter.
Also, lack of wind (“doldrums”) causes more solar/UV stress, which makes bleaching worse.
Ko Racha

Ko Tao
Ko Samet
Thank you.
Part 2 -
How to stop bleaching (?)
West & Salm 2003
What factors help corals against bleaching?
Reviewed all research up until 2003.

Many examples of resistance to or recovery from bleaching.

Many factors contribute to resistance.
Can be included in management plans.
Cumulative stresses worse than one stressor.

Part 3 - Red coral in the Mediterranean
Red coral
Corallium rubrum is a precious coral in the Mediterranean.
Found 10 -250 m.
Harvested for long time, over-exploited.
Harvest reduced 66% in last 15 years.

Population structure
Two population types, large deep colonies and shallow small colonies.
Large drop off in shallow water at age 4, due to sponges and collection.

Genetic distance becomes significant at 100s of kms.
Thus, preservation of numerous populations needed.
Management on regional scale needed.
Must avoid local extinctions.
Conservation recommendations
Must be managed at national and international scales.
Only policy that works for such species.
Set minimum colony sizes, maximum yield per area, harvesting seasons.

Mumby et al. 2004
Reef fish often use mangroves as nurseries.
But can use other environments, not confined.
Also, despite deforestation, other pressures (fishing, larval supply) likely larger.


Management should include connected habitats, not islands of each type.
Future destruction of mangroves will have negative influence on reef.
Mumby et al. 2007
Caribbean reefs have damage from loss of Diadema antillarum and two species of coral.
“Sick” reefs characterized by macroalgae.
Can macroalgae be reversed? Or is it a stable state?

Used computer modeling and simulation.
Showed reefs can easily change to other states once D. antillarum died off.
With only parrotfish as grazers, small negative change in parrotfish numbers results in macroalgae blooms.
Coral becomes unstable state with low grazing.

Regular impact of hurricanes worsens with lack of grazers (fish and urchins).
Modeling useful for conservation targets.
Part 5 - Community conservation of coral reefs
History
Philippines consist of 7000+ islands.
Centuries have used reefs for livelihood.
Since 1970s, threatened by over-exploitation and destructive fishing methods.

Conservation started in 1974. Many projects failed.
Politics tied to conservation.
Local governments have authority but not knowledge or budget.
To be successful, combination of local and national people.
Within local group, must include users of reef; fishermen, resort owners, coastal residents, scuba divers.
Start of conservation
MDCP started in 1986 on three islands (62-166 households); Apo, Pamilacan, Balicasag.
All had less fish catch, increasing destruction and poverty.

MCDP plan
Marine reserves with buffer areas to increase number and diversity fish.
Development of local knowledge and alternative work.
Community center.
Outreach and replication program.
MCDP steps
Integration into community.
Education - marine ecology and resource management.
Group building, formalizing, strengthening.
Results
Apo & Pamilacan remain strong.
Balicasag protection groups somewhat weakened due to large PTA resort and less local “ownership”.
PTA has good points too.
All islands have stronger municipal laws now.
Results
Local fisherman believe sanctuary has helped.
Comparison of 1985-86 data with 1992 shows increases in fish, stable coral cover.
Conclusions
MPAs work on small islands by preventing destructive fishing and making locals understand value of conservation.
Small islands easier to implement plans.
Immediate benefits must be seen.
Baseline data necessary.
Local fishermen help with MPA location decisions.
Conclusions
Locals must understand how problem and answer related.
Management groups must have respected members.
Link with all potentially helpful groups.
All plans vulnerable to politics and outside groups.
Part 6 - Conclusions


Towards the future
In the future, more conservation plans will be implemented.
The gap between well protected areas and those not protected will widen.

Towards the future
Very few non-protected reefs will survive.

Thanks!
References cited:
1. West & Salm. 2003. Resistance and resilience to coral bleaching. Conservation Biol 17: 956-967.
2. Santangelo & Abbiati. 2001. Red coral: conservation and management of an over-exploited Mediterranean species. Aquatic Conserv Mar Freshwater Ecosys 11: 253-259.
3. Hughes et al. 2002. Biodiversity hotspots, centres of endemicity, and the conservation of coral reefs. Ecol Let 5: 775-784.
4. Roberts et al. 2002. Marine biodiversity hotspots and conservation priorities for tropical reefs. Science 295: 1280-1284. 8. 5. 5. Mumby et al. 2004. Mangroves enhance the biomass of coral reef fish communities in the Caribbean. Nature 427: 533-536. 9.
6. Mumby et al. 2007. Thresholds and the resilience of Caribbean coral reefs. Nature 450: 98-101.
7. White & Vogt. 2000. Philippine coral reefs under threat: lessons learned after 25 years of community-based reef conservation. Mar Poll Bull 40: 537-550.