Transcript Threats to the Mesoamerican Barrier Reef

Threats to the Mesoamerican
Barrier Reef
Igor Kontrec
June 27, 2011
Picture taken from padi.com
What is causing the destruction of
the reef?
2 major threats include:
o Climate change
o Introduced species
Climate Change
Coral bleaching
• Is a sign that a coral is in stress and is on the verge of death
• Caused by the lack of photosynthetic
zooxanthella, which gives corals their
colour(Buccheim 1998). They live in the cells
of corals and provide oxygen while using the
waste material and carbon dioxide the coral
Partially bleached coral.
Taken from
releases.
globalwarmingart.com
• The paling and depletion of zooxanthellae can be caused by a
change in water temperature, rising water levels, and severe
storms.
Coral Bleaching locations worldwide. Large
concentration in Caribbean. Graph taken from
marinebiology.org
Climate Change Cont’d
Rise in Temperature
• Optimal temperature for corals to thrive is between 25 and 30
°C.
• A drop of 3-5 °C for 5-10 days can cause bleaching but it is
more frequent for bleaching to occur during summer months.
A rise in temperature of only 1-2 °C for 5-10 weeks will cause
evident bleaching (Buccheim 1998).
• Water holds less oxygen at higher temperatures(Buccheim
1998).
• Due to the lack of oxygen, corals are deprived of energy and
begin to stress and bleach
Climate Change
Rise in Sea Levels
• Corals thrive in relatively shallow areas reaching a maximum
depth of 50m.
• When water levels rise, sunlight does not penetrate as deep
therefore does not reach corals in vulnerable places.
• The rise in sea levels are caused by severe storms and large
amounts of run-off water.
Dead coral from Hawaii.
Photo taken by myself.
Climate Change
Severe Storms
• Storms in the Mesoamerica area are becoming more frequent
and unpredictable(worldwildlife.org).
• The large amounts of freshwater being deposited are
changing the salinity of the water. For corals, the optimal
salinity is 34 -37 parts out of 1000(oceanworld.edu). When
severe storms occur, the habitat of the corals is slightly
diluted.
• Usually occurs in shallow areas.
• If storms are more frequent and more severe, it can lead to
higher amounts of coral death.
Introduced Species
Tilapia
• Originally in fish farms but managed to expand locations.
• Over the past 25 years they have been found in streams,
rivers, lagoons, and costal waters.
• Eating native fish species.
• Upsetting to the native Mayangna people.
Tilapia farm in Belize.
Photo taken from
fis.com
Introduced Species
Lionfish
• Originally from the Indo-Pacific area but have been
introduced to the Caribbean and Atlantic.
• First sighting in Belize was in 2008 and are now seen daily.
• Lionfish are successful in this habitat because they have very
active reproductive systems; reproducing every four days
spawning 30,000 eggs every time. The eggs are buoyant which
is very unusual.
• Lionfish have venomous spikes.
• Eats fish half its size in one gulp and has been observed to eat
20 fish in 30 minutes (ambergriscaye.com).
Lionfish cont’d
• Lionfish have no predators in the Caribbean, except other
lionfish. They are cannibalistic.
• Experiments involving moray eels have been unsuccessful.
Only a shark has eaten the lionfish but it was very difficult to
do so.
• By eating all other fish it is ruining the fishing industry and
killing the diversity of the reef. This will also affect tourism.
• Efforts to stop the lionfish have been through organizations
such as the “Belize Lionfish Project”.
Lionfish.
Animalsspecies.com
• The “Belize Lionfish Project” is encouraging fisherman to
catch as many lionfish as possible seeing as it will increase
their income.
• Raising awareness to scuba divers and marine guides.
• Government permits issued to divers to use lionfish as culling
devices.
• Lionfish tournaments are held.
• Restaurants are persistently told to serve Lionfish because it is
edible. (ecomarbelize.org)
• Video on the “Belize Lionfish Project” cooking Lionfish
http://www.youtube.com/watch?v=YfAxeKv6TYQ&feature=bf
_next&list=WLB4D8B8E1F0712C9F&index=2
Conclusion
• Climate change has changed water depths and
salinity due to storms. It has also changed
water temperatures of the areas. All these
factors have caused coral bleaching and
ultimately the death of corals.
• Introduced species have devastated native fish
populations and ruined food webs in the
worlds second largest barrier reef.
The End