Studies conducted
• Coral Species Richness visual survey
• Substrate (Coral & Algae) Abundance survey
• Diadema (Long-spined black urchin) survey
• Coral Recruit survey
Coral Species Richness
• 32 species in Jamaica above 25 feet
• 13 species at Tern Cay above 25 feet
• 40% of maximum species richness
Coral and Algal AbundanceTern Cay Feb 2013
0.7
75.3
21.7
4.3
45.5
35.6
0
20
40
60
80
100
coral algae sand & rubble
Pe
rce
nt
cove
r (%
+/-
1sd
)
Backreef Forereef
Character of reef depends on interaction between slow growing corals and fast growing algae.
This interaction is mediated by herbivorous fish and urchins
Herbiverous fish (parrot, doctor)population reduced by fishing
Before 1983 Caribbean reefs still had high densities of Diadema antillarum and
algae was not a problem
After Diadema mass mortality
Before Diadema mass mortality
Phase-shift from coral to algal dominated reefs Discovery bay, Jamaica (Hughes, 1994)
Impact of Diadema die-offExample from Discovery Bay
Diadema Survey
13.9
0.2 0
4.8
1.32.35
0.1 0.20
2
4
6
8
10
12
14
16
1982 1983 1984 2007 2008 2009 2011 2013
Dia
de
ma
pe
r m
2
Mass mortality of Diadema
Discovery Bay
Mexico Puerto Rico
Bahamas This Study
Impact of storms on algal abundancein the Backreef of Tern Cay
0
20
40
60
80
100
sept oct nov dec jan feb mar
Pe
rce
nt
co
ver
(%+/
-SD
)Hurricane Sandy strikes Jamaica
24th Oct 2012
Bio
rock
reef
inst
alle
d
2012 2013
Impact of Hurricane Sandy on algal abundancein the Backreef of Tern Cay
12th October 2012 2nd November 2012
Path of Hurricane Sandy across Jamaica
24th October 2012
Second Conclusion
• No biological control (by herbivores) of macroalgae at Tern Cay
• Abundance of macroalgae dependant only on intensity wave action and time elapsed since last storm
Data Labels on ruler –
Fluorescent on frame b
Skirt- blocks
excess light
Black cloth to mimic
dark conditions
Position of camera a
b
Coral Recruitment Survey Method
Coral Recruitment Results(Jamaica)
Year No of Recruits per m2 Location Study
1980 60 Discovery Bay Sammarco (1980)
1983 378 Discovery Bay Ryslardam (1983)
2002 1- 6.4 Rackhams Cay Wilkinson et al (2002)
2005 0.3 - 8 Discovery Bay Quinn & Kojis (2005)
2013 0.2 Tern Cay Present Study
Diadema mass mortality
Third Conclusion
• Natural recruitment very low
• Regeneration of reef unlikely/very slow without intervention
Summary of Conclusions
1. Relative species richness is high (40%).– Good for reef rehabilitation
2. No biological control of macroalgae at Tern Cay.– Abundance of macroalgae dependant only on
intensity wave action and time elapsed since last storm
3. Natural recruitment very low.– Regeneration of reef unlikely/very slow without
intervention
Recommendations
1. Use biorock reef as reproductive hub
– Attach large reproductively mature corals
• Increase chance of fertilization
• Ideal location for transport of gametes/larvae to other reefs in PBPA
Biorock Reef in Thailand
Recommendations
2. Increase herbivory– Already in fishing sanctuary (no-fishing zone)– Actively restore Diadema in sanctuary
• Move adult Diadema into sanctuary• Grow Diadema in laboratory
3. Monitor condition of reefs to determine if actions are working
4. Extend study to other sites in PBPA