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Coral Disease On Little Cayman
Adam Catevenis
Steven Savard
Coral Disease on Little CaymanIntroduction
• Historical data suggests that White plague was most abundant between 1999 and 2004 on Little Cayman. Dark Spot was more prevalent between 2004 and 2006. It also suggests that the distribution of white plague affected colonies was found to be clumped [1].
• Diseases are found to be more prevalent in degraded sites, and silt in run-off has been the leading cause of coral mortality worldwide [2]
• White Plague, Black Band, White Band, White pox, and Dark Spot Syndrome are the primary diseases on Little Cayman.
• Coral diseases may be found more prevalent in areas of high stress such as sites out of the marine park and where there is development.
• Increased areas of disease will also be related to increased areas of water flow, sedimentation, and high wave energy.
• A greater abundance of diseased coral is found in close proximity rather than random locations.
Methods•Surveyed 12 sites around the island. •5 transects were done for each site •Transects were 30m long•Along each transect, a record of each coral species and coral diseases was taken for coral colonies directly underneath the transect tape.• Pictures were taken of each diseased colony encountered. A ruler was placed beside the affected area to more accurately calculate the percent cover of the disease for each coral. •While one recorder is taking a picture, the other swam a circle with a 1-2 meter radius around the diseased coral and recorded the amount and type of diseases in the area. •A record of water flow, sedimentation, and wave energy was decided for each site based on a 1-5 scale where 1 is the lowest and 5 is the highest
Results
References[1] Brandt M.E, Mabfrino C, McManus J.W, Coehlo V. The epizootiology of white plague in relationship to coral community change in a protected reef environment (Little Cayman, Cayman Islands, British West Indies). In review[2] Harvell C.D, et al. (1999) Emerging Marine DiseasesÑClimate Links and Anthropogenic Factors. Science vol. 285 p. 1505-1510
Figure 1Diseased coral in Population
0%10%20%30%40%50%60%
S. si
dere
a
D. stri
gosa
D. cliv
osa
Gorgo
nian
M. f
aveo
lata
M. a
nnul
aris
P. po
rites
A. aga
racit
ies
A. palm
ata
Coral Species
% d
isea
sed
% Aspergillosis
% WB
% Wpox
% BB
% DS
% WP
Figure 2aSedimentation vs % of total coral diseased
0%2%4%6%8%
10%12%14%16%
1 2 3 4 5
Sedimentation (1 - 5 scale)P
erc
en
t o
f to
tal
co
ral
dis
ea
se
d
Sedimentation
, Sedimentation)Outlier(stormy day
( Linear)Sedimentation
Figure 2bWater flow vs % diseased coral
0%2%4%6%8%
10%12%14%16%
0 1 2 3 4 5
Water flow (1 - 5 scale)
Per
cen
t o
f to
tal c
ora
l d
isea
sed
Water Flow
Water Flow (Outlier, stormy(day
( Linear)Water Flow
Figure 2cWave Energy vs % of total disease in the area
0%
5%
10%
15%
20%
1 2 3 4 5
Wave Energy (1 - 5 scale)
Pe
rce
nt
of
tota
l c
ora
l d
ise
as
e
Percent of totaldisease
Percent of total, disease)outlier(stormy day
Linear (Percent of(total disease
Figure 3aAverage % Diseased Coral Inside and Out of the Marine Park
00.020.040.060.08
0.10.120.140.16
1Perc
ent o
f tot
al d
isea
sed
cora
l
In marine park
Outside of marine park
Figure 3bAverage % Diseased Coral for Developed vs Nondeveloped Sites
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
1
Perc
ent o
f tot
al c
oral
dis
ease
Developed
Nondeveloped
Figure 3cAverage % of Coral Diseased for the North and South
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
1
aver
age
% o
f cor
al d
isea
sed
North
South
Coral disease affected a total of 9 species out of 16 identified. As seen in Figure 1, disease was found most prevalent in A. palmata (50% of population were diseased) and S. siderea. (22% of population were diseased). Figure 1, also shows the percent of the population affected by each disease. Dark spot was the most prevalent disease affecting mostly S. siderea and A. agaracities.
The result of the t-test depicts how there is no significant difference in the percent of total coral diseased inside and out of the park, where there is development and lack of, and between the north and south side of the island. This can be seen by the overlapping error bars of the three graphs in Figure 3.
When comparing sedimentation, water flow, and wave energy to the percent of diseased coral, it appears to be inversely related; as seen in Figure 2. However, comparison of the calculated R values indicate that there is no significant relationship between these factors and the percentage of disease.
DiscussionOur results are consistent with the previous data in that dark spot is the most prevalent disease affecting coral around Little Cayman. The most affected species were A. palmata and S. siderea. None of the factors studied were related to the percent of coral diseased. There was also no difference between location and the prevalence of disease. Further data should be collected to validate these observed results. Other unknown environmental factors may cause the spread of disease and should be studied.
Introduction• Historical data suggests that White plague was
most abundant between 1999 and 2004 on Little Cayman. Dark Spot was more prevalent between 2004 and 2006. It also suggests that the distribution of white plague affected colonies was found to be clumped [1].
• Diseases are found to be more prevalent in degraded sites, and silt in run-off has been the leading cause of coral mortality worldwide [2]
• White Plague, Black Band, White Band, White pox, and Dark Spot Syndrome are the primary diseases on Little Cayman.
• Coral diseases may be found more prevalent in areas of high stress such as sites out of the marine park and where there is development.
• Increased areas of disease will also be related to increased areas of water flow, sedimentation, and high wave energy.
• A greater abundance of diseased coral is found in close proximity rather than random locations.
Methods• Surveyed 12 sites around the island• 5 transects were done for each site• Transects were 30m long• Along each transect, a record of each coral species and coral
diseases was taken for coral colonies directly underneath the transect tape.
• Pictures were taken of each diseased colony encountered. A ruler was placed beside the affected area to more accurately calculate the percent cover of the disease for each coral.
• While one recorder is taking a picture, the other swam a circle with a 1-2 meter radius around the diseased coral and recorded the amount and type of diseases in the area.
• A record of water flow, sedimentation, and wave energy was decided for each site based on a 1-5 scale where 1 is the lowest and 5 is the highest
Figure 1Diseased coral in Population
0%
10%
20%
30%
40%
50%
60%
Coral Species
% d
isea
sed
Aspergillosis %WB %Wpox %BB %
DS %WP %
Results
Coral disease affected a total of 9 species out of 16 identified. As seen in Figure 1, disease was found most prevalent in A. palmata (50% of population were diseased) and S. siderea. (22% of population were diseased). Figure 1, also shows the percent of the population affected by each disease. Dark spot was the most prevalent disease affecting mostly S. siderea and A. agaracities.
Figure 3bAverage % Diseased Coral for Developed vs Nondeveloped Sites
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
1
Perc
ent o
f tot
al c
oral
dis
ease
Developed
Nondeveloped
Figure 3aAverage % Diseased Coral Inside and Out of the Marine Park
00.020.040.060.08
0.10.120.140.16
1Perc
ent o
f tot
al d
isea
sed
cora
l
In marine park
Outside of marine park
Figure 3cAverage % of Coral Diseased for the North and South
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
1
aver
age
% o
f cor
al d
isea
sed
North
South
The result of the t-test depicts how there is no significant difference in the percent of total coral diseased inside and out of the park, where there is development and lack of, and between the north and south side of the island. This can be seen by the overlapping error bars of the three graphs in Figure 3.
Figure 2aSedimentation vs % of total coral diseased
0%
5%
10%
15%
20%
1 1.5 2 2.5 3 3.5 4 4.5 5
Sedimentation (1 - 5 scale)
Per
cent
of t
otal
cor
al
dise
ased
Sedimentation
Sedimentation (Outlier, stormy(day
( Linear)Sedimentation
Figure 2bWater flow vs % diseased coral
0%
5%
10%
15%
20%
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5
Water flow (1 - 5 scale)
Perc
ent o
f tot
al c
oral
di
seas
ed
Water Flow
( Water Flow )Outlier ,stormy day
( Linear)Water Flow
Figure 2cWave Energy vs % of total disease in the area
0%
5%
10%
15%
20%
1 2 3 4 5
Wave Energy (1 - 5 scale)
Pe
rce
nt
of
tota
l c
ora
l
dis
ea
se
Percent of totaldisease
Percent of total, disease)outlier(stormy day
Linear (Percent of(total disease
When comparing sedimentation, water flow, and wave energy to the percent of diseased coral, it appears to be inversely related; as seen in Figure 2. However, comparison of the calculated R values indicate that there is no significant relationship between these factors and the percentage of disease.
Discussion
• Our results are consistent with the previous data in that dark spot is the most prevalent disease affecting coral around Little Cayman. The most affected species were A. palmata and S. siderea. None of the factors studied were related to the percent of coral diseased. There was also no difference between location and the prevalence of disease. Further data should be collected to validate these observed results. Other unknown environmental factors may cause the spread of disease and should be studied.
References
• [1] Brandt M.E, Mabfrino C, McManus J.W, Coehlo V. The epizootiology of white plague in relationship to coral community change in a protected reef environment (Little Cayman, Cayman Islands, British West Indies). In review
• [2] Harvell C.D, et al. (1999) Emerging Marine DiseasesÑClimate Links and Anthropogenic Factors. Science vol. 285 p. 1505-1510