11th ICRS Abstract book - Nova Southeastern University

7-33
Dynamics Of A Back Band Disease Outbreak At Pelorus Island On The Great
Barrier Reef
Yui SATO* 1 , David BOURNE 2 , Bette WILLIS 1
1 School of Marine and Tropical Biology, and ARC Centre of Excellence for Coral Reef
Studies, James Cook University, Townsville, Australia, 2 Australian Institute of Marine
Scinece, Townsville, Australia
Black band disease (BBD) is challenging the health of reef building corals worldwide and
reaching outbreak proportions for the first recorded time at several sites on the Great
Barrier Reef (GBR). Although abundance of BBD on the GBR is generally low, long
term monitoring of infected coral populations is required to assess the potential
consequences of the disease for this reef system. This study examined detailed dynamics
of a BBD outbreak in plating Montipora species at Pelorus Island, located at
approximately 18°33′N, 146°30′E, in the central section of the Great Barrier Reef
Marine Park. Individual diseased colonies were tagged and monitored over 2 years within
permanent quadrats, each of which was 10m x 10m. Abundance of BBD-infected
colonies and linear progression rate of the BBD band across colonies were recorded
approximately monthly. Temporal patterns in BBD abundance were striking and tightly
correlated with seasonal changes in seawater temperature. Abundance was higher in the
Austral summer (15 cases/100m2) than winter (0 case/100m2), and it was stable at low
levels during cooler months. Similarly, progression rate of the BBD band was greater in
summer (3.0 mm/day) than winter (0.5 mm/day). Temporal patterns in progression rate
were positively correlated with seasonal patterns of seawater temperature and light levels.
Results suggest that both water temperature and light incidence are environmental drivers
of BBD activity. If seawater temperatures continue to rise with global warming, the
consequences of BBD for host coral populations is likely to be severe, even in this wellmanaged
coral reef system. Knowledge of seasonal variability of BBD prevalence and
environmental drivers is essential to provide accurate assessment of reef health and to
develop effective reef management.
7-34
Dynamics Of The Coral Disease White Plague; Insights From A Simulation Model
Marilyn BRANDT* 1 , John MCMANUS 1
1 Division of Marine Biology and Fisheries, Rosenstiel School of Marine and
Atmospheric Science (RSMAS), University of Miami, Miami, FL
Understanding the dynamics of coral diseases among the heterogeneous populations in
which they act is critical for determining how the structure of reef communities has
changed as a result of enzootic or epizootic levels of these important sources of mortality.
This information can also form a basis for predicting the impact of disease in the near
future. The work presented here combined field studies with the development and testing
of a spatially-explicit, individual-based epizootiological computer model with the aim of
providing a useful tool for exploring disease dynamics in reef communities of the past,
present and future. This study focused on the disease white plague, a significant source of
mortality on reef-building corals in the Caribbean. Field studies focused on the incidence
and distribution of all sources of coral mortality, including white plague (type II) in situ,
at Little Cayman Island (Cayman Islands, British West Indies). Results indicated that
white plague was the most significant source of mortality during the monitoring time
period, and that it is likely contributing to major structural changes. The simulation
model was developed using this data, and results of model calibration indicated that white
plague on these reefs is transmissible between colonies within a limited field and requires
a yearly input from an outside source, and that host susceptibility to infection is low and
likely not variable among species. Parameters describing the distribution and composition
of the simulated coral population were then varied, and results showed a significant effect
of colony density, aggregation, and mean size on the impact of disease. Scenario testing
of various disease management strategies indicated that should local prevention measures
be developed in the future, it is they, and not treatment, that will likely be the most
effective in limiting the impact of disease.
Oral Mini-Symposium 7: Diseases on Coral Reefs
7-35
Metapopulation Dynamics Of Coral Infectious Disease
Susanne SOKOLOW* 1 , Patrick FOLEY 2 , Janet FOLEY 1 , Alan HASTINGS 1 , Laurie
RICHARDSON 3
1 University of California Davis, Davis, CA, 2 California State University Sacramento,
Sacramento, CA, 3 Florida International University, Miami, FL
Adaptation of epidemiological models to the study of marine diseases represents an
underdeveloped field and a research priority for understanding and managing emerging diseases
in the world’s oceans. Recent evidence suggests that metapopulation models may provide an
appropriate framework for modeling coral populations at the regional scale, and we expand this
approach to investigate the effects of infectious disease. Some key features that characterize
many coral disease systems include: (1) coral reefs are generally patchy, (2) adult coral are
predominantly sessile and new recruits represent the main mode of host dispersal to new
patches, (3) the pathogens have a hypothesized reservoir which can move widely and
independently of the hosts, and (4) environmental factors such as water temperature and
seasonality may affect pathogen survival and transmission. Testable predictions emerge when
considering coral disease in a metapopulation framework, including thresholds for regional
epidemic and endemic disease dynamics. Model results are compared with an original coral
disease dataset which spans a decade of patch-level monitoring for white plague type II (WPII)
on coral in the Florida Keys, and some qualitative patterns predicted by the model are consistent
with empirical evidence. By exploring a mechanistic model with minimal complexity, this
research offers preliminary insight for the ecology and epidemiology of coral diseases on reefs,
and allows critical evaluation of the long-term effects that disease pressure, environmental
change, and management may have on coral health and persistence.
7-36
Applying Medical Geography To Identify Spatial Hotspots Of Coral Diseases
Jennifer LENTZ* 1 , Andrew CURTIS 2,3 , Paul SAMMARCO 4 , Philippe MAYOR 5
1 Oceanography & Coastal Sciences, Louisiana State University, Baton Rouge, LA, 2 Geography,
Louisiana State University, Baton Rouge, LA, 3 Geography, University of California, Los
Angeles, 4 Louisiana Universities Marine Consortium, Chauvin, LA, 5 Buck Island Reef National
Monument, U.S. National Park Service, Christiansted, Virgin Islands (U.S.)
Given the current world-wide decline in coral reef health, it is important to understand those
factors contributing to, or directly causing, this decline, so that we can attempt to stabilize our
reefs and hopefully restore some of what has been lost. The problem is highly complex, and
requires the use of stringent multi-disciplinary analytical techniques. Here, we apply some of
the methods of Medical Geography to the problem of coral disease; specifically those used to
map and spatially analyze epidemics and general public health concerns to further our
understanding of coral reef health. This study compares the results of several spatial analytical
techniques applied to the same dataset. We used data regarding white-band diseased (WBD)
Acropora palmata at Buck Island Reef National Monument, initially presented by Mayor et al’s
2006 study. Overall, we found that the Disease Mapping and Analysis Program (DMAP) was
the strongest of the spatial analyses performed, resulting in detailed maps of the rates of WBD
clustering and Monte Carlo estimated areas of statistically significant (p