11th ICRS Abstract book - Nova Southeastern University

7-29
Can the Presence of Disease Signs Explain Levels of Tissue Fragmentation on
Colonies of the Genus Montastraea spp.?
Adán JORDÁN-GARZA* 1 , Eric JORDÁN-DAHLGREN 1
1 Laboratorio de Sistemas Arrecifales Coralinos, Universidad Nacional Autónoma de
México, Puerto Morelos, Mexico
A disease is a disruption of the normal structure or function of an organism. On
scleractinian corals diseases are diagnosed through signs on the coral tissue with an
associated rate of partial mortality. In a coral with low resistance to the pathogen(s),
disease progression may result in dead. Otherwise if progression rate is low or halted, the
original coral might have been fragmented into smaller colonies (sensu Connell), with
reduced fecundity and higher probability of dead by infections or other causes. This study
quantified the degree of tissue loss associated to different disease signs in fragmented and
non-fragmented corals. On Montastraea faveolata, M. annularis and M. cavernosa
permanent marks were laid along the colony edge in order to measure lateral tissue
growth or loss. The presence of disease signs on the edge-tissue was recorded and the
sign was classified as typical (known to be potentially lethal) or non-typical (might be
potentially lethal or harmless). A total of 546 marks on M. faveolata, 79 on M.
annularis and 161 on M. cavernosa were followed for a year. Rates of tissue loss
depended on the disease sign, time of year and habitat. In general, prevalence of signs
and tissue loss was higher on M. faveolata (rate of tissue loss -2.44±6.9 mm/y,
MEAN±SD, n=382) than on M. annularis (-0.52±0.5 mm/y, n=69) and M. cavernosa
(-0.1±0.8 mm/y, n=96) but colonies of M. faveolata with low prevalence of disease
signs, showed lower rates (-0.56 ± 1.4 mm/year). A continuous trend of tissue loss, like
the one observed during this study, leads to colony shrinkage and fragmentation and a
simulation shows that it can have serious effects on populations of this key reef-building
corals.
7-30
White Band Syndromes in Acropora cervicornis off Broward County, Florida:
Transmissibility and Rates of Skeletal Extension and Tissue Loss
Abraham SMITH* 1 , James THOMAS 2
1 Oceanographic Center, Nova Southeastern University, Hollywood, FL, 2 Oceanographic
Center, Nova Southeastern University, Dania Beach, FL
The high latitude thickets of Acropora cervicornis off Broward County flourish
despite the presence of natural and anthropogenic impacts. These populations provide a
unique study opportunity which stands out against the disease stricken areas of the
Florida Keys. This study uses time sequenced photographs to examine how A.
cervicornis is coping with white band syndrome stressors. Variables being monitored
include healthy colony skeletal extension rates, diseased colony skeletal extension rates,
and tissue loss. The transmissibility of the white band syndromes is being examined
through tissue grafting including healthy controls. Healthy skeletal extension rates rage
from 0.3-5.2 mm/month. Diseased skeletal extension rates range from 0.5-4.8 mm/month.
Tissue loss from disease signs range from 0.6-4.5 mm/day. Transmission experiments
show that not all direct tissue contact results in the transfer of white band syndrome signs.
Up to 60% show mild to no disease sign transmission. The A. cervicornis thickets in
Broward County are growing slower compared to most studies in other areas of the
Western Atlantic. Tissue loss is also low compared to other reports. White band
syndromes are always present in Broward County, but the low incidence of transmission
of the syndromes seems to limit its affect on the thickets.
Oral Mini-Symposium 7: Diseases on Coral Reefs
7-31
Dynamics And Ecological Relevancy Of A Viral Disease in Caribbean Spiny Lobster
Mark BUTLER 1 , Behringer DONALD* 2 , Thomas DOLAN 1 , Jeffery SHIELDS 3 , Robert
RATZLAFF 1
1 Department of Biological Sciences, Old Dominion University, Norfolk, VA, 2 Department of
Fisheries & Aquatic Sciences, University of Florida, Gainesville, FL, 3 Virginia Institute of
Marine Science, Glouchester Point, VA
Coral diseases have deservedly garnered much attention, yet ecologically significant diseases
also occur among reef-dwelling motile taxa within which disease dynamics may be quite
different from corals. In 2000, we discovered a deadly virus (PaV1) that infects Caribbean
spiny lobster (Panulirus argus), and we have confirmed infections in Florida, Mexico, Belize,
and the US Virgin Islands. PaV1 is the first viral disease known for any species of lobster, and
it alters the behavior and ecology of this species in fundamental ways. The prevalence of
infection varies with ontogeny, with most infections occurring among the smallest size classes.
In Florida, mean prevalence of PaV1 in early benthic juvenile lobsters approaches 25%
compared to < 1% in adults. The virus is pathogenic with successful transmission demonstrated
via injection of hemolymph from infected donors, ingestion of infected tissue, contact with
infected lobsters, and – among the smallest lobsters – over short distances in the water.
Decapods that co-occupy dens with lobster (stone crab, Menippi mercenaria; channel clinging
crab, Mithrax spinomosissimus; spotted lobster, P. guttatus) do not harbor the virus. Most
remarkable is that healthy lobsters, which are normally social, chemically detect and avoid
diseased conspecifics prior to their becoming infectious. This behavior along with lethargy in
infected lobsters may break the expected density-dependence of infection. Traditional
epizootiological models are not applicable in this and presumably other situations because of
their dependence on mass-action principals, so we developed a unique spatially-explicit,
individual-based model simulating PaV1 dynamics among lobsters in the Florida Keys. We are
using the model to examine the: (a) role of risk avoidance behavior in pathogen transmission,
(b) effect of fishing on PaV1 transmission, and (c) effect of large-scale degradation of nursery
habitat structure on disease dynamics in lobster.
7-32
Blood Parasite Infection Dynamics Of Fish in The Indo-Pacific Region
Lynda CURTIS* 1 , Angela DAVIES 2 , Nico SMIT 3 , Alexandra GRUTTER 1
1 School of Integrative Biology, University of Queensland, Brisbane, Australia, 2 Biomedical and
Pharmaceutical Sciences, Kingston University, Kingston, United Kingdom, 3 Department of
Zoology, University of Johannesburg, Johannesburg, South Africa
To date there has been little work done on Haemogregarine blood parasites in coral reef fish.
Traditionally, haemogregarines have a two host life-cycle with a vertebrate intermediate host
and an invertebrate definitive host vector. This study conducted a survey between March 2005
and August 2007 throughout the Indo-Pacific to determine the variability in intensity and
prevalence of haemogregarine infections, spatially and temporally. To test whether gnathiid
isopods are the vector of blood parasites in coral reef fish transmission experiments were
conducted at Lizard Island on the Great Barrier Reef, Australia. Gnathiid isopods, not
previously exposed to blood parasites, were allowed to feed on the blood of fish infected with
blood parasites. The gut contents of these gnathiid isopods were then examined from one to ten
days post-feeding to determine if transmission had taken place. While there were variations in
the intensity of the blood parasite infection over time in triggerfish at Lizard Island this was not
associated with season. Therefore water temperature does not appear to play a role in the
differences detected. There was also a difference in the intensity of the blood parasite infection
in the triggerfish sampled at different geographical locations. These variations could be related
to the distribution of the potential vector, the gnathiid isopod, at particular sites. We found
convincing evidence for the theory that gnathiid isopods are the vector, as various stages of
development of the blood parasites were found from four days post feeding in the gnathiid gut
contents. This study is the first quantitative investigation into the blood parasites of coral reef
fish and will hopefully increase our understanding of coral reef fish blood infections and their
impact on host ecology.
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