11th ICRS Abstract book - Nova Southeastern University

Oral Mini-Symposium 11: From Molecules to Moonbeams: How is Reproductive Timing Regulated in Coral Reef Organisms?
11-5
Evidence For Opsin-Regulated Long-Wavelength Photosensitivity in Coral Larvae
Benjamin MASON* 1 , Matthew BEARD 2 , Margaret MILLER 3 , Jonathan COHEN 4 ,
Valery SHESTOPALOV 5 , Vladlen SLEPAK 6
1 RSMAS, University of Miami, Miami, FL, 2 Biological Sciences, Florida State
University, Tallahassee, FL, 3 NOAA - Southeast Fisheries Science Center, Miami, FL,
4 Marine Science, Eckerd College, St. Petersburg, FL, 5 BascomPalmer Eye Institute,
McKnight Vision Center, Leonard M. Miller School of Medicine, University of Miami,
Miami, FL, 6 Molecular and Cellular Pharmacology, Leonard M. Miller School of
Medicine, University of Miami, Miami, FL
Research has demonstrated that light influences the swimming behavior and settlement of
coral larvae, yet a physiological and molecular basis for photosensitivity has not been
described in corals. Here we provide evidence for long-wavelength photosensitivity in
several species of scleractinian coral larvae and demonstrate the presence of an opsin–
like protein, localized in solitary, sensory epithelial cells. Settlement experiments with
Porites astreoides and Acropora palmata demonstrated that these larvae are attracted to
and preferentially settle on red substrates. Larvae settled and metamorphosed on red
fluorescent plastic substrate but not on plastic substrates of other colors. Preference for
red was not observed when larvae were maintained in the dark, suggesting that
phototaxis, rather than a chemical cue, was responsible for the observed preference.
Electrophysiology (electroretinographic traces) confirmed sensitivity to long-wavelength
light in larvae of P. astreoides. Immunoblots, using a rabbit polyclonal antibody directed
against squid opsin, indicated the presence of a ~50 kDa, opsin-like protein in larvae of
A. palmata, and Diploria strigosa. Immunofluorescence and confocal imaging of
sectioned larvae demonstrated this opsin-like protein is localized in solitary, ciliary
epithelial cells in P. astreoides, D. strigosa, Montastraea faveolata, and Favia fragum.
Protein blasts of M. faveolata larval contig ESTs with Nematostella vectensis and squid
opsin sequences, revealed the expression of two 7-transmembrane receptors with
significant similarity (2e^-9 to 2e^-18) to the query sequences. Efforts to determine the
remaining sequence and confirm the identity of these proteins are currently in progress.
11-6
Bleaching Has No Short-term Effect on Reproduction in the Scleractinian Coral
Montipora capitata
Evelyn COX* 1
1 University of Hawaii West Oahu, Pearl City, HI
Bleaching is generally expected to produce detrimental impacts on coral reproduction.
This study compared the fecundity of bleached and unbleached colonies of the Hawaiian
coral Montipora capitata. It was hypothesized that bleaching would have no effect on
reproduction because previous studies have shown that Montipora capitata can increase
heterotrophic feeding following bleaching. Reproductive parameters, total reproductive
output (bundles released ml-1 coral colony), number of eggs bundle-1, and egg size,
measured in the summer of 2005 did not differ between colonies that bleached or did not
bleach during 2004. These data were collected following a single bleaching event and
cannot be used to predict the outcome should bleaching episodes become more frequent
or severe.
11-7
Reproduction in The Coral Reef Herbivore Scarus Ferrugineus (Scaridae): Its Timing
And Seasonality
Yohannes AFEWORKI* 1,2 , John VIDELER 2 , Henrich BRUGGEMANN 3
1 Applied Marine Science, College of Marine Science, Massawa, Eritrea, 2 Marine Biology,
University of Groningen, Haren, Netherlands, 3 Laboratoire ECOMAR, Université de La
Réunion, La Réunion, France
Reproductive behavior of the rusty parrotfish Scarus ferrugineus was studied in a fringing reef
in the Southern Red Sea (Eritrea). Observations on territory holding Terminal Phase Males
(TTP) were conducted to record the following parameters: the location of the territory, timing
and duration of territory holding, territory size, size of the TTP, number of Initial Phase females
(IP) and non-territorial Terminal Phase males (TP) arriving at the territory, frequency of
spawning and streaking. The mating system of S.ferrugineus is lek-based where large TTPs
occupy a temporary breeding territory in the deep fore reef (6 – 10 m depth). Territory holding
and spawning occurred daily year-round. But the timing was different for the cold (November –
April) and warm (May – October). During the warm months (July – September) breeding
territories were kept at around high tide time. The timing of spawning shifted with the peak
high-tide-time as it progressed through the consecutive days. Only when the day high tide
occurred after 3:00 pm the fish switched to the early hours of the morning just after the night
high tide. Duration of the breeding ranged between 1 – 3.5 hours with the longest periods
occurring during the morning. In the colder months (December – March) territory holding
invariably took place during the morning hours between 7:30 and 11:00 irrespective of the
period of the tide. Intensity of reproductive behavior was highest during the cold months.
During that period 70 % of females that were striped had hydrated eggs compared to 40 %
during the warm months. A tradeoff between reproduction and growth is evident in the cold
months as reflected in the low body condition of all the social categories. This tradeoff appears
to be caused by lost feeding opportunities while spawning, high energetic costs of spawning and
territory keeping and low primary production during that period.
11-8
Patterns of Egg Predation at Reef Fish Spawning Aggregation Sites and the Role of Target
Egg Predators
Matthew FRASER* 1 , Mark MCCORMICK 1
1 Marine and Tropical Biology, James Cook University, Townsville, Australia
Predator-prey interactions at reef fish spawning aggregations are poorly understood yet form the
foundation of hypotheses explaining spawning site selection and temporal patterns of spawning
aggregations. The current study examined egg predation by reef based obligate and facultative
planktivores at reef fish spawning aggregation sites at Kimbe Bay, Papua New Guinea. The
objective of this study was to quantify egg predation levels among spawning aggregation sites
and among three reef fish species, and examine characteristics of both the spawners and
spawning sites in order to explain the patterns of egg predation. Spawning activity was
monitored daily at seven spawning aggregation sites across three reefs over a two month period.
During each spawning event the number of spawning rushes released, the number of rushes
preyed upon and the species of egg predators that fed on each rush. Attributes of each spawning
aggregation site measured were density of egg predators during a spawning event and
substratum topographic complexity. Egg predation was greatest for the surgeonfish,
Ctenochaetus striatus, and differed significantly among sites. Levels of egg predation for C.
striatus correlated significantly with egg predator density while egg predation levels for the
parrotfish, Chlorurus bleekeri, and wrasse, Thalassoma hardwicke, did not. Similarly, levels of
egg predation for C. striatus correlated significantly with substrate topographic complexity
while egg predation levels for C. bleekeri and T. hardwicke did not. This study shows the
immediate predation of eggs by target egg predators is an important source of mortality and
directly influences the number of propagules being effectively liberated from spawning sites
used by C. striatus. The differences in the levels of egg predation between spawning species
suggests that the intensity of target egg predation may not be an important determinant in the
choice of spawning aggregation sites.
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