11th ICRS Abstract book - Nova Southeastern University

Oral Mini-Symposium 11: From Molecules to Moonbeams: How is Reproductive Timing Regulated in Coral Reef Organisms?
11-29
The Reproductive Biology And Recruitment Ecology Of Porites Bernardi
Jonathan MARTINEZ* 1 , Robert RICHMOND 1 , Jorg ANSON 2 , Sean MCDUFF 3
1 Pacific Biomedical Research Center, University of Hawaii at Manoa, Honolulu, HI,
2 Kewalo Marine Laboratory, Honolulu, HI, 3 University of Hawaii at Manoa, Honolulu,
HI
Porites cf. bernardi is a scleractinian coral described by Vaughn 1904. Its worldwide
distribution remains uncertain although it has been reported from locations in Japan,
Hawai’i & São Tomé e Principe. In Hawai’i, this coral inconspicuously grows in
encrusting forms rarely larger than 10 cm2 in areas of high wave motion, inhabiting the
subtidal zone to depths of 13m. No previous data are available describing the
reproductive biology and larval ecology of this species.
P. bernardi is a brooding coral, which reproduces year-round. Colonies do not appear to
be dependent on sperm from conspecifics for planulae production and release larvae most
days of the year with peak planulation near the lunar third quarter. There is a positive
relationship between adult size and reproductive output. A regression model predicts that
adults larger than 0.7225 cm2 may be reproductively mature, and adults as small as 0.882
cm2 have been observed to planulate. The larvae of P. bernardi have not been observed
to swim in the water column under laboratory conditions, but rather only crawl along the
substrata along a single axis Larval recruitment occurred mainly in response to coralline
algal chemical metabolites although modest recruitment has been observed in presence of
bacterial biofilms. In bioassays, almost all of the larvae settled within 48 hrs of exposure
to appropriate crustose coralline algae.
The availability of P. bernardi planulae throughout the year, and the larvae’s responses to
metamorphic inducers makes this a good model organism for studies of the effects of
anthropogenic stressors such as pollution, elevated temperatures, acidification and
sedimentation on coral reproduction and recruitment.
11-30
A Review Of Sexual Reproduction in Octocorallia
Samuel KAHNG* 1 , Yehuda BENAYAHU 2 , Howard LASKER 3
1 College of Natural Science, Hawaii Pacific University, Kaneohe, HI, 2 Tel Aviv
University, Tel Aviv, Israel, 3 University at Buffalo, Buffalo, NY
Since its initial discovery on Oahu in 1966, the azooxanthellate octocoral, Carijoa riisei
(Duchassaing and Michelotti, 1860), has spread across the main Hawaiian Islands and
proliferated in abundance. To help understand the substantial ecological success of C.
riisei in Hawaii, its sexual reproduction was examined. Carijoa riisei is gonochoric with
a male to female ratio of one. Gametogenesis is asynchronous, continuous, and does not
exhibit seasonal or lunar periodicity. Carijoa riisei spawns negatively buoyant eggs
which suggest external fertilization and possibly benthic larvae. Under favorable
conditions, C. riisei exhibits high polyp fecundity. Asynchronous, continuous spawning
of gametes is an unusual mode of reproduction which forgoes the advantages of
concentrating gametes in space and time and requires dense aggregations of male and
female colonies in close proximity to ensure fertilization success. Other life history traits
such as fast growth, early age of sexual maturity, vegetative propagation, and superior
competitive ability enable C. riisei to form dense, multi-colony aggregations thereby
facilitating sexual reproduction. Provided C. riisei can achieve a critical density, this
unusual sexual reproductive strategy probably enables it to exploit the ephemeral
availability of space across time with a high and continuous production of larvae.
11-31
Sexual Reproduction In The Soft Coral Lobophytum Sp. In Tung Ping Chau Marine
Park, Hong Kong Sar, China
Chung Wing YEUNG* 1 , Put ANG 1
1 Marine Science Laboratory, Department of Biology, The Chinese University of Hong Kong,
Hong Kong, Hong Kong
The soft coral genus Lobophytum is a carpet-like encrusting coral and is commonly found in
Hong Kong waters. The reproductive biology of Lobophytum, as well as that of other soft corals
in Hong Kong has never been investigated. This study provides the first baseline information on
the reproductive biology of soft corals in Hong Kong.
The sampling site in this experiment was Lung Lok Shui in Tung Ping Chau Marine Park.
Three samples from five marked Lobophytum aggregations were collected monthly from 16
Aug 2006 to 7 Jul 2007. Histological sections of each sample were prepared and their gonadal
development was observed under the microscope. All colonies in the same aggregation were
assumed to come from the same mother colony, since Lobophytum was reported to undergo
asexual reproduction and thus, its daughter colonies would remain in close proximity forming
the aggregation.
From the histological analysis of the samples, all colonies bore only eggs. As Lobophytum was
reported to be gonochoric, all the colonies sampled were therefore female. Male colonies may
be missed during sampling. Oocytes from the samples measured increased in mean (±SD)
diameter from 116.5±18.8 µm in Aug 2006 to 239.3±82.2 µm in Jun 2007, and dropped back to
93.0±23.2 µm in Jul 2007. This indicates that spawning of Lobophytum probably occurred in or
before Jul 2007. The oocyte development appeared synchronized as shown in the simultaneous
increase in their sizes. However, new oocytes likely developed before the release of the mature
ones so that each cycle of development took more than one year to complete. Additional
samples will be processed in order to confirm this initial observation.
11-32
Reproductive Biology Of Temperate Soft Corals (Alyonacea: Nephtheidae) in Korean
Waters
Sung-Jin HWANG* 1 , Jun-Im SONG 1
1 Division of EcoScience, Ewha Womans University, Seoul, Korea, Republic of
There was little information about the reproductive biology of family Nephtheidae. This study
were examined the reproductive diversity on three soft coral species from 2003 to 2007, and
two of them were belonged to genus Dendronephthya and one was to genus Scleronephthya.
They are all sympatric species in the Jejudo Island area (33° 22′ N, 126° 33′ E), and highly
distributed on the horizontal and vertical rocky substrata from 3 to 50 m in depth. One species,
Dendronephthya castanea, was a gonochoric internal brooder and two, D. spinulosa and
Scleronephthya gracillimum, were gonochoric broadcasters. They showed annual reproductive
cycles and similar patterns in gametogenesis. Gametes of them were matured as seawater
temperatures increased, reflecting a seasonal correlation in reproductive cycle. While oocytes
were observed at all times of the year, spermaries were found during a short period. D. castanea
released lecithotrophic planulae from July to September, and D. spinulosa and S. gracillimum
spawned gametes asynchronously from August to December and in August, respectively. The
ratio of female to male was 2.5: 1 in an internal brooder (D. castanea) and 1.5: 1 in broadcasters
(D. spinulosa and S. gracillimum), suggesting the correlation to mode of reproduction.
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