Ecological and physiological differences between two colour morphs of the coral Pocillopora damicornis

Pocillopora damicornis (Linnaeus) is a ubiquitous branching coral found throughout the Indo-Pacific region. Like many other species of coral, P. damicornis displays a large range of morphologies. At One Tree Island, it occurs as two distinct morphs that are easily distinguished by the presence or absence of pink pigmentation. The two colour morphs of P. damicornis were found to differ in their distribution and abundance in the One Tree Island Lagoon. The brown morph was more abudant than the pink morph in the shallows (<1 m),whereas the pink morph was more abundant at deeper sites (>3 m). The two morphs also differed physiologically. The brown morph tended to have a greater calcification rate than the pink morph, regardless of environmental conditions. However, the difference in the calcification rate between the two morphs became non-significant under shaded conditions (5% full sunlight), indicating some degree of physiological plasticity of the morphs. The pink colour in P. damicornis was due to a hydrophilic pigment with a major peak absorbance at 560 nm. The expression of pink pigment had both genetic and phenotypic components. The brown morph has a reduced genetic capacity to express the pigment relative to the pink morph. On the other hand, pigment expression could be induced by light in the pink morph. Although genetic differences ultimately determine the differences between the two morphs of P. damicornis, the extent of pigment expression is under some degree of environmental influence.     

Substratum preferences in planula larvae of two species of scleractinian corals, Goniastrea retiformis and Stylaraea punctata

To test whether coral planulae recruit randomly to different coral reef habitats or have specific substratum preferences, the settling behavior of planulae from two shallow water coral species from Pago Bay, Guam (13°25.02N, 144°47.30E) were examined in the laboratory in June and July of 1995. Goniastrea retiformis is generally restricted to the shallow reef front (<10 m depth) in areas dominated by crustose coralline algae (CCA), while Stylaraea punctata is abundant on inner reef flats were CCA coverage is low and sand and carbonate rubble covered by biofilms is common. When presented with four substrata (1) carbonate rock scrubbed free of biofilm and dried as a control, (2) the CCA Hydrolithon reinboldii, (3) the CCA Peyssonelia sp., and (4) naturally conditioned carbonate rubble covered by a biofilm, G. retiformis larvae showed a significant preference for H. reinboldii, and S. punctata larvae for the carbonate biofilm treatment. The preference shown by S. punctata larvae for biofilmed surfaces did not diminish with increasing larval age up to 11 days. These results suggest that the larvae of both species are capable of habitat selection, and that the preferred substrata among those tested bears a relationship to the habitats in which adult colonies were found. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Larval survivorship, competency periods and settlement of two brooding corals, Heliopora coerulea and Pocillopora damicornis

Larval dispersal and recruitment are important in determining adult coral distribution; however, few studies have been made of coral larval dispersal. This study examined the larval behavior, survivorship competency periods and settlement of two brooding corals, Heliopora coerulea and Pocillopora damicornis, in relation to different potential larval dispersal patterns. We also examined the lipid content of H. coerulea as a means of flotation and a source of energy. Planulae of H. coerulea were on average 3.7 mm in length, lacked zooxanthellae, and were mostly benthic, probably because of restricted movement and low lipid content (54% by dry weight). Planulae of P. damicornis were on average 1.0 mm in length, had zooxanthellae and swam actively. The competency period of H. coerulea was shorter (30 days) than that of P. damicornis (100 days). Forty percent of H. coerulea planulae crawled onto the substrata within 1 h of release, and 47% settled within 6 h. By contrast, fewer than 10% of P. damicornis planulae crawled onto the substrata within the first hour and 25% settled within 6 h of release. The planulae of H. coerulea may have a narrower dispersal range than those of P. damicornis, settling and recruiting near parent colonies. Thus, brooding corals exhibit variations in larval dispersal patterns, which are characterized by their position in the water column and competency periods.     

Mode and timing of reproduction in some common hermatypic corals of Hawaii and Enewetak

Common Hawaiian and Enewetak corals were examined to determine the method and mining of reproduction. Of the 7 Hawaiian species examined for the release of planulae, only 2 have planulated in captivity, Pocillopora damicornis and Cyphastrea ocellina. Both planulate year-round and both are characteristic of reef flats. Four of the 5 species which did not planulate were found to contain eggs, but not planulate, when polyps were examined microscopically. These 5 species do not usually occur on reef flats. Seven of the 12 Enewetak species examined in June, July, August and January planulated; 4 of these were pocilloporids, all of which are common in shallow water. Only 3 of the 8 species of Acropora planulated, and these 3 occur solely in shallow water. A greater proportion of the Pocillopora spp. colonies than Acropora spp. colonies planulated and they released more planulae per head. In previous studies and in this one, coral species which have released planulae are characteristic of shallow-water environments such as reef flats. Most of the 10 species reported on here which failed to planulate in captivity are not commonly found on reef flats. The failure to detect planulation in so many species, particularly those of deeper water, suggests that common hermatypic corals may not all reproduce in the same way, and that mode of reproduction may be related to habitat.     

Sexual and asexual production of planulae in reef corals

Electrophoresis was used to provide genetic evidence of the mode of production of brooded planulae in each of four species of scleractinian coral collected from the central region of the Great Barrier Reef during September, October and November 1984. Comparisons were made of the multi-locus genotypes of planulae and their broodparents for two ahermatypic (non zooxanthellate) species,Tubastraea diaphana andT. coccinea and two hermatypic (zooxanthellate) species,Acropora palifera andSeriatopora hystrix. For both ahermatypic species, all planulae were found to be genetically identical to their broodparents, including 91 planulae which were heterozygous for at least one locus. These results are consistent with asexual (ameiotic) reproduction. In contrast, non-parental genotypes were detected in the majority of hermatypic broods, which is consistent with expectations for sexual reproduction with at least some outcrossing. These data confirmed that brooded planulae may be produced both sexually and asexually and countered the suggestion that electrophoretic studies of hermatypic corals may be weakened by the contaminating effect of the enzymes of their symbiotic xooxanthellae.Contribution No. 306 of the Australian Institute of Marine Science     

Allozyme electrophoresis demonstrates that the scleractinian coral Montipora digitata is two species

Allozyme electrophoresis at five loci was used to clarify the species status of two morphs of the scleractinian coral Montipora digitata (Dana, 1846), using specimens collected from three locations off the Queensland coast between October 1991 and April 1993. The two morphs, occurring sympatrically, were distinguished by one fixed gene difference at Locus LT-2 and frequency differences at three other loci, indicating reproductive isolation between them. Populations of both morphs were generally in Hardy-Weinberg equilibrium, suggesting that sexual reproduction does occur. Despite sampling designed to reduce the chance of collecting clonemates, the genetic diversity ratio (G _O:G_E) indicated that asexual reproduction also occurs. This is in agreement with the known modes of reproduction for this species. There was significant genetic differentiation between populations of one of the morphs of M. digitata. This could have been influenced by greater degrees of asexual reproduction in this morph, selection within sites, or variation in larval survival and recruitment patterns. Relatively low F _st (differentiation among populations) values found for a broadcast spawning species during this study are in accordance with the hypothesis that brooded planulae are adapted for rapid settlement, whereas planulae produced by broadcast spawners are adapted for widespread dispersal.     

Life cycle of the jellyfish <Emphasis Type="Italic">Lychnorhiza lucerna</Emphasis> (Scyphozoa: Rhizostomeae)

The life cycle of Lychnorhiza lucerna (Scyphozoa: Rhizostomeae) and the settlement preferences of its larvae were studied using laboratory-based rearing experiments. Mature medusae of L. lucerna were collected from the beach of the Río de la Plata estuary, Argentina. This species displayed the typical metagenetic, (i.e. medusoid and polypoid), life cycle reported for other rhizostomes. The fertilized eggs developed into motile and short lived planulae. The majority of planulae settled on the air-water interface (p < 0.001). Of those that settled on the settlement plates provided, no significant differences were observed between styrene slides, glass slides and shells of the bivalve Mactra isabelleana (p > 0.05). No planulae settled on stones. Several hours after planulae settled, they metamorphosed into sessile four-tentacled scyphistomae. Most scyphistomae attached onto the air-water interface. At 19–22°C, the scyphistomae grew up to 22 tentacles and reached 1,500 μm height. The scyphistomae increased their numbers by means of formation of podocysts from which new polyps emerged and strobilated. Strobilation occurred 46 days after settlement. Only polydisk strobilation was observed and each strobila always produced three ephyrae. After releasing ephyrae, strobilae returned to normal scyphistomae and were capable of repeating strobilation. A single founder polyp was estimated to produce up to 60 ephyrae over 4 months. Ephyrae developed into metephyrae 15 days after release at 19–22°C. In this paper we describe the morphological and some behavioural features of L. lucerna in the polypoid and early medusoid stages.     

The relative contribution of dinoflagellate photosynthesis and stored lipids to the survivorship of symbiotic larvae of the reef-building corals

The long-distance dispersal of larvae provides important linkages between populations of reef-building corals and is a critical part of coral biology. Some coral planulae have symbiotic dinoflagellates (Symbiodinium spp.) that probably provide energy in addition to the lipids provisioned within the egg. However, our understanding of the influence of symbionts on the energy metabolism and survivorship of planulae remains limited. This study examines the relative roles of symbiotic dinoflagellate photosynthesis and stored lipid content in the survivorship of the developing stages of the corals Pocillopora damicornis and Montipora digitata. We found that survivorship decreased under dark conditions (i.e. no photosynthetic activity) for P. damicornis and M. digitata at 31 and 22 days after release/spawning, respectively. The lipid content of P. damicornis and M. digitata planulae showed a significant decrease, at a higher rate, under dark conditions, when compared with light conditions. When converted to energy equivalents, the available energy provided by the depletion of lipids could account for 41.9 and 84.7% of larval metabolism for P. damicornis (by day 31) and 38.4 and 90.1% for M. digitata (by day 21) under light and dark conditions, respectively. This finding indicates that not all energy requirements of the larvae are met by lipids: energy is also sourced from the photosynthetic activities of the symbiotic dinoflagellates within these larvae, especially under light conditions. In addition, the amounts of three main lipid classes (wax esters, triglycerides, and phospholipids) decreased throughout the experiment in the planulae of both species, with the wax ester content decreasing more rapidly under dark conditions than under light conditions. The observations that the planulae of both species derive considerable amounts of energy from wax esters, and that symbiotic dinoflagellates enable larvae to use their stores at lower rates, suggested that symbiotic dinoflagellates have the potential to extend larval life under light conditions.     

Temporal reproductive isolation and gametic compatibility are evolutionary mechanisms in the<Emphasis Type="Italic"> Acropora humilis</Emphasis> species group (Cnidaria; Scleractinia)

Patterns of interbreeding between individuals are fundamental to the structure and maintenance of evolutionary boundaries between species. In corals, both hybridisation and reproductive isolation appear to be important evolutionary mechanisms. In this study, I examine evolutionary boundaries using morphological, molecular and reproductive criteria within the Acropora humilis species group at Lizard Island on the Great Barrier Reef, Australia. Five species and seven morphs are recognised on the basis of morphological appearance of features traditionally used to identify corals of the genus Acropora. In a molecular phylogenetic analysis, I examine relationships for the mitochondrial DNAs putative control region, using maximum-parsimony and maximum-likelihood methods. The reproductive criteria explore whether species and morphs are reproductively isolated on the basis of temporal or fertilisation barriers. Timing of gamete maturity is surveyed for each species and morph, from the month prior to and 3 months after the mass spawning. Time of spawning is documented at the levels of night and hour of spawning, and time taken for egg-sperm bundles to separate. Laboratory fertilisation experiments tested the potential of species and morphs to interbreed. High levels of intraspecific and extremely low or zero fertilisation levels between the five species indicated that they are valid species. Based on the combined assessment of morphological, molecular and reproductive criteria, A. humilis and A. gemmifera appear to be the most closely related species, which are most closely related to the remaining species in the following order: A. samoensis, A. monticulosa and A. digitifera. Evidence derived from one or more of these criteria suggest that the morphs (1) are at various stages of divergence from the species with which they share morphological characters, and (2) may indicate possible zones of speciation and hybridisation. Identification of morphs avoided the possibility of taxonomic error and was essential for accurate interpretation of evolutionary boundaries. Confirmation of morphology as an informative character of evolutionary boundaries is of great significance because most coral research projects rely on morphology as the primary tool for identification of species.Communicated by M.S. Johnson, Crawley     

Degradation and proliferation of zooxanthellae in planulae of the hermatypic coral Stylophora pistillata

Zooxanthellae in different stages of two opposite processes, degradation and proliferation, were found in the planulae of hermatypic corals. The formation of new zooxanthellae is balanced by degraded zooxanthellae in newly released planulae. The number of dividing zooxanthellae and degraded zooxanthellae during the day amounted to approximately 2 to 3% of the standing stock. In settled planulae and particularly in motionless planulae of Stylophora pistillata (Esper, 1797), the degraded zooxanthellae outnumbered proliferous zooxanthellae. The proliferation and degradation of zooxanthellae and the extrusion of degraded remnants of zooxanthellae are significantly phased. Swimming planulae are more autotrophic than motionless planulae. The physiological parameters of settled planulae with exoskeleton are similar to those of adult polyps. The significance of zooxanthella degradation in the vital functions of planulae is discussed. We suggest that the degradation of zooxanthellae in planulae occurs by the digestion of symbionts by host cells. Received: 5 March 1997 / Accepted: 6 August 1997     

Genetic connectivity among color morphs and Pacific archipelagos for the flame angelfish, <Emphasis Type="Italic">Centropyge loriculus</Emphasis>

Color variation is used in taxonomic classification of reef fishes, but it may not reliably indicate evolutionary divergence. In the central Pacific, there are three color morphs of the flame angelfish, Centropyge loriculus: a red morph that occurs primarily in the Hawaiian archipelago, the endemic Marquesan color morph with reduced black markings, and an orange morph that occurs throughout the rest of Oceania. The red and orange morphs co-occur at Johnston Atoll (1,300 km south of Hawai’i), but intermediate forms have not been reported. To determine whether the three color morphs represent distinct evolutionary lineages, we compared 641 base pairs of mitochondrial cytochrome b. Forty-one closely related haplotypes were observed in 116 individuals. Analysis of molecular variance (AMOVA) indicated no significant genetic structure among color morphs (Φ_ST = 0.011, P = 0.147). Likewise, there was no significant pairwise structure between sampling locations, separated by up to 5,700 km, after a Bonferroni correction (Φ_ST = 0.000–0.080, P = 0.0130–0.999). Genetic studies in conjunction with larval distribution data indicate that Centropyge species are highly dispersive. While there is a strong geographic component to the distribution of color morphs in C. loriculus, we find no evidence for corresponding genetic partitioning. We do not rule out an adaptive role for color differentiation, but our data do not support emerging species.     

Depth limits of Bermudan scleractinian corals: a submersible survey

Depth distribution, zonation pattern and growth morphology of 17 hermatypic and 4 ahermatypic coral species were investigated at eight different locations along the Bermuda platform with the research submersible GEO and by SCUBA diving in August–September 1983. Hermatypic coral growth occurs to a depth of 50 to 70 m, with a single Montastrea cavernosa growing at 78 m. Dominant forms in shallow-water coral communities are Diploria sp. and Porites astreoides, while M. cavernosa, Agaricia fragilis and Scolymia cubensis occur in deep-water associations below 60 m. Vertical visibilities (up to 178 m) and distribution of the photosynthetically active radiation revealed good light penetration values (1% level at about 100 m depth), which should favour hermatypic coral growth to a much greater depth than it actually occurs. Nor should the prevailing temperatures limit the depth of coral growth. Most deep-water hermatypes observed grow on remnants of Pleistocene reefs down to about 60 m. The vast areas of large massed rhodolith nodules below 50 to 60 m are unsuitable bottom for coral colonisation. Macroalgae growth seems to be the strongest factor controlling coral growth in deep water. Bermuda stony corals have a low growth form diversity. Various intraspecific morphs may occur at the same as well as at different depths, with a general trend towards flatter shapes with depth. Comparison with a similar study on Red Sea corals suggests that annual distribution of radiant energy on the most northern Atlantic reefs of Bermuda may be responsible for the occurrence of flat and cuplike growth forms in relatively shallow water, and for the shallower depth limits of hermatypic growth.     

Effects on growth and reproduction of the coral Stylophora pistillata by the mutualistic damselfish Dascyllus marginatus

Although coral dwelling fishes are common on coral reefs, the nature of their effect on the host corals is poorly understood. The present study, conducted in the Gulf of Eilat (Red Sea) between July 1989 and August 1990, demonstrated that the branching coral Stylophora pistillata (Esper) benefits, in two components of coral fitness, from the presence of the damselfish Dascyllus marginatus (Rüppell), an obligate coral dweller. The growth rate of damselfish-inhabited corals was significantly higher than that of corals without damselfish. This was observed, using two growth assessment methods, in long-term (>7 mo) comparisons between: (1) corals where the damselfish were experimentally removed versus corals with unaltered fish groups; and (2) naturally inhabited versus non-inhabited corals. The presence of damselfish did not affect the coral's specific (per surface area) reproductive output, whether it was assessed by the number of female gonads per polyp or by the number of planulae released cm^-2 surface area d^-1. However, the more rapid increase in branch size in damselfish-inhabited corals resulted in an apparent increase in the total reproductive output, with age, in growing corals. These findings demonstrate that the association between the damselfish D. marginatus and its host coral, S. pistillata, is mutualistic.     

Density-dependent settlement and mortality structure the earliest life phases of a coral population

The local densities of heterospecifics and conspecifics are known to have profound effects on the dynamics of many benthic species, including rates of settlement and early post-settlement survivorship. We described the early life history of the Caribbean coral, Siderastrea radians by tracking the population dynamics from recently settled planulae to juveniles. Through three years of observation, settlement correlated with the abundance of other benthic organisms, principally turf algae (negatively) and crustose coralline algae (positively). In addition, adult density showed independent effects on coral settlement and early post-settlement survivorship. Settlement rates increased across low levels of adult cover and saturated at a maximum around 10% cover. Early post-settlement survivorship decreased with adult cover, revealing structuring density dependence in coral settlers. The earliest life stages of corals are defined by low survivorship, with survivorship increasing appreciably with colony size. However, recent settlers (one-polyp individuals, < 1-year-old) are more likely to grow into two-polyp juveniles than older single polyps (> 1-year-old) that were delayed in their development. The early benthic phase of corals is defined by a severe demographic bottleneck for S. radians, with appreciable density-dependent and density-independent effects on survivorship. For effective management and restoration of globally imperiled coral reefs, we must focus more attention on this little studied, but dynamic, early life history period of corals.     

Sexual reproduction of three coral species from the Mexican South Pacific

Our understanding of the reproductive biology of corals from the Mexican southeastern Pacific is limited, and consequently, the role of reproduction in structuring coral communities is unclear. As a first attempt to understand the importance of sexual reproduction in structuring and maintaining of the coral communities from this region, we documented the reproductive cycles over 2 years (2003–2004) in three main reef-building corals species in the region. Pocillopora damicornis was shown to be hermaphroditic with asynchronous gamete development observed only in 2004; P. gigantea was characterized as both gonochoric and cosexually hermaphroditic. Absence of mature gametes was documented in both species, and an observation may be attributed to the 2003 El Niño Southern Oscillation event, which may have inhibited reproductive maturation via thermal stress. Porites panamensis was gonochoric with asynchronous development, and planulae were generally brooded. The presence of mature gametes and planulae in P. panamensis polyps suggests that this species is an important contributor to local and, likely, regional recruitment of this species. Further research should seek to identify important source populations for these coral recruits and document the exchange of larvae between coral populations of the Mexican Pacific.     

Genetic and color morph differentiation in the Caribbean sea anemone<Emphasis Type="Italic"> Condylactis gigantea</Emphasis>

The distribution of phenotypic and genetic variation across environments can provide insights into local adaptation. The tropical sea anemone Condylactis gigantea inhabits a broad spectrum of coral-reef habitats and displays a variety of phenotypes, particularly with respect to color. At the coast of Discovery Bay, Jamaica, individuals with either pink or green tentacle tips show distinct distributions. Pink morphs are more abundant in the lagoon and in deeper areas, while green morphs are more abundant in the forereef and in shallower areas. We use DNA sequence data (ITS1-5.8S) to investigate if variation in color is associated with genetic differentiation in lagoon and forereef habitats about 5 km apart. Population genetic analyses reveal two distinct ITS1-5.8S variants, which differ in relative frequency. The two variants are present in both habitats, but a dearth of intermediates suggests reduced gene flow. In the lagoon, but not the forereef, ITS variants show an association with color. In order to address the potential ecological significance of color, we study UV absorbance and UV acclimatization capacities of pink and green color morphs in the lagoon. Color morphs differed significantly in UV-B absorbance. These results suggest genetic and ecological differentiation in the face of gene flow over short distances.Communicated by O. Kinne, Oldendorf/Luhe     

Influence of UV radiation on the survival of larvae from broadcast-spawning reef corals

Effects of ambient ultraviolet light on the survivorship of eggs and planulae larvae was investigated for three species of broadcast-spawning reef corals, Acropora palmata, Montastraea annularis, and M. franksi. Eggs and larvae from these corals contain high concentrations of lipids (60–70% by weight) and float in surface waters for 3–4 days following spawning. Larvae originating from colonies living at deeper sites on the reef exhibited significantly lower survivorship than conspecifics originating from parents in shallow water when experimentally exposed for up to 4 days to ambient surface levels of ultraviolet radiation (UVR). Concentrations of the UVR-protective compounds correlated positively with survival and matched concentrations found in parent colonies, implying that higher concentrations of ultraviolet B protective compounds are responsible for greater survival of eggs and larvae from shallow compared to deeper-dwelling parents. Ultraviolet B appears to be responsible for most of the observed differences in larval survivorship with ultraviolet A playing a minor or insignificant role. Data presented here indicate that coral recruits on Caribbean reefs and elsewhere may originate primarily from adult colonies dwelling in shallow water.Communicated by P.W. Sammarco, Chauvin     

Reproductive ecology of the azooxanthellate coral <Emphasis Type="Italic">Tubastraea coccinea</Emphasis> in the Equatorial Eastern Pacific: Part V. Dendrophylliidae

The reproductive ecology of Tubastraea coccinea Lesson, an azooxanthellate tropical scleractinian coral, was studied over various periods from 1985 to 2006 at four principal eastern Pacific locations in Costa Rica, Panamá, and the Galápagos Islands (Ecuador). This small (polyp diameter 0.8–1.0 cm), relatively cryptic species produced ova and planulae year round, including colonies with as few as 2–10 polyps. Of 424 colonies examined histologically, 13.7% contained both ova and sperm. Mature ova varied in diameter from ∼300 to 800 μm and the time from spawning and fertilization of oocytes to release of brooded planulae was about 6 weeks. Planulae were 0.5–1.5 mm long and they settled and metamorphosed on a variety of substrates after 1–3 days. Spermaries, though more difficult to distinguish in histological sections, were present throughout the year. Spent spermaries were never observed in sections, but several colonies in Panamá and the Galápagos Islands released sperm from night one to night five after full moon, indicating the potential for cross-fertilization among colonies. Planula release was observed at Uva Island (Panamá) in March, May, June, and July, and in general planula presence was higher at warm ocean temperatures at all sites, whether or not the sites were influenced by seasonal upwelling. Annual fecundity estimates for T. coccinea are comparable with other high fecundity brooding species, including the zooxanthellate Porites panamensis, with which it co-occurs in Panamá. Tubastraea coccinea is widely distributed in the tropical Indo-Pacific and has colonized substrates in the western Atlantic. In addition to the reproductive characteristics described in the present study, other features of the biology of T. coccinea, such as an ability to withstand conditions that produce bleaching and mortality in zooxanthellate species, may account for its widespread, low-latitude distribution in multiple oceans. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. An erratum to this article can be found at     

Asexual production of planulae in the coral Pocillopora damicornis

The reproduction of scleractinian corals through planular larvae has traditionally been viewed as a strictly sexual process. Here, the results of an electrophoretic study of a ubiquitous Indo-Pacific coral, Pocillopora damicornis, show an exact inheritance of parental genotypes by brooded planulae, demonstrating the existence of an asexual mode of production of planular larvae. Comparisons of the genetical structure of a number of populations with structures predicted for sexual reproduction suggest that, although there is probably also a sexual form of reproduction, asexually produced planulae can be of major importance in the maintenance of populations of this species.     

Reproductive biology and larval development of the temperate soft coral <Emphasis Type="Italic">Dendronephthya gigantea</Emphasis> (Alcyonacea: Nephtheidae)

Dendronephthya gigantea (Verrill, 1864), the dominant species in the waters surrounding Jeju Island, Korea, is a gonochoric internal brooder that releases its planulae from July to September. The ratio of females to males in this azooxanthellate soft coral is 2:1. Oogenesis takes place for 12 months and spermatogenesis for 3–5 months. Gametes mature as seawater temperatures increase, suggesting a seasonal factor in the reproductive cycle. Planulae brooded in the gastrodermal canal were expelled around the times of the full moon and the new moon; a significant difference in numbers expelled was not found between day and night. Ciliated planulae had negative buoyancy after planulation, and showed rapid metamorphosis into a primary polyp stage within 2 days.