Coral Aquaculture Research Articles

Effect of light intensity on survival and photosynthetic efficiency of cultured corals of different ages

In this present study, we investigated the effects of increase and decrease of light intensity and photoperiods on growth, survival, and photosynthetic efficiency in three different corals, Pocillopora damicornis (Linnaeus, 1758), Acropora millepora (Ehrenberg, 1834) and Platygyra sinensis (Milne Edwards and Haime, 1849) with different ages (6-, 12-, and 24-month old). All experimented corals were cultured from sexual propagation. In light intensity trials, juvenile corals were transferred and exposed to different treatments (0, 21, 42, 85, and 169 μmol m−2 s−1 provided by 400-W metal halide lamps or equal to daily light integrals (DLI) of 0, 0.95, 1.89, 3.8, and 7.6 μmol m−2 s−1) for 2 weeks, while in the photoperiod experiment, the coral colonies were exposed to 5 different treatments (24/0, 18/6, 12/12, 6/18, and 0/24 h light-and-dark cycle). The results from the light intensity experiment showed that 2-year old Platygyra sinensis survived (100%) under all light intensity levels, while the survival rates of other coral species decreased, ranging between 20 and 80%, when the light intensity levels changed from the ambient light condition. For the photoperiod experiments, the results showed that 2-year old Platygyra sinensis and 1-year old Acropora millepora survived (100%) under all photoperiod levels. However, there was no significant difference on the growth of corals between different light intensity levels and different photoperiods. From this study, Platygyra sinensis seemed to have more tolerance to wider ranges of light intensities and photoperiods than other coral species. In addition, the results implied that corals were able to acclimate to a prolonged light period and light intensity, which can be feasible for future coral aquaculture.

Microbiome differences in disease-resistant vs. susceptible Acropora corals subjected to disease challenge assays

In recent decades coral gardening has become increasingly popular to restore degraded reef ecosystems. However, the growth and survivorship of nursery-reared outplanted corals are highly variable. Scientists are trying to identify genotypes that show signs of disease resistance and leverage these genotypes in restoring more resilient populations. In a previous study, a field disease grafting assay was conducted on nursery-reared Acropora cervicornis and Acropora palmata to quantify relative disease susceptibility. In this study, we further evaluate this field assay by investigating putative disease-causing agents and the microbiome of corals with disease-resistant phenotypes. We conducted 16S rRNA gene high-throughput sequencing on A. cervicornis and A. palmata that were grafted (inoculated) with a diseased A. cervicornis fragment. We found that independent of health state, A. cervicornis and A. palmata had distinct alpha and beta diversity patterns from one another and distinct dominant bacteria. In addition, despite different microbiome patterns between both inoculated coral species, the genus Sphingomonadaceae was significantly found in both diseased coral species. Additionally, a core bacteria member from the order Myxococcales was found at relatively higher abundances in corals with lower rates of disease development following grafting. In all, we identified Sphingomonadaceae as a putative coral pathogen and a bacterium from the order Myxococcales associated with corals that showed disease resistant phenotypes.

The Life Cycle of the Acropora Coral-Eating Flatworm (AEFW), Prosthiostomum acroporae; The Influence of Temperature and Management Guidelines

As coral aquaculture is increasing around the world for reef restoration and trade, mitigating the impact of coral predators, pathogens and parasites is necessary for optimal growth. The Acropora coral-eating flatworm (AEFW), Prosthiostomum acroporae (Platyhelminthes: Polycladida: Prosthiostomidae) feeds on wild and cultivated Acropora species and its inadvertent introduction into reef tanks can lead to the rapid death of coral colonies. To guide the treatment of infested corals we investigated the flatworm’s life cycle parameters at a range of temperatures that represent those found in reef tanks, coral aquaculture facilities and seasonal fluctuations in the wild. We utilized P. acroporae from a long-term in vivo culture on Acropora species to examine the effects of temperature (3°C increments from 21-30°C) on flatworm embryonation period, hatching success, hatchling longevity, and time to sexual maturity. Our findings show that warmer seawater shortened generation times; at 27°C it took, on average, 11 days for eggs to hatch, and 35 days for flatworms to reach sexual maturity, giving a minimum generation time of 38 days, whereas at 24°C the generation time was 64 days. Warmer seawater (24–30°C) also increased egg hatching success compared to cooler conditions (21°C). Taken together these results indicate that warmer temperatures lead to higher population densities of P. acroporae. Temperature significantly increased the growth rate of P. acroporae, with individuals reaching a larger size at sexual maturity in warmer temperatures, but it did not influence hatchling longevity. Hatchlings, which can swim as well as crawl, can survive between 0.25 to 9 days in the absence of Acropora, and could therefore disperse between coral colonies and inter-connected aquaria. We used our data to predict embryonation duration and time to sexual maturity at 21°C-30°C, and discuss how to optimise current treatments to disrupt the flatworm’s life cycle in captivity.

Morphological and histological characterization of a new Acropora-eating flatworm: A potential threat to captive acroporid corals

The high demand for live corals for decorative and reef-restoration purposes has caused increased interest in land-based coral farming. However coral cultivation is frequently threatened by disease outbreaks and corallivores. Small corallivores, such as the Acropora-eating flatworm (AEFW), can cause the loss of tissues and result in the death of the acroporid corals within a short period. Here, for the first time, this study reports a new Acropora-eating flatworm (new AEFW) that feeds on corals (Acropora). There were significant differences in the size, shape, and appearance between the new AEFW and the polyclad AEFW, Prosthiostomum acroporae, which is the only reported AEFW to date. The new AEFW underwent a life history of direct development. Transmission electron microscope (TEM) observations revealed that the dorsal epidermis of the new AEFW consisted of a single layer of epidermal cells with numerous microvilli and cilia with a typical “9 + 2” pattern in the axoneme structure. The vertical rootlet was approximately three times longer than the horizontal rootlet in the anchored-rootlet system. The basal membrane was well developed with a fibrous microfibrillar layer. The new AEFWs secreted rhabdites that did not have a lamellated structure. All of these morphological and physiological traits suggested that the new AEFWs were different from the polyclad AFEW from the order Polycladida. They were likely from the order Tricladida or Proseriata. Additionally, new AEFWs exhibited acroporid-specific feeding behavior when given seven scleractinian corals. The results indicated that the new AEFWs could be a potential threat to captive acroporid corals.

The Active Reef Restoration Toolbox is a Vehicle for Coral Resilience and Adaptation in a Changing World

The accelerating marks of climate change on coral-reef ecosystems, combined with the recognition that traditional management measures are not efficient enough to cope with climate change tempo and human footprints, have raised a need for new approaches to reef restoration. The most widely used approach is the “coral gardening” tenet; an active reef restoration tactic based on principles, concepts, and theories used in silviculture. During the relatively short period since its inception, the gardening approach has been tested globally in a wide range of reef sites, and on about 100 coral species, utilizing hundreds of thousands of nursery-raised coral colonies. While still lacking credibility for simulating restoration scenarios under forecasted climate change impacts, and with a limited adaptation toolkit used in the gardening approach, it is still deficient. Therefore, novel restoration avenues have recently been suggested and devised, and some have already been tested, primarily in the laboratory. Here, I describe seven classes of such novel avenues and tools, which include the improved gardening methodologies, ecological engineering approaches, assisted migration/colonization, assisted genetics/evolution, assisted microbiome, coral epigenetics, and coral chimerism. These are further classified into three operation levels, each dependent on the success of the former level. Altogether, the seven approaches and the three operation levels represent a unified active reef restoration toolbox, under the umbrella of the gardening tenet, focusing on the enhancement of coral resilience and adaptation in a changing world.

Neuroactive compounds induce larval settlement in the scleractinian coral Leptastrea purpurea

Settlement of pelagic coral larvae is commonly induced by chemical cues that originate from biofilms and coralline algae. These natural settlement cues initiate signal pathways leading to attachment and metamorphosis of the coral larva. In order to investigate the settlement process and its natural inducers, it is necessary to gain a better understanding of these signal pathways. At present, the pathways and neurotransmitters involved in this signal transduction are still widely unknown. In this study, we exposed larvae of the brooding coral Leptastrea purpurea to five neuroactive compounds known to be present in cnidarians, and K+ Ions. All compounds were applied at different dilutions and settlement behavior of the larvae was documented over 48 h. Dopamine, glutamic acid and epinephrine significantly induced settlement in the coral larvae. The highest observed metamorphosis response was 54% in 10−5 M dopamine. Serotonin, L-DOPA and K+ ions did not have an influence on settlement behavior in our experiments. Exposing larvae to settlement-inducing neurotransmitters and thus bypassing the initial induction could be utilized in coral aquaculture. The active neurotransmitters should be used to further study the settlement process in L. purpurea in greater detail. Their role and relevance should also be assessed for other coral species as they may represent or reveal a universal inducer for coral settlement.

Is gardening corals of opportunity the appropriate response to reverse Philippine reef decline?

Hard coral cover (HCC) in the Philippines has been declining over the past decades. Restoration practices that utilize “gardening” corals of opportunity (COPs) are actively being adopted throughout the country. However, the use of COPs in coral gardening has not yet been examined in terms of its effectiveness in addressing nationwide‐scale reef decline. The feasibility of using COPs for coral gardening was determined through a spreadsheet model that derives COP numbers needed to increase HCC in a reef. The model showed that 280,112 COPs of 5‐cm radius need to be transplanted to increase HCC in a hectare of reef from 0% to 22%, the current national average. Annual COP mortality must be less than 31.5% to achieve an increase in HCC above 22% over a span of 10 years following a gardening effort. Actual counts and generic composition of available COPs were recorded from transects in 20 reef stations across three locations in the Philippines (Lian, Luzon; Lubang Island; and Balabac, Palawan). Natural COP densities suggest that large areas of healthy reefs must be searched to obtain enough COPs for an effective gardening effort. Furthermore, the COPs measured in Lian were below the recommended fragment size for transplantation, thus needing nursery rearing to attain the 5‐cm radius prescribed for increased probability of transplant survivorship. These findings indicate that applying coral gardening at a nationwide scale is not likely to be feasible, effective, or sustainable.

Effects of live rock on removal of dissolved inorganic nitrogen in coral aquaria

Maintaining stable water quality is one of the key processes for recirculating coral aquaculture. Traditional aquarium systems which mainly utilized a nitrification of nitrifying bacteria attached to the surface of massive artificial filter material are difficult to maintain the oligotrophic conditions necessary for coral aquaculture. This study investigated the removal effects of dissolved inorganic nitrogen (ammonia and nitrate) by live rock (LR), a key component in the "Berlin system" coral aquarium. The expression levels of bacterial functional genes, AOA3, amoA and nosZ, were measured on the exterior and interior of LR. The nitrifying and denitrifying bacterial abundance on LR was quantified and the nitrogen nutrient regulatory effects of LR were evaluated. The results demonstrated that LR mainly removed ammonium (NH4 +) from the water with a mean efficiency of 0.141 mg/(kg·h), while the removal of nitrate (NO3 –) was not significant. Bacterial diversity analysis showed that ammonia-oxidizing bacteria (AOB) were the most common bacteria on LR, which accounted for 0.5%–1.4% of the total bacterial population, followed by denitrifying bacteria, which accounted for 0.2% of the total population, and the ammonia-oxidizing archaea (AOA) were the least common type (<0.01%). The low abundance of denitrifying bacteria may be responsible for the poor nitrate (NO3 –) removal of LR. Thus, other biological filtration methods are needed in coral aquaria to control nitrates generated from nitrification or biological metabolism.

A new technique to increase polyp production in stony coral aquaculture using waste fragments without polyps

The wild harvest of corals for the aquarium trade has had negative impacts on coral reef ecosystems. Although this problem can be directly addressed by increased availability of cultured corals, improvements to current aquaculture techniques are needed to increase coral production. Here, we carried out a manipulative experiment using the large polyp reef-building scleractinian coral Duncanopsammia axifuga to test whether the presence or absence of polyps, the orientation of the fragment's trunk (upside-down or right way up), or heterotrophic diet (unfed, normal Artemia and lipid-enriched Artemia) influences polyp production, growth, survival, and overall health of the coral. There was an 85% survivorship of fragments across all experimental treatments regardless of trunk orientation. D. axifuga produced the highest number of new polyps from fragments initially fixed without polyps, with diet having no effect on polyp production. Conversely, normal and lipid-enriched Artemia diets significantly enhanced growth and polyp production in fragments that were initially fixed with one polyp. Overall, we conclude that D. axifuga is suitable for coral aquaculture purposes due to high survival rates and also because polyp production was successful from what was previously considered waste fragments (i.e. without polyps). Further work is required to determine whether these aquaculture techniques enhance polyp production in other coral species with similar morph types used in commercial aquaculture.

Genotype and attachment technique influence the growth and survival of line nursery corals

AbstractThe Caribbean staghorn coral, Acropora cervicornis, was once a dominant habitat creating coral, but its populations have declined dramatically in recent decades. Numerous restoration efforts now utilize coral gardening techniques to cultivate this species, growing colonies on fixed structures or from line/suspended nurseries. Line nurseries have become increasingly popular because of their small footprint and ease of use, replacing fixed structures in many nurseries. To evaluate the efficacy of the line technique, this study evaluated growth, condition, and survivorship of A. cervicornis nursery colonies of three distinct genotypes grown via two line nursery techniques (suspended and direct line attachment [vertical]). Direct line attachment of nursery colonies resulted in poor survival (43%) and growth (9.5 ± 1.33 cm/year), whereas suspended culture had 100% survival and increased growth (61.1 ± 4.19 cm/year). Suspended culture had significantly reduced disease prevalence and prevented colony predation. Suspended coral growth was also comparable to a neighboring fixed structure nursery (55.2 ± 7.86 cm/year), and found to be as effective in propagating corals as fixed structures.

Regional restoration benchmarks for Acropora cervicornis

Coral gardening plays an important role in the recovery of depleted populations of threatened Acropora cervicornis in the Caribbean. Over the past decade, high survival coupled with fast growth of in situ nursery corals have allowed practitioners to create healthy and genotypically diverse nursery stocks. Currently, thousands of corals are propagated and outplanted onto degraded reefs on a yearly basis, representing a substantial increase in the abundance, biomass, and overall footprint of A. cervicornis. Here, we combined an extensive dataset collected by restoration practitioners to document early (1–2 yr) restoration success metrics in Florida and Puerto Rico, USA. By reporting region-specific data on the impacts of fragment collection on donor colonies, survivorship and productivity of nursery corals, and survivorship and productivity of outplanted corals during normal conditions, we provide the basis for a stop-light indicator framework for new or existing restoration programs to evaluate their performance. We show that current restoration methods are very effective, that no excess damage is caused to donor colonies, and that once outplanted, corals behave just as wild colonies. We also provide science-based benchmarks that can be used by programs to evaluate successes and challenges of their efforts, and to make modifications where needed. We propose that up to 10% of the biomass can be collected from healthy, large A. cervicornis donor colonies for nursery propagation. We also propose the following benchmarks for the first year of activities for A. cervicornis restoration: (1) >75% live tissue cover on donor colonies; (2) >80% survivorship of nursery corals; and (3) >70% survivorship of outplanted corals. Finally, we report productivity means of 4.4 cm yr−1 for nursery corals and 4.8 cm yr−1 for outplants as a frame of reference for ranking performance within programs. Such benchmarks, and potential subsequent adaptive actions, are needed to fully assess the long-term success of coral restoration and species recovery programs.

Elaborating an eco-engineering approach for stock enhanced sexually derived coral colonies

Despite all traditional conservation management efforts, coral reefs worldwide continue to face a future of degradation and destruction. Current studies call for the augmentation of coral reef management with restoration practices, particularly alternative reef management approaches, such as the ‘coral gardening’ tenet of active reef restoration. This includes the stock creation of sexually derived coral colonies and their mariculture in mid-water coral nurseries. In this study, single and aggregated (resulting in non-fusion and chimeric entities) spats of the branching coral Stylophora pistillata were studied. Planula larvae were settled and spat were reared ex situ for 50–75days before they were transplanted to the in situ mid-water nursery in Eilat, Israel, where they were followed for up to two years, showing a very low (<2%) detachment rate. Spats were cultured in horizontal and vertical orientations, in caged (for the first 9 nursery months) and noncaged scenarios, and on two nursery beddings (nets and ropes). Caging of horizontally situated young spats on the net substrate resulted in the highest survival (>80% after 2years). Corals farmed in a vertical orientation had the lowest survival rate of the caged experiments (36.7%) but showed that chimeric/aggregated entities performed significantly better than the single colonies. The uncaged experiments had low (32.7%) to zero surviving spats after two years in situ. The surviving colonies reared under the uncaged conditions were significantly smaller than the caged colonies after the 9months in situ ‘caging period’. Generally, the placement of the young spats in the mid-water nursery resulted in high growth rates: After two years in situ, coral colony diameter increased from 0.1cm to 8.16±1.58cm for the vertical caged scenario, and 7.08±1.72cm, 7.02±1.48cm for the two caged horizontal designs (HN and HR). This is nearly twice the growth rate observed in natal colonies. The midwater coral nursery is a much cheaper solution for growing corals compared to ex situ water tables, which require high maintenance and expensive facilities to mimic in situ conditions. Non-caged coral stocks showed reduced survival and growth rates, similar to previously published results. The culturing of caged spats in a horizontal position in a midwater nursery exponentially augment survival and growth rates, thus enhancing stock creation yields. This offers new possibilities for creating stocks of sexually derived spats from eco-engineering coral species such as S. pistillata.

Ecological solutions to reef degradation: optimizing coral reef restoration in the Caribbean and Western Atlantic.

Reef restoration activities have proliferated in response to the need to mitigate coral declines and recover lost reef structure, function, and ecosystem services. Here, we describe the recent shift from costly and complex engineering solutions to recover degraded reef structure to more economical and efficient ecological approaches that focus on recovering the living components of reef communities. We review the adoption and expansion of the coral gardening framework in the Caribbean and Western Atlantic where practitioners now grow and outplant 10,000’s of corals onto degraded reefs each year. We detail the steps for establishing a gardening program as well as long-term goals and direct and indirect benefits of this approach in our region. With a strong scientific basis, coral gardening activities now contribute significantly to reef and species recovery, provide important scientific, education, and outreach opportunities, and offer alternate livelihoods to local stakeholders. While challenges still remain, the transition from engineering to ecological solutions for reef degradation has opened the field of coral reef restoration to a wider audience poised to contribute to reef conservation and recovery in regions where coral losses and recruitment bottlenecks hinder natural recovery.

Identifikasi lingkungan perairan untuk budi daya karang hias di desa Arakan Kabupaten Minahasa Selatan

This research aimed to gather data and information as well as to evaluate the waters condition and water quality suitable for ornamental coral aquaculture, so the characteristic of Arakan waters for ornamental coral aquaculture could be examined. The research applied Explorative Descriptive method with Purposive Sampling. Research stations were established at 20 points representing the overall ecosystem of Arakan waters. Data collected consisted of physical conditions (bottom substrate, flow rate, turbidity, water depth, salinity, temperature, TSS) and chemical conditions (pH, DO, nitrate, phosphate). Data were analyzed using Matching Method by matching the data obtained from sea water standard quality table for marine biota in accordance to Kep.Men. LH No. 51/2004 and data from Hutabarat and Evans (1984). Based on physical and chemical conditions, Arakan waters was suitable for ornamental coral aquaculture or categorized as suitable. However, water temperature at the time of measurement was not proper, thus monitoring of this parameter for longer period was required. Keywords: Arakan Village, ornamental coral, water quality, waters condition, matching method

Community-based coral aquaculture in Madagascar: A profitable economic system for a simple rearing technique?

Since a couple of decades, coral aquaculture has been developed in many countries to face an increasing live coral market and to support conservation of endangered natural coral reefs. To evaluate the potentiality of community-based coral aquaculture in Madagascar, we experienced suitable farming techniques using the species Acropora nasuta and Seriatopora caliendrum. Survival and growth rate of the nubbins were monitored during wet, warm and dry, cold seasons. To determine economical feasibility, the coral market was investigated and the yields were also calculated using the technical, biological and social parameters of the production. Coral nubbins were reared in situ at appropriate conditions. Coral nubbins reared during the wet, warm season showed a final survival rate of 67±6% and 57±4% respectively for A. nasuta and S. caliendrum, while in the dry, cold season, the survival rates were of 85±7% and 69±1% respectively. A. nasuta had a significantly higher survival rate than S. caliendrum during both seasons. During the wet, warm season, growth rates were 0.46±0.16%d−1 and 0.54±0.16%d−1 respectively for A. nasuta and S. caliendrum. In the dry, cold season, A. nasuta had 0.63±0.18%d−1 of growth rate, while S. caliendrum grew 0.65±0.15%d−1. Significant difference was observed between both species during the wet, warm season, but not during the dry, cold season. Furthermore, both species grew faster during the dry, cold season. These results are in the range of reference values for corals. The activity can be profitable from 25 coral nubbins sold per month. Profit can already be perceived from the second year and a total of more than EUR 27,000 earned after 5years of developing project, for an initial investment of EUR 1978. Marine animals wholesale companies and biodiversity conservation NGOs seem to be the appropriate clients for this form of aquaculture on Madagascar. Statement of relevanceThis paper provides new form of coral aquaculture: the community-based coral aquaculture. The socially and environmentally responsible production of coral is among the benefits of this new economically viable form of aquaculture.

The effect of mixotrophy in the ex situ culture of the soft coral Sarcophyton cf. glaucum

In toto aquaculture is a promising approach towards the bioprospecting and production of bioactive compounds from the coral holobiont. Coral aquaculture ex situ allows a better control of culture conditions to maximize coral growth and reduce production costs. Light (either the Photosynthetically Active Radiation—PAR, or the emitted spectrum) is one of the most important factors affecting the growth of symbiotic corals, due to their association with photosynthetic dinoflagellates. Additionally, the balance between autotrophy and heterotrophy is also known to play a key role in the successful growth of mixotrophic corals. The present study aimed to evaluate the effect of: 1) light spectrum (white and blue light), 2) PAR intensity (50 and 120μmolquantam−2s−1), and 3) heterotrophic feeding (rotifers—Brachionus plicatilis), in the physiology, photobiology and growth of coral fragments obtained from three mother colonies of the mixotrophic soft coral Sarcophyton cf. glaucum, cultured ex situ in recirculated systems during 80days. The supply of rotifers did not affect coral growth and promoted the increase of dissolved inorganic nitrogen and phosphorous concentrations (DIN and DIP, respectively) in the water column. Coral fragments originating from the different mother colonies presented distinct responses to the tested light PAR intensities and spectra, as well as to the interaction of these factors with the supply of rotifers. We concluded that the variability displayed between different mother colonies of the same species can affect the growth response of corals under contrasting scenarios of mixotrophy. Statement of relevanceImprovement of in toto aquaculture of Sarcophyton cf. glaucum.

Assessing an abridged nursery phase for slow growing corals used in coral restoration

The continued decline of coral reefs worldwide due to natural and anthropogenic drivers necessitates the development of effective restoration schemes. Two of the approaches frequently used nowadays are (1) the direct transplantation of coral fragments/colonies to degraded reefs; and (2) the “coral gardening” approach, which supports coral transplantation only following an intermediate nursery phase, where corals are farmed until reaching suitable sizes. Both approaches are evaluated for the quality of transplanted coral material, employing two field experiments on fragments from Echinopora lamellosa and Merulina scabricula, non-branching, slow growing coral species (Scleractinia) commonly residing in the reef of Bolinao, Pangasinan, northwestern Philippines. Each experiment included an abridged (shortened) nursery phase of 1 year. The first experiment assessed the performance of two newly collected groups of coral fragments, one reared in situ within a coral nursery and the second directly transplanted to coral-denuded bommies. The second experiment evaluated the post-transplantation performance of nursery-reared colonies against similar-sized freshly collected coral fragments, both transplanted onto denuded bommies. Growth rate (buoyant weight and size increments), survivorship and attachment were compared within each experiment. While in the first experiment, clear patterns for enhanced growth, survivorship and attachment rates were recorded in the nursery farmed fragments as compared to directly transplanted nubbins, no such differences were found between the two coral groups in the second experiment, indicating that short-term nursery farming of slow growing corals does not improve their post-transplantation performance. However, since growth and survivorship during the nursery phase are enhanced, an abridged nursery farming stage may serve as an ecological engineering tool for the production of augmented numbers of coral material for transplantation. Follow-up studies such as testing the fragment size along with nursery time for various coral species of different growth patterns are indispensable for the improvement of the “coral gardening” protocols.

Reef fishes recruited at midwater coral nurseries consume biofouling and reduce cleaning time in Seychelles, Indian Ocean

In coral reef restoration, coral gardening involves rearing coral fragments in underwater nurseries prior to transplantation. These nurseries become fish-aggregating devices and attract biofouling. We hypothesised that: (1) the presence of corals at a nursery is critical to recruit fish assemblages and (2) the recruited fish assemblages control biofouling, reducing person-hours invested in nursery cleaning. Three midwater coral nurseries were deployed at 8 m depth for 27 months within the marine protected area of Cousin Island Special Reserve, Seychelles, Indian Ocean. Each nursery consisted of a 6 m×6 m PVC pipe frame, layered with a recycled 5.5-cm-mesh tuna net. Human cleaning effort was calculated based on daily dive logs. Nursery-associated fish assemblages and behaviour were video-recorded prior to harvesting corals after a 20-month growth period and seven months post-coral harvesting. The density (ind. m–2) of blue-yellow damselfish Pomacentrus caeruleus was 12–16 times higher when corals were present than when corals were absent at the nurseries. Fish assemblages recruited into the nurseries included three trophic levels, from herbivores to omnivores, in six families: Ephippidae, Pomacentridae, Labridae (Scarinae), Gobiidae, Siganidae and Monacanthidae. Higher abundance of large fish (total number of individuals) resulted in 2.75 times less person-hours spent in nursery cleaning. These results have important implications for cost-effective coral reef restoration.

Bacterial communities from corals cultured ex situ remain stable under different light regimes — Relevance for in toto aquaculture

Microbial communities associated with corals are an important source of bioactive metabolites with great potential for drug discovery. However, culturing these symbiotic microbes is extremely complex and often impossible. In toto coral aquaculture performed ex situ (the culture of the holobiont–cnidarian host and associated microorganisms) has been suggested as a potential solution to solve the constraints of supplying metabolite biomass to fuel the drug discovery pipeline. In the present study we investigated if coral fragmentation and different light intensities (photosynthetically active radiation (PAR) of 50, 80 and 120μmolquantam−2s−1) significantly affect the diversity and structure of the microbial communities present in the leather coral Sarcophyton cf. glaucum assessed through polymerase chain reaction denaturing gradient gel electrophoresis (PCR-DGGE). The diversity and structure of the bacterial communities present in mother colonies and fragments stocked under identical conditions remained stable two months post fragmentation, as well as between coral fragments stocked under different PAR intensities. The observed stability in the microbial community supports that in toto coral aquaculture may be a suitable option to produce metabolite biomass from symbiotic microorganisms. The possibility to employ a low PAR intensity to grow coral fragments without significantly affecting their microbial diversity and structure is likely to decrease aquaculture production costs and improve its economic viability.

Some Physical, Chemical, and Biological Parameters of Samples of Scleractinium Coral Aquaculture Skeleton Used for Reconstruction/Engineering of the Bone Tissue.

Physical and chemical (phase and chemical composition, dynamics of resorption, and strength properties), and biological (cytological compatibility and scaffold properties of the surface) properties of samples of scleractinium coral skeletons from aquacultures of three types and corresponding samples of natural coral skeletons (Pocillopora verrucosa, Acropora formosa, and Acropora nobilis) were studied. Samples of scleractinium coral aquaculture skeleton of A. nobilis, A. formosa, and P. verrucosa met the requirements (all study parameters) to materials for osteoplasty and 3D-scaffolds for engineering of bone tissue.