Plectropomus Leopardus Research Articles

Growth of Sunu Grouper (Plectropomus leopardus) Larvae That Given Rotivera (Bachionus rotundiformus) Enriched with Taurine and Glutamine

This study aims to determine the effect of taurine and glutamine enriched Brachionus on the growth and survival rate of Sunu Grouper (Plectropomus leopardus). This research was conducted in Marine Research and Fisheries Extension Center Gondol, Bali. The study was conducted for 1 month on September 2017. The research method used was using Completely Randomized Design (CRD) consisting of 4 treatments and 4 replication, namely treatment A (without Taurine and Glutamine; (B) 0,5 gram Taurine / 10 L media; (C) 0,5 gram Glutamine / 10 L media; (D) 0,5 gram Taurine and 0,5 Glutamine / 10 L media. The age of Sunu Grouper was D-2 until D-10, parameters observed were Survival Rate, Average Daily Length, Relative Growth Rate, number of Brachionus in the digestive tract, and water quality. Which included DO, temperature and pH. Data were analyzed using analysis of variance with F test with 95% confidence level and the difference between treatments was tested by Duncan multiple-range test, then water quality was analyzed descriptively by comparing to related literature and water quality standard according to SNI 1999. The results showed that the use of 0,5 gram Taurine and 0,5 gram Glutamine enriched Brachionus, had an effect on the growth of Sunu Kerapu.

Fear effects associated with predator presence and habitat structure interact to alter herbivory on coral reefs.

Non-consumptive fear effects are an important determinant of foraging decisions by consumers across a range of ecosystems. However, how fear effects associated with the presence of predators interact with those associated with habitat structure remain unclear. Here, we used predator fish models (Plectropomus leopardus) and experimental patches of the macroalga Sargassum ilicifolium of varying densities to investigate how predator- and habitat-associated fear effects influence herbivory on coral reefs. We found the removal of macroalgal biomass (i.e. herbivory) was shaped by the interaction between predator- and habitat-associated fear effects. Rates of macroalgal removal declined with increasing macroalgal density, likely due to increased visual occlusion by denser macroalgae patches and reduced ability of herbivorous fishes to detect the predators. The presence of the predator model reduced herbivory within low macroalgal density plots, but not within medium- and high-density macroalgal plots. Our results suggest that fear effects due to predator presence were greatest at low macroalgal density, yet these effects were lost at higher densities possibly due to greater predation risk associated with habitat structure and/or the inability of herbivorous fishes to detect the predator model.

Financial analysis of coral trout grouper (Plectropomus leopardus) in Gusung Island, Selayar archipelago regency

This research was conducted from January until April 2016, located on Gusung Island, Selayar Archipelago Regency. The research aimed to analyze the income of fishermen coral trout grouper (Plectropomus leopardus) in the research area. The study used a survey method with quantitative data analysis. The results of the study found that revenue of fishing rod higher than traps, the total cost of fishing rod higher than traps, but the profit of traps higher than a fishing rod. Revenue from fishing rod equal to IDR 45,000,000 and revenue from trap equal to IDR 36,000,000. Total cost from fishing rod equal to IDR 23,931,000 and total cost from trap equal to IDR 7,056,000. Profit from fishing rod equal to IDR 21,069,000 and profit from trap equal to IDR 28,944,000.

Influence of dietary protein level on growth performance, digestibility and activity of immunity‐related enzymes of leopard coral grouper, Plectropomus leopardus (Lacépède, 1802)

An 8‐week feeding trial was conducted to assess the interaction between dietary protein levels and fish growth, digestibility and activity of immunity‐related enzymes of Plectropomus leopardus. Five diets with different protein levels (400 g/kg, 450 g/kg, 500 g/kg, 550 g/kg and 600 g/kg protein) were designed. P. leopardus fed with 500 g/kg, 550 g/kg and 600 g/kg dietary protein, showed higher weight gain rates than fish fed 400 g/kg and 450 g/kg dietary protein. Ingestion rate in fish fed with 500 g/kg dietary protein was significantly higher than those with other diets. P. leopardus fed with 500 g/kg, 550 g/kg and 600 g/kg dietary protein, showed that feed coefficients were significantly lower than those fed with 400 g/kg and 450 g/kg dietary protein. Net protein utilization was significantly lower in fish fed with 400 g/kg diet than those with other diets. Fish fed with 400 g/kg and 450 g/kg dietary protein had an apparent feed digestibility coefficient for dry matter that was significantly lower than that with other diets. Protease activity was highest in fish fed on 500 g/kg dietary protein. Fish fed with 500 g/kg dietary protein, had the highest superoxide dismutase activity. Fish fed with 600 g/kg dietary protein, had the highest alkaline phosphatase activity. Thus, a diet containing 500 g/kg protein is recommended for P. leopardus aquaculture.

Preferences and perceptions of the recreational spearfishery of the Great Barrier Reef.

Recreational fishing practices can have significant impacts on marine ecosystems but their catch dynamics are often difficult to quantify, particularly for spearfishing. On coral reefs, the impacts of recreational spearfishing are often considered to be negligible compared to other practices, but the highly selective method adopted by spearfishers can result in locally distinct ecological consequences. Here we investigated the spatial patterns and catch composition of recreational spearfishers on the Great Barrier Reef using an online survey (n = 141 participants) targeted at spearfishers active along the coastline of Queensland. Observations from within the Queensland spearfishing community were also used to explore perceived changes in catches of three functionally distinct spearing targets. Preferred reef regions (coastal, inshore, offshore) differed among spearfishers from Bundaberg (south) to Cooktown (north). The piscivorous coral trout, Plectropomus leopardus, was suggested to be the preferred target comprising 34% (±1.5 SE) of spearfishers’ reported catch composition. Spearfishers also noted a variety of changes in their catch composition over time, particularly regarding parrotfishes (decreased landings) and tuskfishes (increased landings). How this relates to the relative abundance and population biology of these taxa on the Great Barrier Reef requires attention. Spearfishers can provide important information regarding the status of their fishery through direct observations, which can inform legislation when acknowledged.

Increasing survival and growth in larval leopard coral grouper (Plectropomus leopardus) using intensively cultured Parvocalanus crassirostris nauplii

AbstractLeopard coral grouper, Plectropomus leopardus are a heavily exploited, high‐value fish commonly found in the Asian live reef food fish trade. In past decades, many attempts at the mass culture of various grouper species have been undertaken; however, their small mouth gape at first feed has resulted in very low survival when using traditional live feeds such as rotifers. The use of wild caught or extensively cultured copepods has yielded potentially promising increases in survival and growth, but overall survival to the juvenile stage remains low, making mass culture currently impractical. The current study sought to build on past developments in grouper culture and recent advancements in copepod culture technology by observing how growth and survival were influenced by the addition of intensively cultured copepods to the early diet of P. leopardus larvae. Six tanks of larvae, three replicates per treatment, were fed either eggs and nauplii of the calanoid copepod Parvocalanus crassirostris, at a starting density of 5 mL−1, and the rotifer Brachionus rotundiformis, at a starting density of 10 mL−1, or were fed only B. rotundiformis, at a density of 15 mL−1, starting on the evening of 2 days post‐hatch (dph) and continuing until 9 dph. After this initial period, all larvae were fed the same diet of rotifers, Artemia, and dry feed until the cessation of the trial at 21 dph. Larvae fed P. crassirostris in addition to rotifers had a significantly higher survival, 9.9 versus 0.5%, than those fed only rotifers. Growth was also significantly enhanced in larvae offered copepods. Larvae only fed rotifers were, on average, 1.5 mm shorter at 21 dph than those that had been fed copepods. More rapid development and the earlier onset of flexion were also noted in the larvae that were offered copepods. The use of intensively cultured copepods, in this study, increased survival tenfold over previous studies, with P. leopardus larvae fed wild‐caught copepods. The application of intensively cultured copepods to the early diet of P. leopardus, along with future research to evaluate late‐stage mortality issues, may facilitate commercial production of this species.

Marine reserves stabilize fish populations and fisheries yields in disturbed coral reef systems.

Marine reserve networks are increasingly implemented to conserve biodiversity and enhance the persistence and resilience of exploited species and ecosystems. However, the efficacy of marine reserve networks in frequently disturbed systems, such as coral reefs, has rarely been evaluated. Here we analyze a well-mixed larval pool model and a spatially explicit model based on a well-documented coral trout (Plectropomus spp.) metapopulation in the Great Barrier Reef Marine Park, Australia, to determine the effects of marine reserve coverage and placement (in relation to larval connectivity and disturbance heterogeneity) on the temporal stability of fisheries yields and population biomass in environmentally disturbed systems. We show that marine reserves can contribute to stabilizing fishery yield while increasing metapopulation persistence, irrespective of whether reserves enhance or diminish average fishery yields. However, reserve placement and the level of larval connectivity among subpopulations were important factors affecting the stability and sustainability of fisheries and fish metapopulations. Protecting a mix of disturbed and non-disturbed reefs, rather than focusing on the least-disturbed habitats, was the most consistently beneficial approach across a range of dispersal and reserve coverage scenarios. Placing reserves only in non-disturbed areas was the most beneficial for biomass enhancement, but had variable results for fisheries and could potentially destabilize yields in systems with well-mixed larval or those that are moderately fished. We also found that focusing protection on highly disturbed areas could actually increase variability in yields and biomass, especially when degraded reef reserves were distant and poorly connected to the meta-population. Our findings have implications for the design and implementation of reserve networks in the presence of stochastic, patchy environmental disturbances.

Yield-per-recruit modeling as biological reference points to provide fisheries management of Leopard Coral Grouper (Plectropomus leopardus) in Saleh Bay, West Nusa Tenggara

Leopard coral grouper (Plectropomus leopardus) is an important fisheries commodity in Saleh Bay, both ecologically and economically. Continuous exploitation of this species has caused population collapses in some waters due to high fishing pressure. Therefore, it is very important to estimate its population stock. Yield per recruit models usually being used to evaluate population stock also to estimate biological reference point. We estimated life-history parameters using length-based stock assessment, while stock size was estimated by virtual population analysis (VPA), and finally, prediction models was estimated using Beverton & Holt’s yield per recruit model. We used the following variables: growth parameters, fishing mortality, length at first capture, and age at 50% recruitment into the fishery. From these variables we found that the Fcurrent (0.26) is higher than the target reference point (FMSY= 0.24), which confirmed the indication of slight increased exploitation rate (E=0.62). It is shown that the Plectropomus leopardus was overexploited with spawner biomass-per-recruit at 20.6% of pristine levels. The regulation measures to correct the exploitation pattern and to reduce fishing mortality smaller than Fmsy including limiting the catch size and control on fishing gear by limiting fishing effort.

PENINGKATAN SINTASAN LARVA IKAN KERAPU SUNU (Plectropomus leopardus) MELALUI MANAJEMEN PEMELIHARAAN YANG SESUAI

Survival rate of coral trout seed produced from aquaculture was relatively low. In 2015, high mortality was found at the early stage of larval development (<D10), approximately 64.37 % of the total production. There has been no standard management for coral trout (Plectropomus leopardus) larval rearing, which was used to adopt management for grouper (Epinephelus spp.) larval rearing. This study was to apply suitable management for coral trout larval rearing into aimed to decrase mortality at early stage larval development and to increase survival rate. There were two different managements in this study: A. applying the results of previous research of coral trout larval rearing from 2004 to 2015, and B. using standard management for grouper larval rearing. The results showed that management A was more suitable management for coral trout larval rearing compared to management B. Management A resulted in the increasing of survival rate by five times (p=0.0056) and of growth rate at early stage by 1.15 times (p=0.2338) higher than those of management B.

Population Dynamics and Exploitation Rate of Coral Grouper Plectropomus leopardus in the Sarappo Islands, Pangkep Regency, South Sulawesi

The coral grouper Plectropomus leopardus is a fish which plays important ecological roles in coral reef ecosystems. It is also a well-known and sought-after commodity in both local and export markets, leading to pressure on wild P. leopardus populations. The aim of this study was to describe the population dynamics and determine the exploitation rate of coral grouper (P. leopardus) populations in the Sarappo Islands, Pangkep Regency South Sulawesi, Indonesia. Coral grouper samples from Sarappo Island were caught using hand-line gear. Class length and weight data were analysed using the Bhattacharya method, von Bertalanffy model and Pauly empirical equation incorporated in the FiSAT II program to determine growth rate, mortality, and exploitation rate. The length frequency distribution of coral groupers sampled had length class means ranging from 20.0 cm to 57.1 cm. The 30.1 cm midpoint class had the highest catch frequency (162 fish) while the 57.1 cm class had the lowest frequency (3 fish). The length-weight relationship indicated an allometric growth pattern (b<3), with a growth coefficient (K) of 0.7. The total mortality (Z), natural mortality (M) and fishing mortality (F) were 3.03, 1.28, and 1.75, respectively, giving an exploitation rate E = 0.58 which exceeded the MSY limit (0.5). Coral grouper (P. leopardus) size structure was dominated by fish with immature gonad indices, increase in body length was faster than weight gain, fishing mortality was high, and the rate of exploitation exceeded the sustainable limit.

The Distribution of Planktivorous Damselfishes (Pomacentridae) on the Great Barrier Reef and the Relative Influences of Habitat and Predation

Planktivorous damselfishes (Pomacentridae) are diverse and abundant on the Great Barrier Reef (GBR), are important prey for commercially harvested coral trout (Plectropomus spp.) and their feeding mode plays a central role in transferring energy from the plankton to the reef. However, little is known about their distribution patterns throughout the GBR and how those patterns are influenced by predators and habitat despite increasing pressures on both. Here we quantify the distribution and abundance of GBR planktivorous damselfishes, then examine the role of coral trout and habitat in shaping their assemblages. The assemblage structure of planktivorous damselfishes varied across the continental shelf, yet their total abundances varied sub-regionally, dependent on differences in coral habitat. Latitudinal patterns were relatively weak. Damselfish assemblages generally retained characteristics of their sub-regional setting over 20 years and assemblage degradation was only associated with major coral losses. Damselfish numbers were not negatively influenced by top-down control from coral trout. Instead, numbers of coral trout and damselfishes were both positively associated with coral habitat and each other. Our findings suggest that a complexity of factors and interactions shape reef fish assemblages and reinforce the fundamental importance of coral as the foundation of healthy reef communities.

The growth and survival rate of the larvae of the sunu grouper (Plectropomus leopardus) in different temperatures

The sunu grouper, known as the starch grouper, is one of Indonesia’s leading export commodities of marine culture. Temperature is an environmental factor that directly affects fish life. Temperature fluctuations affect the hatchability of the eggs. Water temperatures in the often-changing cultivation medium can produce egg hatching rates ranging from 60 - 70%. The growth stage where the sunu grouper fish larvae become seeds lasts for 45 - 55 days at a water temperature of 27 - 29°C. This study was conducted with the aim of determining the optimum temperature of the development of the early stages of larvae (D0 - D7) for sunu. This research was conducted at Universitas Airlangga Laboratory PSDKU Banyuwangi between May and October 2017. The test material consisted of the eggs of sunu grouper obtained from Balai Besar Riset Budidaya Laut dan Penyuluhan Perikanan Bali. The method used in the implementation of this research was an experimental design that was Randomized Completely (RAL). The treatment consisted of one factor, temperature, and 4 treatments (26, 28, 30, 32°C) repeated 5 times. The results showed that the optimum temperature for the larvae of sunu was in at 30°C with a HR value of 99%, a growth length of 0.96 mm and an SR of 23%.

Latitudinal and seasonal variation in space use by a large, predatory reef fish,Plectropomus leopardus

AbstractTemperature directly affects the metabolic rate and resource requirements of ectothermic animals, which is likely to influence their movement and habitat use. Space use is a fundamental component of an animal’s ecology, and the extent of an animal’s home range has consequences for individual distributions, community structure and ecosystem function. As ocean temperatures continue to rise as a result of global warming, determining the effects of temperature on space use and movement patterns of important fisheries species is vital.Our aim was to investigate the spatial and temporal variation in space use by a tropical fisheries species, the leopard coralgrouper (Plectropomus leopardus), from two latitudinally distinct locations on Australia’s Great Barrier Reef to determine the potential response of large‐bodied tropical fishes to ocean warming through behavioural modification.Using passive acoustic telemetry of 36 tagged individuals, we found that both core use areas (50%KUD) and home range extent (95%KUD) varied with respect to location, season, body size and temperature. Average home range extent (95%KUD) for taggedP. leoparduswas 0.32 km2at the high‐latitude location (Heron Island) compared to 0.23 km2at the low‐latitude location (Opal Reef). However, core use areas (50%KUD) did not differ significantly between the two locations.Seasonal differences were also apparent at both locations withP. leopardusshowing contraction in home range extent during the summertime. This effect was most pronounced at the low‐latitude location where home range was significantly reduced during summer when temperatures exceeded 27°C.Taken together, our findings indicate that higher ambient temperature may elicit a sustained and significant decline in space use by a commercially important reef fish. Given projected increases in ocean temperature due to global climate change, large‐bodied reef fishes may be increasingly constrained in their movement and space use, which will have ramifications for individual fitness, population viability, fisheries productivity and ecological function.Aplain language summaryis available for this article.

Chart Datum and Bathymetry Correction To Support Managing Coral Grouper In Lepar And Pongok Island Waters, South Bangka Regency

Corrected bathimetry data is highly required to improve the quality of sea floor map, for a range of purposes including coastal environmental monitoring and management. This research was aimed to know chart datum values used for correctting bathymetry data at Bar-cheeked coral trout grouper (Plectropomus maculates) fishing ground in Lepar and Pongok Island waters 02o57’00”S and 106o50’00”E and 02o53’00”S and 107o03’00”E, respectively, South Bangka Regency, Indonesia. The study was carried out from November 2016 to October 2017, tidal data used for 15 days from September 16–30, 2017 using simple random sampling technique with the total of 845 points of measurements. To calculate tyde harmonic constituents values this study employed admiralty method resulting 10 major components. Results of this research indicated that harmonic coefficient values of M2, M2, S2, N2, K1, O1, M4, MS4, K2, and P1, were 0.0345 m, 0.0608 m, 0.0276 m, 0.4262 m, 0.2060 m, 0.0119 m, 0.0082 m, 0.0164 m, and 0.1406 m, respectively. Values of mean sea level, chart datum, and F, were 0.9620 m, 0.0500 m, and 0.0664 m, respectively, with diurnal type (F= 6.64). Correcting bathymetry values of surveyed location results a deviation about 1.2 m in depth. The calculated chart datum as well as corrected bathymetry provides information that can be used as vertical refrerence datum for generating sea floor map for determining the fishing ground area of bar-cheeked coral trout grouper. Fishing depth usually ranges between 4.2 and 40.8 m. Average water depth in the fishing ground ranged from 14.7 to 22.5 m.

Trophic niches determined from fatty acid profiles of sympatric coral reef mesopredators

Previous research has identified similar trophic levels in a wide range of coral reef sharks and large teleost fishes but has been unable to resolve the extent of dietary overlap and resource sharing that lead to interpretation of functional roles and, hence, adequately describe interaction strengths in food webs. We used fatty acid (FA) profiles of muscle and plasma reflecting the diet of several mesopredators to better understand the trophic structure and functioning of Great Barrier Reef ecosystems. Multivariate analysis identified significant dietary overlap between 2 shark species (whitetip reef shark Triaenodon obesus and grey reef shark Carcharhinus amblyrhynchos), but whitetip reef sharks occupied a smaller niche area than grey reef sharks. We also found clear niche separation between sharks and teleost fishes (red throat emperor, coral trout, and grass emperor). All mesopredators sampled had high proportions of polyunsaturated FAs linking them to carnivory, but differences among species in trophic biomarker ratios suggest distinctive dietary sources. However, based on a degree of niche overlap of species sharing common diet, reef-dwelling teleost fishes such as coral trout also derive nutrients from pelagic environments. A faster analytical method to determine FA profiles, proven highly useful in tuna, was tested and deemed viable for muscle tissue of tropical teleost fishes and sharks, while questions remain for use of FA extraction of plasma in ecological studies. These results demonstrate that fine-scale inter-specific differences in diet exist between mesopredators in coral reef ecosystems. Our results raise important questions about the ecological influences of these species and energy flow among mesopredators in coral reef ecosystems.

Barcoding of Fin Clip Samples Revealed High Exploitation of Plectropomus leopardus in Spermonde Archipelago

Spermonde Archipelago in South Sulawesi is among groupers sources in Indonesia for International Marine Live Trade. It was not much known which species are mostly exploited in those areas during the study because only fin clip samples could be obtained. Here we performed DNA forensic analysis to groupers fin clips collected from Spermonde Archipelago using barcode marker to know what species were exploited and which ones was the most exploited species. A total of 110 fin clip samples were obtained during the field trips. Sequencing of the cytochrome c oxidase 1 gene was successful for only 36 samples. Species determination was based on sequences similarity to conspecific sequence available in barcoding of life database (BOLD). BOLD similarity test placed the 36 fin clip samples into four different species, namely Cromileptes altivelis, Epinephelus ongus, Plectropomus leopardus, and Plectropomus maculatus. The K-2P taxonomic tree showed clear separation among species which was supported by high K2P genetic distances among species. Most of fin clips were identified as Plectropomus leopardus indicates that this species was the most exploited in Spermonde Archipelago. This proved that molecular identification not only can be used to biodiversity study in certain area but also in forensic analysis of a threatened wildlife. This study has important contribution for conservation effort of those groupers species, especially P. leopradus and provides new approach for taxonomist and conservation managers to identify samples, especially when only incomplete specimens are available.

Contrasting population genetic structure in three aggregating groupers (Percoidei: Epinephelidae) in the Indo-West Pacific: the importance of reproductive mode

BackgroundUnderstanding the factors shaping population genetic structure is important for evolutionary considerations as well as for management and conservation. While studies have revealed the importance of palaeogeographic changes in shaping phylogeographic patterns in multiple marine fauna, the role of reproductive behaviour is rarely considered in reef fishes. We investigated the population genetics of three commercially important aggregating grouper species in the Indo-West Pacific, namely the camouflage grouper Epinephelus polyphekadion, the squaretail coral grouper Plectropomus areolatus, and the common coral trout P. leopardus, with similar life histories but distinct spatio-temporal characteristics in their patterns of forming spawning aggregations.ResultsBy examining their mitochondrial control region and 9–11 microsatellite markers, we found an overarching influence of palaeogeographic events in the population structure of all species, with genetic breaks largely coinciding with major biogeographic barriers. The divergence time of major lineages in these species coincide with the Pleistocene glaciations. Higher connectivity is evident in E. polyphekadion and P. areolatus that assemble in larger numbers at fewer spawning aggregations and in distinctive offshore locations than in P. leopardus which has multiple small, shelf platform aggregations.ConclusionsWhile palaeogeographic events played an important role in shaping the population structure of the target species, the disparity in population connectivity detected may be partly attributable to differences in their reproductive behaviour, highlighting the need for more investigations on this characteristic and the need to consider reproductive mode in studies of connectivity and population genetics.

Classification of marine microdebris: A review and case study on fish from the Great Barrier Reef, Australia

Marine debris, and in particular plastic pollution, is ubiquitous throughout global marine environments. Here, we present a classification of marine microdebris (i.e. debris between 0.1 μm and <5 mm) tailored to represent synthetic, semi-synthetic and naturally-derived items. The specific aim of this classification is to introduce a level of consistency in the higher-level characterisation of marine microdebris, thereby improving the overall reporting on marine microdebris contamination. We first conducted an extensive literature review on the accumulation of ingested debris in fish to identify discrepancies in marine microdebris reporting as a basis for the new classification. The review reveals the diverse nature of ingested marine microdebris, including items that are non-plastic but often incorrectly reported on as microplastics. We then applied our classification to a case study on wild-caught juvenile coral trout, Plectropomus spp., from the Great Barrier Reef World Heritage Area, Australia. This first report on accumulation of ingested marine debris in commercial fish on the reef demonstrates a high frequency of occurrence and a prevalence of semi-synthetic and naturally-derived fibres. Based on our findings, we offer recommendations on potential improvements for the classification presented, ultimately contributing to a more realistic assessment of the ecological risks of marine microdebris.

In situ TS measurement of Mackerel Scad (Decapterus macarellus), Leopard Coral Trout (Plectropomus leopardus), and Largehead Hairtail (Trichiurus lepturus)

Acoustic target strength (TS) measurements were performed on one small pelagic fishes, and two demersal fishes, which are very important for Indonesia fisheries, namely: mackerel scad (Decapterus macarellus), coral trout (Plectropomus leopardus), and largehead hairtail (Trichiurus sp.) on various fish sizes (fork length, FL) and orientation. The fish was successfully measured using tethered technique, where each individual fish was places and hang in web using monofilament string. The TS data analysis is performed numerically using the best-fit technique to establish the relationship between length, fish orientation, and TS. The TS-length relationship was obtained as follow: for mackerel scad, TS = TS = 20log - 84,38; for coral trout, TS = 20Log - 76,68, and for large headhairtail, TS = 20Log -91.88.

Intestinal microbiota composition is altered according to nutritional biorhythms in the leopard coral grouper (Plectropomus leopardus).

Aquaculture is currently a major source of fish and has the potential to become a major source of protein in the future. These demands require efficient aquaculture. The intestinal microbiota plays an integral role that benefits the host, providing nutrition and modulating the immune system. Although our understanding of microbiota in fish gut has increased, comprehensive studies examining fish microbiota and host metabolism remain limited. Here, we investigated the microbiota and host metabolism in the coral leopard grouper, which is traded in Asian markets as a superior fish and has begun to be produced via aquaculture. We initially examined the structural changes of the gut microbiota using next-generation sequencing and found that the composition of microbiota changed between fasting and feeding conditions. The dominant phyla were Proteobacteria in fasting and Firmicutes in feeding; interchanging the dominant bacteria required 12 hours. Moreover, microbiota diversity was higher under feeding conditions than under fasting conditions. Multivariate analysis revealed that Proteobacteria are the key bacteria in fasting and Firmicutes and Fusobacteria are the key bacteria in feeding. Subsequently, we estimated microbiota functional capacity. Microbiota functional structure was relatively stable throughout the experiment; however, individual function activity changed according to feeding conditions. Taken together, these findings indicate that the gut microbiota could be a key factor to understanding fish feeding conditions and play a role in interactions with host metabolism. In addition, the composition of microbiota in ambient seawater directly affects the fish; therefore, it is important to monitor the microbiota in rearing tanks and seawater circulating systems.