Leopard Coral Grouper Plectropomus Leopardus Research Articles

Effects of Dietary Mannan-Oligosaccharide (Mos) and Multi-Species of Bacillus on Growth and Feed Utilization in Leopard Coral Grouper Plectropomus leopardus Juvenile

This study assessed the growth and feed utilization in leopard coral grouper Plectropomus leopardus juvenile fed dietary prebiotic mannan-oligosaccharide (MOS) and multi-species of probiotic bacteria (Bacillus cereus BS6, B. subtilis BS3, and B. amiloliquefaciens BS4). The experiment was performed by feeding four replicates groups of juveniles weighing 3.61±0.60 g on four experimental diets, and each diet included: only MOS (PRE); the multi-species of Bacillus (PRO); a combination of MOS and the multi-species of Bacillus (SYN) and without supplementation (CON). When MOS (PRE) or the multi-species of Bacillus (PRO) was included in the diet solely, the growth of the fish was fairly good, although there was no significant difference with the control diet (p>0.05). Unexpectedly, the combined inclusion of MOS and the multi-species of Bacillus (SYN) did not increase the growth and feed utilization in Plectropomus leopardus juvenile. Presumably, MOS did not exert any favorable effects on the multi-species of Bacillus. This study suggested that no advantage was obtained when MOS and the multi-species of Bacillus were included in the diet simultaneously. In addition, the inclusion of MOS in higher levels may be necessary for better feed utilization and growth in leopard coral grouper Plectropomus leopardus.

Low Genetic Diversity Study on Leopard Coral Grouper Plectropomus leopardus (Perciformes: Serranidae) from Sulawesi, Indonesia

Highlight ResearchThe leopard coral grouper Plectropomus leopardus was identified and analysed based on molecular approach.Genetic diversity within two regions in Gorontalo, Sulawesi successfully performed using connectivity analysis.Three haplotypes of Plectropomus leopardus from two region in Gorontalo as one of economical important marine fish species. AbstractBar-cheek coral trout (P. leopardus) is the flagship of the grouper in the live fish market in Asia. Unfortunately, the potential of the grouper is still partly produced from natural catches. Even though hybridisation activities have also started to be carried out, there still have not been many studies on the genetic diversity of these fish. The application of molecular identification has been widely applied in marine aquatic animal species, which are very likely to occur due to errors in terms of shape and colour in the morphological character. DNA information has been beneficial in efforts to the breeding program and develop grouper aquaculture activities. DNA barcoding was used for the molecular identification and haplotype analysis of P. leopardus from two locations in Gorontalo, Sulawesi, Indonesia. A total of 14 fish samples were collected from two traditional fish markets around Kwandang and Sumalata Gulf in the northern part of Gorontalo Province, Sulawesi. This study identified and found three haplotypes from both regions. Molecular identification using Cytochrome c Oxidase subunit I (COI) gene region on mitochondrial DNA. Besides Mega7 for phylogenetic reconstruction, the data analysis using DnaSP6, Arlequin Ver.3.5.2.2, and Network 5.0.1.1. The first Haplotype is a mixed population between the Kwandang Gulf and the Sumalata Gulf, then the Kwandang Gulf haplotype and the Sumalata Gulf haplotype. The genetic distance between Kwandang Gulf haplotype and Sumalata Gulf haplotype is 0.003984, classified as a shallow genetic distance and needs more samples from another region to figure out leopard coral grouper around Indonesia.

Waterborne Cr3+ and Cr 6+ exposure disturbed the intestinal microbiota homeostasis in juvenile leopard coral grouper Plectropomus leopardus

BackgroundChromium (Cr) mainly has two stable forms: Cr3+ and Cr6+. Cr and its compound are widely used in the printing, dyeing, leather making, and metallurgy industry. They are evitably released into the environment and pose a significant threat to creatures, for instance, the excessive chromium (Cr) burden in the marine ecosystem is often harmful to fish. Intestinal microbiota greatly affects fish performance, but how waterborne Cr affects fish intestinal microbiota is unclear. To test the hypothesis that the waterborne Cr exposure could significantly affect fish’ intestinal microbiota homeostasis, and the effect was highly dependent on Cr concentration and speciation, the juvenile leopard coral grouper Plectropomus leopardus were exposed to waterborne Cr3+ and Cr6+ (0.1, 0.5 ppm) for 7 days, and the intestinal microbiota was determined by Amplicon sequencing of the 16S rRNA. ResultsIn all Cr treatment groups, the alpha diversity of intestinal microbiota communities of P. leopardus was decreased. The phyla Proteobacteria, Firmicutes, Actinobacteria, Chloroflexi and Bacteroidetes were the dominant intestinal microbiota. The Chao index diversity significantly declined in Cr treatment group, indicating the intestinal microbiota community structure was changed. Among the dominant intestinal microbiota, Proteobacteria was most sensitive to Cr exposure, and it increased after xposure. The PICRUSt predicted that 0.5 ppm Cr3+ expousure caused metabolism disordered in the intestinal of P. leopardus. ConclusionsWaterborne Cr3+ and Cr6+ significantly disturbed intestinal microbiota homeostasis in P. leopardus, including their diversity, composition, and community structure. The metabolism level of intestinal microbiota in P. leopardus was decreased by Cr3+ exposure. High concentrations of Cr3+ may pose potential risks to the intestinal homeostasis of P. leopardus.

Fear effects and group size interact to shape herbivory on coral reefs

AbstractFear of predators (‘fear effects’) is an important determinant of foraging decisions by consumers across a range of ecosystems. Group size is one of the main behavioural mechanisms for mitigating fear effects while also providing foraging benefits to group members. Within coral reef ecosystems, fear effects have been shown to influence the feeding rates of herbivorous fishes, a key functional group that prevents macroalgal overgrowth. Yet, how fear effects and group size interact to shape macroalgal removal on coral reefs remains unclear.Here, we conducted field‐based experiments using models of a common piscivorous fish, the leopard coral grouperPlectropomus leopardusand a series of macroalgalSargassum ilicifoliumassays positioned at increasing distances from the models (1, 2, 3 and 4 m) on two coral reefs in Singapore to investigate how acute fear effects shape the intensity of herbivory, and whether these effects were influenced by variation in the group size of herbivorous fishes feeding on the assays.We found acute fear effects strongly influenced the foraging behaviour of herbivorous fishes over small spatial scales. Rates ofSargassumbiomass removal, feeding rates and the total number of individual feeding events were all lower near the predator model. These effects dissipated rapidly with increasing distance from the predator model and were undetectable at a distance of 4 m. We also found generally larger group sizes of herbivorous fishes further from the predator model, presumably reflecting decreased risk. Furthermore, the number of individual bites/event increased significantly with increasing group size for two common browsing fishes,Siganus virgatusandSiganus javus.Our findings highlight that acute fear effects influence the distribution and intensity of herbivory over small spatial scales. Fear effects also interacted with herbivore group size resulting in changes in the number of individual feeding events and bite rates that collectively shape the realized ecosystem function of macroalgal removal on coral reefs. Group size is an important context‐dependent factor that should be considered when examining fear effects on coral reefs.A freePlain Language Summarycan be found within the Supporting Information of this article.

<i>Benedenia akajin</i> n. sp. (Monogenea: Capsalidae) from Leopard Coral Grouper <i>Plectropomus leopardus</i> Reared in Okinawa Prefecture, Japan

The grow-out stage of leopard coral grouper Plectropomus leopardus reared in land-based tanks in Okinawa Prefecture, Japan, were often heavily infected with capsalid monogeneans, up to a few millimeters in size, on the fins and skin. ​Morphological investigation revealed that the parasite belongs to Benedenia (Monogenea: Capsalidae). ​Benedenia akajin n. sp. is proposed here and described morphologically, based on the unique structures in the vaginal duct with a thick-walled distal one-third, the penis with a teat-shaped tip and the testes smaller than the germarium. ​A positive relationship between the lengths of three haptoral sclerites (anterior sclerites and anterior and posterior hamuli) and body length indicates that these taxonomically important structures keep growing as the parasite ages. ​Molecular analyses showed that the present species is most closely related to B. epinepheli and B. sargocentron, with the highest 28S rDNA identity of 98.1%, but no identical sequences were found in the database. ​Both morphological and molecular evidences suggest Benedenia akajin n. sp. as an undescribed species, and this new skin fluke deserves further investigations for the stable aquaculture of P. leopardus.

Combining information on otolith morphometrics and larval connectivity models to infer stock structure of Plectropomus leopardus in the Philippines

The leopard coral grouper Plectropomus leopardus is a high-value fish species in the live reef fish for food trade (LRFFT), with stocks declining continually due to increasing market demands and unsustainable fishing practices. Managing this resource is difficult due to lack of biological information on local stocks. This paper utilized phenotypic- and model-based methods to discriminate stocks of P. leopardus in 3 LRFFT hubs in the Philippines (Taytay, Quezon, and Tawi-Tawi). Phenotypic variation among sites was assessed using shape descriptors and landmark data of otoliths, while patterns of connectivity were inferred from a dispersal model of coral grouper larvae. Inferences suggest (1) the presence of distinct phenotypic stocks and (2) limited larval connectivity among sites. There was an inconsistency with how otolith shape discriminated stocks. While shape descriptors identified Tawi-Tawi as a separate unit, landmark data differentiated Quezon from the other sites. This suggests that different processes may influence otolith shape, thereby presenting a caveat when using otolith morphometrics in stock discrimination. Meanwhile, the dispersal model showed that Quezon and Tawi-Tawi distribute larvae primarily to the West Philippine Sea and Celebes Sea, respectively. Although the model showed that Taytay supplies larvae to both Quezon and Tawi-Tawi, these connections were weak. Model inferences showing all sites as important larval sources to different reefs, coupled with the presence of distinct phenotypic stocks based on otolith shape, suggest that each LRFFT hub is an independent management unit. Thus, identifying key drivers of stock decline is crucial in developing site-specific fishery management approaches.

New records of anisakid nematodes from marine fishes off New Caledonia, with descriptions of five new species of Raphidascaris (Ichthyascaris) (Nematoda, Anisakidae).

Recent examinations of anisakid nematodes (Anisakidae) from marine fishes off New Caledonia, collected in the years 2003–2008, revealed the presence of the following five new species of Raphidascaris Railliet et Henry, 1915, all belonging to the subgenus Ichthyascaris Wu, 1949: Raphidascaris (Ichthyascaris) spinicauda n. sp. from the redbelly yellowtail fusilier Caesio cuning (Caesionidae, Perciformes); Raphidascaris (Ichthyascaris) fasciati n. sp. from the blacktip grouper Epinephelus fasciatus (Serranidae, Perciformes); Raphidascaris (Ichthyascaris) nudicauda n. sp. from the brushtooth lizardfish Saurida undosquamis (Synodontidae, Aulopiformes); Raphidascaris (Ichthyascaris) euani n. sp. from the Japanese large-eye bream Gymnocranius euanus (Lethrinidae, Perciformes); and Raphidascaris (Ichthyascaris) elopsis n. sp. from the Hawaiian ladyfish Elops hawaiensis (Elopidae, Elopiformes). An additional two congeneric species, R. (I.) etelidis Moravec et Justine, 2012 and R. (I.) sillagoides (Bruce, 1990) were found in the deep-water red snapper Etelis carbunculus (new host record) and the deepwater longtail red snapper Etelis coruscans (both Lutjanidae, Perciformes), and the silver sillago Sillago sihama (Sillaginidae, Perciformes) (new host and geographical records), respectively. Two unidentified congeneric species, Raphidascaris (Ichthyascaris) sp. 1 from the trumpet emperor Lethrinus miniatus (Lethrinidae, Perciformes) and Raphidascaris (Ichthyascaris) sp. 2 from the white-spotted puffer Arothron hispidus (Tetraodontidae, Tetraodontiformes) were recorded. Moreover, two species of Hysterothylacium Ward et Magath, 1917, H. alatum Moravec et Justine, 2015 and H. epinepheli (Yamaguti, 1941), were found in the leopard coralgrouper Plectropomus leopardus (type host) and the highfin grouper Epinephelus maculatus (new host) (both Serranidae, Perciformes), respectively. This is the second finding of H. epinepheli since its original description in Japan 79 years ago. Most species are described based on light and electron microscopical studies.

Depth and space use of leopard coralgrouper Plectropomus leopardus using passive acoustic tracking

Understanding fish movements can help define the seasonal importance of different habitats and isolate spatial and temporal vulnerability to exploitation. Leopard coralgrouper Plectropomus leopardus is one of the main targeted fishery species in the Great Barrier Reef; however, there is no information on long-term movement patterns based on continuous and frequent data points. The objective of this study was to determine long-term space use of P. leopardus and identify any seasonal variation in movement trends. A total of 124 P. leopardus were implanted with V13P acoustic transmitters between 2010 and 2012 and passively tracked. Forty-five VR2W receivers were deployed at 2 reefs to track the movements of tagged individuals. The influence of time of day, season, tagging year, location, and water temperature on several movement measures was investigated. Of the 124 fish tagged, 74 individuals had sufficient detections to be included in analysis of horizontal movement, and 55 were used to analyse vertical movements. Results showed increased horizontal movements and higher activity in deeper water during the day in the austral summer. Movement patterns, both vertically and horizontally, appeared to be influenced by water temperature, but also corresponded with spawning season. Despite increased movements during summer, individuals typically remained in a small area ~0.5 km2 throughout detection periods, indicating that long-range spawning-related movements are rare and that adequate resources are obtained within a small section of habitat year-round. This study provides long-term (~3 yr) movement data for an economically significant reef fish and increases knowledge of spatial and temporal space use patterns.

Effects of water temperature on survival, growth, digestive enzyme activities, and body composition of the leopard coral grouper Plectropomus leopardus

The effects of water temperature (15, 20, 25, 30, and 35 °C) on survival, growth performance, digestive enzyme activities, and body composition of Plectropomus leopardus were studied for a period of 6 weeks. One hundred eighty fish with initial body weights of 26.5 ± 1.5 g were randomly arranged into 15 glass aquaria in equal numbers in five recirculating systems to form five groups in triplicate. The results showed that survival of P. leopardus at 35 °C was significantly greater (P < 0.05) than survival at 15 °C. No death was recorded at 20, 25, and 30 °C. Among all treatment groups, the significantly highest average individual harvesting weight, weight gain, feed ingestion rate and protease enzyme activity of P. leopardus were observed in 30 °C group. Similar results were also observed in protein and fat content in this species. Based on the present findings, a culture temperature of 30 °C can be considered to be the optimum temperature for the aquaculture of juvenile P. leopardus. However, more research is still needed to optimize the nutrition and photoperiod of P. leopardus culture.

Capillaria plectropomi n. sp. (Nematoda: Capillariidae), a new intestinal parasite of the leopard coral grouper Plectropomus leopardus (Serranidae) off New Caledonia.

A new nematode species, Capillaria plectropomi n. sp. (Capillariidae), is described from the intestine of the leopard coral grouper Plectropomus leopardus (Lacepède) from coral reefs off New Caledonia. The new species, belonging to the subgenus Neocapillaria Moravec, 1987, differs from other congeneric species of this subgenus from marine fishes mainly in the length (168–186 μm), shape and structure of the spicule. It is characterized, in the male, by the presence of two well-developed dorsolateral caudal lobes, a pair of lateral papillae, a heavily sclerotized spicule with many rough transverse grooves in the middle part, a spinose spicular sheath, and in the female, by eggs measuring 60–66 × 27 μm without protruding polar plugs. The buccal cavity contains a small finger-shaped stylet. Capillaria plectropomi n. sp. is the first known species of this genus parasitizing fishes of the perciform family Serranidae.

Trace element bioaccumulation in reef fish from New Caledonia: Influence of trophic groups and risk assessment for consumers

Fourteen trace elements (Ag, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, V, and Zn) were analyzed in livers and muscles from 22 fish species from the New Caledonia lagoon, which is subjected to important chemical inputs due to intense land-based mining activities (New Caledonia is the third largest world producer of Ni). The results of this baseline research indicated that livers generally concentrated trace elements to a greater extent than muscles. Nevertheless, the overall trace element concentrations in both tissues were barely above the levels reported in fish and thus contamination at the local scale was poorly discriminated. Although these levels were low, preliminary risk assessment from a global health standpoint suggests that As would be an element potentially leading to exposure of concern for fish consumers. Based on the trace element concentrations in livers and the fish trophic preferences, some trends have been observed among trophic groups: Ag, Cu, Fe, Hg, and Zn concentrations were generally higher in liver of fish with the highest trophic position whereas Cd concentrations were lower in these groups. The use of the leopard coral grouper Plectropomus leopardus as a resident top predator allowed determining the geographical variations in contamination levels with significant differences for six out of the fourteen elements investigated. The sampling sites influenced by anthropogenic inputs were revealed by high Ag, Cd, Cu, Hg, and Pb concentrations. Such geographic differences also applied to Zn but surprisingly not for the typical elements associated with Ni mining, i.e., Co, Cr, Mn and Ni.

Influence of light intensity on feeding, growth, and early survival of leopard coral grouper ( Plectropomus leopardus) larvae under mass-scale rearing conditions

This study investigated the effect of different light intensities on feeding, growth and survival of early stage leopard coral grouper Plectropomus leopardus larvae. Four different light intensities (0, 500, 1000 and 3000 lx) were used and larvae were kept under constant light conditions from 0 day after hatching (DAH) to 5 DAH. The larvae were fed a small S-type of Thai strain rotifers at a density of 20 individuals/mL from 2 DAH. The number of rotifers in larval digestive organ and total length of larvae were examined at 3 h intervals between 04:00 and 22:00 h on 3 DAH, and thereafter at 6 h intervals until the end of the experiment (5 DAH). Four experimental trials of the larval rearing were repeated using by 60 kL mass-scale rearing tanks. The results indicate that coral grouper larvae are visual feeders and their food intake increases with increasing light intensity. Food intake of larvae reared at 3000 lx was significantly higher than those reared at 0–1000 lx on 3 DAH despite being the first-feeding day ( P < 0.01). On 4 DAH, total length of larvae reared at 3000 lx was significantly larger than those reared at the lower light intensities (0, 500 and 1000 lx), and thereafter light intensity significantly influenced larval feeding and growth until the end of the experiment. Survival on 5 DAH did not show a significant difference between light intensities, but survival rate at 3000 lx and 1000 lx had a tendency to be higher than those reared at the lower light intensities (0 and 500 lx). In contrast, larvae reared at 0 lx exhibited stagnant and/or negative growth. These results indicate that light intensity is significantly the factor affecting larval feeding, growth, and survival in coral grouper larvae under the rearing conditions.

Endoparasitic Dinoflagellate of the Genus Ichthyodinium Infecting Fertilized Eggs and Hatched Larvae Observed in the Seed Production of Leopard Coral Grouper Plectropomus leopardus

Since 1990, mass mortality of fertilized eggs and hatched larvae of the leopard coral grouper Plectropomus leopardus has occurred repeatedly during its seed production in Okinawa Prefecture. A hitherto unknown protozoan parasite multiplied in the yolk sac in great numbers. The yolk sac of fertilized eggs and hatched larvae eventually burst and parasites were released to sea water. The development of the parasite was briefly described, which is very similar to that of the dinoflagellate Ichthyodinium chabelardi, known to infect yolk of several marine fish larvae in Europe. Based on the similarities of, and minor differences in, the mode of infection, development and SSU rDNA sequence, the parasite is tentatively designated as Ichthyodinium sp. PL (= PL for the abbreviated form of the scientific name for the host). Although the life cycle of the parasite is unknown, the disease outbreak was controlled by rearing the broodstock and incubating fertilized eggs in oxidant-treated seawater. The PCR diagnosis using specific primers designed from part of SSU rDNA sequence of the parasite revealed that disease outbreaks in different years were caused by a single species of parasite. This is the first report of Ichthyodinium infection in tropical fish from the Asia-Pacific region.