Plectropomus Maculatus Research Articles

PENDUGAAN STATUS STOK DAN INDIKATOR BIOEKONOMI PERIKANAN KERAPU DI TELUK SALEH, NUSA TENGGARA BARAT

One of the challenges in managing small-scale fisheries with limited data is the need for indicators to estimate the stock status and the total allowable catch for sustainable utilization of fish resources. This study aims to estimate the stock status, catch, and optimal fishing effort of the grouper fishery in Saleh Bay, West Nusa Tenggara Province by using the Length-based Spawning Potential Ratio analysis, production surplus model, and bioeconomic approach. Based on the results of this study, it is known that Plectopomus leopardus and Epinephelus coioides are in overexploited condition, while Plectropomus maculatus is in fully exploited status. This study also shows that with a bioeconomic approach, optimal conditions for grouper fisheries in these waters are achieved when the catch is 3,862.1 tonnes per year. The results of this study underline the importance of maximum economic yield-based management as a framework for a fishing quota-based system as an additional instrument in implementing sustainable fishery management in the future. The success of applying the quota system and the total allowable effort is determined by the accuracy of the catch data of small vessels around Saleh Bay under regulatory provisions, supervision and effective law enforcement, the socio-cultural conditions of local communities and the level of compliance with regulations.Keywords: fishing effort, grouper, overfished, quota system.

Detection and identification of Red Snapper (Lutjanus gibbus and Lutjanus malabaricus) and grouper (Plectropomus leopardus and Plectropomus maculatus) with deep learning

The Indonesian fishing industry is a major global contributor, particularly in the production and export of snapper and grouper fish. These two groups of fish are known for their high diversity, but distinguishing between the different species can be challenging due to their morphological similarities. In order to overcome this challenge, this paper proposes the application of deep learning methods to identify the two major species of snapper and grouper accurately. The deep learning framework utilized in this study is Detectron2, a state-of-the-art object detection and segmentation model. The datasets used in the study consist of 500 images each for the snapper species Lutjanus gibbus and Lutjanus malabaricus, and the grouper species Plectropomus leopardus and Plectropomus maculatus, totaling 2000 images. The datasets were labeled using Coco Annotator software with a focus on species segmentation. The labeled datasets were then trained using Google Collaboratory, resulting in an accuracy value of 89.51%, a precision of 87.69%, a recall of 99.85%, and an F1-score of 93.38%. These results demonstrate that, even with a relatively limited number of datasets, it is possible to accurately identify the Red Snapper Lutjanus gibbus and Lutjanus malabaricus, as well as the grouper species Plectropomus leopardus and Plectropomus maculatus using deep learning methods. In conclusion, this paper demonstrates the potential of deep learning methods, specifically Detectron2, in accurately identifying snapper and grouper species. The results of this study suggest that this technology can be used to improve the accuracy and efficiency of fish species identification, which could have significant implications for the fishing industry and marine conservation efforts.

Caracterização morfológica e molecular do parasita monogênico de brânquias, Acleotrema maculatus, que infecta o peixe Argyrops filamentosus no Mar Vermelho, Arábia Saudita

ABSTRACT Fish are considered one of the important sources of protein which are invaded by different parasites. This study aimed to shed light on monogenean parasites that infect fish within the family Sparidae in Saudi Arabia. A total of 30 Argyrops filamentosus specimens were collected from the Red Sea, the city of Jeddah (Saudi Arabia), and then examined for the presence of monogenean parasites. Parasitic species were isolated and studied morphologically using light microscopic examination and molecularly via the partial sequencing of the 28S rRNA gene. Only a monogenean parasitic species has been identified. This parasite is morphologically and morphometric compatible with previously Acleotrema maculatus Morsy, El-Fayoumi & Fahmy (2014), identified from Plectropomus maculatus in the Red Sea, Egypt. Phylogeny revealed that this putative diplectanid species nested well within a clade clustering Diplectanidae species, which along with morphological data, suggests it is a member of the genus Acleotrema. Query sequences showed identities of 98.92% for 28S rRNA (AF026118.1) of Acleotrema sp. This study reflects the first account of this genus as endoparasite taxa of the examined sparid fish, as well as providing novel DNA data for this species.

Ageing of juvenile coral grouper (Plectropomus maculatus) reveals year-round spawning and recruitment: implications for seasonal closures.

Temporal patterns in spawning and juvenile recruitment can have major effects on population size and the demographic structure of coral reef fishes. For harvested species, these patterns are crucial in determining stock size and optimizing management strategies such as seasonal closures. For the commercially important coral grouper (Plectropomus spp.) on the Great Barrier Reef, histological studies indicate peak spawning around the summer new moons. Here we examine the timing of spawning activity for P. maculatus in the southern Great Barrier Reef by deriving age in days for 761 juvenile fish collected between 2007 and 2022, and back-calculating settlement and spawning dates. Age-length relationships were used to estimate spawning and settlement times for a further 1002 juveniles collected over this period. Unexpectedly, our findings indicate year-round spawning activity generates distinct recruitment cohorts that span several weeks to months. Peak spawning varied between years with no clear association with environmental cues, and little to no alignment with existing seasonal fisheries closures around the new moon. Given the variability and uncertainty in peak spawning times, this fishery may benefit from additional and longer seasonal closures, or alternative fisheries management strategies, to maximize the recruitment contribution from periods of greatest reproductive success.

Trophic Structure and Diet of Predatory Teleost Fishes in a Tropical Demersal Shelf Ecosystem

Predatory fishes are a major component of many tropical fisheries, although little is known about their diet and trophic structure, which can hinder effective management. We used stable isotopes δ15N and δ13C in conjunction with dietary prey items of five fishes (Lutjanus sebae, Lethrinus punctulatus, Epinephelus areolatus, Epinephelus multinotatus, and Plectropomus maculatus) to describe the diet and trophic structure across this assemblage. A total of 153 isotope and 87 stomach content samples were collected at two locations that were ≈30 km apart, over two sampling trips, separated by three months. There was clear separation of species’ mean δ15N and δ13C values in isotopic space; the highest mean δ15N was exhibited by E. multinotatus (13.50 ± 0.11 SE) and the lowest was L. punctulatus (11.05 ± 0.13). These two species had the lowest overlap of isotopic niche space, whereas the highest overlap occurred between L. sebae and P. maculatus. δ15N increased with fish body size for all species. However, body size was not significantly related to δ13C values for any species. There was a notable shift in both δ15N and δ13C between sampling trips, with δ13C being more depleted in the second trip. There was also a difference in δ13C between locations for all species, suggesting localised foraging. A multiple tissue comparison for L. sebae indicated positive relationships for both δ15N and δ13C between dorsal fin and muscle tissue. Mean δ15N values were the same for both fin (12.1 ± 0.10 SE) and muscle tissue (12.1 ± 0.09 SE), although δ13C was more enriched in fin (-15.6 ± 0.14 SE) compared to muscle tissue (-17.3 ± 0.11 SE). The most common dietary items across species were teleosts and crustaceans, which was consistent with isotope data indicating a reliance on a demersal food web (δ13C values ranging from -18 to -15‰). The results from our study indicate a dynamic spatio-temporal trophic structure and diet for commercially important demersal species and highlight the benefits of a multi-facetted sampling approach.

Genetic diversity of three sunu groupers species (Plectropomus spp)

The quality of fish seed may be decreased as a result of inbreeding that is a marriage between two individuals who have the same genetic trait. Fish seed quality improved with the genetic approach to parent selection and crossbreed. Quality of fish seeds is taking from natural populations are determined by the genetic diversity of a population. Inbreeding can decrease the quality of seed because it can increase the number of homozygosity and decrease the number of heterozygosity. This study aims to determine differences in genetic variation three species of sunu groupers (Plectropomus maculatus, Plectropomus leopardus, and Plectropomus oligacanthus) and know the kinship of the three species of grouper. While the benefits of this research can provide information on genetic diversity in natural coral trout grouper, expected inbreeding can be avoided. Muscle and liver tissue was used as a sample for electrophoresis analysis with twelve kinds of enzymes namely aspartate aminotransferase (AAT), Alcohol dehydrogenase (ADH), Estrase (EST), -Gliserofosfat dehydrogenase (-GPD), Glukofosfat isomerase (GPI), Isocitrate dehydrogenase (IDH), Lactate dehydrogenase (EST), Malic dehydrogenase (MDH), Malic Enzyme (ME), 6-phosphogluconate dehydrogenase (6- PGD), phosphoglucomutase (PGM), and sarcoplasmic enzymes (SP). Three polymorphic loci in Plectropomus oligacanthus species are 6-PGD, GPI-2, and PGM. In Plectropomus maculatus, and Plectropomus leopardus all monomorphic loci. The three polymorphic loci on Plectropomus oligacanthus meet the Hardy-Weinberg balance with X2 value for 6-PGD value is 0.123, GPI-2 is 0.028 and PGM is 0.028. Plectropomus oligacanthus has a polymorphism level of 0.188, the total number of the focusing allele is 1,154, and the average heterozygosity is 0.023. The genetic distance between the sepsis population based on twelve enzymes showed between Plectropomus maculatus, and Plectropomus leopardus had a spacing of 0.134, between Plectropomus leopardus and Plectropomus oligacanthus of genetic distance 0.196 and between Plectropomus maculatus and Plectropomus oligacanthus the genetic distance was 0.200. The larger the genetic distance between the species, the kinship relationship will be farther away. The distant kinship is owned by Plectropomus oligacanthus.

Successful validation of a larval dispersal model using genetic parentage data.

Larval dispersal is a critically important yet enigmatic process in marine ecology, evolution, and conservation. Determining the distance and direction that tiny larvae travel in the open ocean continues to be a challenge. Our current understanding of larval dispersal patterns at management-relevant scales is principally and separately informed by genetic parentage data and biological-oceanographic (biophysical) models. Parentage datasets provide clear evidence of individual larval dispersal events, but their findings are spatially and temporally limited. Biophysical models offer a more complete picture of dispersal patterns at regional scales but are of uncertain accuracy. Here, we develop statistical techniques that integrate these two important sources of information on larval dispersal. We then apply these methods to an extensive genetic parentage dataset to successfully validate a high-resolution biophysical model for the economically important reef fish species Plectropomus maculatus in the southern Great Barrier Reef. Our results demonstrate that biophysical models can provide accurate descriptions of larval dispersal at spatial and temporal scales that are relevant to management. They also show that genetic parentage datasets provide enough statistical power to exclude poor biophysical models. Biophysical models that included species-specific larval behaviour provided markedly better fits to the parentage data than assuming passive behaviour, but incorrect behavioural assumptions led to worse predictions than ignoring behaviour altogether. Our approach capitalises on the complementary strengths of genetic parentage datasets and high-resolution biophysical models to produce an accurate picture of larval dispersal patterns at regional scales. The results provide essential empirical support for the use of accurately parameterised biophysical larval dispersal models in marine spatial planning and management.

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.

Widespread hybridization and bidirectional introgression in sympatric species of coral reef fish.

Coral reefs are highly diverse ecosystems, where numerous closely related species often coexist. How new species arise and are maintained in these high geneflow environments have been long-standing conundrums. Hybridization and patterns of introgression between sympatric species provide a unique insight into the mechanisms of speciation and the maintenance of species boundaries. In this study, we investigate the extent of hybridization between two closely related species of coral reef fish: the common coral trout (Plectropomus leopardus) and the bar-cheek coral trout (Plectropomus maculatus). Using a complementary set of 25 microsatellite loci, we distinguish pure genotype classes from first- and later-generation hybrids, identifying 124 interspecific hybrids from a collection of 2,991 coral trout sampled in inshore and mid-shelf reefs of the southern Great Barrier Reef. Hybrids were ubiquitous among reefs, fertile and spanned multiple generations suggesting both ecological and evolutionary processes are acting to maintain species barriers. We elaborate on these finding to investigate the extent of genomic introgression and admixture from 2,271 SNP loci recovered from a ddRAD library of pure and hybrid individuals. An analysis of genomic clines on recovered loci indicates that 261 SNP loci deviate from a model of neutral introgression, of which 132 indicate a pattern of introgression consistent with selection favouring both hybrid and parental genotypes. Our findings indicate genome-wide, bidirectional introgression between two sympatric species of coral reef fishes and provide further support to a growing body of evidence for the role of hybridization in the evolution of coral reef fishes.

Growth, mortality and exploitation rate of Plectropomus maculatus and P. oligocanthus (Groupers, Serranidae) on Cenderawasih Bay National Park, Indonesia

The present study aims to determine whether the rate of exploitation for grouper stocks is in accordance with their biological attributes (growth and mortality). The results showed that Plectropomus maculatus and P. oligocanthus taken from Cenderawasih Bay National Park (CBNP) were in the size category of actively productive spawning phase. P. maculatus could reach a maximum length (L∞) of 484.05mm and growth rate (K) of 0.34 per year. P. oligocanthus was capable of reaching L∞ of 481.95mm and K of 0.66 per year. Estimation of total mortality (Z) for P. maculatus was 0.988 and P Oligocanthus was 2.056. In addition, fishing mortality (F) for P. maculatus and P. oligocanthus were 0.564 and 0.399 respectively. Based on the estimated mortality values, it was estimated that the exploitation rate (E) of P. maculatus was 0.570, and P. oligocanthus was 0.681. Management settings for P. maculatus and P. oligocanthus can be separately based on the species so that the fishing can be sustainable. The introduction of minimum size limits for fish caught can be applied as a protection from hook and hand line fishing activities in CBNP.

Coral reef mesopredators switch prey, shortening food chains, in response to habitat degradation.

Diet specificity is likely to be the key predictor of a predator's vulnerability to changing habitat and prey conditions. Understanding the degree to which predatory coral reef fishes adjust or maintain prey choice, in response to declines in coral cover and changes in prey availability, is critical for predicting how they may respond to reef habitat degradation. Here, we use stable isotope analyses to characterize the trophic structure of predator–prey interactions on coral reefs of the Keppel Island Group on the southern Great Barrier Reef, Australia. These reefs, previously typified by exceptionally high coral cover, have recently lost much of their coral cover due to coral bleaching and frequent inundation by sediment‐laden, freshwater flood plumes associated with increased rainfall patterns. Long‐term monitoring of these reefs demonstrates that, as coral cover declined, there has been a decrease in prey biomass, and a shift in dominant prey species from pelagic plankton‐feeding damselfishes to territorial benthic algal‐feeding damselfishes, resulting in differences in the principal carbon pathways in the food web. Using isotopes, we tested whether this changing prey availability could be detected in the diet of a mesopredator (coral grouper, Plectropomus maculatus). The δ13C signature in grouper tissue in the Keppel Islands shifted from a more pelagic to a more benthic signal, demonstrating a change in carbon sources aligning with the change in prey availability due to habitat degradation. Grouper with a more benthic carbon signature were also feeding at a lower trophic level, indicating a shortening in food chains. Further, we found a decline in the coral grouper population accompanying a decrease in total available prey biomass. Thus, while the ability to adapt diets could ameliorate the short‐term impacts of habitat degradation on mesopredators, long‐term effects may negatively impact mesopredator populations and alter the trophic structure of coral reef food webs.

Large-scale, multidirectional larval connectivity among coral reef fish populations in the Great Barrier Reef Marine Park.

Larval dispersal is the key process by which populations of most marine fishes and invertebrates are connected and replenished. Advances in larval tagging and genetics have enhanced our capacity to track larval dispersal, assess scales of population connectivity, and quantify larval exchange among no-take marine reserves and fished areas. Recent studies have found that reserves can be a significant source of recruits for populations up to 40km away, but the scale and direction of larval connectivity across larger seascapes remain unknown. Here, we apply genetic parentage analysis to investigate larval dispersal patterns for two exploited coral reef groupers (Plectropomus maculatus and Plectropomus leopardus) within and among three clusters of reefs separated by 60-220km within the Great Barrier Reef Marine Park, Australia. A total of 69 juvenile P.maculatus and 17 juvenile P.leopardus (representing 6% and 9% of the total juveniles sampled, respectively) were genetically assigned to parent individuals on reefs within the study area. We identified both short-distance larval dispersal within regions (200m to 50km) and long-distance, multidirectional dispersal of up to ~250km among regions. Dispersal strength declined significantly with distance, with best-fit dispersal kernels estimating median dispersal distances of ~110km for P.maculatus and ~190km for P.leopardus. Larval exchange among reefs demonstrates that established reserves form a highly connected network and contribute larvae for the replenishment of fished reefs at multiple spatial scales. Our findings highlight the potential for long-distance dispersal in an important group of reef fishes, and provide further evidence that effectively protected reserves can yield recruitment and sustainability benefits for exploited fish populations.

Planning Marine Reserve Networks for Both Feature Representation and Demographic Persistence Using Connectivity Patterns

Marine reserve networks must ensure the representation of important conservation features, and also guarantee the persistence of key populations. For many species, designing reserve networks is complicated by the absence or limited availability of spatial and life-history data. This is particularly true for data on larval dispersal, which has only recently become available. However, systematic conservation planning methods currently incorporate demographic processes through unsatisfactory surrogates. There are therefore two key challenges to designing marine reserve networks that achieve feature representation and demographic persistence constraints. First, constructing a method that efficiently incorporates persistence as well as complementary feature representation. Second, incorporating persistence using a mechanistic description of population viability, rather than a proxy such as size or distance. Here we construct a novel systematic conservation planning method that addresses both challenges, and parameterise it to design a hypothetical marine reserve network for fringing coral reefs in the Keppel Islands, Great Barrier Reef, Australia. For this application, we describe how demographic persistence goals can be constructed for an important reef fish species in the region, the bar-cheeked trout (Plectropomus maculatus). We compare reserve networks that are optimally designed for either feature representation or demographic persistence, with a reserve network that achieves both goals simultaneously. As well as being practically applicable, our analyses also provide general insights into marine reserve planning for both representation and demographic persistence. First, persistence constraints for dispersive organisms are likely to be much harder to achieve than representation targets, due to their greater complexity. Second, persistence and representation constraints pull the reserve network design process in divergent directions, making it difficult to efficiently achieve both constraints. Although our method can be readily applied to the data-rich Keppel Islands case study, we finally consider the factors that limit the method’s utility in information-poor contexts common in marine conservation.

Dietary shift in juvenile coral trout (Plectropomus maculatus) following coral reef degradation from a flood plume disturbance

Acute environmental disturbances impact on habitat quality and resource availability, which can reverberate through trophic levels and become apparent in species' dietary composition. In this study, we observed a distinct dietary shift of newly settled and juvenile coral trout (Plectropomus maculatus) following severe coral reef habitat degradation after a river flood plume affected the Keppel Islands, Australia. Hard coral cover declined by similar to 28 % in the 2 yr following the 2010-2011 floods, as did the abundance of young coral trout. Gut contents analysis revealed that diets had shifted from largely crustacean-based to non-preferred prey fishes following the disturbances. These results suggest that newly settled and juvenile coral trout modify their diet and foraging strategy in response to coral habitat degradation. This bottom-up effect of habitat degradation on the diet of a top coral reef predator may incur a metabolic cost, with subsequent effects on growth and survival.

Altered transcription levels of endocrine associated genes in two fisheries species collected from the Great Barrier Reef catchment and lagoon

The Great Barrier Reef (GBR) is chronically exposed to agricultural run-off containing pesticides, many of which are known endocrine disrupting chemicals (EDCs). Here, we measure mRNA transcript abundance of two EDC biomarkers in wild populations of barramundi (Lates calcarifer) and coral trout (Plectropomus leopardus and Plectropomus maculatus). Transcription levels of liver vitellogenin (vtg) differed significantly in both species amongst sites with different exposures to agricultural run-off; brain aromatase (cyp19a1b) revealed some differences for barramundi only. Exposure to run-off from sugarcane that contains pesticides is a likely pathway given (i) significant associations between barramundi vtg transcription levels, catchment sugarcane land use, and river pesticide concentrations, and (ii) consistency between patterns of coral trout vtg transcription levels and pesticide distribution in the GBR lagoon. Given the potential consequences of such exposure for reproductive fitness and population dynamics, these results are cause for concern for the sustainability of fisheries resources downstream from agricultural land uses.

Establishment and management of fisheries refugia in Phu Quoc Marine Protected Area, Vietnam

and management of fisheries refugia have recently been recognized as important tools in sustainable use/ management of fish stocks and their associated habitats. To initiate the fisheries refugia management approach in Phu Quoc, several activities were conducted to collect baseline information for establishment of fisheries refugia in Phu Quoc Archipelago since 2007, including local consultations and field surveys involving local communities and concerned stakeholders. Site selection for the establishment of model/ fisheries refugia was based on scientific data and consultations with local communities and based on criteria of habitat representativeness, target species diversity and abundance and site management potential. Results from the baseline surveys recorded 11 spawning and nursery grounds of several target species including; octopus ( Octopus dollfusi), cuttlefish (Sepioteuthis lessoniana ), the Strombus shell (Strombus canarium), swimming crab (Portunus pelagicus), seahorses (Hippocampus spp.), rabbitfishes (Siganus spp.) associated with seagrass habitat and squids (Loligo spp.) associated with sandy bottom habitat. In the coral reef habitats, there were 10 locations where nursery grounds of barred-cheek coral trout (Plectropomus maculatus) were found in the waters surrounding most of the group of islands (An Thoi) in the southern part of Phu Quoc big island. Two pilot sites were selected for fisheries refugia management, one to protect the nursery grounds of grouper associated with coral reef habitats at Hon Roi fishing village and the other to protect the spawning/nursery grounds of the Strombus shell, octopus, swimming crab and seahorses associated with the sea

Description of Acleotrema maculatus sp. nov. (Monogenea: Diplectanidae) infecting the spotted coral grouper Plectropomus maculatus (F:Serranidea) from the Red Sea and its histopathological impact

Acleotrema maculatus sp. nov. (Monogenea: Diplectanidae) was described from the gills of The spotted coral grouper Plectropomus maculatus (F:Serranidea, Forsskal, 1775). Fish were collected from boot landing sites and fishermen at different water locations along the Red Sea at Hurghada City, Egypt. The morphology and morphometric characterization of the recovered worms were described by means of light microscopy. Eight (53.3%) out 15 specimens of P. maculatus were infected. Most of the infected fish had very pale gills. Morphologically, the adult worm of A. maculatus sp. nov., possessed a body which was elongated, fusiform with a total length 0.86–0.90 (0.88 ± 0.02) mm, and a maximum width 0.09–0.13 (0.11 ± 0.02) mm at the level of ovary. Haptor, broad, differentiated from the rest of the body, measured 0.04–0.08 (0.06 ± 0.02) mm and provided with continuous rows of squamodiscs. Two pairs of lateral hamuli, three bars and 14 marginal hooklets were also observed. Lateral (dorsal) bars two, stout, dumbbell-shaped, measured 0.052–0.056 (0.054 ± 0.002) mm in length. Ventral bar slender, with transverse groove, measured 0.09–0.11 (0.10 ± 0.01) mm in length. Ventral hamuli measured 0.02–0.06 (0.04 ± 0.02) mm in total length with an outer root that was very long measured 0.016–0.02 (0.018 ± 0.002), stout, slightly notched at broad proximal end; inner root was conical and measured 0.013–0.017 (0.015 ± 0.002) mm, with shaft measured 0.025–0.029 (0.027 ± 0.002) mm and point length 0.007–0.009 (0.008 ± 0.002) mm. Dorsal hamuli measured 0.034–0.038 (0.036 ± 0.002) in total length; base large, stout, with only lateral rudiment of roots; blade and point were long and curved with shaft length measured 0.024–0.028 (0.026 ± 0.002) mm and 0.02–0.06 (0.04 ± 0.02) mm point length. The worm is hermaphrodite, male copulatory organ measured 0.058–0.062 (0.060 ± 0.002) mm in length with a sclerotized part composed of a well-defined, sclerotized anterior sheath. The new species was compared with those described previously from the same genus, it was shown that there were significant morphological and morphometric, which was a strong criteria for the placement these monogenean parasites as new species with new host and locality records in Egypt.

Trophic ecology of large predatory reef fishes: energy pathways, trophic level, and implications for fisheries in a changing climate

Large predatory fishes are disproportionately targeted by reef fisheries, but little is known about their trophic ecology, which inhibits understanding of community dynamics and the potential effects of climate change. In this study, stable isotope analyses were used to infer trophic ecology of a guild of large predatory fishes that are targeted by fisheries on the Great Barrier Reef, Australia. Each of four focal predators (Plectropomus leopardus, Plectropomus maculatus, Lethrinus miniatus and Lutjanus carponotatus) was found to have a distinct isotopic signature in terms of δ13C and δ15N. A two-source mixing model (benthic reef-based versus pelagic) indicated that P. leopardus and L. miniatus derive the majority (72 and 62 %, respectively) of their production from planktonic sources, while P. maculatus and L. carponotatus derive the majority (89 and 74 %, respectively) of their production from benthic reef-based sources. This indicates that planktonic production is important for sustaining key species in reef fisheries and highlights the need for a whole-ecosystem approach to fisheries management. Unexpectedly, there was little isotopic niche overlap between three of four focal predators, suggesting that inter-specific competition for prey may be low or absent. δ15Nitrogen indicated that the closely related P. leopardus and P. maculatus are apex predators (trophic level > 4), while δ13C indicated that each species has a different diet and degree of trophic specialisation. In view of these divergent trophic ecologies, each of the four focal predators (and the associated fisheries) are anticipated to be differentially affected by climate-induced disturbances. Thus, the results presented herein provide a useful starting point for precautionary management of exploited predator populations in a changing climate.

Recruitment hotspots boost the effectiveness of no-take marine reserves

No-take marine reserves are widely advocated as a means to conserve biodiversity and sustain fisheries. Within adequately protected reserves, the abundance, mean size and age of targeted fish and invertebrate species are often increased. However, the magnitude and rate of recovery within reserves varies among locations and species, and increases in abundance in reserves are not universal. One potential contributing factor to variability in reserve performance is spatial variability in the supply of recruits. Many reef fish species exhibit disproportionate levels of recruitment in relatively small areas (so-called “recruitment hotspots”). Here we tested the hypothesis that the presence of recruitment hotspots enhances the effectiveness of reserves for two important fishery species, coral trout (Plectropomus maculatus) and stripey snapper (Lutjanus carponotatus), on coral reefs of the Keppel Island group, Great Barrier Reef. To do this we compared fish densities in areas that did or did not contain previously identified recruitment hotspots, both inside and outside reserves. For both species, the mean densities of adult fish above the minimum legal size were approximately three times as high in reserves with hotspots than in reserves without hotspots. Furthermore, the mean densities in reserves without hotspots were similar to those in nearby areas that were open to fishing. In contrast, the densities of sub-legal size individuals of both species were primarily explained by the presence of recruitment hotspots, irrespective of reserve protection. Our results suggest that identifying and incorporating recruitment hotspots into the selection of sites for reserves could enhance both conservation and fisheries objectives.

Bucephalidae (Platyhelminthes: Digenea) of Plectropomus (Serranidae: Epinephelinae) in the tropical Pacific.

We examined four species of Plectropomus Oken, 1817 (Serranidae: Epinephelinae), Plectropomus areolatus (Rüppell), Plectropomus laevis (Lacepède), Plectropomus leopardus (Lacepède) and Plectropomus maculatus (Bloch) from sites off Heron Island and Lizard Island on the Great Barrier Reef, Australia (GBR), and the Gambier Islands, French Polynesia. Three new species of Neidhartia Nagaty, 1937, five new species of Prosorhynchus Odhner, 1905, and one previously described species, Prosorhynchus freitasi Nagaty, 1937, are characterised. The three species of Neidhartia, Neidhartia haywardi n. sp., Neidhartia plectropomi n. sp. and Neidhartia tyleri n. sp. are readily distinguishable morphologically. Two of the six species of Prosorhynchus (Prosorhynchus lesteri n. sp. and Prosorhynchus wrightae n. sp.) are easily distinguished from their other congeners by morphology but the other four species (P. freitasi, Prosorhynchus heronensis n. sp., Prosorhynchus munozae n. sp. and Prosorhynchus plectropomi n. sp.) are generally similar in morphology and were only distinguished initially by comparing their ITS2 rRNA sequences. Three additional taxa, one from the GBR and two from French Polynesia, were recognised as distinct on the basis that their ITS2 rRNA sequences differed from those of the new taxa described here; these species remain unnamed for the present. Inter-specific divergence observed within these genera in the ITS2 rRNA ranged from 10 to 42 base pairs (4-16%) for species of Neidhartia and 2-57 base pairs (3-21%) for species of Prosorhynchus. Inter-generic divergences were 42-55 base pairs (17-21%). No intraspecific variation in the ITS2 rRNA region was observed for any of the six species for which multiple sequence replicates were obtained. Phylogenetic analysis of 12 operational taxa from Plectropomus together with sequences of three other species from epinepheline serranids demonstrated that Neidhartia and Prosorhynchus were reciprocally monophyletic with the exception that P. wrightae n. sp. fell either within or basal to the Neidhartia species. The richness of bucephalids in species of Plectropomus appears to be exceptional within the Serranidae relative to that observed in other serranid genera in the tropical Indo-West Pacific.