Coral Trout Plectropomus Leopardus Research Articles

Identification of Vibrio ponticus as a bacterial pathogen of coral trout Plectropomus leopardus.

Vibrio ponticus is a vital pathogen with potential danger for aquaculture animals. Yet V. ponticus pathogenic to the coral trout Plectropomus leopardus is still unknown. In this study, a virulent bacterial strain, temporarily named DX2, was isolated from diseased coral trout suffering liver necrosis with cell vacuolar degeneration, and was identified molecularly and phenotypically as V. ponticus. Besides, the DX2 isolate showed an LD50 value of 6.64×105 CFU mL-1, developed multiple resistances to cephalosporins, macrolides, penicillins, peptides, and sulfonamides antimicrobials, and was highly susceptible to doxycycline and florfenicol in aquaculture use. To the best of our knowledge, this is the first report of the pathogenicity of V. ponticus to the coral trout, and the findings provide a reference for the control of pathogenic V. ponticus in the coral trout.

Ultrastructure and regulation of color change in blue spots of leopard coral trout Plectropomus leopardus.

The leopard coral trout generally exhibited numerous round, minute blue spots covering its head (about the size of nostril) and body (except ventral side). This is a characteristic that distinguishes them from similar species. Recently, however, we found the leopard coral trout with black spots. Here, the distribution and ultrastructure of chromatophores in the blue and black spots were investigated with light and transmission electron microscopies. The results showed that in the blue spots, two types of chromatophores are present in the dermis, with the light-reflecting iridophores located in the upper layer and the aggregated light-absorbing melanophores in the lower layer. Black spots have a similar chromatophore composition, except that the melanosomes within the melanophores disperse their dendritic processes to encircle the iridophores. Interestingly, after the treatment of forskolin, a potent adenylate cyclase activator, the blue spots on the body surface turned black. On the other hand, using the skin preparations in vitro, the electrical stimulation and norepinephrine treatment returned the spots to blue color again, indicating the sympathetic nerves were involved in regulating the coloration of blue spots. Taken together, our results revealed that the blue spots of the leopard coral trout can change color to black and vice versa, resulting from the differences in the distribution of melanosomes, which enriches our understanding of the body color and color changes of fishes.

The role of zooplankton as live feeds on the thyroid hormone profile related to metamorphosis of marine fish larvae coral trout Plectropomus leopardus (Lacepède, 1802)

Coral trout Plectropomus leopardus is a high-economical value of marine fish commodity. So, the larviculture for this species should be performed in hatchery scale for their sustainability. One of the important thing in larval stage is hormonal mechanisms. Thyroid hormone is known plays an important role in the metamorphosis of marine fish larvae. The source of that hormone is assumed derived from zooplankton as their live feeds. The live feeds commonly used for marine fish larvae in hatchery are zooplankton copepods and rotifers. The purpose of this research to determine the influence of feeding copepods and rotifers on thyroid hormone profile activity, consisted of triiodothyronine (T3) and thyroxine (T4), related to the metamorphoses of coral trout larvae. The research was conducted using three feeding schemes: copepods (A), copepods-rotifers (B), and rotifers (C). It was done for 50 Days After Hatching (DAH). The results showed that larvae from treatment (A) and (B) achieved the highest level of T3 and T4 earlier at 30 DAH, which indicated that both of those larvae have entered the metamorphosis stage earlier. On the other hand, larvae from treatment (C) achieved it and entered the metamorphosis stage later at 40 DAH. In addition, iodine levels in the copepods were significantly higher than those of in rotifers (P < 0.05). Based on this research, live feeds copepods and rotifers have effect on thyroid hormone activity. Copepods have better potential in accelerating the metamorphosis achievement of coral trout larvae with the fact that they have higher iodine content.

Could the gut microbiota community in the coral trout Plectropomus leopardus (Lacepède, 1802) be affected by antibiotic bath administration?

Gut microbiota in fish plays an important role in the nutrient digestion, immune responses and disease resistance. To understand the effect of fluoroquinolone antibiotic bath administration on fish gut microbiota, the gut microbiota community in the coral trout Plectropomus leopardus (Lacepède, 1802) was studied after enrofloxacin bathing treatment at two concentrations (5 and 10 mg/L) and 0 mg/L as control. A total of 90 fish were used in this study, and three replicates were used for each treatment. After a 24‐hr bath, the gut bacterial composition was analyzed using high‐throughput Illumina sequencing. The results indicated that the richness, diversity and the dominant bacterial taxa of P. leopardus gut bacteria were not affected by enrofloxacin bathing (p > .05). Proteobacteria and Firmicutes were the dominant phyla, and Exiguobacterium, Citrobacter, Vibrio, Acinetobacter, Pseudomonas were the dominant genus. The findings in the present study provide an understanding on the relationship between fish gut bacteria community and antibiotic bath administration. The findings of this study are instructive on the antibiotic bath administration applied for the management of P. leopardus health in aquaculture.

The hemisphere of fear: the presence of sharks influences the three dimensional behaviour of large mesopredators in a coral reef ecosystem

Predators can exert strong ecological effects on their prey either via consumption or by altering their behaviour and morphology. In marine systems, predators and their prey co‐occur in a three‐dimensional environment, but to date predator–prey studies have largely focussed on behaviours of prey on horizontal (distance from shelter) rather than vertical (height in water column) axes. We used life‐size shape‐models of a blacktip reef shark Carcharhinus melanopterus (threatening shape‐model), a juvenile coral trout Plectropomus leopardus (non‐threatening shape‐model) and a shape‐control to examine the impact of perceived instantaneous (measured by time to first feeding) versus sustained (measured by time to consume the entire bait) predation threats on the feeding behaviour and three‐dimensional use of space by mesopredatory reef fishes in a coral reef environment. We found that mesopredatory fishes such as red snapper Lutjanus bohar and spangled emperor Lethrinus nebulosus took longer to begin feeding and to consume predation assays (fish baits) at greater distances from the shelter of a patch reef across both horizontal and vertical axes and that this phenomenon was stronger in the vertical axis than the horizontal. The presence of a life‐size shape‐model of a shark, which we used to increase the perception of predator threat, magnified the instantaneous effect compared to non‐threatening models, but not the sustained effect. We found no evidence for a difference in the level of predation risk posed by the shape‐model of the juvenile coral trout (a non‐threatening reef fish) and a negative control (no shape‐model). Our study suggests that mesopredators modify their behaviours in response to the perceived risk of predation across both horizontal and vertical axes away from shelter, and that this response is most severe on the vertical axis, potentially limiting daytime foraging behaviour to a hemisphere around shelter sites.

Effects of dietary Spirulina platensis on growth performance, hematological and serum biochemical parameters, hepatic antioxidant status, immune responses and disease resistance of Coral trout Plectropomus leopardus (Lacepede, 1802)

The present study investigated the effects of dietary Spirulina platensis supplementation on growth performance, hematological and serum biochemical parameters, hepatic antioxidant status, immune responses and resistance to the pathogen infection in Coral trout Plectropomus leopardus. The fish were fed for 8-week with diets containing different levels of S. platensis: 0% (C), 2% (SP2), 4% (SP4), 6% (SP6), 8% (SP8) and 10% (SP10) as treatment groups, followed by a Vibrio harveyi infection test for 14 d. The study indicated that dietary supplementation with Spirulina platensis could significantly improve growth performance, and the highest weight gain rate (WGR) and specific growth rate (SGR) were observed in group SP10 (P < .05). Red cell count (RBC), white cell count (WBC), hemoglobin (Hb) and total antioxidant capacity (T-AOC) in the S. platensis supplemented groups were significantly higher than those of group C (P < .05). However, the levels of cholesterol, triglyceride and malondialdehyde (MDA) contents, and superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) activities decreased with the increasing of dietary S. platensis levels. Compared with group C, the lysozyme (LYZ) and respiratory burst activities (RBA), and immunoglobulin (Ig) and complement contents in group SP4, SP6, SP8 and SP10 increased significantly than those of group C respectively (P < .05). After challenge with V. harveyi, the survival rate in group SP4, SP6, SP8 and SP10 was significantly higher than that of group C, and the highest survival rate was in group SP10 (P < .05). These results indicated that P. leopardus fed a diet supplemented with S. platensis (especially at 10%) could significantly promote its growth performance, improve its hepatic antioxidant status, and enhance its immune ability and resistance to V. harveyi infection.

Development of a validation protocol of enzyme immunoassay kits used for the analysis of steroid hormones in fish plasma

The analysis of steroid hormones 17β-estradiol, testosterone and 11-ketotestosterone in fish plasma provide insight into fish reproductive behavior and development. Typically, steroid hormones are analyzed using gold standard approaches, such as radioimmunoassay and liquid chromatography coupled with tandem mass spectrometry. However, these methods are not always available to small-to-medium research facilities due to their large capital outlay, expensive running costs and ongoing maintenance needs, in addition to requiring a costly radioisotope license and skilled staff to handle and perform the assays. One approach being increasingly used by researchers is commercial enzyme immunoassay (EIA) kits (also known as ELISA kits), analyzed with the use of a UV–vis spectrometer. However, with their increased use, many studies fail to validate their EIA kits or fail to report on the kits sensitivity, accuracy and precision. As such, the aim of this paper is to propose a standardized protocol for reporting EIA kit validation. The proposed protocol was then applied to three fish species in order to demonstrate parallelism, accuracy and precision. Specifically, we tested plasma concentrations of 17β-estradiol for the red and black anemonefish Amphiprion melanopus, and 17β-estradiol, testosterone and 11-keto-testosterone for the barramundi Lates calcarifer and the common coral trout Plectropomus leopardus. Steroid hormones were extracted from fish plasma using a liquid-liquid solvent extraction method with ethyl acetate and n-hexane (50:50 v:v). Following extraction, the plasma dilution curves showed good linearity and parallelism, steroid recoveries were found to be within 90–120% accuracy, and precision variance was <10% in the majority of assays, for the species and steroids measured. Utilization of the proposed standardized validation protocol of EIA kits will assist scientific, fisheries and aquaculture researchers in obtaining reliable steroid hormone measurements, particularly in the field and in smaller research laboratories.

Molecular changes in skin pigmented lesions of the coral trout Plectropomus leopardus

A high prevalence of skin pigmented lesions of 15% was recently reported in coral trout Plectropomus leopardus, a commercially important marine fish, inhabiting the Great Barrier Reef. Herein, fish were sampled at two offshore sites, characterised by high and low lesion prevalence. A transcriptomic approach using the suppressive subtractive hybridisation (SSH) method was used to analyse the differentially expressed genes between lesion and normal skin samples. Transcriptional changes of 14 genes were observed in lesion samples relative to normal skin samples. These targeted genes encoded for specific proteins which are involved in general cell function but also in different stages disrupted during the tumourigenesis process of other organisms, such as cell cycling, cell proliferation, skeletal organisation and cell migration. The results highlight transcripts that are associated with the lesion occurrence, contributing to a better understanding of the molecular aetiology of this coral trout skin disease.

Large predatory coral trout species unlikely to meet increasing energetic demands in a warming ocean.

Increased ocean temperature due to climate change is raising metabolic demands and energy requirements of marine ectotherms. If productivity of marine systems and fisheries are to persist, individual species must compensate for this demand through increasing energy acquisition or decreasing energy expenditure. Here we reveal that the most important coral reef fishery species in the Indo-west Pacific, the large predatory coral trout Plectropomus leopardus (Serranidae), can behaviourally adjust food intake to maintain body-condition under elevated temperatures, and acclimate over time to consume larger meals. However, these increased energetic demands are unlikely to be met by adequate production at lower trophic levels, as smaller prey species are often the first to decline in response to climate-induced loss of live coral and structural complexity. Consequently, ubiquitous increases in energy consumption due to climate change will increase top-down competition for a dwindling biomass of prey, potentially distorting entire food webs and associated fisheries.

Maternal size, not age, influences egg quality of a wild, protogynous coral reef fish Plectropomus leopardus

Maternal effects are widely known to influence early life-history traits of offspring, including egg and larval quality. We studied the relationships between maternal length, weight, age and hepatosomatic index, with indicators of egg quality (egg size, oil droplet size, total lipid content and lipid classes) of a wild, protogynous reef fish, the common coral trout Plectropomus leopardus. Of the egg wet weight, 3% was lipids, with the neutral lipids, triacylglycerol (34% of total lipids) and wax esters (40%), being the main source of lipid energy within the egg. Polar lipids comprised 24% of total lipid content. Egg size and oil droplet size increased positively with maternal weight, and egg size increased positively with maternal length (p < 0.05). None of the variation in total lipid or triacylglycerol content was explained by the maternal traits we examined, but the proportion of long-term storage lipid wax esters increased with maternal length and weight (p < 0.05). Maternal age had no effect on any indicators of egg quality. Hepatosomatic index influenced sterols, although only with fish weight (p < 0.01). Our study highlights the variability in egg characteristics of a protogynous fish in the wild, and provides a greater understanding of variation in maternal traits as indicators of egg quality for teleost fishes. Our results suggest that offspring from larger females may have an advantage during the critical transition to successful exogenous feeding through enhanced provisioning, and that size-truncation through fishing may have negative consequences for recruitment and replenishment of P. leopardus populations.

Sensory cues of a top‐predator indirectly control a reef fish mesopredator

Behavioural trophic cascades highlight the importance of indirect/risk effects in the maintenance of healthy trophic‐level links in complex ecosystems. However, there is limited understanding on how the loss of indirect top–down control can cascade through the food‐web to modify lower level predator–prey interactions. Using a reef fish food‐web, our study examines behavioural interactions among predators to assess how fear elicited by top‐predator cues (visual and chemical stimuli) can alter mesopredator behaviour and modify their interaction with resource prey. Under experimental conditions, the presence of any cue (visual, chemical, or both) from the top‐predator (coral trout Plectropomus leopardus) strongly restricted the distance swum, area explored and foraging activity of the mesopredator (dottyback Pseudochromis fuscus), while indirectly triggering a behavioural release of the resource prey (recruits of the damselfish Pomacentrus chrysurus). Interestingly, the presence of a large non‐predator species (thicklip wrasse Hemigymnus melapterus) also mediated the impact of the mesopredator on prey, as it provoked mesopredators to engage in an ‘inspection’ behaviour, while significantly reducing their feeding activity. Our study describes for the first time a three‐level behavioural cascade of coral reef fish and stresses the importance of indirect interactions in marine food‐webs.

Ion Torrent next-generation sequencing reveals the complete mitochondrial genome of black and reddish morphs of the Coral Trout Plectropomus leopardus

Using Ion Torrent next-generation sequencing (NGS) technology, we sequenced the complete mitochondrial genome (mitogenome) of black and reddish morphs of the coral trout Plectropomus leopardus. High-throughput sequencing generated a total of 958,614 sequence reads covering 164.80 Mb of two mitogenomes with a coverage of 4800X. Thirty-seven mitochondrial genes and gene order of P. leopardus was quite similar to that of other teleostean fishes. Most genes were either abutted or overlapped, and all the protein-coding genes began with an ATG start codon except for COX1 and ATP6. The number of stop codon was different for the black and reddish P. leopardus. Comparisons between the mitochondrial sequences of the two morphs revealed a total of 74 variable sites and one indel. Nucleotide diversity across protein-coding gene varied from 0.0006 (16s rRNA) to 0.0070 (Cytochrome b). As expected, the highest level of nucleotide diversity (0.0291) was detected in the control region. Our results demonstrate the NGS technology based on Ion torrent platform can be used to assemble the mitogenome of fish species.

Spatial variation in the effects of size and age on reproductive dynamics of common coral trout Plectropomus leopardus

The effects of size and age on reproductive dynamics of common coral trout Plectropomus leopardus populations were compared between coral reefs open or closed (no-take marine reserves) to fishing and among four geographic regions of the Great Barrier Reef (GBR), Australia. The specific reproductive metrics investigated were the sex ratio, the proportion of vitellogenic females and the spawning fraction of local populations. Sex ratios became increasingly male biased with length and age, as expected for a protogyne, but were more male biased in southern regions of the GBR (Mackay and Storm Cay) than in northern regions (Lizard Island and Townsville) across all lengths and ages. The proportion of vitellogenic females also increased with length and age. Female P. leopardus were capable of daily spawning during the spawning season, but on average spawned every 4·3 days. Mature females spawned most frequently on Townsville reserve reefs (every 2·3 days) and Lizard Island fished reefs (every 3·2 days). Females on Mackay reefs open to fishing showed no evidence of spawning over 4 years of sampling, while females on reserve reefs spawned only once every 2-3 months. No effect of length on spawning frequency was detected. Spawning frequency increased with age on Lizard Island fished reefs, declined with age on Storm Cay fished reefs, and declined with age on reserve reefs in all regions. It is hypothesized that the variation in P. leopardus sex ratios and spawning frequency among GBR regions is primarily driven by water temperature, while no-take management zones influence spawning frequency depending on the region in which the reserve is located. Male bias and lack of spawning activity on southern GBR, where densities of adult P. leopardus are highest, suggest that recruits may be supplied from central or northern GBR. Significant regional variation in reproductive traits suggests that a regional approach to management of P. leopardus is appropriate and highlights the need for considering spatial variation in reproduction where reserves are used as fishery or conservation management tools.

Movement, habitat utilization and behaviour of coral trout Plectropomus leopardus during and after the reproductive period on the southern Great Barrier Reef

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 496:33-45 (2014) - DOI: https://doi.org/10.3354/meps10645 Theme Section: Tracking fitness in marine vertebrates Movement, habitat utilization and behaviour of coral trout Plectropomus leopardus during and after the reproductive period on the southern Great Barrier Reef C. M. Bunt1,*, M. J. Kingsford2 1Biotactic Fish and Wildlife Research (Biotactic, Inc) 691 Hidden Valley Road, Kitchener, Ontario N2C 2S4, Canada 2School of Marine and Tropical Biology and ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville QLD 4811, Australia *Corresponding author: cbunt@biotactic.com ABSTRACT: Coral trout Plectropomus leopardus (mean total length = 498.9 ± 19.7 mm, n = 10) were tagged and tracked with ultrasonic transmitters over 81 d at an intra-lagoonal location at One Tree Island, Great Barrier Reef, Australia (23.4979°S, 152.0712°E). Movement and habitat preferences were compared during the transition between the reproductive and post-reproductive period. Overall, mean movement was highest between 05:00 and 10:00 h, with the most movement during the crepuscular period and the least movement at night. There was no difference in nighttime movement during or after the reproductive period. Mean daily movement (14.48 ± 0.26 km d-1) and fish depths (4.23 ± 0.02 m) during the post-reproductive period were significantly greater than both movement (10.63 ± 0.13 km d-1) and depths occupied (3.38 ± 0.01 m) during the reproductive period, which was likely related to reallocation of bioenergetic resources to foraging related activities rather than spawning. Most fish movement was localized (within 0.04 km2), with some movements recorded outside of this area to a maximum distance of 0.6 km. Fish traversed sand and small scattered coral out-croppings to reach areas of continuous reef. The ranges of movement and habitat preferences described in this study are important for future research on habitat requirements and behavioural changes across the transition period between reproductive and post-reproductive states. Furthermore, this study provides additional information that may be used for focusing and delineating species-specific Marine Protected Area management plans. KEY WORDS: Plectropomus leopardus · Serranidae · Movement · Habitat preference · Habitat requirements · Ultrasonic telemetry · Marine Protected Area Full text in pdf format PreviousNextCite this article as: Bunt CM, Kingsford MJ (2014) Movement, habitat utilization and behaviour of coral trout Plectropomus leopardus during and after the reproductive period on the southern Great Barrier Reef. Mar Ecol Prog Ser 496:33-45. https://doi.org/10.3354/meps10645 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 496. Online publication date: January 27, 2014 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2014 Inter-Research.

Evaluating the effectiveness of teeth and dorsal fin spines for non‐lethal age estimation of a tropical reef fish, coral trout Plectropomus leopardus

This study investigated whether teeth and dorsal fin spines could be used as non-lethal methods of age estimation for a vulnerable and highly valued tropical fisheries species, coral trout Plectropomus leopardus. Age estimation of individuals from 2 to 9 years old revealed that dorsal spines represent an accurate ageing method (90% agreement with otoliths) that was more precise [average per cent error (APE) = 4·1, coefficient of variation (c.v.) = 5·8%] than otoliths (APE = 6·2, c.v. = 8·7%). Of the three methods for age estimation (otoliths, dorsal spines and teeth), spines were the most time and cost efficient. An aquarium-based study also found that removing a dorsal spine or tooth did not affect survivorship or growth of P. leopardus. No annuli were visible in teeth despite taking transverse and longitudinal sections throughout the tooth and trialling several different laboratory methods. Although teeth may not be suitable for estimating age of P. leopardus, dorsal spines appear to be an acceptably accurate, precise and efficient method for non-lethal ageing of individuals from 2 to 9 years old in this tropical species.

Increasing ocean temperatures reduce activity patterns of a large commercially important coral reef fish

Large-bodied fish are critical for sustaining coral reef fisheries, but little is known about the vulnerability of these fish to global warming. This study examined the effects of elevated temperatures on the movement and activity patterns of the common coral trout Plectropomus leopardus (Serranidae), which is an important fishery species in tropical Australia and throughout the Indo West-Pacific. Adult fish were collected from two locations on Australia's Great Barrier Reef (23°S and 14°S) and maintained at one of four temperatures (24, 27, 30, 33 °C). Following >4 weeks acclimation, the spontaneous swimming speeds and activity patterns of individuals were recorded over a period of 12 days. At 24-27 °C, spontaneous swimming speeds of common coral trout were 0.43-0.45 body lengths per second (bls(-1)), but dropped sharply to 0.29 bls(-1) at 30 °C and 0.25 bls(-1) at 33 °C. Concurrently, individuals spent 9.3-10.6% of their time resting motionless on the bottom at 24-27 °C, but this behaviour increased to 14.0% at 30 °C and 20.0% of the time at 33 °C (mean ± SE). The impact of temperature was greatest for smaller individuals (<45 cm TL), showing significant changes to swimming speeds across every temperature tested, while medium (45-55 cm TL) and large individuals (>55 cm TL) were first affected by 30 °C and 33 °C, respectively. Importantly, there was some indication that populations can adapt to elevated temperature if presented with adequate time, as the high-latitude population decreased significantly in swimming speeds at both 30 °C and 33 °C, while the low-latitude population only showed significant reductions at 33 °C. Given that movement and activity patterns of large mobile species are directly related to prey encounter rates, ability to capture prey and avoid predators, any reductions in activity patterns are likely to reduce overall foraging and energy intake, limit the energy available for growth and reproduction, and affect the fitness and survival of individuals and populations.

Referential gestures in fish collaborative hunting

In humans, referential gestures intentionally draw the attention of a partner to an object of mutual interest, and are considered a key element in language development. Outside humans, referential gestures have only been attributed to great apes and, most recently, ravens. This was interpreted as further evidence for the comparable cognitive abilities of primates and corvids. Here we describe a signal that coral reef fishes, the grouper Plectropomus pessuliferus marisrubri and coral trout Plectropomus leopardus, use to indicate hidden prey to cooperative hunting partners, including giant moray eels Gymnothorax javanicus, Napoleon wrasses Chelinus undulatus and octopuses Octopus cyanea. We provide evidence that the signal possesses the five attributes proposed to infer a referential gesture: it is directed towards an object, mechanically ineffective, directed towards a potential recipient, receives a voluntary response and demonstrates hallmarks of intentionality. Thus, referential gesture use is not restricted to large-brained vertebrates.

Informing the vulnerability of species to spawning aggregation fishing using commercial catch data

Fish spawning aggregations (FSAs) present a unique challenge for fishers and managers as aggregation fishing can be economically rewarding yet lead to overfishing and population collapse. Assessing the vulnerability of FSAs to fishing is often problematic due to a paucity of data. We present a tiered analysis for interrogating fishery logbook data for signals that fishing targets FSAs. We use two line fisheries that operate on Australia's Great Barrier Reef as models. The Reef Line Fishery (RLF) and Pelagic Line Fishery (PLF) operate across 9° of latitude, fishing occurs year round and the RLF has a seasonal spawning closure. A recent review reduced temporal closure days from 27 days to 10 days per year, though in the absence of any quantitative assessment of the vulnerability of targeted fish to increased harvest and hence risk. These fisheries target three reef fish groups (common coral trout Plectropomus leopardus, redthroat emperor Lethrinus miniatus, and a “other species” group mostly comprised of lethrinids and lutjanids) and a pelagic Scomberomorus commerson (narrow-barred Spanish mackerel). The tiered analyses captured the complete annual cycle of fish and fisher interaction across all latitudes and explored a number of catch metrics (landed catch, catch-per-unit-effort, and timing and size of large catch anomalies). No clear evidence of increased vulnerability of any of the three coral reef fish groups to fishing during spawning was found. Conversely the pelagic S. commerson is clearly more vulnerable to fishing during spawning. The tiered analytical approach is recommended as increased vulnerability of FSAs to fishing may not be identified by single analyses and without relative comparisons among species, the most vulnerable may be overlooked.

Evidence of Melanoma in Wild Marine Fish Populations

The increase in reports of novel diseases in a wide range of ecosystems, both terrestrial and marine, has been linked to many factors including exposure to novel pathogens and changes in the global climate. Prevalence of skin cancer in particular has been found to be increasing in humans, but has not been reported in wild fish before. Here we report extensive melanosis and melanoma (skin cancer) in wild populations of an iconic, commercially-important marine fish, the coral trout Plectropomus leopardus. The syndrome reported here has strong similarities to previous studies associated with UV induced melanomas in the well-established laboratory fish model Xiphophorus. Relatively high prevalence rates of this syndrome (15%) were recorded at two offshore sites in the Great Barrier Reef Marine Park (GBRMP). In the absence of microbial pathogens and given the strong similarities to the UV-induced melanomas, we conclude that the likely cause was environmental exposure to UV radiation. Further studies are needed to establish the large scale distribution of the syndrome and confirm that the lesions reported here are the same as the melanoma in Xiphophorus, by assessing mutation of the EGFR gene, Xmrk. Furthermore, research on the potential links of this syndrome to increases in UV radiation from stratospheric ozone depletion needs to be completed.

Effects of different photoperiods on first-feeding success, early survival and digestive enzyme activities in coral trout Plectropomus leopardus larvae

Effects of different photoperiods on first-feeding success, early survival and digestive enzyme activities in coral trout Plectropomus leopardus larvae