Search Results (59)

The brown-marbled grouper (Epinephelus fuscoguttatus), a high-value species in international trade, has experienced population declines due to intensive fishing. It is one of 12 grouper and snapper species prioritized for management in Saleh Bay, West Nusa Tenggara, Indonesia. This study analyzed catch data (2017–2022) and biological samples (2020–2021) to update key life history parameters, including natural mortality, von Bertalanffy growth parameters, asymptotic length, and size at maturity. Growth was estimated using an ELEFAN-optimized model applied to catch length–frequency data, while maturity was determined through macroscopic examination of gonads. The updated estimates (L₅₀ = 488 mm for both sex; L₉₅ = 568 mm for females and 616 mm for males) were incorporated into a length-based spawning potential ratio (SPR) assessment. Annual SPR values ranged from 0.13 to 0.28, substantially higher than previous estimates of 0.05–0.07, mainly due to the lower L₅₀ used in this study. Despite this improvement, SPR values remain below the management target of 0.30 for groupers and snappers in Saleh Bay. Limited biological samples, particularly the scarcity of larger individuals and males, introduce uncertainty in the estimates. These findings emphasize the value of locally derived life history information and highlight the need for continued biological sampling to refine growth and reproductive parameters and support sustainable fisheries management. Full article

Recirculating aquaculture systems (RAS) address pollution, disease, and sustainability in commercial fish farming, but marine RAS are limited by biofilter maturation and nitrification. This study investigated the effects of air nanobubbles on water quality, fish growth, and bacterial communities in marine RAS stocked with juvenile Malabar red snapper, barramundi and saline-tolerant hybrid tilapia. Flow cytometry was evaluated as a rapid management tool for non-culturable microbes, finding viable bacterial counts 30–100 times higher than conventional total plate counts. There were no significant differences in fish growth, survival, or Feed Conversion Ratio between groups, likely due to low stocking densities (<20 kg/m³) and high water exchange rates (>100%/hour), indicating low system stress. Air nanobubbles did not significantly increase dissolved oxygen levels. While bacterial abundance in water was consistently higher in nanobubble-treated RAS (RAS-N), tank walls showed less biofilm. RAS-N also exhibited a higher abundance of nitrifying bacteria like Nitrospira and Marinobacter, leading to improved nitrogenous waste breakdown and lower nitrite levels. Future research should investigate nanobubbles’ benefits at higher stocking densities and longer durations to fully assess their impact on intensive aquaculture. Full article

The physiological and gill health responses of juvenile spotted rose snapper (Lutjanus guttatus) were evaluated at four salinities—8, 16, 24, and 32‰—over a 70-day period. Fish reared at 8‰ exhibited the highest final body weight (126.8 ± 2.6 g), which was significantly higher than their congeners kept at 24‰ (116.0 ± 2.3 g) and 32‰ (116.0 ± 2.3 g). This superior growth at 8‰ coincides with the complete absence of parasitic monogenean infestations. In contrast, parasite prevalence increased with salinity, reaching 87.5% at 24‰, and was associated with gill pathologies like hyperplasia. Plasma osmolality and chloride levels decreased at lower salinities, while sodium and potassium levels showed a compensatory increase. Plasma cortisol and glucose levels remained stable across all treatments, indicating an absence of chronic stress. These findings suggest that the optimal rearing salinity for juvenile L. guttatus is near 8‰. The enhanced growth at this salinity appears to be the result of a net energy gain, stemming from a trade-off between the minor cost of osmoregulation in a hypo-osmotic environment and the major energetic benefit of avoiding parasitic disease. Full article

Global production of fisheries and aquaculture products continues to increase, with the fisheries sector increasingly considered essential for global food security and nutrition. As public demand for seafood increases, implementation of safety management to minimize risks and ensure the safety of seafood products becomes important. This study was conducted to monitor 198 chemicals, comprising 161 pesticides and 37 pesticide metabolites, and to assess their risks in saltwater and freshwater fish in the Republic of Korea, based on the analysis of 471 fishery samples (298 saltwater and 173 freshwater). Among the fifteen saltwater fish species analyzed, pesticides were detected in eight species (croaker, flatfish, sea bass, flounder, snapper, yellow tail, salmon, and gizzard shad) and in all seven freshwater species (carp, catfish, crucian carp, eel, leather carp, loach, and trout). Four pesticides (ethoxyquin, lufenuron, metaflumizone, and propiconazole) were detected in saltwater fish, while nine pesticides (ethoxyquin, ipfencarbazone, isoprothiolane, lufenuron, metaflumizone, oxadiargyl, pendimethalin, phoxim, and trichlorfon) were found in freshwater fish. Ethoxyquin was the most frequently detected pesticide in both fish types, mostly in the form of its metabolite, the ethoxyquin dimer. The estimated daily intake (EDI) was calculated based on the maximum concentrations of pesticides detected and the average consumption of fishery products by sex and age group. The hazard quotients, expressed as a percentage of acceptable daily intake (%ADI) and calculated using the EDI and ADI of the pesticides detected, were evaluated to be no more than 5.6%. These results suggest that consumption of saltwater and freshwater fish in the Republic of Korea poses a low risk to human health. This approach can be applied to pesticide residue monitoring and risk assessment in the fisheries sector, providing valuable data for evaluating contamination levels and supporting the regulation and management of chemical residues. Full article

Gray snapper (Lutjanus griseus; Family: Lutjanidae) local habitat preferences have been assessed, but the biotic and abiotic factors influencing age and growth rates in Mosquito Lagoon, Florida, have not been quantified. To address this knowledge gap, the goal of this study was to estimate mean age and growth rate of gray snapper, and use generalized linear mixed models to investigate if prey and/or other environmental factors (e.g., abiotic/biotic conditions, time, location, or habitat restoration status) impact size at both the lagoon- and habitat-specific scales. Age data were extracted via otolith microstructural analyses, and incorporated with size into a lagoon-scale linear growth model. Based on microstructural analyses, mean age of gray snapper at the lagoon scale was 175 ± 66 days (range = 56–350 days). The results indicate the most common life stage of gray snapper in Mosquito Lagoon is juveniles, with living shoreline habitats having a greater proportion of relatively young juveniles (111 ± 36 days) and oyster reef habitats having a greater proportion of relatively older juveniles (198 ± 58 days). The estimated growth rate was 0.43 mm/day. Body mass and body length were correlated positively with habitat quality and lagged salinity levels. Hence future studies should strive to characterize benthic habitat characteristics, and investigate biotic and abiotic factors that potentially influence gray snapper growth. Collectively, this study increases our understanding of environmental drivers affecting juvenile gray snapper development and shows that the restoration of benthic habitats can produce conditions conducive to gray snapper growth. The age-, size-, and habitat-specific growth rates of juveniles from this study can be incorporated into stock assessments, and thereby be used to refine and develop more effective ecosystem-based management strategies for gray snapper fisheries. Full article

The Lutjanidae family includes multiple species highly important to the global fishing industry. In Brazil, approximately 40% of the fishing landings come from a species of this family, the dog snapper, Lutjanus jocu, among the most abundant in the northeast-region fisheries. This study aimed to analyze the genetic diversity and population structure of this species in the states of Bahia and Espírito Santo through the use of microsatellite markers. The dog snapper presented a high genetic variability in the studied populations, with the presence of a distinct population stock in northern Bahia probably driven by habitat suitability, larvae retention, and fishing pressure. The L. jocu sampling sites exhibited an excess of heterozygosity, a low allelic richness, and M-ratio values close to critical levels, probably indicating a recent population decline. Additionally, the low inbreeding indices and high genetic diversity values suggest a significant connectivity and considerably effective population sizes. Although these characteristics may reflect population stability, anthropogenic factors such as habitat loss, fragmentation, and overfishing may pose threats to the sustainability of the species, particularly along the northeastern coast of Brazil. Full article

Background: Snapper is a significant commercial, recreational, and cultural teleost species in New Zealand, with aquaculture potential. The impact of long-term (chronic) temperature changes on immune and stress responses have not been studied in snapper, yet they have a critical importance to the health status of the fish. Methods: We investigated a set of genes in 30 individual snapper including fin, head kidney, and liver tissue, fish (10 per group) were exposed to either warm (22 °C), cold (14 °C), or ambient temperatures (10.5–18.6 °C) for 3 months. Results: Analyses of experimental fish using NanoString technologies to assess stress- and immune-related genes in the three tissue types showed that 22 out of 25 genes changed significantly in the experiment, indicating the significant impacts of chronic temperature changes on stress and immune responses. Furthermore, using a combined dataset based on this study and a previous one testing the impact of acute temperature changes in snapper, we identified five genes in the non-lethal fin-clip samples that can predict internal organ health status. Conclusions: Taken together, our experiments demonstrate the potential of the NanoString gene expression assessment tool for the rapid monitoring of stress responses in snapper, which can aid in the selection of stress-resilient wild stocks, monitor species in aquaculture environments, and inform the selection of locations for aquaculture. Full article

Coral reef and their ecological services of food production and shoreline protection are threatened by unsustainable use. To better understand their status, multiple approaches to estimating fisheries sustainability were compared, namely fisheries-independent stock biomass and recovery rates, fisheries-dependent landed catches, balanced harvest and gear use metrics, and fish length measurements. A community biomass recovery was established over a 45-year no-fishing stock recovery time series from seven fisheries reserves and compared to catch- and length-based estimates of sustainability. The logistic production rates (r = 0.09 ± 0.06 95% confidence interval (CI)) and maximum equilibrium total biomass (~150 ± 30 tons/km²) indicated a broad range of potential maximum sustainable yields, with a likely range of 1.1 to 3.9 (95% CI; mean = 3.8) tons/km²/year. In contrast, the mean annual linear biomass growth rates in reserves were lower but less variable than logistic surplus production estimates, ranging from 2.1 to 3.5 (mean = 2.8 tons/km²/year). Realized catches at landing sites were lower still, ranging from 1.43 to 1.52 (mean = 1.48 ± 0.2 tons/km²/y). Differences between production estimates and capture were largely attributable to changes in taxonomic composition and an imbalance in the estimated proportionality of production potential versus actual capture rates. Lost potential capture was likely due to differences in the vulnerability of taxa to fishing and a lack of compensatory increased production among fishing-resistant taxa. Large proportional losses of catch were measured among snappers, unicorn fish, sweetlips, goatfish, and soldierfish, while smaller proportional gains in the catch samples were found among resident herbivorous rabbitfish, parrotfish, and groupers. Many of these declining taxa have vulnerable schooling life histories that are likely to require special habitat and reserve characteristics. Evaluations of sustainability from length measurements found 17 or 7% of total and 12% of caught species had sample sizes minimally sufficient for evaluation (>30 individuals from 413 catches, 2284 captured individuals composed of 144 species) of length and spawning metrics of sustainability. Seven of these species met length-based and three met spawning potential ratio thresholds for sustainability. Consequently, length-based evaluations had poor species coverage and therefore we were unable to evaluate the sustainability of the larger fish community. Recommendations for future research include a better understanding of the consequences of variability in spillover and proportionality of production potential for sustainability. Management recommendations are to focus management on the recovery of species abundant in unfished locations but not contributing to fisheries yield. Full article

Gray snapper (Lutjanus griseus) move from inshore to offshore habitats as they mature and spawn along the West Florida Shelf. The connectivity between offshore spawning sites and inshore settlement regions along the Eastern Gulf of America (formerly Gulf of Mexico, hereafter Gulf) coast is unknown, and this study therefore predicted these larval dispersal pathways. To determine larval transport, an ocean model was integrated with the Connectivity Modeling System (CMS), which is a biophysical model that allowed for the inclusion of larval behavior and updated spawning information for the gray snapper. Our larval dispersal model showed that spawning sites offshore of Tampa, in the Florida Keys, and in the Florida Middle Grounds had the highest percentages of successfully settled larvae inshore. Larvae that were spawned at the offshore Tampa Bay and offshore Southwest Florida spawning sites were mostly transported to the Tampa Bay and Southwest Florida settlement regions, showing local retention. In contrast, larvae spawned offshore in the Florida Middle Grounds were transported northwest, exclusively to the Florida Panhandle. In addition, there was no difference in the proportion of successful larval settlers between full and new moon spawning events. Since gray snapper are an important recreational fishery in the eastern Gulf, especially off the west coast of Florida, it is important to identify spawning sites that have the largest proportions of settling larvae, such as offshore Tampa Bay. Full article

Ice-stored farmed barramundi (Lates calcarifer), snubnose pompano (Trachinotus blochii) and sobaity bream (Sparidentex hasta), as well as wild-caught cobia (Rachycentron canadum), coral trout (Plectropomus leopardus), giant trevally (Caranx ignobilis), milkfish (Chanos chanos) and mangrove red snapper (Lutjanus argentimaculatus), were compared for their freshness/spoilage using sensory, chemical and microbiological methods. Quality Index Method schemes were developed to determine alterations in the sensory freshness. The shelf lives ranged from 8 (coral trout) to 18 days (sobaity bream). The farmed species always exhibited a significantly longer shelf life than the wild-caught species. The adenosine triphosphate (ATP) breakdown followed different patterns in the studied species. The K-values at the time of sensory rejection ranged from 30 to 80% depending on the species, while the microbial load reached or exceeded a level of 6 log cfu/g. Although the shelf life duration was dependent on the origin of the fish (wild or farmed), the ATP breakdown scheme, as well as the K-values and microbial loads at the time of rejection, were species-dependent and independent of the origin. Full article

Three people in England consumed fish steaks labeled as Red Snapper (Lutjanus bohar) originating from the Indian Ocean. Within 12 h, all three experienced sickness including nausea, vomiting, diarrhea, as well as myalgia and paresthesia. Three steaks from a single package of fish obtained from a grocery store were consumed, leaving one uneaten, which was submitted for analysis. Cytotoxicity testing via the mouse neuroblastoma assay confirmed the presence of sodium channel specific activity consistent with a ciguatoxin standard, and the levels detected were above established guidance limits for safe consumption. Chemical detection using liquid chromatography coupled with high-resolution mass spectrometry of both intact toxins and periodate oxidation products was used to confirm the presence of chromatographic peaks consistent with tri- and di-hydroxylated Pacific ciguatoxin 3C congeners. Taking the shared medical symptoms of patients, the recent dietary history, and the known potential for ciguatera poisoning to occur in snapper species, the subsequent evidence for CTX-like activity and CTXs in the same fish sample provides very strong evidence that the fish steaks consumed were similarly contaminated with CTXs. Furthermore, given the levels reported, such toxicity would be expected to cause intoxication in humans. Fish species identification based on DNA barcoding confirmed that the fish products were mislabeled, with the tissues instead being the Pinjalo snapper, Pinjalo pinjalo. This is the first confirmed ciguatera poisoning incident in both the UK and from the Pinjalo snapper and highlights the need for monitoring of these emerging toxins in reef fish imports to prevent future human intoxication. Full article

Relatively little is known about size- and age-based reproductive characteristics of Gray Snapper (Lutjanus griseus) despite a large recreational fishery along the west coast of Florida in the Southeastern U.S.A. The purpose of this study was therefore to determine the spawning parameters of Gray Snapper and to quantify female reproductive potential on an age- and size-basis. From 2022 to 2023, 4563 Gray Snapper were collected off the west coast of Florida. Gray Snapper were observed to be actively spawning from late May to early September; however, the percent of females spawning in May and September were both <3%. Batch fecundity for 12 hydrated females showed a hyperallometric relationship with size and age. The spawning fraction also increased disproportionately with female length and age, suggesting older, larger females spawn in greater proportions and more often than younger, smaller females. For females, the length and age at 50% physiological maturity was 292 mm total length (TL) and 2.9 years, and those at 50% functional maturity was 301 mm TL and 3.2 years. Male Gray Snapper reached 50% sexual maturity at 259 mm TL and 1.8 years. The minimum size limit of 10 inches (254 mm) TL in Florida state waters appears to be too low to protect maturing females in particular. These new spawning metrics should be incorporated into future stock assessments to improve estimates of Gray Snapper reproductive output, stock status, and management. Full article

Background: Larvae development is a critical step in aquaculture, yet the development of immune and stress responses during this early phase of life is not well understood. Snapper is a species that has been selected as a candidate for aquaculture in New Zealand. Methods: In this study we explore a set of 18 genes identified as potentially being involved in the stress and immune responses of snapper larvae during the first 30 days of development. Larvae were collected between 11:45 a.m. and 16:10 p.m. each day. Results: Most genes did not deviate from baseline expression throughout the 30 days, with some exceptions between Days 0 and 6 with glyceraldehyde-3-phosphate dehydrogenase and superoxide dismutase, mitochondrial uncoupling protein 2-like, peroxiredoxin-5 mitochondrial, and hepcidin, which predominantly increased and then stabilized by Day 6 until Day 30. Some genes were affected by the time of day, such as actin cytoplasmic 1 and catalase isoform X2. Conclusions: This exploratory study is the first to look at a panel of stress- and immune-related marker gene expression during early snapper development. It sets methods in place to explore the expression of these markers and determine the impact of different potential stressors, such as alternative food sources and other environmental changes. It also highlights the importance of same time of day collections for gene expression studies. Full article

Singapore’s aquaculture sector is critical to achieving the nation’s ‘30 by 30’ food security goal, which aims to produce 30% of its nutritional needs locally by 2030. However, the sector faces several significant challenges. Limited land and water resources, high operational costs, disease outbreaks, reliance on imported seedstock, and environmental impact are among the key issues. Additionally, the industry struggles with a shortage of skilled manpower and high dependency on foreign labour. This study explores these challenges in detail and suggests potential solutions to enhance the sustainability and productivity of Singapore’s aquaculture. Innovative farming techniques such as recirculating aquaculture systems (RASs) and vertical farming, advanced water quality management, and the adoption of renewable energy sources are recommended to address space and cost constraints. Developing local breeding facilities, enhancing education and training programs, and adopting sustainable practices are also crucial. The establishment of a national hatchery and increased investment in research and development (R&D) are essential for long-term growth. By implementing these strategies, Singapore can overcome the challenges in its aquaculture sector and ensure a sustainable future for local food production. Full article

Yellowtail snapper Ocyurus chrysurus has great potential as a production fish in aquaculture, yet there is very limited information on its nutritional requirements. To establish baseline data, two trials were conducted to evaluate the effects of dietary protein and lipid levels in practical diets on growth and protein retention. The first trial, conducted over 14 weeks, used a series of diets with varying levels of protein (36%, 40%, and 44%) and lipids (6%, 10%, and 14%). The second trial, conducted for 10 weeks, used a series of diets with 36% protein and scaled lipid levels (7%, 10%, 13%, and 16%). Additionally, a commercial reference diet with 44% protein and 12% lipids was included. Growth performance and feed utilization parameters for Trial 1 indicated that the yellowtail snapper were able to effectively utilize practical diets containing 36% protein and 10% lipids, which produced the highest apparent net protein retention (ANPR; %) and survival. No significant differences were found in growth performance metrics, though there were numerical differences in final weight, weight gain, and survival. Similarly, in Trial 2, most growth metrics did not show significant differences. There were variations in weight gain, feed offered, and ANPR, with the highest performance observed in the fish given feed with 13% lipids. Based on the growth performance and ANPR values across these trials, we recommend 36% protein and dietary lipid levels of 7–13%, which are lower than the currently used commercial diets for marine finfish. The data gathered from the current study may be helpful for nutritionists in formulating feed to include more sustainable and cheaper feedstuffs and promote sustainable yellowtail snapper aquaculture production. Full article