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Quantifying the population dynamics of marine species is difficult when good, comprehensive data are not available. We sought to determine if the kingfish Scomberomorus commerson stock in the Persian Gulf was overfished. The ICES data‐limited assessment framework was used to provide precautionary advice, with a 20% decrease advised in situations where only catch or bycatch data were available. The length‐based Bayesian biomass (LBB) was used to model fork length from landing records of licensed fishers in the Khuzestan Province during 2002–2018, which had increased despite sought being overexploited. Most kingfish were immature and smaller than optimum length of the catch (Lc‐opt = 88 cm) and optimum length (Lopt = 104 cm). Relative biomass (B/Bmsy) ranged 0.62–0.66 and exceeded 0.5. The B/Bmsy ratio (1.25) was >1.1. The stock appeared to be healthy and exploitable, but wide confidence intervals of the B/Bmsy ratio complicated interpretation of stock status. The kingfish stock appeared to use waters of the study area as a spawning and nursery ground, so many young immature individuals were present. If current exploitation of young individuals continues, this the stock will eventually be overfished. Long‐term increases in the catch of young immature kingfish can have a side effect on stock maturation and recruitment. We recommend that the mesh size of fishing gear be selected based on optimum length, to enhance economic, and commercial viability of the kingfish fishery. [ABSTRACT FROM AUTHOR]

Carangidae is an economically important fish family comprised of 32 genera with more than 140 circumglobally distributed species. Its members exhibit vast differences in morphology and lifestyle, thus making them compelling subjects for evolutionary studies. Recently, more works on carangids have detected the presence of cryptic lineages through molecular and/or non-molecular techniques. Credited for its inherent amplification efficiency, mitophylogenomics became effective in opening avenues to further understand higher-level interrelationships in many fish groups. However, the mitophylogenomic approach has not yet been widely applied to infer evolutionary history at the lower-level interrelationships, especially on cryptic representatives. In this study, we evaluated the diagnostic applicability of mitogenomes in detecting population-level divergences within Carangidae. Using the mitogenomes, we detected intraspecific divergences on some taxa, namely Caranx melampygus, Selaroides leptolepis, Seriola lalandi, Decapterus maruadsi, and Trachurus trachurus, with divergences highly correspondent to that of their geographic origins. Additionally, a widespread Pacific arrangement was also detected for S. rivoliana. Our discoveries were highly corroborative with findings from other Carangidae studies which utilized different diagnostic markers (e.g., SNPs, microsatellites, morphometrics, parasites). Dated phylogeny also suggested that intraspecific diversifications occurred during the Late Neogene. Likewise, we characterized two mitogenomes from different cryptic lineages of Selaroides leptolepis and revealed that the two mitogenomes were K2P pairwise = 5.58% different from each other. Its genetic compositions included 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes, and a control region. These findings paved way for future evolutionary insights into the divergence histories of other fish populations. [ABSTRACT FROM AUTHOR]

The yellowtail snapper Ocyurus chrysurus Bloch, 1791 (Perciformes: Lutjanidae) is targeted by recreational or commercial fisheries across much of its range in the western Atlantic Ocean, from Massachusetts, USA, to São Paulo, Brazil. Genomic resources to support conservation of this species are needed. Here, we assembled, annotated and characterised in detail the mitochondrial genome of O. chrysurus. The mitochondrial genome of O. chrysurus is 16,502 bp in length and encodes 13 protein-coding genes (PCGs), 22 transfer RNA genes (tRNA), and two ribosomal RNA genes (rRNA). The putative control region, 827 bp in length, is located between the tRNA P and tRNA F genes. Most genes are encoded on the positive strand, while a single PCG (nad6) and six tRNA genes (in order from 5′ to 3′: tRNA N, tRNA P, tRNA E, tRNA Q, tRNA C and tRNA Y) are encoded on the negative strand. All tRNA have a typical 'cloverleaf' secondary structure except tRNA S1 (Serine1) that lacks the D arm. Calculated Ka/Ks values of all PCGs were <1, suggesting that these genes are under purifying selection. A maximum likelihood (ML) phylogenetic analysis confirmed monophyly of the family Lutjanidae and indicated that the genus Lutjanus is paraphyletic given that O. chrysurus clustered together with Lutjanus peru and L. guttatus in a strongly supported clade. Data published herein will inform conservation and management strategies for this fished snapper. [ABSTRACT FROM AUTHOR]

The catch of butterfly kingfish Gasterochisma melampus, a large pelagic species in southern temperate waters, is strongly biased (73%) towards females. Whether this is caused by differences in sex-specific spatiotemporal distributions or mortality of sexes is investigated herein. Analysis of sex ratios using a generalized additive model (GAM) for year, month, latitude, longitude, sea surface temperature, and fork length from Japanese longline catch data for areas where immature and adult fish occur revealed the influence of space and time on sex ratios to be small, and that of fork length to be large. Based on observation of the increments in vertebrae of immature fish (N = 179), the fork length at the time of increment formation was back-calculated from distances between increments on the anterior and posterior cones, generating 2–8 measurements per vertebra and 865 data points in total. Growth equations were calculated for each sex, with females growing faster. The age composition of males and females in the catch was similar, meaning that the mortality rate in males is unlikely to be higher than that of females. The data suggest that biased sex ratios in catches are representative of the natural sex ratio in a population for fish more than 60 cm in fork length. [ABSTRACT FROM AUTHOR]

Summary: The effects of hydrostatic thawing (HT), flowing water thawing (FT), ultrasonic thawing (UT), microwave thawing (MT), and microwave‐combined ultrasonic thawing (MUT) on the quality of yellowtail fillets were investigated via thawing time, physicochemical quality, water retention, microstructure and water migration distribution. The results showed that MUT had a shorter thawing time, second only to microwave thawing (MT) and significantly shorter than other thawing methods. Moreover, MUT could retain a better performance of the samples, such as colour, texture, water retention and moisture distribution, and prevent damage to the microstructure. In addition, freshness analysis showed that pH, total volatile saline nitrogen and K values were optimal for MUT. Therefore, MUT could be a viable thawing method that increases the thawing rate of yellowtail fillets while maintaining their quality characteristics. [ABSTRACT FROM AUTHOR]

Hyperoxia has been shown to expand the aerobic capacity of some fishes, although there have been very few studies examining the underlying mechanisms and how they vary across different exposure durations. Here, we investigated the cardiorespiratory function of yellowtail kingfish (Seriola lalandi) acutely (~20 h) and chronically (3–5 weeks) acclimated to hyperoxia (~200% air saturation). Our results show that the aerobic performance of kingfish is limited in normoxia and increases with environmental hyperoxia. The aerobic scope was elevated in both hyperoxia treatments driven by a ~33% increase in maximum O2 uptake (MO2max), although the mechanisms differed across treatments. Fish acutely transferred to hyperoxia primarily elevated tissue O2 extraction, while increased stroke volume-mediated maximum cardiac output was the main driving factor in chronically acclimated fish. Still, an improved O2 delivery to the heart in chronic hyperoxia was not the only explanatory factor as such. Here, maximum cardiac output only increased in chronic hyperoxia compared with normoxia when plastic ventricular growth occurred, as increased stroke volume was partly enabled by an ~8%–12% larger relative ventricular mass. Our findings suggest that hyperoxia may be used long term to boost cardiorespiratory function potentially rendering fish more resilient to metabolically challenging events and stages in their life cycle. [ABSTRACT FROM AUTHOR]

California yellowtail (CYT), Seriola dorsalis, is a promising candidate for aquaculture due to its rapid growth and high-quality flesh, particularly in markets like Japan, Australia, China, and the United States. Soy protein has shown success as a replacement for marine protein sources in CYT diets, reducing fishmeal levels, though concerns about potential intestinal inflammation persist with the inclusion of solvent-extracted soybean meal. To address this, processing strategies like fractionation, enzymatic treatment, heat treatment, and microbial fermentation have been employed to mitigate the negative impacts of soybean meal on fish nutrition and immune systems. This study focuses on optimizing soybean meal inclusion levels by incorporating advanced soy variants into CYT diets. The eight-week feeding trial, conducted in a recirculation system, featured six diets with sequential inclusion levels (0, 50, 100%) of high protein low oligosaccharide soybean meal (Bright Day, Benson Hill, St Louis, MO) and enzyme-treated soybean meal (HP 300, Hamlet Protein Inc., Findlay, OH), replacing solvent-extracted soybean. The study compares these formulations against a soy-free animal protein-based diet. At the end of the trial, fish were sampled for growth performance, body proximate composition, intestinal morphology, and immune response from gut samples. Results showed consistent FCR (P = 0.775), weight gain (P = 0.242), and high survival rate (99.4 ± 0.5%) among dietary treatments (P>0.05). Histological evaluations revealed no gut inflammation and gene expression analysis demonstrated no significant variations in immune, physiological, and digestive markers apn (P = 0.687), mga (P = 0.397), gpx1 (P = 0.279), atpase (P = 0.590), il1β (P = 0.659). The study concludes that incorporating advanced soybean meal products, replacing up to 20% of fishmeal does not negatively affect CYT's growth and intestinal health. This suggests that all three soy sources, contributing 35% of total protein (15.4 g 100 g-1 diet), can be included in practical diets without compromising CYT's intestinal integrity or growth. These findings have positive implications for the commercial production of CYT and future research on the incorporation of plant-based proteins in aquaculture diets. [ABSTRACT FROM AUTHOR]

Garlic (Allium sativum) can improve the fish's immune system and modulate the gut microbiota composition, vital in host nutrition and health. This work aimed to evaluate the effect of garlic addition in formulated food on the taxonomic composition of the California yellowtail (Seriola dorsalis) intestinal microbiota, a marine fish with aquaculture potential. California yellowtail juveniles were fed diets with different garlic powder concentrations (4%, 10%, and 25%) for 30 days. Extraction and quantification of genomic DNA from two intestine sections (foregut and hindgut) were performed. Subsequently, the V4 region of the 16S rRNA gene from the samples was amplified and sequenced using the Illumina MiSeq technology. The QIIME2 bioinformatics suite was used for the taxonomic assignment of the sequences and further statistics. Functions were predicted using PICRUSt2 and LefSe (MicrobiomeAnalyst Platform). As a result, the structure of the intestinal microbiota was modified in both intestine fractions, particularly at higher garlic concentrations. The Gammaproteobacteria class was the most abundant group in both intestine tissues, while Bacteroidia, Bacilli, Thermoleophilia, and Acidimicrobia decreased as garlic concentration increased. Changes in the predicted functions also accompanied changes in the taxonomic structure of the intestinal microbiota; briefly, the tricarboxylic acid cycle, gluconeogenesis, glycolysis, and pentose phosphate pathways tended to decrease with increasing garlic concentration; in addition, several other functions, including protein and lipids metabolism and synthesis of biomolecules, were decreased as the garlic concentration increased. Our results suggest that dietary garlic supplementation induced changes in the structure and functionality of the gut microbiota in a dose-response manner. [ABSTRACT FROM AUTHOR]

Docosahexaenoic acid (DHA) enrichment of live food is a common practice to improve growth and survival of larvae. The current research aimed to test the effect of rotifer enrichment with DHA on growth, survival, fatty acid profile, digestive enzymes, antioxidant parameters, and histology in yellowtail clownfish (Amphiprion clarkii) larvae. Four levels of enrichments emulsions with DHA were considered, including DHA6 (6% DHA), DHA12 (12% DHA), DHA24 (24% DHA), and DHA36 (36% DHA). No substantial differences in growth data were recorded, suggesting that even 6% DHA emulsion enrichment which resulted in 4.22% DHA in rotifers is enough to fulfil the DHA requirements of yellowtail clownfish larvae to maximise the growth rate. Excessive levels of DHA (36%) decreased the survival rate of larvae. This fatty acid accumulated in the larvae body at high levels (24.72%). The DHA12 group had the lowest growth, possibly due to lower digestive enzymes and antioxidant activities in this treatment. There was a positive correlation between final weight and lipase (59%), protease (73%), and lactate dehydrogenase (69%). Furthermore, amylase, lipase, protease, and alkaline phosphatase had significant positive correlations with catalase (72%, 84%, 74%, and 66%, respectively) and lactate dehydrogenase (64%, 85%, 79%, and 77%, respectively). Superoxidase dismutase and catalase also had positive correlations with arachidonic acid levels in the body. Increased DHA levels, based on histology data, caused lipid vacuoles in enterocytes and hepatocytes. In conclusion, yellowtail clownfish larvae can grow well with high survival even with feeding rotifers enriched with 4.22% DHA or less. [ABSTRACT FROM AUTHOR]

The ability to detect and respond to the presence of predation risk is under intense selection, especially for small‐bodied fishes. Damselfishes (Pomacentridae) use auditory vocalizations during inter‐ and intrasexual interactions, but it is not known if they can use vocalizations in the context of predator–prey interactions. Here, we test if yellowtail damselfish, Chrysiptera parasema, can learn to associate the territorial vocalization of heterospecific humbug damselfish Dascyllus aruanus with predation risk. In conditioning trials yellowtail damselfish were presented with the territorial call of humbug damselfish while either blank water (control treatment) or chemical alarm cue derived from damaged skin of conspecific yellowtail damselfish was introduced. In conditioning trials, fish exposed to alarm cue exhibited increased activity and spent more time in the water column relative to fish that received the control treatment. After a single conditioning trial, conditioned fish were exposed again to the territorial call of humbug damselfish. Fish conditioned with the call + alarm cue showed increased activity and spent more time in the water column relative to fish that had been conditioned with the control treatment. These data indicate associative learning of an auditory stimulus with predation risk in a species that regularly uses auditory signalling in other contexts. Recordings of conditioning and test trials failed to detect any acoustic calls produced by test fish in response to the perception of predation risk. Thus, although yellowtail damselfish can associate risk with auditory stimuli, we found no evidence that they produce an alarm call. [ABSTRACT FROM AUTHOR]

Agouti-related protein (Agrp) is an orexigenic peptide hormone found in fish and other vertebrates. Understanding appetite regulation is important for improving production performance in aquaculture systems. However, information on appetite-related hormones in yellowtail is still fragmentary. In this study, two distinct agrpgenes (i.e., agrp1 and agrp2) were cloned from the yellowtail brain. Brain distribution and response of the agrp genes to fasting, along with other candidate orexigenic peptide hormone-related genes including neuropeptide Y (npy) and melanin-concentrating hormones (mch1 and mch2), were studied. The highest expression level of those genes was observed in the hypothalamus, except for npy. After fasting, agrp1 and npy increased significantly in the hypothalamus, whereas agrp2 in the olfactory bulb and cerebellum decreased significantly. After feeding with a fishmeal (FM)-based diet and addition of a fishmeal soluble fraction (FMS), hypothalamic agrp1, agrp2, mch1, and mch2 increased, whereas hypothalamic npy decreased significantly. From the fasting experiment, agrp1 and npy may function as orexigenic hormones in yellowtail; however, the function of other hormones warrants further research. Expression of all the analyzed appetite-related hormonal genes might respond to the smell/taste of fishmeal through sensory organs. Furthermore, npy and agrp1 may enhance appetite through different mechanisms in yellowtail. [ABSTRACT FROM AUTHOR]

Despite widespread interest in John Ruskin and the theatre in recent years, little consideration has been given to his presence in the works of one major playwright, Henry Arthur Jones (1851–1929). Although Ruskin's influence on Jones has been examined in broad terms by commentators such as Kate Newey and Peter Yeandle, a detailed textual analysis of Jones's plays has not been forthcoming. In this essay, I discuss three plays by Jones – The Silver King (1882), Wealth (1889) and The Middleman (1889) – and demonstrate how they dramatise key elements of Ruskin's well-known works 'Of Queens' Gardens' (1864) and Unto This Last (1862). I argue that with these commercially successful and critically admired plays, Jones was at the forefront of communicating and popularising Ruskinian thinking for theatre audiences in the West End and across the world. [ABSTRACT FROM AUTHOR]

Feeds based on small (trash) fish contain much persistent phosphorus (P), such as Ca bound (Ca-P) and refractory P (Ref-P), which accumulates in high concentrations in the bottom sediments immediately below fish farms using this type of feed. This study designated three sampling locations based on their history concerning yellowtail fish farming (current, formerly or never) to investigate the sediment vertical distribution of phosphorus fractions and to test for detection of P impact on the bottom sediment. The aquaculture-free site was relatively low in Ca-P and Ref-P compared with continuous and previous aquaculture sites. The latter had high Ca-P and Ref-P content only in the depth range 17–29 cm, coinciding with the period during which aquaculture was conducted (1960–1998). The techniques used are expected to be useful to indicate bottom condition improvements and as a tracer of the effects of previous aquaculture farming. [ABSTRACT FROM AUTHOR]

The study calculated the Length-Based Spawning Potential Ratio (LB-SPR) for several species, including red grouper (Epinephelus morio), black grouper (Mycteroperca bonaci), gag grouper (M. microlepis), yellowtail snapper (Ocyurus chrysurus), lane snapper (Lutjanus synagris), hogfish (Lachnolaimus maximus), and white grunt (Haemulon plumierii). Data were obtained from the small-scale commercial fleet operating in the red grouper fishery on the Campeche Bank within the Yucatan Peninsula. Monthly records of total length (cm) from April 2017 to May 2018, totaling 10,182 fish, were collected from five fishing ports along the Yucatan Peninsula coast. Biological data, such as growth and reproductive patterns and exploitation parameters were gathered from scientific literature. The LB-SPR package on the R Core Team platform was utilized for analysis. Despite being the largest, groupers exhibited immaturity ( SL 50 < L 50 ) and low Spawning Potential Ratio (SPR). Red and black groupers showed particularly low SPR values (0.10 and 0.05, respectively), indicating a looming risk of local extinction. The gag grouper achieved the highest SPR value (0.26) among groupers, although it was very close to the minimum critical value (i.e., 0.20). Snappers, hogfish, and white grunt were generally captured in the adult state ( SL 50 > L 50 ). Yellowtail, hogfish, and white grunt displayed high SPR values (0.44, 0.72, and 0.98, respectively). Lane snapper had a low SPR (0.28) but fell within the range for maintaining satisfactory stock productivity, albeit with reduced yields. The findings emphasize the urgent need to adjust the current management framework for the red grouper fishery, focusing on improving fishing gear selectivity to address heightened pressure on both juvenile groupers and adult lane snapper. Implementing these measures is crucial to mitigate the risks of local extinction and population decline for each species. [ABSTRACT FROM AUTHOR]

We evaluated the changes in the quality and microflora of yellowtail flesh cold-stored until spoilage. Based on the sensory evaluation, odor palatability was deemed unacceptable for dark muscle (DM) and the dorsal part of the ordinary muscle (OD) after >10 days and 14 of storage, respectively. Log 7 CFU/g in DM as well as OD was obtained on days 10 (Aeromonas spp.) and 14 (Enterobacteriaceae and Pseudomonas spp.) of storage, whereas log 5 (Brocothrix thermosphacta) and 6 (H2S-producing bacteria) CFU/g in them were obtained on day 14 of storage. In these bacteria, the viable bacterial counts of Pseudomonas spp. and Aeromonas spp. in DM were significantly higher than those in OD only at some storage times. Amplicon sequencing revealed that in both muscles, Pseudomonas became predominant after storage, with greater than 90% recorded after more than 10 days of storage. The relative abundances of Acinetobacter, Unclassified Gammaproteobacter, and Shewanella were relatively high in both muscles after more than 10 days of storage; however, these values were less than 5%. Ethyl butyrate in the OD and DM and 2,3-butanedione in the OD were first detected on days 14 and 10 of storage, respectively. Acetoin in the OD increased by 81-fold after 14 days of storage and was significantly increased in the DM after more than 10 days compared with the amount detected pre-storage. Volatiles, such as (E)-2-pentenal in the OD and 1-pentanol in the DM, decreased and increased linearly, respectively, throughout the 14-day storage period. Altogether, these volatile components may cause quality deterioration due to spoilage and/or lipid oxidation during cold storage of the OD and DM. [ABSTRACT FROM AUTHOR]

Objective: The carnivorous Yellowtail Snapper Ocyurus chrysurus has the potential for production in aquaculture. However, there is a lack of studies investigating the digestibility of ingredients needed to formulate balanced diets for this species. Methods: The in vitro protein digestibility of fish meal (FM), poultry by‐product meal (PBM), poultry meal (PM), protiblend, canola meal (CM), soybean meal, and wheat gluten was evaluated using the pH‐stat technique. The in vivo digestibility was determined by formulating test diets with a 70:30 ratio of the reference diet and the test ingredients. Result: In terms of in vitro digestibility, FM, PBM, and PM exhibited the highest degree of hydrolysis (DH). Conversely, PBM displayed the lowest apparent digestibility coefficient of protein (ADCprotein) in the in vivo digestibility test. Meanwhile, FM, PM, and CM demonstrated higher values of protein digestibility. Beta regression between ADCprotein and the DH and ash content of the ingredients resulted in a high correlation (R2 = 0.94). Conclusion: The results of the present study indicate that Yellowtail Snapper efficiently digested and absorbed FM, PM, and CM ingredients, which contain a lower content of ash. Impact statementSeveral fish species are overexploited in the production of fish meal, the primary ingredient in fish feed. Therefore, the comprehensive evaluation of potential ingredient substitutes for fish meal is imperative to foster the sustainable development of aquaculture. [ABSTRACT FROM AUTHOR]

Simple Summary: The yellowtail kingfish is a highly active and fast-growing marine fish with promising potential for aquaculture. In this study, we learned about the energy that these fish spend by measuring heart rate and acceleration during both a test where fish had to swim at increasing speeds and a test where fish were subjected to four steps of increasing stress load. Yellowtail kingfish need to swim to provide sufficient water flow over the gills to be able to extract sufficient oxygen. Oxygen consumption, heart rate and acceleration all increased when the fish had to swim faster. The oxygen levels that the fish consumed when swimming were high and heart rate values were even among the highest ever measured for fishes. Oxygen consumption and heart rate were only correlated when fish were swimming steadily near the optimal swimming speed, which is when all of their energy is required for fueling the muscles. With every stress step, the acceleration peak decreased, possibly suggesting that fish knew what was coming, until the fourth step, when fish were also chased, where the acceleration and heart rate showed their highest peaks. Acceleration and heart rate data can be used for modelling the energy flows that are required for steady swimming and unsteady stress movements. Such an energy economy model can then be applied for estimating the energy that the fish spend in field studies and for optimal farming of this species by exercising them. The yellowtail kingfish is a highly active and fast-growing marine fish with promising potential for aquaculture. In this study, essential insights were gained into the energy economy of this species by heart rate and acceleration logging during a swim-fitness test and a subsequent stress challenge test. Oxygen consumption values of the 600–800 g fish, when swimming in the range of 0.2 up to 1 m·s−1, were high—between 550 and 800 mg·kg−1·h−1—and the heart rate values—up to 228 bpm—were even among the highest ever measured for fishes. When swimming at these increasing speeds, their heart rate increased from 126 up to 162 bpm, and acceleration increased from 11 up to 26 milli-g. When exposed to four sequential steps of increasing stress load, the decreasing peaks of acceleration (baseline values of 12 to peaks of 26, 19 and 15 milli-g) indicated anticipatory behavior, but the heart rate increases (110 up to 138–144 bpm) remained similar. During the fourth step, when fish were also chased, peaking values of 186 bpm and 44 milli-g were measured. Oxygen consumption and heart rate increased with swimming speed and was well reflected by increases in tail beat and head width frequencies. Only when swimming steadily near the optimal swimming speed were these parameters strongly correlated. [ABSTRACT FROM AUTHOR]

We investigated the effects of combinations of heating and pre-heat storage on the texture and taste-active compounds in yellowtail Seriola quinqueradiata meat. Yellowtail was stored on ice for one day and 14 days and heated by high-temperature/short-time heating (85 °C for 90 s) or low-temperature/long-time pasteurization (63 °C for 30 min, LTLT). The moisture content, pH, texture profile, sample thickness, nucleotide-related compounds (NRCs), and free amino acids (FAAs) were determined. The hardness and sample thickness of the dorsal ordinary muscle were only affected by heating conditions, but those of the dark muscle were affected by both storage and heating conditions; in particular, they tended to be tender with LTLT or storage. Hierarchical cluster analysis based on the analyzed data of NRCs and FAAs showed that these compounds were affected by both storage and heating conditions, especially the storage period. However, the equivalent umami concentration in both muscle parts tended to decrease with storage. These results indicate that in the case of yellowtail, heat processing without aging and with the establishment of optimal heating conditions is important for preparing highly palatable fish meat. [ABSTRACT FROM AUTHOR]

To determine the optimal method for monitoring the size distribution of cultivated yellowtail growth, we employed three different approaches: capture measurement, manual measurement using stereo cameras, and automatic measurement through stereo camera-based image recognition technology. Conventional capture measurements showed inadequate prediction interval owing to limited sample size, preventing accurate assessment of growth. Both manual and automatic camera measurements successfully conformed to a growth model exhibiting periodicity. The expected values derived from each model closely matched with the mean of landings conducted at the end of the study. However, the 95% prediction interval for manual measurement with cameras was comparable to that for the landing measurement, whereas the prediction interval for the automatic measurement with cameras was overestimated. Additionally, the growth rate of farmed yellowtail demonstrated seasonal fluctuations. Notably, the mean obtained from a single automatic measurement with cameras, prior to landing, significantly deviated from the overall mean of all measurements. This suggests a potential risk associated with relying on accidental outliers in a single measurement. Therefore, it is crucial to employ a growth model unaffected by outliers in continuous measurements to ensure reliable predictions. [ABSTRACT FROM AUTHOR]

Objective: Ectothermic fish are directly affected by temperature changes in the environment. The aim of this study was to evaluate the metabolic responses in the gills of Yellowtail Lambari Astyanax lacustris under thermal stress. Methods: To this end, we used spectrophotometry to evaluate the biomarkers of carbohydrate and protein metabolism, antioxidant defense, and oxidative damage in fish subjected to low (15°C) and high (31°C) temperatures, with control groups held at 23°C, for 2, 6, 12, 24, 48, and 96 h. Result: The results showed that cold thermal stress did not change the energy demand, and the antioxidant defense was reduced; therefore, the gills were vulnerable to the action of reactive oxygen species (ROS), presenting increased protein carbonylation at 12 h. With heat thermal stress, a higher energy demand was observed, which was verified by an increase in aerobic metabolism by glycolysis and the citric acid cycle. High‐temperature stress also increased the antioxidant defenses, as verified by the increased activities of glutathione peroxidase, glutathione reductase, and glutathione S‐transferase. However, the antioxidant defense system could not protect tissues from the action of ROS, as protein carbonylation increased at 6 and 24 h, indicating oxidative stress. Conclusion: The results showed that (1) temperature variations caused metabolic adjustments in the gills of Yellowtail Lambari, (2) the adaptive responses were different for winter and summer temperatures, and (3) Yellowtail Lambari recovered homeostasis when subjected to thermal stress, even with the occurrence of oxidative stress. Impact statementThis study explores cellular stress responses in terms of metabolism, providing a comparison between low and high temperatures within an evolutionary and environmental context. These findings are crucial for fish farming and conservation efforts, revealing possible impacts of global climate change. [ABSTRACT FROM AUTHOR]

The use of games to model and understand complex systems has an extensive history in military circles. Gaming is used by commanders at all levels to inform their understanding of the operational environment, evaluate disparate courses of action, and refine future concepts of operation. The current article examines the use of gaming by the U.S. Air Force to mature and promote its Agile Combat Employment operational concept. The case is made that this approach is extensible to allow leaders with varying problem sets a tool to develop a deeper understanding of their leadership options. [ABSTRACT FROM AUTHOR]

Fishmeal and fish oil substitution in aquafeeds might have adverse effects on fish growth and health, mainly in carnivorous species, such as Mediterranean yellowtail (Seriola dumerili). Mediterranean yellowtail shows great potential as an alternative aquaculture species due to its fast growth and high price on the market, but the need for high-quality protein and fatty acid content in its diets is limiting its production. In order to improve the sustainability of its production, this study was conducted with 360 fish of 35 g to evaluate the effects on fish growth and health. Six diets were used: one control diet without replacement, three with FM replacement (FM66, FM33, and FM0) (33%, 66%, and 100% FM replacement), and two with FO replacement (FO50 and FO0) (50% and 100% FO replacement). The substitution of FM was with vegetable (VM) (corn gluten) and animal (AM) (krill and meat meal) meals. The reductions in FM and FO of up to 33 and 0%, respectively, did not affect the growth and survival of S. dumerili at the intestinal morphology level, except for the anterior intestine regarding the lower villi length and width and the posterior intestine regarding the lower width of the lamina propria. On the other hand, the substitution of fish ingredients in the diet affects liver morphology, indicating alterations in the major diameter of hepatocytes or their nuclei. Finally, diet did not affect the gut microbiota with respect to the control, but significant differences were found in alpha and beta diversity when FO and FM microbiota were compared. A 66% FM replacement and total FO replacement would be possible without causing major alterations in the fish.

Objective: California Yellowtail (CYT) Seriola dorsalis are continuous spawners and rely entirely on their diet to supply nutrients like fatty acids (FAs) to their eggs to support early development. The objective of this study was to determine whether commercial diets could replace a diet consisting of fresh fishery products (FFP‐D) without compromising egg quality and biochemical composition, specifically FAs. Methods: In 2017, one broodstock group (one female and two males) was fed a formulated reference feed (REF‐D; Bio‐Oregon). This pilot experiment showed that it was possible for a minimum of one female and two male broodfish to spawn repeatedly in a tank, a finding that led to a replicated diet experiment during 2018 in which 18 CYT broodfish were divided into six replicate tanks, with one female and two males per tank. Three tanks were fed the FFP‐D as a control, and three tanks were fed a commercial diet (COM‐D; Breed‐M, INVE). For each spawning event, egg quality metrics were collected, along with samples for FA analysis. Result: The 2017 REF‐D treatment produced eggs that met arachidonic acid (ARA) and eicosapentaenoic acid (EPA) requirements and had egg metrics comparable to those obtained from the FFP‐D, with higher viability and average batch fecundity. However, the REF‐D treatment had insufficient docosahexaenoic acid (DHA) and no tank replicates. The 2018 COM‐D treatment produced eggs with large egg and oil diameters and met ARA and EPA requirements but was associated with very poor spawning and hatch success and had insufficient DHA levels. The FFP‐D treatment produced below‐average viability and batch fecundity rates and was unable to meet most essential FA requirements, but it yielded the greatest number of spawning events. Conclusion: None of the experimental treatments, including the control, was able to fully meet the nutritional requirements of CYT broodstock. These results reveal crucial data about current CYT broodstock diets that can facilitate future research for developing nutritionally complete diets, especially in terms of essential FAs. Impact statementThis study investigates three different feed types in California Yellowtail broodstock. We explored if standard fish feeds could replace a standard raw fish diet without compromising egg quality. This is especially relevant to producers because understanding the right feed for broodstock helps ensure a reliable production of high quality eggs. The replacement of a raw fish diet with commercial pellets allows producers to reduce the use of wild‐caught fish as a primary food source for these broodstock, resulting in more sustainable aquaculture practices. [ABSTRACT FROM AUTHOR]

Identifying the species response to changing environments can contribute towards proactive and adaptable resource management and, although obtaining observations can be logistically challenging for aquatic species, can be postulated through monitoring.A network of acoustic tracking receivers (n = 93) across south‐eastern Australia was used to identify the effects of environmental conditions on the activity of the yellowtail kingfish (Seriola lalandi, n = 63), an economically important species with a crucial role in pelagic ecosystems. Activity (measured via tri‐axial acceleration) provides an insight into the energetic expenditure of animals, which is linked to movement, behaviour, and physiological processes.Kingfish activity was strongly influenced by sea surface temperature and hour of day, with smaller effects from distance to nearest landmass and bathymetry. Activity also decreased during higher tides and periods of greater moon fraction. Findings show that the energetic responses of kingfish are sensitive to long‐ and short‐term changes, which can regulate behaviours and physiological processes. Changes in kingfish activity and movement (residency and space use) were further investigated at a seasonal aggregation in a small temperate estuary (approx. 120 km2; Coffin Bay, South Australia), where individuals remained during the austral spring and summer (September–April), with a complete exodus in winter. Fifty per cent of tagged fish returned to this estuary in three consecutive years, indicating its importance for aggregating kingfish.While residing in Coffin Bay, kingfish activity varied between interconnected areas, with temperature, hour of day, tide height, and moon fraction again identified as important explanatory variables. These findings have implications for the energetic budgets of large pelagic fish in subtropical and temperate regions, which are facing rapidly changing climates.These results are important for understanding and accounting for the potential responses and physiological impacts of future climatic conditions on migratory pelagic species. [ABSTRACT FROM AUTHOR]

Copyright of Science & Technology of Food Industry is the property of Science & Technology of Food Industry Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Cold aging of fish has gained substantial attention because of improving its taste quality. However, fish aging typically requires approximately 2 weeks to 2 months. Thus, the production of aged fish has several challenges, such as food hygiene concerns and refrigeration costs, preventing its commercialization. In response to these challenges, this study aimed to develop a novel technology to promote the aging of greater amberjack Seriola dumerili meat by low-temperature heating. Proteolysis, an indicator of fish aging, was promoted by heating at ≥ 30 °C. Heating at 25–30 °C did not induce fish meat discoloration, which is caused by protein unfolding. The free amino acid (FFA) content increased with heating time at 30 °C. The fish samples were sufficiently softened at 30 °C for 120 min. Inosine-5′-monophosphate (IMP) content and total viable bacteria count were relatively constant at 30 °C, independent of heating time (0–120 min). Therefore, low-temperature heating at 30 °C for 120 min was optimal for promoting the aging of greater amberjack meat, resulting in improved taste and texture. This novel technology significantly enhanced proteolysis and consequently achieved the required properties, such as texture softening and increased FAA, for the aged fish with prevention of protein denaturation typically caused by conventional low-temperature heating. Furthermore, it is more useful than conventional aging because it significantly shortens the aging duration, contributes to safety, and maintains the IMP content. [ABSTRACT FROM AUTHOR]

In this study, the otolith morphology of yellowtail snapper (Ocyurus chrysurus) was used for stock identification based on different shape analyses viz. morphometric parameters with shape indices, Elliptical Fourier descriptors (EFD), wavelet transform (WT), and landmarks. The samples were collected from Fortaleza (Ceará) and Recife (Pernambuco) in the coastal waters of Brazil to identify stocks and determine the best method for stock discrimination of O. chrysurus. The result showed no significant difference between these two regions which was supported by the Linear Discriminant Analysis (LDA). To select the best discrimination methods a correct classification through jack-knifed and Wilks’ λ test was performed. The morphometric parameters with shape indices showed a correct classification of 25% and the landmark method’s correct classification was 33.1%. These two methods had a lower correct classification than the otolith contouring methods (EFD = 42.3% and WT = 43.5%). Also, the Wilks’ λ test showed lower power discrimination for morphometric with shape indices and landmark method (λ= 0.904 and λ= 0.808, respectively), in comparison with the two contouring methods (EFD λ = 0.688 and WT λ = 0.601). These results indicate that the most suitable methods for observing small variations in O. chrysurus otoliths can be EFD and WT. [ABSTRACT FROM AUTHOR]

Objective: The effectiveness of bycatch avoidance programs relies on changes in fishing behavior in response to spatiotemporal information on bycatch patterns. A voluntary bycatch avoidance program in the U.S. sea scallop Placopecten magellanicus fishery designed to prevent triggering bycatch allocation of Yellowtail Flounder Limanda ferruginea was implemented and maintained concurrently with other management measures. Detecting bycatch avoidance behavior and relative effectiveness for bycatch mitigation presents an analytical challenge. Methods: We evaluated effectiveness of the bycatch avoidance program over the course of 4 years based on fishing behavior relative to bycatch advisories. Using loglinear models to compare frequencies, we examined the relationship between bycatch reports from participating vessels and bycatch advisories throughout the year in each of the 4 years. We compared results from self‐reported catch to data from a mandatory observer program for participating and nonparticipating vessels in the bycatch avoidance program. Result: Significant associations between bycatch advisories and fishing locations indicated bycatch avoidance behavior, while accounting for the effect of sea scallop density on fishing location decisions. Evidence of avoidance behavior was stronger in earlier years of the program and varied spatially. Decreasing avoidance behavior coincided with revised bycatch management measures, which appear to have altered the incentives for bycatch avoidance. Conclusion: We found differences in the fishing behavior of fishing captains who participated in the bycatch avoidance program when Yellowtail Flounder bycatch was perceived to threaten economic yield due to fishery closures. Bycatch mitigation program evaluations should consider the program objectives as well as incentives (and disincentives) in interpreting behavior. Impact statementThis study demonstrates a method to address the analytical challenge of detecting bycatch avoidance behavior and relative effectiveness for bycatch mitigation. Consideration of program objectives and external incentives is important in the interpretation of fishing behaviors when evaluating bycatch mitigation programs. [ABSTRACT FROM AUTHOR]

Evaluation of viability of new marine species in aquaculture systems is important to reduce negative social and environmental externalities, offering sustainable options for supply to fish markets. The objective was to describe the performance indicators of late juvenile yellowtail snapper (243.2 ± 57.1 mean weight of total fish) in an experimental recirculating aquaculture system (RAS) system supplied by seawater to determine its pre‐feasibility. Two densities were stocked, D1: 10 fish/tank (2.6 kg/m3, mean weight 258.3 ± 57 g) and D2: 20 fish/tank (4.7 kg/m3, mean weight 235.6 ± 55.9 g). Fish were fed to satiety with an extruded diet containing 46% crude protein and 12% crude lipid. After 238 days, survival rate was 93% for both densities, and mean weight and biomass were 534.5 ± 19.4 g and 5.7 kg/m3 for D1, and 606.9 ± 34.5 g and 10 kg/m3 for D2. Final feed conversion rate (3.13 for D1 and 3.03 for D2) did not differ significantly between densities. The exponents (b) of the length–weight relationship calculated for D1 (3.15) versus D2 (3.10) and condition factor (2.12 ± 0.07 for D1, and 2.03 ± 0.04 for D2) demonstrated a higher condition factor than those of their wild counterparts. This study is one of the few reports on this species' performance in late juvenile stage in RAS. [ABSTRACT FROM AUTHOR]

Dietary supplementation of immunostimulants might be effective to reduce the economic losses due to infectious diseases and the use of antibiotics in aquaculture. To investigate the immune response of interleukin-12 (IL-12) in yellowtail Seriola quinqueradiata to heat-killed Lactobacillus plantarum strain L-137 (HK L-137), we performed a leukocyte culture, feeding trial with diets containing L-137 and an immersion challenge with Lactococcus garvieae. IL-12 (IL-12p70) is a heterodimeric cytokine composed of IL-12p35 and IL-12p40 subunits. In the yellowtail-leukocyte culture, HK L-137 treatment stimulated the mRNA expression of one IL12p35 subunit (p35a) and all IL12p40 subunits (p40a, p40b, and p40c) in a dose-dependent manner. Furthermore, mRNA expression of type-I helper (Th-1) cytokine (tumor necrosis factor α, TNF-α, and interferon γ, IFN-γ) was also stimulated by HK L-137. After 6 weeks of feeding yellowtails with diets containing 0, 20, and 100 ppm of HK L-137, the mRNA expression of p35a and p40b in the spleen leukocytes increased with the dietary concentration of HK L-137, and that of p40b, p40c, and ifng in the head kidney leukocytes were the highest in the 20 ppm HK L-137 group. Survival rates in the 20 ppm HK L-137 group after immersion challenge with L. garvieae were significantly higher than the control (0 ppm of HK L-137). The 100 ppm HK L-137 group did not significantly suppress mortality. HK L-137 showed immunostimulant activity by increasing the expression of il-12, tnfa, and ifng mRNA in both in vitro and in vivo tests in yellowtail. Our results suggest that dietary supplementation with 20 ppm HK L-137 is the most efficient dose for improving immunity in yellowtail. Furthermore, a high dose of HK L-137 and/or long-term feeding of a diet containing HK L-137 might suppress the immune response, which probably decreases the survival rate of fish. To maintain a high immune response in yellowtail, the optimal dietary concentration of HK L-137 and/or feeding regime should be investigated further.

Peach being a climacteric fruit has a limited shelf life. Cold storage of peaches is an essential measure to maintain their quality. However, prolonged exposure to cold temperatures causes chilling injury in peaches, resulting in significant economic losses. Approximately, 40% of the produced commodity is lost in postharvest handling in which chilling injury contributes to about 25%. Melatonin can be a green solution and plays a key role in protecting peaches from chilling injury. Therefore, this experiment aimed to determine the effect of melatonin on the "Silver King" peaches by dipping them in 100 μM melatonin for 2 hours followed by storing them at chilling temperatures of 2 ± 1°C and 90–95% relative humidity for 21 d. The results showed that while control fruit experienced chilling injury and poor fruit quality, increased respiration rate, and enhanced senescence, 100 μM melatonin treatment was successful in preserving the fruit quality at chilling temperatures and was associated with the delayed respiration rate and lower malondialdehyde levels, along with the preservation of certain physicochemical parameters, namely, total soluble solids, pH, fruit firmness, and titratable acidity. Moreover, a 1.5 times higher proline concentration was observed in melatonin-treated peaches when compared to that of nontreated peaches. This rise was linked to the enhanced activity of Δ1-pyrroline-5-carboxylate synthetase and ornithine-δ-aminotransferase along with a decrease in the activity of proline dehydrogenase during 21 d of storage. [ABSTRACT FROM AUTHOR]

Aquaculture practices expose fish to several factors that may generate stress, modifying the balance between the production of reactive oxygen species (ROS) and the activity of antioxidant defenses that induce cell damage. Alpha-tocopherol (VE) improves the antioxidant capacity against ROS production in fish. A 50-day trial with longfin yellowtail (Seriola rivoliana) juveniles was conducted to compare the dietary supplementation of 500 mg/kg of VE against a control diet without VE supplementation on growth, lymphoid tissue enzymatic activity, immune-system-related gene expression, and the histology of the liver and spleen. Growth, weight gain, specific growth rate, feed conversion rate, and survival did not show significant differences (p > 0.05) among treatments. Fish fed with an α-tocopherol-enriched diet showed a higher enzymatic activity of superoxide dismutase in the liver (p < 0.05) and a lower percentage of melanomacrophage coverage area in the lymphoid organs (p < 0.05). Overexpression was observed of MyD88 and il-10 in the spleen, and il-1b in the liver in fish fed 500 mg/kg of VE, as well as overexpression of Toll-like 3 in the head kidney, spleen, and liver in fish fed the control diet. Dietary supplementation with VE reduces the effects of oxidative stress and improves lymphoid tissue defense and immune-related gene expression in S. rivoliana. [ABSTRACT FROM AUTHOR]

The median lethal concentration (LC50) of unionized ammonia (NH3‐N) in longfin yellowtail, Seriola rivoliana juveniles was assessed after 96 h of exposure using a semistatic water system. Experimental fish were exposed in triplicate to different ammonia concentrations: 0.55 ± 0.00; 0.94 ± 0.02; 1.18 ± 0.00; 1.72 ± 0.02, and 1.97 ± 0.09 NH3‐N mg/L. Additionally, a control group (0.00 ± 0.00 NH3‐N mg/L) was included. The 96 h LC50 of unionized ammonia in S. rivoliana was 0.58 mg/L. Fish exposed to different ammonia concentrations for 96 h displayed several lesions on gill tissues, that is, hyperplasia, epithelial lifting, fusion of the secondary lamellae, and some irreversible damage. Erratic behavior, such as swimming in circles and hyperventilation was observed before the fish died. The safe concentration of unionized ammonia in this study was estimated at 0.06 and 1.68 mg/L of total ammonia nitrogen (TAN). The outcomes observed in this study provide valuable insights into unionized ammonia effects for better water quality management in semi‐intensive and intensive systems for S. rivoliana culture. [ABSTRACT FROM AUTHOR]

Most commercial products available for Artemia sp. enrichment include high levels of docosahexaenoic acid (DHA) to boost its nutritional value, though with limited success. In this regard, the present study evaluated the alternative utilization of eicosapentaenoic acid (20 : 5n-3; EPA) oils to improve the n-3 long-chain highly unsaturated fatty acid content (n-3 LC-HUFA) in enriched Artemia sp. to feed greater amberjack (Seriola dumerili) larvae. Five experimental emulsions containing increasing levels of EPA from 0.8% to 60% of total fatty acids (TFA) and n-3 LC-HUFA (1.3%–70.6% TFA) were formulated. Each diet was fed to greater amberjack larvae (17–35 days posthatch (dph)) in three replicate 200-L tanks. The dietary EPA supplementation significantly improved larval growth during the feeding trial and survival at 35 dph (P < 0.05). In addition, larval fatty acid profiles showed a positive correlation with dietary EPA. Finally, despite the sum of total skeletal anomalies and column anomalies were not significantly affected by dietary EPA, increasing dietary EPA, and n-3 LC-HUFA tended to reduce the incidence of these types of anomalies in greater amberjack larvae at 35 dph. Based on these results, S. dumerili larvae could be successfully grown with low DHA but high EPA-rich oil enrichment products when n-3 LC-HUFA content in Artemia sp. is maintained in sufficient amounts. [ABSTRACT FROM AUTHOR]

The effects of heating duration on digestibility of the muscle powder of three fish (pollock [WP], yellowtail [YT], mackerel [CM]) and the whole-body powder from mackerel (WM) were assessed in vitro using a digestive enzyme complex (EC) extracted from yellowtail pyloric caeca. This research will contribute to establishing a theoretical basis for feed processing conditions for yellowtail. Transcriptomic analysis showed that the most dominantly expressed genes in the pyloric caeca examined were those for trypsin and that their activity was well maintained in the EC. To assess heating effects, the powders were heated at 99 °C for 0, 3, 20, 72 and 240 min, followed by hydrolysis with the EC. After 3 min of heating the WP, YT and CM, the average production of essential amino acids (EAAs) decreased to 81.3%, 72.0% and 66.9%, respectively, compared to that detected in controls without heating. The production further decreased with increased heating duration from 3 to 240 min, but much of the decrease was within the first 3 min in WP, YT and CM. The decreasing rate of EAA production was higher in WM than CM, and increased with heating time. These results suggest that WP is the most suitable feed material for yellowtail of the four samples tested and that the shortening of heating time and removal of viscera are also important factors. [ABSTRACT FROM AUTHOR]

The effects of vacuum packaging (VP) on the odor of yellowtail Seriola quinqueradiata were investigated. VP, before or after primary heating, prevented the progression of lipid oxidation of the dorsal ordinary muscle (OD) and dark muscle (DM) during storage after heating. It also prevented a reduction in polyunsaturated fatty acids. Principal component analysis did not distinguish the vacuum-packed samples after storage from any samples before storage by their volatile composition, regardless of the timing of their treatment. Sensory evaluation indicates that VP, regardless of whether it is before or after primary heating, can suppress the development of the rancid odor of yellowtail meat during storage after heating and, especially for DM, can prevent the loss of palatability due to storage. These findings suggest that vacuum packaging is a valuable method for suppressing the quality deterioration of cooked fish meat. [ABSTRACT FROM AUTHOR]

Simple Summary: The greater amberjack (Seriola dumerili) is an economically important fish with high farming value. This species is intolerant to hypoxia, which makes it susceptible to mass mortality and hinders the progress of amberjack cultivation. Based on a comparative analysis of the liver transcriptome between acute hypoxia-tolerant (HT) and intolerant (HS) groups, this study first explored the molecular mechanisms of acute hypoxia in greater amberjack. The results showed that the glycolipid metabolism, antioxidant activity, and apoptotic pathways of greater amberjack significantly responded when exposed to acute hypoxia. In addition, the relative downregulation of apoptosis and autophagy-related genes, such as endog, hm13, and casp6, was also detected in the HT group. The NF-kB pathway was partly promoted in the HT group relative to the HS group to resist apoptosis. This investigation will offer significant technical assistance in the prevention of death caused by acute hypoxia and the subsequent reduction in financial losses. Acute hypoxia is a common abiotic stress in commercial aquaculture and has significant effects on fish physiology and metabolism. Due to its large size and rapid growth, the greater amberjack (Seriola dumerili) is an economically important fish with high farming value. This species is intolerant to hypoxia, which makes it susceptible to mass mortality and hinders the progress of amberjack cultivation. Based on a comparative analysis of the liver transcriptome between acute hypoxia-tolerant (HT) and -intolerant (HS) groups, this study first explored the molecular mechanisms of acute hypoxia in greater amberjack. By simulating the acute hypoxic environment and using RNA sequencing (RNA-Seq), the differences in liver transcriptional changes between the acute hypoxia-tolerant (HT) and hypoxia-intolerant (HS) groups of greater amberjack were probed. Based on differential expression analysis, 829 differentially expressed genes (DEGs) were screened in both groups. Relative to the HS group, 374 DEGs were upregulated and 455 were downregulated in the HT group. Compared with the HS group, genes such as slc2a5 and prkaa2 related to promoting sugar transport and inhibiting lipid syntheses were upregulated, while genes that inhibit gluconeogenesis and promote lipid syntheses, such as pgp and aacs, were downregulated. The expression of odc1 was significantly and relatively downregulated in the HT group, which would lead to the inhibition of intracellular antioxidant activity and decreased scavenging of ROS. The NF-kB pathway was also promoted to some extent in individuals in the HT group relative to the HS group to resist apoptosis. In addition, the relative downregulation of apoptosis and autophagy-related genes, such as endog, hm13, and casp6, was also detected in the HT group. The present findings first reported the regulation mechanism by which liver tissue coped with the acute hypoxia stress in greater amberjack, which will provide important technical support for preventing acute hypoxia-induced death in advance and reducing economic losses. [ABSTRACT FROM AUTHOR]

Reproductive dysfunctions have been recently documented in male greater amberjack Seriola dumerili caught from the wild and reared in captivity. In the present study, we compared testis transcriptome in wild fish (WILD), hatchery-produced fish with apparently normal spermatogenesis (Normal Farmed; NormalF) and hatchery-produced fish with evident reproductive dysfunction (Dysfunctional Farmed; DysF). Gene expression analysis identified 2157, 1985 and 74 differentially expressed genes (DEGs) in DysF vs WILD, NormalF vs DysF and NormalF vs WILD comparisons, respectively. In DysF, a dysregulation of several interconnected biological processes, including cell assembly, steroidogenesis and apoptosis was found. Gene enrichment of progesterone-mediated oocyte maturation, oocyte meiosis and cell cycle pathways were identified in the DysF vs NormalF comparison. Most of the DEGs involved in the enriched pathways were downregulated in DysF. The comparison of NormalF vs WILD showed that most of the DEGs were downregulated in NormalF, including a gene that encodes for a regulatory protein with a protective role in apoptosis regulation (ptpn6), indicating that spermatogenesis was dysfunctional also in the apparently "normal" hatchery-produced fish. Hence, rearing of male greater amberjack in captivity, from eggs produced by captive breeders, did not prevent the appearance of reproductive dysfunctions, and these dysfunctions involved several biological processes and metabolic pathways. [ABSTRACT FROM AUTHOR]

Copyright of Food Research & Development is the property of Food Research & Development Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Wildlife tourism can have adverse effects on the behaviours and movements of animals, with implications for the health and fitness of individuals and populations. We used acoustic-tracking to show that food-based attractants used in shark-tourism increases activity (15%) and burst behaviours (60%) in yellowtail kingfish (Seriola lalandi, n  = 18). Increased activity was restricted to periods when kingfish were on the same side of the island group as berleying tourism vessels, but decreased after operators left the site. Despite the raised activity and frequency of burst swimming events, the physiological condition of kingfish (n  = 39, 6 tagged, and 33 untagged) measured using bioelectrical impedance analysis remained consistent with kingfish from control sites not exposed to tourism. This suggests that kingfish were able to compensate raised energy expenditure by feeding on bait and berley used by operators or through natural foraging. We highlight that the effects of provisioning from wildlife tourism can extend beyond changes in behaviours and movements and can additionally influence the energetic condition of non-focal animals through increased activity. However, supplemental food-sources provided through wildlife tourism may be sufficient to compensate for the increased energy expenditure and lessen the effects of tourism on individual fitness and health. [ABSTRACT FROM AUTHOR]

Greater amberjack (Seriola dumerili) is a new species in marine aquaculture with high mortalities at the larval stages. The microbiota of amberjack larvae was analyzed using 16S rDNA sequencing in two groups, one added copepod nauplii (Acartia tonsa) in the diet, and one without copepods (control). In addition, antagonistic bacteria were isolated from amberjack larvae and live food cultures. Proteobacteria was the most abundant phylum followed by Bacteroidota in amberjack larvae. The composition and diversity of the microbiota were influenced by age, but not by diet. Microbial community richness and diversity significantly increased over time. Rhodobacteraceae was the most dominant family followed by Vibrionaceae, which showed the highest relative abundance in larvae from the control group 31 days after hatching. Alcaligenes and Thalassobius genera exhibited a significantly higher relative abundance in the copepod group. Sixty-two antagonistic bacterial strains were isolated and screened for their ability to inhibit four fish pathogens (Aeromonas veronii, Vibrio harveyi, V. anguillarum, V. alginolyticus) using a double-layer test. Phaeobacter gallaeciensis, Phaeobacter sp., Ruegeria sp., and Rhodobacter sp. isolated from larvae and Artemia sp. inhibited the fish pathogens. These antagonistic bacteria could be used as host-derived probiotics to improve the growth and survival of the greater amberjack larvae. [ABSTRACT FROM AUTHOR]

To clarify the population genetic structure, intrapopulation diversity, and interpopulation differentiation of yellowtail kingfish (Seriola aureovittata), we sampled 143 individuals from five collections of yellowtail kingfish: farmed (n = 30) and wild (n = 33) collections in China, a wild collection in Japan (n = 20), and farmed (n = 31) and wild (n = 29) collections in Australia. Using 2b-RAD simplified genome sequencing, we obtained an average of 287,594 unique tags per population, with an average sequencing depth of 27.13×. Our final genotype dataset included 48,710 SNPs (Single Nucleotide Polymorphisms). The five collections were all in Hardy–Weinberg equilibrium, and the interpopulation differentiation varied among the sample collections. The genetic differentiation coefficients (Fst) between the Chinese and Japanese yellowtail kingfish collections were low and the gene flow (Nm) values were high. These results suggest continuous gene flow occurs frequently between the collections, indicating that they belong to the same population. In contrast, genetic differentiation was high between the Australian collections and the Chinese and Japanese populations, suggesting different evolutionary origins and belonging to different populations. The farmed and wild Australian collections fell into distinct clades in a neighbor-joining phylogeny tree, suggesting farmed fish have begun to differentiate from the wild collection. A similar level of genetic diversity between the wild collections in China and Japan suggests that they originated from the same spawning ground. This, therefore, reminds us that in future aquaculture processes attention is needed regarding implementing targeted breeding strategies. In addition, our data will contribute to Chinese yellowtail kingfish genetic breeding and the sustainable use of Chinese yellowtail kingfish germplasms. [ABSTRACT FROM AUTHOR]

The current study was conducted to comprehend the variation of the growth pattern and the physiological status of Pangasius pangasius (Hamilton, 1822) reared in the pond from July 2021 to September 2021. A total of 90 brood individuals were collected from the Meghna River and studied for the present experiment. The overall growth pattern for P. pangasius was isometric (b = 3.00) in the Meghna River, while the male fish showed positive (b > 3.00) and the female showed a negative allometric growth pattern (b < 3.00). The Fulton's condition factor (KF) value was greater than 1, indicating a healthy population and a habitat with abundant food sources. Moreover, the KF value was found to be substantially related to total body mass. On the other hand, both sexes of P. pangasius had relative weight average values of more than 100, simply indicates the fish is naturally obese and has enough stored energy to maintain its physiology. The calculated form factors suggested an elongated body shape, which is typical of many riverine fishes. In addition, a small number of morphological traits varied significantly in the current study. Likewise, in the case of morphometric features, the principal component analysis showed a considerable degree of connectedness between the male and female individuals. The blood values showed no significant difference between the sexes. This might result from feeding fish the same kind of food and maintaining them in the same environment. However, the higher temperature might have caused slight blood abnormalities in both sexes. The current findings strongly support raising this fish in captivity and would offer useful information for fish farm owners, entrepreneurs, stakeholders, and other concerns in Bangladesh and surrounding nations. [ABSTRACT FROM AUTHOR]

Simple Summary: Optimization of metamorphosis, a key stage in development where fish undergo several morphological and physiological changes, may assure the efficient mass production of greater amberjack (Seriola dumerili) juveniles. Application of probiotics as feed and/or water additive benefits nutrient utilization through modulation of the digestive enzymes. Therefore, following the addition of biofilters with the probiotic Phaeobacter inhibens in the rearing water throughout the early development of greater amberjack, crucial in metamorphosis, cellular pathways were investigated. The probiotic treatment increased the growth of greater amberjack, while hypertrophy was the main growth process in the metamorphosis. Additionally, the rearrangement of structures and tissues may have been facilitated through the observed induced cell death. The present findings are of great importance and may be applied in the aquaculture industry in order to enhance greater amberjack development and growth. Metamorphosis entails hormonally regulated morphological and physiological changes requiring high energy levels. Probiotics as feed supplements generate ameliorative effects on host nutrient digestion and absorption. Thereby, the aim of the present research was to investigate the impact of the probiotic Phaeobacter inhibens as a water additive on cellular signaling pathways in the metamorphosis of greater amberjack (Seriola dumerili). Activation of insulin-like growth factor type 1 receptor (IGF-1R), protein kinase B (Akt), mitogen-activated protein kinases (MAPKs) and AMP-activated protein kinase (AMPK), induction of heat shock proteins (Hsps), and programmed cell death were assessed through SDS-Page/immunoblot analysis, while energy metabolism was determined through enzymatic activities. According to the results, greater amberjack reared in P. inhibens-enriched water entered the metamorphic phase with greater body length, while protein synthesis was triggered to facilitate the hypertrophic growth as indicated by IGF-1/Akt activation and AMPK inhibition. Contrarily, MAPKs levels were reduced, whereas variations in Hsps response were evident in the probiotic treatment. Apoptosis and autophagy were mobilized potentially for the structural remodeling processes. Furthermore, the elevated enzymatic activities of intermediary metabolism highlighted the excess energy demands of metamorphosis. Collectively, the present findings demonstrate that P. inhibens may reinforce nutrient utilization, thus leading greater amberjack to an advanced growth and developmental state. [ABSTRACT FROM AUTHOR]

Copyright of China Rural Water & Hydropower is the property of China Rural Water & Hydropower Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)