Activin A receptor, type II (Acvr2) is a member of the transforming growth factor beta receptor family and can function as a negative regulator of skeletal muscle mass. Acvr2 plays an important role in regulating muscle development that can inhibit skeletal muscle growth in mice. However, there is very little research reported on the function of acvr2 in muscle development of teleost. In this study, we analyzed the effect of acvr2aa and acvr2ba on muscle development in zebrafish. Growth rates of WT and acvr2a−/−b−/− were measured from juvenile stage to adult stage. In addition, effects of acvr2 on skeletal muscle were tested in histological, protein and molecular levels. As a result, acvr2a−/−b−/− exhibited a wider body trunk than WT and showed a significant increase in body weight and width from two months old. Histological analysis of skeletal muscle indicated that the size of muscle fiber in acvr2a−/−b−/− (female:1809 ± 123 μm2; male: 2261 ± 130 μm2) was larger than that in WT (709.8 ± 49 μm2; 815 ± 53 μm2). In addition, western blot of fast MyLc protein showed the protein synthesis of acvr2a−/−b−/− are increased. Besides, Histological analysis of heart showed the ventricle area is aslo increased in acvr2a−/−b−/−. Our results demonstrated acvr2 attends the development of muscle fiber and will cause muscle hypertrophy when they were knocked out in zebrafish. In conclusion, acvr2 in zebrafish can control the development of muscle fibers during posthatch growth.

In triangle sail mussel (Hyriopsis cumingii), shell biomineralization is a complicated process that involves multiple gene products. Shell matrix proteins are involved in the formation of the organic framework and play an important role in the regulation of calcium carbonate deposition. In this study, A new shell matrix protein gene Hc-transgelin was identified in H. cumingii. The full-length cDNA of Hc-transgelin was 1200 bp, including a 501 bp open reading frame, which encoded 166 amino acids. Hc-transgelin is rich in lysine, it accounts for 11.40% of the protein. The predicted transgelin protein contained a conserved calmodulin homologous domain. A tissue-specific expression assay indicated that Hc-transgelin exhibited significantly highest expression in the mantle. Furthermore, Hc-transgelin in situ hybridization detected positive signals at the edge of the mantle outer fold, where nacre and prismatic layer biomineralization occur. An RNA interference assay showed that the shape of aragonite flakes in nacre changed and their growth was inhibited, and cracks appeared in the prismatic layer organic sheath when the expression of Hc-transgelin was suppressed. In a shell repair assay, a higher expression of Hc-transgelin appeared from day 12 to day 25 when the nacre accumulated quickly. These findings indicate that Hc-transgelin may be involved in the formation of aragonite flakes in the nacre and play a role in the formation of the organic sheath in the prismatic layer of the shell. This study provides new insights into the role of the Hc-transgelin gene and also contributes to the molecular understanding of mollusk shell formation.

Tunas are among the most economically important fish species and play critical roles in food composition and nutrition of humans. As apex predators, they also keep the marine ecosystem healthy and balanced. Both natural and human factors influence the status of this important marine resource and their habitats. There is a large cadre of studies on how tunas are of great significance to the exploitation and management of their fisheries, yet there are few summaries of this research. We aimed to quantitatively and qualitatively synthesize the global knowledge structure and emerging trends in tuna research using bibliometric software. References with "Tuna", "Katsuwonus", or "Thunnus" as the subject in the Web of Science Core Collection Database from 1995 to 2019 were visually analyzed using CiteSpace. Publication rate and output, active countries, institutions, authors, and co-cited references were performed. Results suggested that the number of international tuna research papers increased significantly between 2000 and 2010, as a considerable number of high-impact articles emerged during this period. Researchers paid more attention to 19 main topics during this period, notably "overfishing", "bycatch", "climate change", "marine pollution", and "fish management", which all posed potential risks and challenges to tuna survival. Future research should emphasize resolving these challenges and building international cooperation for the proper management of tuna populations.

The mud crab Scylla paramamosain is a key species in China due to its high nutritional value and great economic worth and has grown in popularity. Myo-inositol can modulate versatile physiological functions in aquatic animals. In the present study, S. paramamosain megalopa were given graded concentrations of myo-inositol (0, 1, 2, 4, and 8 ppm) by water immersion to explore how their metamorphosis would be affected. The results showed that supplementing with myo-inositol remarkably increased transformation and survival rate from megalopa to crablet by at least 1.16 and 1.26 times, respectively. To decipher the molecular mechanism of how myo-inositol increases metamorphosis and survival rate, we further performed transcriptome-based gene expression profiling of both megalopa and crablet treated with myo-inositol. The integrative transcriptome analyses predicted that the differentially expressed genes (DEGs) were significantly enriched in chitinase activity, structural constituent of cuticle, and chitin binding, which are associated with the decomposition and reconstruction of cuticle. qPCR results confirmed that myo-inositol mediated gene expression levels of the above cuticle-related pathways. Considering the importance of the cuticle in exoskeleton formation and molting, it can be concluded that myo-inositol-induced changes in the cuticle decomposition and reconstruction might have accelerated the transformation from megalopa to crablet of S. paramamosain. Besides, numerous DEGs were significantly enriched in protein digestion and absorption, amino sugar and nucleotide sugar metabolism. It implies that myo-inositol may improve survival by regulating energy or nutrient absorption. Additionally, the accelerated metamorphosis by myo-inositol may improve survival from megalopa to crablet of S. paramamosain. Overall, this study will provide the first insights into the underlying molecular mechanisms by which myo-inositol increases metamorphosis and survival.

The giant freshwater prawn (Macrobrachium rosenbergii) is a commercially cultured species in China. A sex chromosome-specific marker is crucial for sex identification and distinguishing sex chromosomes. Here, based on the results of reduced-representation genome sequencing and genome survey of M. rosenbergii, we identified steady sex-linked markers. Further nucleotide alignment analysis revealed 83.42% nucleotide similarity between the amplified W- and Z-chromosome fragments. qPCR confirmed that Z chromosome-specific fragments were present in males approximately twice as often compared to females. Similarly, the W chromosome-specific fragments were present in super females approximately twice as often compared to females. Our findings elucidate the ZW/ZZ sex determination type and contribute to exploring sex-related or sex-determining genes present on the sex chromosomes of M. rosenbergii.

In brackishwater aquaculture, pond engineering is essential to meet the cultured species' bio-physical requirements and potentially minimizing social and environmental impacts. This study evaluated the suitability of pond engineering designs and pond, dyke, and canal construction at family-run, extensive brackishwater aquaculture farms in Barru regency of South Sulawesi, Indonesia. Soil properties, topography, hydrological data, field surveys, and high resolution (0.6 m) Quickbird imagery were used to assess the suitability of local pond engineering designs and the efficiency of canals. The study shows that in 752 of the evaluated pond units (430 ha), about 70% of pond beds were not constructed at the optimal pond elevation. Basic engineering requirements for pond layout and dyke and canal designs were not addressed in more than 70% of the pond units. Cease-to-flow conditions commonly occur due to the sedimentation of canals. Flows are also attenuated due to collapsed dykes. Farmers disregarded soil limitations and the impacts of tidal conditions and wave regimes. It is unlikely that shrimp and fish production in the region can increase without significant improvements in pond engineering. The problems identified by the study are not unique to Barru; they also occur in other extensive aquaculture areas in Indonesia and the region. Increased awareness of the need for improved pond engineering techniques is urgently needed to safeguard the economic and environmental sustainability of Indonesia's valuable aquaculture industry.

Frozen storage of emulsion-type sausages may be one approach to avoid or reduce the use of sodium nitrite, which is associated with health risks. Silver carp (Hypophthalmichthys molitrix) mince (M0) was washed for 1 (M1) or 3 (M3) times and the impact of washing on the properties frozen storage (−18 °C) during 4 months were determined and results were compared to those of conventional silver carp sausages (Mt). Lipid oxidation, as evidenced by changes in thiobarbituric acid reactive substances and FFAs, took place during storage in the order of M0 > M1 = M3 = Mt with M0 being highly oxidized (P ≤ 0.05). Total volatile base nitrogen formed during storage and the ranking for the quality loss was as follows M0 > M1 > M3 = Mt. Washing (M1 = M3) led to less hardness (P ≤ 0.05). Mt had better redness, while M1 and M3 led to higher expressible moisture, water release and lightness (P ≤ 0.05). Results indicated the lower sensory and consumer-liking properties of frozen M1 and M3 sausages. Therefore, washing and frozen storage influenced silver carp mince sausages.

To stop the decline of swimming crab (Portunus trituberculatus) stocks in the East China Sea, escape vents on crab pots are urgently required to improve pot selectivity and enable release of sublegal-sized crabs. This study presents field comparative fishing experiments, which examined the effectiveness of different shapes and sizes of escape vents in crab pots for the release of swimming crabs. Two sizes each of rectangular, elliptic, and circular escape vents were tested. The results of comparative fishing experiments indicated that experimental pots with escape vents, regardless of their configuration, caught significantly fewer sublegal-sized crabs (

The butter catfish, Ompok bimaculatus, belonging to the silurid family, is widely regarded as an important food fish for aquaculture diversification in India. Furthermore, the species poses a threat due to habitat degradation and other anthropogenic factors, and has been categorised as “near threatened”, therefore, its culture promotion is warranted. To establish a successful breeding programme, a precise understanding of the life history, and biology (reproductive/feeding) of the fish will assist hatchery managers and researchers. Studies in these areas have been undertaken by several groups over the years, but without much coherence, the data are still fragmented. Few attempts on the culture attributes of this catfish have been performed under both mono- and polyculture systems to bring about parallel promotion through aquaculture in a larger part of the subcontinent. Highlighting this, we have tried to analyse and present a consolidated account of the morphological characteristics, feeding habits, reproductive biology, early developmental ontogeny, and culture potentials of O. bimaculatus in India. This review was also prompted by the paucity of information on the cultural aspects of the species. Additionally, based on the reported studies, future directions and perspectives of the culture promotion of the species are proffered to ensure future research initiatives.

There has been an increasing emphasis on reducing the environmental impacts of penaeid trawls by modifying their anterior sections. In one Australian estuary, this approach has culminated in a new generic trawl comprising a slightly smaller mesh size, and steeper and shorter side panels than traditional trawls, combined with a top panel extending forwards of the bottom panel (termed ‘lead-ahead’) and no headline floats. This study sought to investigate if an additional simple, cumulative modification (tickler chain) might help promote adoption of the new trawl, via improved penaeid catches. Six volunteer fishers towing pairs of either the traditional or new trawls in double rigs were asked if an observer could accompany fishing trips, and alternately attach a light tickler chain (∼3 kg) anterior to the ground gear of one trawl. Regardless of the trawl design, the tickler chains significantly increased the catch weights of penaeids, but relatively more so in the new trawls (by 1.11 × vs 1.08 × ). The tickler chains also significantly increased the number and weight of total bycatch in the traditional trawls (by up to 1.22 × ), but not in the new trawls—although there were variable species-specific effects. In terms of total effects, the data support using tickler chains to increase the efficiency of the new trawls and their cumulative benefits, and could be promoted to facilitate broader inter- and intra-fleet adoption.

An 8-week feeding trial investigated the optimum dietary vitamin K3 requirements of largemouth bass. A total of 600 healthy fish (12.96 ± 0.07 g) were fed diets containing varying levels of vitamin K3 at 0.78 (K0), 5.80 (K5), 10.82 (K10), 15.84 (K15), and 20.85 (K20) mg/kg with four replicates per level. Results showed that dietary vitamin K3 enhanced growth, with weight gain rate and specific growth rate in K15 trials significantly higher than K0 trials (P  0.05). However, the supplementation of vitamin K3 significantly contributed to calcium accumulation in muscle tissues and vertebrae (P  0.05). The antioxidant capacity was improved with the addition of vitamin K3, which was inconsistent with the changes in malondialdehyde and MK-4 (a form of menaquinone) within liver and serum, suggesting that the toxicity of excessive artificial vitamin K3 may account for this difference. Using regression analysis, the appropriate dietary vitamin K3 levels within a largemouth bass diet was determined to be in the range of 9.93–15.22 mg/kg, which will provide a reference for the preparation of vitamin premix and artificial diet for largemouth bass.

China has been the top aquaculture producer in the world since 2002. Over 800 species and 240 improved varieties have been used in China's aquaculture, which is the most diverse collection of species on this planet. Species diversification, along with other aquaculture technologies, contributes significantly to the increase of China's aquaculture production, whereas the use of too many species in aquaculture has resulted in some issues related to the environment and sustainability. We provide an updated overview of the species currently used in Chinese aquaculture in this paper. We examine critically the main drivers of species diversification in China with examples. We also introduce Chinese approaches to improve and certify new species and varieties for commercial production. We believe that further species diversification is not a priority in China's aquaculture, while further improvement of aquaculture technologies for major and native species is essential for green, profitable, and sustainable (GPS) aquaculture. The implications of China's experiences with species diversification for global aquaculture species diversification are discussed.

The growth of aquaculture demands intense consumption of formulated foods, scarce natural resources such as water and land. The increase in aquaculture production needs to be sustainable in several aspects of the activity, including the use of more sustainable farming systems that provide reduced water demand, less space dependence for increased production, and availability of complementary natural food. In this perspective, the biofloc system (BFT), presents itself as a more friendly cultivation technology as a way to mitigate some impacts of aquaculture production. Much research has been carried out, addressing different aspects important to the production of fish in BFT. In this review, we address how stocking density, carbon sources and carbon nitrogen ration (C/N) affect animal performance and the nutritional value of bioflocs; the use of microbial aggregates as “in situ” and “ex situ” food and the benefits in feed conversion, and their influence on the immune system and disease resistance.

Management of fed-fish culture practices, at present, stands on two broad feed categories, (i) formulated proteinaceous aquafeeds and (ii) the natural resources. Judicious use of the later is gaining popularity since it offers sustainability to fish culture. Polyculture often targets phyto- and zooplanktonic resources, but mostly ignores periphyton. This review discusses the works on feed diversification performed independently at different times. Fishes, viz. Cyprinus carpio, Labeo rohita and Amblypharyngodon mola were projected as potential candidates for resource - nutrient management with feed diversification in rice fish culture. With C. carpio the rice fish culture called Aji Gnui Assonii in terrace water-logged rice field of Apatani Plateau, Arunachal Pradesh (India) is referred as self-substrating aquaculture practice. This monoculture practice experiences high carp productivity since there remains surplus of resources below the threshold level in these rice fields. Similarly, L. rohita, explores periphytic resources in ponds when substrates are installed. As a result, filter feeders get more foraging aquatic phase intensifying the resources for exploration in pond. This concept is suggested for rice fields with water depth above 50 cm where rice stems act as substrate. With trenches or refuge canals, resource intensification may be managed for more cultivable fishes in rice fields with

This study was aimed at preparing chitosan (CS)-phenolic acids copolymers to obtain better preservation effect in marine products. In this work, CS was grafted onto phenolic acids such as gallic acid (GA) and protocatechuic acid (PA) by a carbodiimide coupling method. The copolymers (CS-grafted-GA (CS-g-GA) and CS-grafted-PA (CS-g-PA)) were further confirmed through physicochemical properties including ultraviolet–visible (UV–Vis) spectrophotography, fourier transform infrared (FTIR) spectrometry, differential scanning calorimetry (DSC) thermogram, rheological behaviour, scanning electron microscope (SEM) and antioxidant activity analysis. Subsequently, the effects of copolymers on preservation of refrigerated sea bass (Lateolabrax japonicus) fillets were investigated. The results showed that the CS-g-GA (110.82 mg GA/g) exhibited higher grafting rate than CS-g-PA (62.63 mg PA/g). According to the assessment of UV–Vis and FTIR spectrometry, both the GA and PA were grafted onto CS successfully. SEM analysis demonstrated that the microstructure of copolymers became irregular. Meanwhile, both the CS-g-GA and CS-g-PA copolymers displayed superior thermal stability, rheological properties and antioxidant capacity than the pure CS. Furthermore, the copolymers also revealed a significantly stronger preservation effect on sea bass fillets including inhibiting microbial growth and delaying the deterioration of color, texture and sensory quality. Therefore, CS-g-GA and CS-g-PA could be used as promising preservatives for seafood.

Knowledge about the population dynamics within a specific spatial area is vital for the effective planning and management of important fishery resources. Population parameters, including the asymptotic length (L∞), growth coefficient (K), mortalities (Z, F, and M), recruitment pattern, exploitation level (E), and yield per recruit (Y'/R), of the tropical oyster Magallana bilineata in Mengkabong Bay, Tuaran, Malaysia were analyzed by using the FiSAT software, using on the monthly shell length-frequency data collected from April 2019 to March 2020. A total of 435 oysters with shell lengths ranging from 3.64 to 11.16 cm were analyzed. Habitat water temperature, salinity, dissolved oxygen, hydrogen ion concentration (pH), and chlorophyll concentration were measured at 29.0–33.7 °C, 26.68–35.74 psμ, 3.18–6.99 mg/L, 6.57–8.29 and 1.51–98.93 μg/L, respectively. The logarithmic relationship between the length and weight of Log W = 1.9055 Log L + 0.1049 (R2 = 0.5431) with exponent b of 1.9055 for combined sexes showed a negative allometric growth (b 

Understanding the reproductive characteristics of a species is of crucial for accurate stock assessment and management plans to ensure sustainable fisheries. In this study, the size at 50% sexual maturity (L50) parameters in different bio-ecological provinces were estimated for bigeye tuna, Thunnus obesus, sampled from the Eastern Pacific Ocean tuna fisheries-dependent survey from 2013 to 2019. The overall sex ratio of the catch during the sampling differed significantly from 1:1. Bigeye tuna exhibit sexual dimorphism in the growth of males and females, with a clear shift in predominance from female to male with increasing sizes. In the North Pacific Sub-tropical Gyre (east) (NPST-east), North Pacific Tropical Gyre (NPTG), Pacific North Equatorial Countercurrent (PNEC), and Pacific Equatorial Divergence (PEQD), females (meals) reached sexual maturity round 102 cm (106 cm), 106 cm (100 cm), 125 cm (110 cm), and 113 cm (110 cm), respectively, the estimated L50 of bigeye tuna was 124.08 cm, 121.97 cm, 139.92 cm and 132.45 cm, respectively. The degree of populations mixing between equatorial (PNEC and PEQD) and high-latitude regions (NPST-east and NPTG) is extremely small, but it is reasonably high between the NPST-east and NPTG or PNEC and PEQD. These parameters were significantly different, suggesting the occurrence of a spatial difference in the size-at-maturity of bigeye tuna between these bio-ecological provinces. The findings of this study provide the key information for understanding the life history of bigeye tuna in the Eastern Pacific Ocean and will contribute to the conservation and sustainable yield of this species.

This study focuses on the analysis of seasonal dynamics of physicochemical parameters (pH and Eh) and organic matter content in the sediments accumulated within the impact zone of the cage trout farm (Lake Ladoga, Russia). The Ladoga is the largest lake in Europe and there are more than 20 fish farms located in the northern part of the waterbody. The geochemical research is necessary for predicting the negative impact of the polluted sediments on both the cage fish and the aquatic ecosystem. The sampling was conducted during various seasons of the year (February, June, August, October) which were characterized by the different fish feeding regimes. The sediment cores were collected at 7 points, including the cage and reference sites (150 m and 600 m far from the farm). The results showed that the accumulation of organic material released from the studied fish farms was local and the wastes did not enter the sediments at the control sites. Furthermore, the accumulated organic layer can be compacted and partially mineralized during winter period. Nevertheless, strongly reducing conditions in sediments occur due to the accumulation of organic material and low rate of water exchange within the studied bay. Therefore, there is a potential risk of formation of toxic gases and release of accumulated nutrients and metals from sediments to water. It can have a negative impact on benthic and nekton organisms, in particular cage fish.

In Amazonia, small-oriented family businesses or communities cultivate freshwater organisms as a source of income. Although effective management is fundamental for optimizing cultivated stocks, Amazonian aquaculture belittles the importance of genetic diversity, relying primarily on phenotypical characteristics during breeders’ selection. To provide a “proof of concept” built on the premise that implementing modern technologies is crucial to optimizing fish stocks in rural Amazonian fish farms, we conducted a pilot study assessing genetic diversity on cultivated Piaractus brachypomus from Caquetá, Colombia. We used mitochondrial control region (CR) sequences to evaluate heterogeneity. Our data revealed low genetic diversity and suggested that most sampled individuals probably originated from a single maternal lineage. Haplotype diversification resulted from discrete point mutations not associated with geographical location. Polymorphisms accumulate in non-conserved CR regions, yet the most divergent haplotypes display mutations in conserved CR sequences with roles in mitochondrial metabolisms and proliferation. Overall, our results indicate a need in the local industry to design breeding strategies to enhance diversity to avoid deleterious effects caused by inbreeding and domestication.

Changes in protein quality during ice storage affects the muscle structure, the textural quality, functional properties and the eating quality. Dynamic viscoelastic behaviour and gelling properties ofmeat proteinsin relation to histological changes in white leg shrimp muscles were assessed for 14 days in ice storage. Reduction in Ca2+ ATPase activity of fresh myofibrillar protein (MFP), fading of myosin banding pattern and increased gapping in myofibrils were clearly observed with progress of storage. The quality indices of the shrimp muscle were well correlated with histological and functional properties as a function of ice storage. Solubility of fresh MFP was 86.76% which decreased to 77.06% on the 14th day of storage period. Emulsion capacity found to increase during storage period. Gel strength of white leg shrimp meat was low (81 ± 14 g cm) and further, reduced nearly 60% compared to fresh sample at the end of storage. The considerable reductions (from 535.77 kPa to 246.56 kPa) in storage modulus values were evident of diminishing elasticity and gelling ability of the meat due to ice storage.Therefore, this study usherd that the histological deterioration in myofibrils may be used as an indication of diminishing biochemical quality and gelling behaviour of the proteins.

In recirculating aquaculture systems, nitrification is usually accelerated by inoculating nitrifier or mature biocarriers. In this study, the performance of the establishment of nitrification in the MBBR according to three different strategies: conventional method (Control group A), inoculation with biofloc recovered from a tilapia biofloc culture system (Group B), and addition with extra nitrite (Group C) in the Moving bed biofilm reactor (MBBR) was compared. Among them, the biofloc-inoculated group considerably accelerated the nitrification process in the MBBR (38 d), which is roughly 18 d faster than the control group (A) (56 d) and 21 d faster than group C (59 d). Less ammonia (8 mg/L NH4+-N, 10 mg/L in other groups) and external nitrite (2 mg/L NO2−-N) in the influent caused effluent ammonia to drop more slowly (5 d slower than the control group, 8 d slower than the B group), which is detrimental to the nitrification process' development. Notably, the influent's hydraulic retention time (HRT) was reduced from 12 h to 6 h following the successful establishment of nitrification. During the adaptation to reduced HRT, the MBBR inoculated with biofloc experienced short-term changes in the water quality index of the effluent water, whereas the other groups did not. The biofilm seeded with biofloc had the highest mean gray value ratio (1.42) of live/dead cell fluorescence, which grew better and could cover the entire groove under multiple microscope observations. However, the other groups did not demonstrate a similar trend. In summary, the research found that seeding biofloc use as nitrification bioaugmentation into the MBBR of the recirculating aquaculture system (RAS) to greatly speed up the nitrification process.

Responsible stock enhancement initiatives require baseline data of wild population demographic conditions that can be used in testing management outcomes. This study provides the first fishery-independent assessment of length- and age-based biological characteristics of exploited populations of Platycephalus fuscus in eastern Australia prior to stock enhancement. Sampling was conducted over seven estuaries spanning seven degrees of latitude and the geographical range of proposed stock enhancements. Populations in all estuaries showed evidence of length and age truncation, especially those subject to commercial fisheries where young individuals of both sexes dominated populations. Maximum longevities were 12 and 11 years for females and males respectively, but few females >5 years and males >3 years were generally sampled. Females dominated populations, and on average, the mean lengths and ages of females were greater than males within each estuary and across all age classes. Sexually dimorphic variation in growth was evident across all estuaries, with females attaining greater maximum lengths than males. Estuary-specific differences in individual growth were not identified. On average, over 50% of females sampled in each estuary were > the minimum legal length (MLL), but the opposite was evident for males. In contrast, over 25% of males in each estuary were > the mean length at maturity (L50), whereas in all but one estuary the L50. Stocked male and female P. fuscus should recruit to the fishery in 2 and 3 years, and contribute to the spawning stock in 1.5 and 4.5 years, respectively. This study provides important historical baseline data that can contribute to testing stock enhancement outcomes on populations.

Genetic breeding is an important approach to improve the economic traits of aquaculture animals. Unfortunately, the genetic basis for important economic traits of red swamp crayfish, including growth-related traits, has not yet been reported. In the present study, two full-sib families and two natural populations were employed to identify quantitative trait loci (QTLs) for growth-related traits of red swamp crayfish. In total, 28 QTLs for five growth-related traits, including body weight, body length, carapace length, carapace width, and abdomen length, were repeatedly identified in more than two families/populations, by means of association analysis; nine of these displayed a heterosis effect. The phenotypic variations of the five investigated traits explained by the 28 QTLs ranged from 4.2% to 19.0%. Eight additive and three heterosis QTLs were further successfully validated using comparative analysis of favoured alleles between the small and big size crayfish groups in the natural population. In conclusion, this study investigated the genetic basis of growth-related traits in red swamp crayfish, which is of great significance for their application in the future molecular breeding of the species.

Pampus argenteus and Pampus chinensis form the high-value demersal Pomfret fishery of Bangladesh. But, due to a monotonic decline in catches over the last five years, it is essential to explore the current stock status concerning the removal rate to ensure the sustainability of this fishery. Therefore, given the reliability and minimal data requirements, this study employed an extended Bayesian State-Space Surplus Production Model, JABBA (Just Another Bayesian Biomass Assessment), to assess the stock rigorously. The results revealed that the stock biomass of the Pomfret fishery in the final year of the time series is significantly lower than BMSY, the biomass required to produce MSY. Consequently, this study recommends a yearly catch limit (TAC) of 10,000 metric tons to prevent further depletion of the stock biomass. Furthermore, to avoid growth overfishing by allowing all immature fishes to reproduce at least once before being caught, this study also calculated the optimum length (Lopt) for catch for both species at which biologically maximum yield and revenue can be obtained. The estimated Lopt is 25 cm for P. argenteus and 30 cm for P. chinensis, and not to capture fishes with lengths lower than these limits, this study further calculated the minimum mesh size limits for gill and set bag nets is 7.5 cm. Though the mesh size regulation was estimated using length-based reference points derived from an empirical equation, this regulation can be used as an associate reference point when TAC is applied to assure the sustainability of this fishery.

Occurrence of biogenic amines in fresh fish and fishery products constitute a significant safety concern. Ingestion of histamine is identified as the causative agent of several food poisoning incidences on an annual basis. In addition, cadaverine, putrescine and tyramine have been recognized as potentiators of histamine poisoning. Accumulation of biogenic amines in fresh fish and fishery products has been mainly attributed to growth of bacteria possessing amino acid decarboxylase activity, which is facilitated by lack of hygienic conditions and strict temperature control during their storage. To this end, the effectiveness of traditional and modern approaches to control biogenic amine accumulation has been in the epicenter of intensive study. The aim of the present review article is to update and integrate current knowledge regarding the biogenic amine content of fresh fish and fishery products as well as the capacity of traditional and emerging control strategies.

IGS is abundant in polymorphism, which is widely used in the analysis of intraspecific genetic diversity and phylogenetic relationships among geographical populations. In this study, the 45S rDNA repeat unit of Saccharina japonica was obtained for the first time by BAC clone sequencing. The total length of the 45S rDNA repeat unit of S. japonica was 8 995 bp, including 5 420 bp of 18S-5.8S–25S rDNA, and 3 575 bp of IGS (Intergenic Spacer), with the GC content of 51.4 %. The IGS was composed of a 465 bp of 3â€⊃2;-outer transcribed spacer (ETS), an 874 bp 5â€⊃2;-ETS, and a 2 236 bp non-transcribed spacer (NTS), with the GC content of 50.1 %. Fiber-FISH (fiber-fluorescence in situ hybridization) analysis of the distribution of 45S rDNA repeat units on the bacterial artificial chromosome illustrated that each fiber had at least five continuously moniliform hybridization signal points. This study provided a new candidate molecular marker for detecting intraspecific polymorphisms of S. japonica. In addition, the successful fiber-FISH analysis of the 45S rDNA on BAC molecule would contribute to the construction of the physical map and map-based cloning of this kelp.

Gastrin (gas) is a peptide hormone that stimulates gastric acid secretion by gastric parietal cells and stimulates gastric motility. The cholecystokinin B receptor (cckbr) can act as a receptor for gastrin, conveying regulatory information on gastrin, but there are fewer studies on its function in fish. The Lateolabrax maculatus is one of the marine aquaculture species in China, it widely distribute in coastal areas. In the study, we cloned the genes of Lateolabrax maculatus gastrin (Lm-gas) and Lateolabrax maculatus cholecystokinin B receptor (Lm-cckbr). The results showed that the full-length gene of Lm-gas is 638bp and the carboxy-terminal conserved domain (DFGRR) is the core functional domain of gastrin protein. The Lm-cckbr gene has a total nucleotide sequence of 2066 bp, and the open reading frame encodes a total of 453 amino acids. The result of protein sequence alignment showed that the similarity between Lm-cckbr protein and other different species was 50.11%–89.67%. The PCR results showed that Lm-gas and Lm-cckbr were expressed in brain and stomach. Further localization by immunehistochemical staining showed that Lm-gas protein was located in the mucosal layer of the gastric wall, but the expression signal was weak in the brain. Hunger causeed a significant decrease in these two genes. The results provided basic research data for further study on the function of Lm-gas and its recepter Lm-cckbr in the in the central nervous system and digestive system of Lateolabrax maculatus.

Lysine-specific demethylase 4A (KDM4A) catalyzes demethylation of histone lysine residues, which regulates chromatin state and transcription. In drosophila and mice, KDM4A plays an important role in multiple biological processes including development, aging, metabolism, and immunity, however the functions of KDM4A in fish are still unclear. There are two copies of the kdm4a gene in zebrafish, namely kdm4aa and kdm4ab, kdm4aa was edited using CRISPR/Cas9 technology in the present study, then homozygous kdm4aa mutants (kdm4aa−/−) were obtained, and loss of kdm4aa was confirmed by sequencing and increased H3K9me3. Whole-mount in situ hybridization showed that kdm4aa is widely expressed during the embryonic development of zebrafish. Compared with WT zebrafish, kdm4aa−/− zebrafish showed no significant difference in gamete formation and fertilization, but the survival rate of kdm4aa−/− embryos dramatically reduced to 21% at 26 hpf. Further observation showed that about 80% of survived kdm4aa−/− zebrafish experienced disruption in stripe formation, and 10% of survived kdm4aa−/− zebrafish underwent vertebral malformation. Alizarin red S staining demonstrated the abnormal spinal development in kdm4aa−/− zebrafish. These results indicated that kdm4aa is required for normal embryonic development of zebrafish, loss of kdm4aa function leads to decreased survival during the early stages of zebrafish development and morphological variation in adult zebrafish.

The aim of this study was to record demersal species from lagoon in Luang Island, a small and remote island in Maluku, Indonesia. Quantitative and qualitative methods were employed with the assistance of the local fishers using 4 different methods of fishing: gillnets, spear guns, traps, and handlines. Fisher knowledge informed fish abundance and frequency of occurrence. A total of 348 individual fish distributed across 53 species were recorded from the catch of 4 gear types. Bray-Curtis similarity scores of fish assemblages at different habitats was ranged from 7.19% to 10.35%. The nMDS bi-plot visualized a distinct dimension with which to allocate 3 habitats separately from the sand-seagrass habitat. Significant similarity of species at 4 different habitats (ANOSIM R2 = 0.124, P = 0.002) suggested that the habitat parameter was not able to predict different communities of fish. This paper is the first contribution on the composition of lagoon ichthyofaunal in Southwest Maluku Regency. Wise attitude towards marine resource exploitation such as traditional conservation, less fishing pressure and marine culture will maintain the healthy ichthyofaunal assemblages in a tropical lagoon ecosystem.

Microfungi have been explored further as supplement constituents in shrimp culture due to their rich protein, lipid, essential amino acids, fatty acids, and various bioactive compounds. The researchers have evaluated the effects of two microfungi powders (Mucor circinelloides and Trichoderma harzianum) as feed supplements on growth performance, bacterial communities, and the biomass nutritional profile of white shrimp (Litopenaeus vannamei). The results showed that commercial/artificial feed (Feng-Li) with supplementation microfungi powder had a different effect on white shrimp growth performance than control after 62 days of the grow-out period. Supplementation with 1.5% M. circinelloides powder (M-2) could improve the growth performance of white shrimp, especially the survival rate (81.33%), final body weight (5.21 g), and shrimp biomass (211.35 g). In contrast, supplementation with 1.5% T. harzianum powder (T-2) did not improve the growth performance of white shrimp compared to control (p > 0.05). Furthermore, it also affected the profile of the bacterial community in culture water as well as in shrimp intestines. Supplementation with both microfungi could reduce the total number of bacteria in culture water at the end of the experiment, where the lowest number was obtained in treatment T-2 (3.9 × 10 5 CFU/mL), followed by M-2 (9.9 × 10 5 CFU/mL) and control (4.4 × 10 6 CFU/mL). In the culture water, 20 isolates of culturable bacteria were found during the trial, with the dominant bacteria in M-2: Bacillus cereus, Bacillus velezensis, Gordonia polyisoprenivorans, T-2: Acinetobacter sp., Gordonia polyisoprenivorans, Micrococcus luteus. Based on average well colour development (AWCD), the highest bacterial activity was in the M-2 (0.297–0.707), followed by T-2 (0.226–0.717) and control (0.094–0.694). The highest substrate group utilised in M-2 and T-2 were polymers (0.896 and 1.348) and control: amines (0.100). The highest Shannon diversity index was obtained in the M-2 (2.508), followed by control (2.286) and the T-2 (2.157). As many as 11 isolates of culturable bacteria were found in the shrimp intestine, with dominant bacteria in M-2: Bacillus velezensis, Micrococcus luteus, Bacillus cereus, T-2: Bacillus velezensis, Micrococcus sp.2, Demequina activiva. The highest bacterial activity was in M-2 (2.259), followed by control (2.020) and T-2 (0.050). The highest substrate group utilisation was in M-2: polymers (2.564), T-2: carbohydrates (0.094), and control: polymers (2.185). The highest Shannon diversity index was in the M-2 (3.234), followed by control (3.230) and the T-2 (0.751). In addition, 1.5% M. circinelloides and T. harzianum supplementation increased white shrimp muscle protein content up to 79.21% and 80.40%, respectively, compared to control (76.73%). In conclusion, using Mucor circinelloides powder as a feed supplement can improve the growth performance of white shrimp, increase the functional/probiotic bacteria: B. cereus and B. velezensis in cultur and shrimp's intestine, and increase the protein content in shrimp muscle tissue. However, more in-depth research is needed, especially on anti-nutritional compounds from fungi that affect shrimp growth.

China is the most productive seaweed farming country in the world and her seaweed imports and exports have a significant impact on global seaweed trade commodities and food security. Nevertheless, few studies had delved into the main characteristics and development of China's seaweed farming industry. This paper aims to narrow this research gap by analyzing trade patterns in China's seaweed products and the international competitiveness of seaweed product by using the international market share index (IMS), the trade competitiveness index (TC), and revealed comparative advantage index (RCA) from 2002 to 2017. The results showed that Japan, the Association of Southeast Asian Nations (ASEAN), Chile, Peru, and the Republic of Korea are China's main trade partners, the total trade value of China's seaweed products has grown rapidly, its imports have gradually exceeded exports, the trade deficit continues to expand, and its competitiveness keeps decreasing. The reasons for this trend may include the changing seaweed trade commodity structure, product differentiation, increased government support in competing countries, and trade barriers among the trade partners. We propose actively expanding international trade markets, establishing a strong seaweed product processing industry to develop high value-added seaweed products, optimizing the trade commodity structure, and differentiating of seaweed products to improve the competitiveness of China's seaweed products.

In order to develop a method that apply sampling survey data randomly obtained at fishing ports to fish stock assessments, based on fish landing surveys conducted at fishing ports in the northern South China Sea (SCS), 19 Threadfin porgy (Evynnis cardinalis) catch per unit effort (CPUE) datasets were collected for fishing vessels with different gear types and engine powers and incorporated into surplus production models. Considering only the fitting performance, the Schaefer model had the best overall goodness of fit, followed by the Fox, CYP, W–H, and Schnute models. Among fishing vessels with different gears and engine powers, the data were best fitted for single-trawl vessels powered by 301–400-kW engines and for gillnet vessels powered by > 200-kW engines. Eight model expressions were superior and selected for subsequent analyses based on their goodness of fit and relative residuals. The Kobe plot analysis results showed an optimistic fish stock status when using the four model expressions, required more caution when using three model expressions and output pessimistic estimations using one model expression. Considering the incomplete information acquired, a compromising decision-making method was used to derive a 2017 northern SCS E. cardinalis total allowed catch (TAC) of 44,691.21 t. The different conclusions drawn from estimations using CPUEs reflect variable exploitation and utilization fish stock statuses among fishing vessels with different gears and engine powers. Hence, the fishing operations were grouped according to their CPUE relationship, and recommendations regarding optimum fishing efforts were assigned to the groups following a fundamental principle: to improve fishery TAC management, fishing efforts should be reduced if the fish stock assessment is pessimistic and maintained if the assessment is optimistic. This study providing a feasible technical method for the TAC management of China's offshore fisheries.

Good information is the basis for good decisions. For many invaluable salmon species, chemical information is necessary to guide and fine-tune their migrations to and from freshwater mating grounds. A problem is that salmon of the current world are running a gauntlet of toxic chemicals arising from diverse anthropogenic inputs and these chemicals are known to disrupt information. There is sufficient evidence that effluents from cities, mines, agriculture and industry contain chemicals that can rapidly, and sometimes irreversibly, impair the olfactory sense that salmon use to gather information. Some toxic inputs may not only be strong enough to impair migration, but be strong enough to redirect salmon away from their routes. There is also evidence that some synthetic chemicals may serve as the basis for ‘new’ information and be useful in making correct migratory decisions. On the plus side, there are examples of new regulations that limit the input of chemicals of known olfactory toxicity, but on the minus side, increased urbanization and global climate change will likely increase the number and/or severity of some neurotoxic inputs. Here we identify the specific avenues of chemical risks to information disruption and in so doing prioritize and rank the risks to migrating salmon. The data collected here can be used to lay the foundation for modelling the effects of anthropogenic inputs on information disruption in diverse salmonid species from around the world and therefore help secure their longevity in a changing chemical environment.

Melanization of shrimp gills is a general symptom in shrimp black bill diseases (sBG); therefore, the cause is not immediately apparent. This study aimed to determine the primary and secondary agents associated with a black gill outbreak in the Delvar complex in the Bushehr Province of Iran. During July and August of 2020, 450 healthy and affected shrimps were collected based on brown to black gill color from three farms of the Bushehr Province in Iran. Characterization of pathogens was performed by gross signs, wet mounts, microbiological tests, histopathology methods, and sequencing of molecular markers. The mean weight and length of infected shrimps was significantly (P 

International soft law is not legally binding, but nevertheless it embodies mainstream values and influences the formation of hard law in global governance. Marine fisheries have become important arenas of global governance, in which developing states are crucial participants. The interactions between soft law and hard law in global marine fisheries can be mainly summarized as follows: soft law can be the precursor for hard law and be implicitly introduced into hard law to enhance normativity; hard law can also be incorporated into soft law. This paper explores the IUU fishing case to illustrate the significant role of soft law on international fisheries law and identify gaps in global marine fisheries governance. The development of international instruments to combat IUU fishing within FAO undergoes a process from voluntary to legally binding with the engagement and promotion of some developed states for their benefits. But IUU fishing concept is defective in its drafting as well as in practical application and indicates the value of emphasizing conservation over economic and social development, which is contrary to the principle of sustainable development and fails to meet the requirements of the developing states. The paper suggests to fill this gap by converting existing values in soft law to foster fishing rules that benefit all states and provide some insights towards this direction.

Major histocompatibility complex (MHC) molecules play a critical role in the immune response of vertebrate animals by presenting foreign antigens to T lymphocytes. In this study, we first cloned and identified a classical and a novel nonclassical MHC I α molecules from Japanese eel (Anguilla japonica), named as AjMHC I-UBA and AjMHC I-L, respectively. The full-length cDNA of AjMHC I-UBA contains an open reading frame (ORF) of 1047 bp encoding a predicted protein of 348 amino acids, while AjMHC I-L 1089 bp encodes 362 amino acids. The multiple alignment of the amino acid sequence showed that AjMHC I-UBA and AjMHC I-L consist of an N-terminal MHC I superfamily domain within α1 and α2 helices, an IgC-MHC I α3 domain, and a transmembrane region close to the C-terminal, which are similar to other fish and mammal species. Molecular polymorphism analysis showed that eight different major alleles of AjMHC I-UBA, named as AjMHC I-UBA*0101～1001, were identified from six Japanese eel individuals. Furthermore, a distinguishing signature of the nonclassical L-lineage genes specific motif “HINMTL”, including an N-glycosylation site (NXS/T), was present in the α3 domain of AjMHC I-L sequences. Although the predicted three-dimensional structures of AjMHC I-UBA and AjMHC I-L are similar to that of human MHC I α, phylogenetic analysis showed that these two protein molecules belong to classical MHC I UBA gene of U-lineage and nonclassical MHC I gene of L-lineage, respectively. Quantitative real-time polymerase chain reaction (qRT-PCR) analysis revealed that the highest expression of AjMHC I-UBA and AjMHC I-L was found in the intestine and the expression level of AjMHC I-UBA in all of the examined tissues was significantly higher than that of AjMHC I-L. The expressions of AjMHC I-UBA and AjMHC I-L in liver, kidney and spleen were significantly induced following injection with the viral mimic poly I:C, LPS, and Aeromonas hydrophila infection. In vitro, the AjMHC I-UBA and AjMHC I-L transcripts of Japanese eel liver cells were significantly enhanced by the treatment of poly I:C or the stimulation of the high concentration of A. hydrophila. Subcellular localization showed that under natural conditions, AjMHC I-UBA and AjMHC I-L were uniformly distributed in the cytoplasm, and aggregated into spots or flakes in the cytoplasm after the stimulation of poly I:C or LPS. These results collectively suggested that AjMHC I-UBA and AjMHC I-L are important components possibly involved in Japanese eel defense against viral and bacterial infection. Taken together, these findings provide valuable insight into the immune function of MHC class I in the immune system of teleost.

In this study, we investigated the impact of water temperature on pearl formation and the molecular mechanisms underlying this biomineralization process in the mussel Hyriopsis cumingii. In the laboratory experiment, recipient mussels received saibo grafts from donor mussels and then were cultivated at five temperatures (16, 20, 24, 28, and 32 °C) for 1 month. We found that speed of pearl formation varied with water temperature: there was no visible pearl granules at 16 and 20 °C, tawny pearl granules were collected at 24 °C and lustrous pearl granules were collected at 28 and 32 °C. The expressions of several nacreous layer matrix protein genes (hic22, hic24, HcTyr Hc-upsalin and Hcperlucin) at 28 °C and 32 °C were peaked on day 28, and the expressions of other nacreous layer matrix protein genes (hic52 and hic74) on day 28 were significant higher than day 14. In the natural environment, pearl deposition rate also increased as water temperature rose, and the optimum range for pearl growth in H. cumingii was between 28.3 and 30.3 °C. Expression of the prismatic layer-related matrix protein genes hic31 and both prismatic and nacreous layer-related matrix protein gene silkmapin was significantly high in winter, and expressions of the nacreous layer-related matrix protein genes (hic24, hic74, HcTyr, Hc-upsalin and Hcperlucin) were always higher during higher temperature seasons compared with winter. These results indicate that high water temperature can speed up pearl formation and further regulate matrix protein secretion to accelerate pearl nacre deposition.

The study investigated the genetic variation of Parachanna obscura from five rivers (Anambra, Ibbi, Imo, Katsina-Ala and Ogun) in Nigeria using the mitochondrial cytochrome oxidase 1 gene. DNA was extracted from 19, 22, 16, 18 and 21 fin clips per river population, respectively and subjected to polymerase chain reaction. A total of 96 sequences, each with 671 bp were obtained with 38 (5.6%) polymorphic, 27 (3.8%) parsimoniously informative and 659 (98.2%) conserved sites. Mean nucleotide composition was C = 28.07%, T = 29.43%, A = 22.18%, G = 20.32%. A total of 40 haplotypes with 38 unique sequences as well as 24 substitutions with 22 transversions and two transitions were obtained. Nucleotide diversity among populations ranged from 0.00184 to 0.00888 representing Ibbi and Imo, respectively while haplotype diversity ranged from 0.77056 to 0.95000 also, from Ibbi and Imo, respectively. Analyses of molecular variance showed that the intra-population variation accounted for 50.05%. Topology from phylogenetic analyses revealed that P. obscura from Imo River was distinctly different from the rest.

In this paper, we studied the structure, expression and function of black carp insulin gene. The complete Mylopharyngodon piceus insulin (Mp-Ins) gene is 1,965 bp long and includes a 1,499 bp 5Ê⊃1;-untranslated region (UTR), a 139 bp 3â€⊃2;-UTR with a poly(A) tail, and an open reading frame (ORF) of 327 bp. The predicted molecular weight of the recombinant Mp-Ins(rMp-Ins) protein is 11.87 kDa. The mRNA expression of Mp-Ins is upregulated in the brain and liver. After the injection of rMp-Ins, Mp-Ins mRNA transcript abundance was significantly upregulated in the liver. The rMp-Ins protein could inhibit the concentration of glycogen phosphorylase (GP), growth hormone (GH), fatty acid synthase (FAS), and insulin-like growth factors-1 (IGF-1), and it also significantly increased the concentration of PI3K. Additionally, the injection of rMp-Ins did not have a significant impact on the glucose-6-phosphatase (G6Pase) content in blood. In situ hybridization results showed that the positive signal of the Mp-Ins gene was mainly concentrated in the cell nucleus of brain tissue and the cell membrane of liver tissue and muscle tissue. Together, these results demonstrated that Mp-Ins plays an important role in growth and metabolism in M. piceus.