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This study investigated the effects of different water temperatures (20, 23, 26 and 29°C) on the ovarian development and biochemical composition of Portunus trituberculatus (a swimming crab) after mating. The results showed that the higher the water temperature was, the faster the ovarian development, especially the GSI in the 29°C group was significantly higher than that in the 20°C and 23°C groups (P < 0.05). The hepatosomatic index (HSI) decreased with increasing water temperature, but there was no significant difference between the groups at different water temperatures (P > 0.05). The muscle yield (MY) was basically maintained at approximately 34%. The condition factor (CF) of the crab reached 0.62 in the 29°C group, which was significantly higher than that in the 20°C and 23°C groups (P < 0.05). Histological observation revealed that the number of lipid droplets and the degree of homogenization of yolk granules in ovarian oocytes gradually increased with the increase of the water temperature. From the perspective of conventional biochemical composition, the moisture and crude protein contents in muscle and the crude fat content in hepatopancreas did not change much among the groups, but the crude protein content in the ovary of the 29°C group was as high as 24.65%, which was significantly higher than that in the other three groups (P < 0.05). In terms of fatty acid composition, there was little difference in the fatty acid content in the ovaries of the different water temperature groups. The contents of C22 : 2n6 and C18 : 3n3 in polyunsaturated fatty acids were significantly higher in the 29°C group than in the other three groups (P < 0.05). In the hepatopancreas, the contents of C22 : 5n3 (DPA) and C22 : 6n3 (DHA) in the 20°C group were the lowest, 0.07% and 0.15%, respectively, which were significantly lower values than in the 29°C group (P < 0.05). The change of amino acid content is mainly reflected in ovarian tissues, showing a gradual upward trend as a whole. Furthermore, the essential amino acid score (EAAS) and average score of the two tissues in the 20°C and 23°C groups were relatively close, and both reached the highest score in the 29°C group. Overall, with increasing water temperature, the rate of ovarian development significantly accelerated, and the nutritional quality of the tissues improved in these swimming crabs. [ABSTRACT FROM AUTHOR]

Early juveniles of the swimming crab Portunus trituberculatus are known to use drifting seaweed before transitioning to benthic habitats in a behaviour that is thought to be a strategy to avoid shallow water predators. However, little is known about whether the predation risk of P. trituberculatus juveniles is reduced in such seaweed. To assess the nursery function of drifting seaweed for P. trituberculatus as a refuge from predation, we conducted field experiments to compare the relative survival of first to fifth instar (i.e. small to large body size) juveniles tethered to floating macroalgae that mimicked drifting seaweed and to unstructured sand habitats. The survival of tethered juveniles was higher in floating algae than in sand. This was particularly evident among first- to third-instar juveniles, which exhibited less burying behaviour. Thus, first- to third-instar juveniles with small body size and less burying habits are likely to be most vulnerable to predation, and drifting seaweed may function as a nursery vehicle, providing refuge from predators. [ABSTRACT FROM AUTHOR]

The toxic effect and differences of Cr(VI) on superoxide dismutase (SOD) activity, MDA, and metallothionein (MT) content in the hepatopancreas and gill of Portunus trituberculatus were investigated during Cr(VI) enrichment (15 days) and release experiments (15 days). Results showed that the 1.50 and 0.30 mg/L test groups significantly exhibited higher SOD, MDA, and MT content in the hepatopancreas and gill compared with the control group after 15 days of enrichment (p < 0.05). After 15 days of Cr release, the SOD, MDA, and MT content in the hepatopancreas and gill of both test groups recovered to the normal level of the control group (p > 0.05). The gill of P. trituberculatus achieved the highest SOD activity, MDA, and MT content earlier than the hepatopancreas, but the highest values were lower. The gill showed a shorter recovery time than the hepatopancreas. We concluded that the gill of P. trituberculatus exhibited a more rapid response to, and recovery from, Cr(VI) exposure compared to the hepatopancreas, making it a more sensitive tissue for assessing Cr(VI) toxicity, though both tissues showed a capacity for recovery after the removal of the contaminant. [ABSTRACT FROM AUTHOR]

Understanding the feeding behavior of Portunidae crabs with different baits can improve bait selection and is crucial for improving the effectiveness of crab fishing gear. This study, conducted in indoor experimental tanks, used trajectory tracking software and two types of natural baits (mackerel (Scomber australasicus) and squid (Uroteuthis chinensis)) to understand the behavior of Portunus sanguinolentus and Charybdis natator. Spatial distribution results showed that P. sanguinolentus was frequently present in the starting area (S1) and bait area (S3) in the control and treatment groups. However, C. natator was frequently present and concentrated in the S1 area compared to the middle areas S2 and S3, and only in the mackerel treatments were they observed to move to the S3 areas. The spatial distribution results indicate that P. sanguinolentus shows a stronger willingness to explore its surroundings, while C. natator is generally in a stationary, wait-and-see state. The swimming speeds of P. sanguinolentus and C. natator showed different trends. P. sanguinolentus showed continuous movement with no fixed speed when no bait was present in the control groups. However, when treated with mackerel and squid, the average swimming speed of P. sanguinolentus was faster (>5 cm/s) in the first 10 min and showed a more stable movement speed when searching for the baits. C. natator showed a stationary or low movement speed when no bait was present in the control groups. However, when C. natator perceived the presence of the baits in the treatment groups, their movement speed increased in the first 10 min. In addition, there was no significant difference between male and female crabs of P. sanguinolentus and C. natator in movement speed in the control and treatment groups. Compared to C. natator, P. sanguinolentus might be more sensitive to natural baits, as shown by its movement from S1 to S3. The results indicate that the species of Portunidae crabs show different bait selections. Natural baits (mackerel and squid) are recommended for catching P. sanguinolentus in crab fisheries. [ABSTRACT FROM AUTHOR]

Copyright of South China Fisheries Science is the property of South China Fisheries Science 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.)

Background: Anxiety refers to the pathological persistence and intensification of emotional responses to danger, affecting health from psychological and physical aspects. Serotonin is an important neurotransmitter involved in the onset of anxiety. Methods and Results: To explore the biological changes in the formation of anxiety in crustaceans under the regulation of serotonin, we applied the open field-like test method for assessing anxiety states of larval Portunus trituberculatus, a highly aggressive crustacean species with a more simple neural structure compared with rodents and mammals. Compared with the control group, serotonin treatment resulted in a significant decrease in the time spent by the larvae in the central zone, suggesting anxiety-like behavior. Clonazepam treatment reversed this result and provided further evidence that the behavior of larval P. trituberculatus displayed anxiety. Moreover, a non-targeted metabolomic analysis found a significant alteration in the metabolites involved in tryptophan metabolism pathways associated with anxiety, including L-kynurenine, N-acetyl serotonin, and serotonin. These metabolites are involved in the serotonin pathway, the kynurenine pathway, and other pathways that affect anxiety through tryptophan metabolism. There were no significant differences in tryptophan metabolism levels between the control and clonazepam treatment groups. Conclusions: Our results demonstrate the possible existence of anxiety-like behavior in the larvae of P. trituberculatus from two perspectives. Being a species with a simpler neural structure than that of mammals, the larvae of P. trituberculatus offer a convenient model for studying the mechanisms of anxiety in crustaceans. [ABSTRACT FROM AUTHOR]

Sahu, A.; Venkataramani, V.K.; Chandravanshi, S., and Chandran, S., 2024. Spatio-temporal distribution of portunid crabs within the Gulf of Mannar, southeast coast of India. Journal of Coastal Research, 40(5), 937–951. Charlotte (North Carolina), ISSN 0749-0208. To explore the variety of portunid crabs along the Gulf of Mannar coast, an intensive survey was conducted for 1 year from October 2021 to September 2022. The sampling was done biweekly, at four landing sites, i.e., Vedalai, Keelakarai, Therespuram, and Thiruchendur. The Gulf of Mannar has a rich diversity of portunid crabs, and bottom set gillnets are the primary method of capture. Twenty-seven species were recorded in the study area, representing five genera. The genus Charybdis recorded the highest number of species with 11 species, followed by the genus Portunus and the genus Thalamita with eight and four species, respectively. The genus Scylla and the genus Podophthalmus were represented by three and one species, respectively. To conduct the biodiversity assessment, the occurrence and abundance data of portunid crabs were collected for 12 months in all the selected landing centers in the Gulf of Mannar. The data collected were pooled together by month, station and season, which included summer (March-May); pre-monsoon (June-August); monsoon (September-November) and post- monsoon (December-February). From the collected occurrence and abundance data, 15 biodiversity indices were calculated using the PRIMER v7 computer software package. [ABSTRACT FROM AUTHOR]

Objective: Metals have been reported to alter the oxidative status of both redox‐active and redox‐inactive metals accompanying oxidative stress induction. In aquatic ecosystems, metal contamination is regarded as serious pollutants and bioaccumulation, especially when aquatic seafood products are involved, which results in human risk. The blue swimming crab Portunus pelagicus is a highly popular crab species for consumption as seafood in Thailand. The meat parts and the hepatopancreas (HP) together with gonad are consumed and in high demand. Therefore, the present study aimed to investigate bioaccumulation of cadmium (Cd) and lead (Pb) along with tissue oxidative responses in P. pelagicus. Methods: Sixty‐seven samples of P. pelagicus were obtained from small‐scale fishers along the coastline of Trang Province. Bioaccumulation of Cd and Pb and oxidative response in gill, muscle, and HP + gonad were evaluated. Result: Cadmium and Pb accumulation levels were highest in the HP and gonad, followed by the gill and then muscle, indicating that Cd and Pb have a high affinity to be concentrated in the HP and gonad. An organ‐specific oxidative response to Cd and Pb accumulation was demonstrated in which Cd significantly activated superoxide dismutase (SOD) activity in the gills and muscle tissue, while Pb significantly activated the SOD activity only in the HP and gonad. Only Cd accumulation in gill tissue represented a significant activation of lipid peroxidation, as indicated by the malondialdehyde level. Conclusion: This study implied that P. pelagicus exhibits an "adaptive stage" in the oxidative response of tissue due to metal accumulation. Additionally, the data presented here further indicate that the consumption of only the meat parts and removal of the HP and gonad would reduce human exposure to metal toxicity. Impact statementThis is the first report to assay oxidative response related to cadmium (Cd) and lead (Pb) accumulation in blue swimming crabs along the coastline of Trang Province, Thailand. The relative organ accumulation levels for Cd and Pb were highest in the hepatopancreas and gonad, followed by the gill and then muscle. [ABSTRACT FROM AUTHOR]

Short neuropeptide F (sNPF) is a neuropeptide that widely distributed among arthropods. This neuropeptide has been proposed to play pleiotropic roles in insects, but its physiological functions in crustaceans are poorly understood. Here, we cloned the cDNA sequences of sNPF and its putative receptor (sNPFR) from the swimming crab, Portunus trituberculatus, and determined their possible roles during ovarian development. PtsNPF encodes three sNPF mature peptides with a conserved C-terminal "RLRFG" motif. All three PtsNPF peptides concentration-dependently activated PtsNPFR expressed in HEK293T cells, with EC50 values in the nanomolar range. PtsNPF and PtsNPFR transcripts showed a broad distribution among neural and non-neural tissues. During the ovarian development, expression of PtsNPF and PtsNPFR in hepatopancreas and ovary both increased to the highest levels at the late-vitellogenic stage, a period for rapid vitellogenesis. The in vitro experiments further showed that, among the three sNPF peptides, sNPF3 treatments can induce the vitellogenin (Vg) gene and protein levels in the hepatopancreas, as well as the Vg receptor (VgR) gene and protein levels and vitellogenin (Vn) deposition in the ovary. Opposing effects were observed for the dsPtsNPFR treatments, suggesting that PtsNPFR plays a role in the PtsNPF-mediated vitellogenesis. Additionally, it was found that the PtsNPF/PtsNPFR system can activate different second messengers species in hepatopancreas and ovary, suggesting it may act via different G proteins. [ABSTRACT FROM AUTHOR]

Simple Summary: Functional studies of neuropeptides are of great significance in revealing the neuroendocrine regulation mechanism in crustaceans, and in guiding and developing artificial regulation techniques in economic species. In this paper, we investigated the effect of a crustacean neuropeptide corazonin (Crz) on ecdysteroid synthesis based on the high expression of Crz receptor in the Y-organ, the main site of ecdysteroid synthesis. By using Crz treatment and CrzR silencing, we found that Crz/CrzR signaling could cause up-regulation of ecdysteroid synthesis genes and an increase in ecdysteroid levels both in vitro and in vivo. In addition, it was also observed that Crz/CrzR signaling affects the expression level of ecdysis-triggering hormones. Our results provide new insights into the understanding of Crz function in crustaceans. The neuropeptide corazonin (Crz) exerts diverse physiological effects in insects, yet its role in crustaceans remains elusive. The abundant expression of Crz receptor (CrzR) in the Y-organs of several crustaceans suggests a potential involvement of Crz in regulating ecdysteroid synthesis. In this study, we examined the effects of PtCrz on ecdysteroid synthesis during the molting period of Portunus trituberculatus through PtCrz treatments and PtCrzR silencing. Our results showed that PtCrz peptide stimulates ecdysteroid levels and the gene expression involved in ecdysteroidogenesis both in vitro and in vivo, whereas dsPtCrzR treatments had opposite effects on ecdysteroid levels and associated gene expression. Thus, our study suggests that PtCrz may modulate ecdysteroid synthesis via Y-organ-expressed PtCrzR. Furthermore, we also discovered the involvement of PtCrz/PtCrzR signaling in regulating PtETH expression. Notably, the inhibitory effect of dsPtCrzR on ecdysteroid synthesis or PtETH expression can be reversed by PtCrz treatment, suggesting the potential existence of multiple receptors for PtCrz. This study provides new insights into the function of crustacean Crz and, for the first time, elucidates the presence of a neuropeptide that can stimulate ecdysteroid synthesis in crustaceans. [ABSTRACT FROM AUTHOR]

Bone tissue engineering (BTE) provides an alternative for addressing bone defects by integrating cells, a scaffold, and bioactive growth factors to stimulate tissue regeneration and repair, resulting in effective bioengineered tissue. This study focuses on repurposing chitosan from blue swimming crab (Portunus pelagicus) shell waste as a composite scaffold combined with HAP and COL I to improve biocompatibility, porosity, swelling, and mechanical properties. The composite scaffold demonstrated nearly 60% porosity with diameters ranging from 100–200 μm with an interconnected network that structurally mimics the extracellular matrix. The swelling ratio of the scaffold was measured at 208.43 ± 14.05%, 248.93 ± 4.32%, 280.01 ± 1.26%, 305.44 ± 20.71%, and 310.03 ± 17.94% at 1, 3, 6, 12, and 24 h, respectively. Thus, the Portunus pelagicus scaffold showed significantly lower degradation ratios of 5.64 ± 1.89%, 14.34 ± 8.59%, 19.57 ± 14.23%, and 29.13 ± 9.87% for 1 to 4 weeks, respectively. The scaffold supports osteoblast attachment and proliferation for 7 days. Waste from Portunus pelagicus shells has emerged as a prospective source of chitosan with potential application in tissue engineering. [ABSTRACT FROM AUTHOR]

In accordance with the framework of the Circular Blue Bioeconomy in the Mediterranean region, the objective of this study was to evaluate the biotransformation of blue swimming crab (Portunus segnis) residues obtained from the port of Sfax by an extracellular chitinase produced by Nocardiopsis halophila strain TN-X8 isolated from Chott El Jerid (Tozeur, Tunisia). From the analysis of multiple extremophilic Actinomycetota, it was determined that strain TN-X8 exclusively utilized 60 g/L of raw blue swimming crab as its carbon and energy source, achieving a chitinase activity of approximately 950 U/mL following a 6-day incubation period at 40 °C. Pure chitinase, designated as ChiA-Nh30, was obtained after heat treatment, followed by ammonium sulfate fractionation and Sephacryl® S-200 column chromatography. The maximum ChiA-Nh30 activity was observed at pH 3 and 75 °C. Interestingly, compared with cyclohexamidine, ChiA-Nh30 showed a good antifungal effect against four pathogenic fungi. Furthermore, when using colloidal chitin as substrate, ChiA-Nh30 demonstrated a higher degree of catalytic efficiency than the commercially available Chitodextrinase®. In addition, ChiA-Nh30 could be immobilized by applying encapsulation and encapsulation-adsorption techniques. The kaolin and charcoal used acted as excellent binders, resulting in improved ChiA-Nh30 stability. For the immobilized ChiA-Nh30, the yield of N-acetyl-d-glucosamine monomers released from 20% (w/v) blue swimming crab residues increased by 3.1 (kaolin) and 2.65 (charcoal) times, respectively. [ABSTRACT FROM AUTHOR]

This study aimed to assess the sustainability status of the blue swimming crab fisheries resources in Bone Bay through a rapid assessment approach to the dimensions of sustainable fisheries development. A multidimensional scaling (MDS) approach through the rapfish process was used to assess the sustainability status of the blue swimming crab fisheries. The sustainability analysis was expressed in the sustainability index of fisheries management. The results showed that the sustainability status of the blue swimming crab fishery in Bone Bay was categorized as less sustainable with an average value of 38.43%. The ecological, economic, social, technological and institutional dimensions were categorized as less sustainable. 24 attributes contributed to the sustainability index value (leverage analysis) of the blue swimming crab fisheries management in Bone Bay, which requires an important attention in the sustainability of the blue swimming crab fisheries management. [ABSTRACT FROM AUTHOR]

The fabrication of a biodegradable polycaprolactone (PCL)/hydroxyapatite (HAp) scaffold prepared from local waste blue crab shells (Portunus pelagicus) by melt spinning method was investigated. The effect of different KH2PO4 concentrations on the physico‐chemical properties of HAp is evaluated. Furthermore, the influence of PCL/HAp ratios on mechanical strength and particle size distribution is reported. The formation of HAp is confirmed by Infrared (IR) spectroscopy and X‐ray diffraction (XRD). The biocompatibility of the PCL/HAp composites was evaluated using MTT assay and mechanical tests. The results reveal that the increase in KH2PO4 concentration contributed to the higher yield of HAp. However, the crystal and particle sizes are relatively invariable. SEM micrograph shows that the HAp introduction into PCL improves the material's porosity. Moreover, adding 10 % HAp into the PCL matrix significantly improved the mechanical strength of the filament compared to commercial PCL. MTT assay exhibits above 90 % cell viability, implying that the prepared PCL/HAp composite is non‐toxic and biocompatible with artificial bone replacement. After all, this study demonstrates that PCL/HAp filament derived from local blue crab waste is highly promising as a bone scaffolding material. [ABSTRACT FROM AUTHOR]

The blue swimming crab is one of the fishery commodities that constitute the major component of Indonesia's third highest export products after shrimp and fish. The slightly expensive crabs in the market include Portunus pelagicus , which is commonly found in Indonesia alongside Portunus sanguinolentus. However, P. sanguinolentus is considered a secondary species due to the lower catch numbers in the country, specifically on Madura Island. The research about this particular crab is still very limited and the importance of information on secondary species stock units is to restore degraded ecosystems through appropriate programmes. Truss Network Analysis (TNA) was applied to measure the crab's morphometric characteristics. The Kruskal–Wallis test, cluster analysis, and discriminant analysis were the statistical methods used to identify the stock units. The results showed different characteristics of swimming crabs in four locations on Madura Island, namely in the Bangkalan, Sampang, Pamekasan, and Sumenep Regencies. These indicated that different characteristics exist in male crabs found in Bangkalan, Sumenep, and Sampang, which have the highest level of similarity. In contrast, the females formed two clusters consisting of the groups Sampang and Sumenep, as well as Bangkalan and Pamekasan. The group differences show the potential of all crabs in the four locations to have more than one stock unit, hence their management needs to be differentiated. [ABSTRACT FROM AUTHOR]

Portunid crabs are an iconic, high value species in NSW, but catches are highly variable in space and time. Substantial variation in biomass is observed in both exploited and unfished populations, and environmental effects on distribution and abundance are an important factor contributing to this variability. Predicting and responding to this variability is a challenge for management and sustainability of exploited populations. We examine spatial and temporal variation in Blue Swimmer Crab (Portunus armatus) populations, over a 2.5 year trapping survey in two temperate estuaries that differ in tidal flow and riverine input. Specifically, monthly catch rates and distribution throughout the estuary are examined alongside variation in temperature and conductivity. In Wallis Lake, the shallower estuary with a restricted entrance, both water temperature and conductivity impacted abundance and distribution of crabs but there was no evidence that pulses of freshwater flow had a major impact. For a 10 °C increase in temperature the population on average shifted ~ 700 m closer to the ocean. Males were consistently located slightly further into the estuary compared to females, but there was no convincing evidence of estuarine egression in response to lower salinity. In Port Stephens, the deeper, tidal estuary, water temperature and conductivity also impacted abundance, but while males were more dispersed than females, the distribution of crabs within the estuary did not appear to be influenced by temperature, conductivity or flow. These results highlight the links between nuanced environmental relationships and estuarine geomorphology for Blue Swimmer Crab. [ABSTRACT FROM AUTHOR]

Blue swimming crab (Portunus pelagicus) is a type of marine product with high economic value and is popular in society. One of the gear types used in catching blue swimming crab is crab traps. One of the determining factors for the effectiveness of crab trap usage is the selection of suitable bait to enhance catch results. This study aims to assess the impact of using various types of bait on the effectiveness of catching blue swimming crab using foldable crab traps. The research activities were conducted at ten fishing locations in Kendal waters, Central Java, in September 2023. The bait tested in this study included goat skin, salted ponyfish, and salted pufferfish. This study utilized experimental fishing method, where catches were made directly in the natural habitat of blue swimming crab. Data collection and analysis were conducted using a randomized complete block design (RCBD). The results revealed a total catch during the research period of 410 individuals with a total weight of 38,696 grams, involving seven different species. Blue swimming crab dominated the catch results with a percentage of 66.4%, followed by stone crab at 11.9%, and reef crab at 9.2%, as well as other smaller catches. Different bait types were found to affect catch results, with goat skin bait proving to be the most effective in catching blue swimming crab. [ABSTRACT FROM AUTHOR]

A total of 1315 individuals were collected from the catches off the Bawasalo waters during March -August 2023. This study aimed to analyze the population parameters and exploitation rate of blue swimming crab (Portunus pelagicus), caught by fishermen using a bubu naga fishing gear in the waters of Bawasalo, Pangkep District, South Sulawesi. The observed parameters included the size distribution of the carapace width, carapace width-weights relationship, age group, growth rate, total mortality rate, natural rate, fishing rate, and exploitation ratio analyzed with the ELEFAN II program. The size of carapace width ranged from 6.70 to 13.80cm, with the highest proportion observed at carapace widths between 9.10 and 9.60cm (19.7%) and the lowest proportion observed at carapace widths between 13.3 and 13.8cm (0.2%). Carapace widths below 10cm accounted for 66.69% of captures, while those above 10cm accounted for 33.31%. The carapace width-weight relationship was computed as W = 0.1038L2.7334 (negative allometric). The von Bertalanffy growth parameters were estimated to be K = 0.41 yr-1, Lmax = 15.10 cm, and t0 = -0.723 yr. The total mortality (Z), natural mortality (M), and fishing mortality (F) were calculated as 2.70, 1.22, and 1.48 yr-1, respectively. The exploitation rate (E = 0.55) suggests that the stock of P. pelagicus was slightly higher than that of an optimally exploited stock. [ABSTRACT FROM AUTHOR]

This study aimed to assess the influence of varying dietary levels of astaxanthin (AST) on the growth, antioxidant capacity and lipid metabolism of juvenile swimming crabs. Six diets were formulated to contain different AST levels, and the analyzed concentration of AST in experimental diets were 0, 24.2, 45.8, 72.4, 94.2 and 195.0 mg kg−1, respectively. Juvenile swimming crabs (initial weight 8.20 ± 0.01 g) were fed these experimental diets for 56 days. The findings indicated that the color of the live crab shells and the cooked crab shells gradually became red with the increase of dietary AST levels. Dietary 24.2 mg kg−1 astaxanthin significantly improved the growth performance of swimming crab. the lowest activities of glutathione (GSH), total antioxidant capacity (T-AOC), superoxide dismutase (SOD) and peroxidase (POD) were found in crabs fed without AST supplementation diet. Crabs fed diet without AST supplementation showed lower lipid content and the activity of fatty acid synthetase (FAS) in hepatopancreas than those fed diets with AST supplementation, however, lipid content in muscle and the activity of carnitine palmitoyl transferase (CPT) in hepatopancreas were not significantly affected by dietary AST levels. And it can be found in oil red O staining that dietary 24.2 and 45.8 mg kg−1 astaxanthin significantly promoted the lipid accumulation of hepatopancreas. Crabs fed diet with 195.0 mg kg−1 AST exhibited lower expression of ampk, foxo, pi3k, akt and nadph in hepatopancreas than those fed the other diets, however, the expression of genes related to antioxidant such as cMn-sod, gsh-px, cat, trx and gst in hepatopancreas significantly down-regulated with the increase of dietary AST levels. In conclusion, dietary 24.2 and 45.8 mg kg−1 astaxanthin significantly promoted the lipid accumulation of hepatopancreas and im-proved the antioxidant and immune capacity of hemolymph. [ABSTRACT FROM AUTHOR]

Copyright of Jurnal Ilmu dan Teknologi Kelautan Tropis is the property of IPB University 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.)

The quality of crustacean aquatic products is affected by feed. Cholesterol (CHO), an essential element for crustacean growth, has been widely supplemented in diet, but its food quality regulation remains unclear. The study aimed to investigate the effects of different dietary CHO levels (0.12%, 1.00%, and 2.50%) on the nutritional value and flavor quality in the edible parts of female swimming crabs (Portunus trituberculatus). Results showed that dietary CHO levels significantly increased lipid content in the hepatopancreas and promoted the accumulation of n-3 long-chain polyunsaturated fatty acids (LC-PUFA) in the hepatopancreas and muscle by activating the gene expression related to biosynthesis pathways. However, with dietary CHO levels increased, protein content in muscle decreased significantly. This may be related to dietary CHO supplementation (especially 2.50% CHO level) suppressed amino acid accumulation in the hepatopancreas and muscle by downregulating the target of the rapamycin pathway and upregulating amino acid catabolism-related genes. Moreover, 1.00% CHO treatment had higher relative levels of volatiles, producing grassy, fruity, and fatty odors in muscle, which may be due to the upregulation of the branched-chain amino acid transaminase (bcat) expression level. Dietary CHO weakened nucleotide and free amino acid accumulation in hepatopancreas and muscle. Overall, this study suggests that dietary 1.00% CHO level had higher LC-PUFA and pleasing flavor substances in muscle but was not conducive to hepatopancreatic protein and flavor nucleotide deposition of swimming crab. [ABSTRACT FROM AUTHOR]

Portunus sanguinolentus (Herbst, 1783) is an important commercial crab with a wide distribution along the Indian coast. In Kerala it is landed mainly in trawls, and ranks first in the landings in most years, recording about 50% of the crab landings of the state during 2012-2019, with the exception of 2014. Females dominate the fishery and their sizes range between 55 and 170 mm carapace width (CW), with 90-110 mm being dominant in the landings. Berried females are recorded throughout the year, without any regular dominance in a particular month, although during March-May good percentages of these are observed in overall landings. Newly spawned eggs are bright yellow/orange in colour, with an average size of 270 μ m, and by the time of hatching the colour changes to dark grey, and it takes 8-10 days to hatch to the first zoea stage. Fecundity in numbers of eggs varied between 80 960 and 2 357 004 with an average of 512 914 for females of different size groups from 81 to 170 mm CW. Captive studies showed that the species is capable of multiple spawnings, with a maximum of three in an intermoult cycle. Size at maturity (LM50) in females was estimated at 86.5 mm CW and in males at 80.1 mm CW. All the females were mature above 120 mm CW and mature females below 70 mm CW were not recorded in the landed crabs. The smallest size of the mature and berried females recorded in the landings was 71 mm CW/22 g and 80 mm CW/32 g, respectively. In the landings, males comprised sizes between 51-170 mm carapace width (CW) with 91-105 mm forming the major size group contributing to the fishery. In males, 100% maturity was observed in crabs above the size of 95 mm CW, whereas sizes below 60 mm CW were immature. The smallest size of the mature male crab recorded in the landings was 60 mm CW/16 g. Minimum Legal Size (MLS) was implemented in the state in 2016 and for P. sanguinolentus. MLS is fixed at 70 mm CW and it has been proven that this helps in the sustainable utilization of the resource. [ABSTRACT FROM AUTHOR]

To clarify the influence of different water temperatures on the development of Portunus trituberculatus (swimming crab) larvae during off-season (early autumn) breeding, a gradient of four rearing temperatures of 27, 29, 31 and 33°C was set up, and the effects of water temperature on larval development were systematically compared. The results showed that the moulting cycle (MC) from the zoea 1 (Z1)-zoea 2 (Z2) stage was not significantly affected by water temperature (P > 0.05), remaining at approximately 3 days. However, in the Z2-megalopa (M) stage, the MC in the 31°C group was consistently the shortest. The total developmental duration and total effective cumulative temperature during Z1-M in the 31°C group were the lowest at 9.97 days and 250 days · °C, respectively. According to the equation of water temperature and larval development rate, the development rate was the fastest when the water temperature was 31°C. As the water temperature increased, the survival rate (SR) of larvae at various stages gradually decreased. The SR of the 27°C group was consistently significantly higher than that of the 33°C group (P < 0.05), especially in the M stage, where the SR of the 33°C group was only 2%, which was significantly lower than that of the 27°C and 29°C groups (P < 0.05). Among the antioxidant indexes, both superoxide dismutase (SOD) and total antioxidant capacity (T-AOC) were the lowest in the 29°C group at 315.75 U/mg protein and 0.36 mmol/g protein, respectively, and both were significantly lower than those in the 33°C group (P < 0.05). Catalase (CAT) and glutathione peroxidase (GSH-PX) were both the lowest in the 31°C group, and in this group the CAT was significantly lower than in the 33°C group, and GSH-PX was significantly lower than in the 27°C group (P < 0.05). For malondialdehyde (MDA) content, the four groups were basically maintained at about 2.5 nmol/mg protein, and there was no significant difference (P > 0.05). In terms of digestive enzyme activity, the activity of lipase (LPS) was basically maintained at 1.93 U/g protein. The other four digestive enzyme activity differences were mainly reflected in that the 31 and 33°C groups maintained relatively higher levels than the 27 and 29°C groups, especially the activities of α -amylase (AMS), and cellulase (CL) in the 33°C group, which were significantly higher than those in the 27 and 29°C groups (P < 0.05). Comprehensive indicators indicate that a water temperature between 29 and 31°C is the appropriate temperature for the development of the larvae of off-season breeding swimming crabs. [ABSTRACT FROM AUTHOR]

Portunus trituberculatus is important in coastal benthic communities and a favorite seafood for coastal residents. However, microplastics have been detected in different tissues of P. trituberculatus, but the toxicological effects of micro‐ and nanoplastics (MNPs) on the different tissues of P. trituberculatus have not been reported. We found that the lethal effect of MNPs on P. trituberculatus is not obvious, but they can stimulate the body's stress response. The responses of P. trituberculatus tissues to MNPs are different, which may be due to differences in enzyme reactions between tissues and organs. Compared with microplastics (MPs), nanoplastics (NPs) have a more significant physiological and metabolic stress effect on P. trituberculatus because of their smaller particle size. In summary, plastic particles have physiological stress effects on the physiological metabolism of P. trituberculatus, which may be closely related to the plastic's particle size and concentration. [ABSTRACT FROM AUTHOR]

The blue crab (BC) Portunus segnis is considered an invasive species colonizing Tunisian coasts since 2014. This work aims to explore its associated bacteria potential to produce anionic exopolysaccharides (EPSs) in order to open up new ways of valorization. In this study, different BC samples were collected from the coastal area of Sfax, Tunisia. First, bacterial DNA was extracted from seven different fractions (flesh, gills, viscera, carapace scraping water, and three wastewaters from the production plant) and then sequenced using the metabarcoding approach targeting the V3-V4 region of the 16S rDNA to describe their microbiota composition. Metabarcoding data showed that the dominant bacterial genera were mainly Psychrobacter, Vagococcus, and Vibrio. In parallel, plate counting assays were performed on different culture media, and about 250 bacterial strains were isolated and identified by sequencing the 16S rDNA. EPS production by this new bacterial diversity was assessed to identify new compounds of biotechnological interest. The identification of the bacterial strains in the collection confirmed the dominance of Psychrobacter spp. strains. Among them, 43 were identified as EPS producers, as revealed by Stains-all dye in agarose gel electrophoresis. A Buttiauxella strain produced an EPS rich in both neutral sugars including rare sugars such as rhamnose and fucose and uronic acids. This original composition allows us to assume its potential for biotechnological applications and, more particularly, for developing innovative therapeutics. This study highlights bacterial strains associated with BC; they are a new untapped source for discovering innovative bioactive compounds for health and cosmetic applications, such as anionic EPS. [ABSTRACT FROM AUTHOR]

In response to the escalating demand for blue swimming crabs (BSC) and the consequential impact on their habitat and population, this study advocates for sustainable management through a holistic approach. Our comprehensive framework integrates ecological conservation, socioeconomic well-being, and governance principles, aiming to establish a policy framework for the sustainable management of BSC in the Eastern Coast of Lampung. The research emphasizes the urgent issue of overexploitation, with an exploitation rate of 0.71, requiring immediate attention to prevent stock depletion and maintain ecosystem health. Findings reveal that male BSC, measured by carapace width, typically reaches the length at first catch (Lc50) at approximately 118.69mm, while for females, it is about 122.70 mm--indicating that BSC is often caught larger than the 10 cm legal requirement set by the Ministry of Marine and Fisheries of Indonesia. Economic analysis demonstrates the profitability of the blue swimming crab business on Lampung's east coast, with a favorable crab capture per trip (4.63) and total costs ratio (1.18). The study area, featuring an extensive mangrove forest, hosts a crucial crustacean population, contributing significantly to BSC's diet. Beyond ecological significance, mangrove conservation enhances our understanding of environmental sustainability, particularly in carbon stock contributions. Addressing sustainability challenges requires a multi-faceted approach, including precise fishing technologies, effective regulation enforcement, and improved monitoring. Collaborative efforts among government authorities, fishing communities, and conservation groups are essential for balancing economic interests with the longterm ecological health of BSC populations in the study area. [ABSTRACT FROM AUTHOR]

Background: Temperature is an important environment factor that is critical to the survival and growth of crustaceans. However, the mechanisms by which crustaceans detect changes in temperature are still unclear. The transient receptor potential (TRP) channels are non-selective cation channels well known for properties in temperature sensation. However, comprehensive understandings on TRP channels as well as their temperature sensing functions are still lacking in crustaceans. Results: In this study, a total of 26 TRP genes were identified in the swimming crab, Portunus trituberculatus, which can be classified into TRPA, TRPC, TRPP, TRPM, TRPML, TRPN and TRPV. Tissue expression analysis revealed a wide distribution of these TRP genes in P. trituberculatus, and antennules, neural tissues, and ovaries were the most commonly expressed tissues. To investigate the responsiveness of TRP genes to the temperature change, 18 TRPs were selected to detect their expression after high and low temperature stress. The results showed that 12 TRPs showed induced gene expression in both high and low temperature groups, while 3 were down-regulated in the low temperature group, and 3 showed no change in expression in either group. Conclusions: This study characterized the TRP family genes in P. trituberculatus, and explored their involvement in response to temperature stress. Our results will enhance overall understanding of crustacean TRP channels and their possible functions. [ABSTRACT FROM AUTHOR]

In Thailand, the populations of a commercially important crab Portunus pelagicus (Linnaeus, 1758) have been decreasing due to overfishing, raising concerns about the conservation efforts of this crab species. The Crab Bank Project has recently been established to restore crab populations by releasing crab larvae from each crab bank station. However, the fate of crab larvae after the release is poorly understood. Here, we assessed the dispersal and settlement patterns of the larvae P. pelagicus released from crab banks along the coast of Trang Province, Southern Thailand. The Lagrangian particle tracking model was employed to simulate the larval dispersal and settlement patterns after release from the crab banks during the inter-monsoon, southwest monsoon, and northeast monsoon. Our simulation revealed that virtual larvae were predominantly retained within inshore areas after the release for 14 days, regulated by tidal-driven currents, wind-induced currents, and local coastal topography. Monsoon periods affected the larval dispersal, with some larvae being transported into estuaries due to the SW monsoonal effects. After the 14-day release period, our modelled simulations suggested that the crab larvae arrived at numerous seagrass meadows along the coast, indicating potential settlement and growth. This result highlights the connectivity of sources and sinks for crab larvae after release from crab banks. Moreover, significant implications for conservation efforts and the fishery management of P. pelagicus were also discussed based on our modelled simulations. [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.)

The present investigation was set as a database study which estimated the bioaccumulation and potential human health risks of Uranium 238 (U- 238) when consuming Leiognathus sp. and Portunus sanguinolentus from the Madras Atomic Power Station (MAPS) zone, India. In the study, two hypothetical scenarios were applied about the consumption of those fish and crab, calculating the values of some important pollution and human risk assessment indices, such as enrichment factor, bioaccumulation factor, estimated daily intake, daily intake of radioactivity, committed effective dose, lifetime cancer risk hazard, and risk quotient. The results showed that the study area has a moderate enrichment of U-238 (2< EF <5) during all seasons; furthermore, Leiognathus sp. and P. sanguinolentus are a hyperaccumulator (BAF>10.0) from seawater. The finding of this study demonstrates that, in light of the hypothetical 1st and 2nd scenarios, the index values are below the limit set, hence there is no radiation/chemical risk from the consumption of Leiognathus sp. and P. sanguinolentus as a dominant diet from the study area. [ABSTRACT FROM AUTHOR]

Methyl farnesoate (MF), a crucial sesquiterpenoid hormone, plays a pivotal role in the reproduction of female crustaceans, particularly in the vitellogenesis process. Despite extensive research on its functions, the molecular mechanisms that regulate MF levels during the vitellogenic phase remain largely elusive. This study investigates the roles of microRNAs (miRNAs), significant post-transcriptional regulators of gene expression, in controlling MF levels in the swimming crab Portunus trituberculatus. Through bioinformatic analysis, four miRNAs were identified as potential regulators targeting two genes encoding Carboxylesterases (CXEs), which are key enzymes in MF degradation. Dual luciferase reporter assays revealed that let-7b and miR-141 suppress CXE1 and CXE2 expression by directly binding to their 3′ UTRs. In vivo overexpression of let-7b and miR-141 significantly diminished CXE1 and CXE2 levels, consequently elevating hemolymph MF and enhancing vitellogenin expression. Spatiotemporal expression profile analysis showed that these two miRNAs and their targets exhibited generally opposite patterns during ovarian development. These findings demonstrate that let-7b and miR-141 collaboratively modulate MF levels by targeting CXEs, thus influencing vitellogenesis in P. trituberculatus. Additionally, we found that the expression of let-7b and miR-141 were suppressed by MF, constituting a regulatory loop for the regulation of MF levels. The findings contribute novel insights into miRNA-mediated ovarian development regulation in crustaceans and offer valuable information for developing innovative reproduction manipulation techniques for P. trituberculatus. [ABSTRACT FROM AUTHOR]

Cytoplasmic Dynein is a multiple-subunit macromolecular motor protein involved in the transport process of cells. The Dynein intermediate chain (DIC) is one of the subunits of Dynein-1. In our previous studies, we showed that Pt-DIC may play an important role in the nuclear deformation of spermiogenesis in Portunus trituberculatus. Lamin B is essential for maintaining nuclear structure and functions. Surprisingly, Pt-Lamin B was expressed not only in the perinucleus but also in the pro-acrosome during spermiogenesis in P. trituberculatus. Studies have also shown that Dynein-1 can mediate the transport of Lamin B in mammals. Thus, to study the relationship of Pt-DIC and Pt-Lamin B in the spermatogenesis of P. trituberculatus, we knocked down the Pt-DIC gene in P. trituberculatus by RNAi. The results showed that the distribution of Pt-DIC and Pt-Lamin B in spermiogenesis was abnormal, and the colocalization was weakened. Moreover, we verified the interaction of Pt-DIC and Pt-Lamin B via coimmunoprecipitation. Therefore, our results suggested that both Pt-DIC and Pt-Lamin B were involved in the spermatogenesis of P. trituberculatus, and one of the functions of Dynein-1 is to mediate the transport of Lamin B in the spermiogenesis of P. trituberculatus. [ABSTRACT FROM AUTHOR]

The demand for Portunus pelagicus exports is increasing, which is encouraging more Portunus pelagicus capture. As a result, portunus pelagicus resources become available. The aim of this study is to examine the legal protection of portunus pelagicus based on international fisheries law in the Fisheries Management Area of the Republic of Indonesia (WPPRI) 713 and law enforcement against illegal rajuangan capture. The research method is qualitative research using an empirical normative approach. The findings revealed that the Indonesian government has incorporated international fisheries law into national legislation governing the management of Portunus pelagicus in Indonesian fisheries management areas. Administrative sanctions are used by law enforcement to punish non-compliant Portunus pelagicus fishing. In comparison to criminal and civil sanctions, this sanction is effective because it can be directly enforced by administrative officials. The government and the community share responsibility for the protection, utilization, and preservation of portunus pelagicus so that future generations are able to enjoy it. [ABSTRACT FROM AUTHOR]

ObjectiveTo understand the concentration of heavy metal cadmium and cadmium in portunus and mantis shrimp， and to timely identify food safety problems and potential hazards.MethodsPortunus and mantis shrimp samples from different provinces were collected and categorized based on different regions and locations， and some samples were made from tissue parts. Graphite furnace atomic absorption spectrometry was used to detect cadmium items， the cadmium exposure of portunus and mantis shrimp was evaluated simultaneouslyResultsThe detection rate of cadmium in 124 batches of portunus sold in Shanghai was 100% （124/124）， the detection rate of cadmium in 63 batches of mantis shrimp sold in the market was also 100% （63/63）. The cadmium content varied in different tissue parts， and the cadmium enrichment in hepatopancreas was the highest in the edible parts of portunus and mantis shrimp. The average detection value， 50th percentile value， 95th percentile value of cadmium in the hepatopancreas of portunus accounted for 52.64%， 49.28% and 98.65% of the PTMI， respectively. The average detection value， 50th percentile value and 95th percentile value of cadmium in the hepatopancreas of mantis shrimp accounted for 30.76%， 32.04% and 46.16% of the PTMI， respectively.ConclusionThe average residual levels of heavy metal cadmium in portunus and mantis shrimp are within the safe range.

Simple Summary: In this study, we investigated the effects of pathogen infection and low-salinity stress on organismal immunity during Portunus trituberculatus culture by utilizing transcriptome technology. We depicted the dynamic expression process of the transcriptome under pathogenic infection and low-salinity stress. In addition, several immune genes were screened that were jointly affected by immune infection and low-salinity stress. These results contribute to our understanding of the impact of environmental factors on the immunoregulatory mechanisms of P. trituberculatus. Vibrio parahaemolyticus is one of the main pathogenic bacteria of Portunus trituberculatus and causes mass mortality of P. trituberculatus in aquaculture. In addition, low-salinity stimulation makes P. trituberculatus more susceptible to V. parahaemolyticus infections. In order to elucidate the molecular mechanism of resistance to V. parahaemolyticus in P. trituberculatus, comparative transcriptomic analysis of blood cells stimulated by low salinity and V. parahaemolyticus was carried out in this study. Transcriptome sequencing of low-salinity stress and pathogen infection at different time points was completed using Illumina sequencing technology. A total of 5827, 6432, 5362 and 1784 differentially expressed genes (DEGs) involved in pathways related to ion transport and immunoregulation were found under low-salinity stress at 12, 24, 48 and 72 h compared with the control at 0 h. In contrast, 4854, 4814, 5535 and 6051 DEGs, which were significantly enriched in Toll and IMD signaling pathways, were found at 12, 24, 48 and 72 h compared with the control at 0 h under V. parahaemolyticus infection. Among them, 952 DEGs were shared in the two treatment groups, which were mainly involved in apoptosis and Hippo signaling pathway. Cluster analysis screened 103 genes that were differentially expressed in two factors that were negatively correlated, including immunoglobulin, leukocyte receptor cluster family, scavenger receptor, macroglobulin and other innate-immune-related genes. These results provide data support for the analysis of the mechanisms of immunity to V. parahaemolyticus under low-salinity stress in P. trituberculatus and help to elucidate the molecular mechanisms by which environmental factors affect immunity. [ABSTRACT FROM AUTHOR]

The storage quality and microbiome analysis of pickled swimming crabs (Portunus trituberculatus) stored at 20 and 4 °C were investigated. It showed that samples stored at 4 °C had a longer shelf life, lower total viable count (TVC), pH, and total volatile base nitrogen (TVB-N) contents than those stored at 20 °C. The biogenic amine (BA) results demonstrated that tyramine (tyr), putrescine (put), and cadaverine (cad) were the dominant amines in all samples, and samples stored at 4 °C had lower BA contents. A microbiome analysis indicated that a salt–alcohol water mixture significantly inhibited the growth of Tenericutes. Firmicutes, Proteobacteria, Bacteroidetes, Acidobacteria, Actinobacteria, and Cyanobacteria were the dominant bacteria of stored pickled crabs, and storage at 4 °C significantly inhibited the growth of dominant bacteria, more than that of 20 °C. In conclusion, 4 °C storage guaranteed the quality of samples by inhibiting changes in biochemical properties and the growth of dominant bacteria, thereby prolonging its shelf life. [ABSTRACT FROM AUTHOR]

The monitoring of marine ecosystems is crucial due to the growing threat posed by nuclear power plants and other nuclear anthropogenic emissions. In our work, we used a straightforward and low-cost biomonitoring technique called fluctuation asymmetry (FA) to examine the variation between the left and right sides (developmental instability) of organisms' traits that were influenced by genetic and environmental variables in the early stages of ontogenesis. The specimens of fish (Leiognathus sp.) and crabs (Portunus sanguinolentus) were collected seasonally and used as bioindicators to determine the effects of Uranium-238 (U-238) radioactivity around a nuclear power plant. The obtained results revealed that FA values were not considered typical values (FA = 0) in all seasons. Moreover, FA values of Leiognathus sp. exhibited insignificant fluctuation for a particular characteristic through the different seasons, while a significant fluctuation occurred amongst the characteristics themselves throughout the same season. Inversely, FA values of the four characteristics in Portunus sanguinolentus displayed seasonal variation amongst them all. Statistically, there was a strong positive correlation (r = 0.5, p < 0.05) between U-238 radioactivity in the flesh of both organisms and the fluctuation asymmetry of different traits but it is not a sign that any radioactive pollution exists. [ABSTRACT FROM AUTHOR]

Copyright of Jurnal Ilmu dan Teknologi Kelautan Tropis is the property of IPB University 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.)

Copyright of Jurnal Ilmu dan Teknologi Kelautan Tropis is the property of IPB University 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.)

The introduction of non-indigenous species to aquatic ecosystems is one of the main threats to global biodiversity. This paper reports the occurrence of the blue swimmer crab Portunus segnis in southwestern European waters (i.e., the Gulf of Cadiz). We discuss the invasive potential of P. segnis and possible mechanisms of its expansion into this new region. The detection of this species also highlights the importance of involving citizen scientists in the reporting of non-indigenous species. [ABSTRACT FROM AUTHOR]

A single Blue swimming crab Portunus segnis was captured on November 5th 2022 close to the harbor of Ancona, off the central Adriatic coast (Italy) by artisanal fishers. Taxonomic comparisons were performed with collection materials, which also included two unreported specimens of the species from the Ionian coast of Calabria, Italy. The large distance between the Adriatic record of P. segnis and its invasion front, reinforces the hypothesis that human-mediated translocations contribute to the secondary dispersal or introduction of this invasive species in Mediterranean waters. [ABSTRACT FROM AUTHOR]

Simple Summary: To clarify the specific nutritional needs for ovary maturation of the commercially important crab Portunus trituberculatus, we compared the biochemical composition of the ovary, hepatopancreas, and muscle at five ovarian developmental stages, and also analyzed their relation to the ovarian developmental stage of P. trituberculatus. We found that the branched-chain amino acids, long-chain polyunsaturated fatty acids, and monounsaturated fatty acids accumulated in the ovary and hepatopancreas, and positively correlated with the ovary maturation stage. Also, we found an increasing tendency of carotenoid and phosphatidylcholine in phospholipid from the pre-developmental stage to the proliferative stage in the ovary, but not in the hepatopancreas and muscle, indicating their crucial role for oocyte development. Our study suggests the involvement of these compositions in the broodstock diet, which will promote the ovarian maturation of adult P. trituberculatus and ensure high-quality larval production. The swimming crab Portunus trituberculatus is one of the most important economic species in China and its mature ovary often determines its commercial value and production. Although the ovary maturation of crustaceans is generally affected by exogenous nutrition, the specific nutritional needs of ovary maturation of P. trituberculatus are poorly understood. To this end, we collected the P. trituberculatus samples with five ovarian maturation stages and measured their biochemical composition of the ovary, hepatopancreas, and muscle at each ovarian developmental stage. We further analyzed their relation to the ovarian developmental stage of P. trituberculatus by principal components analysis (PCA). We found the levels of branched-chain amino acids, long-chain polyunsaturated fatty acids (LC-PUFA), and monounsaturated fatty acids (MUFAs) in the ovary and hepatopancreas increased during the ovary maturation process, and also passively correlated with ovarian developmental stage, which highlights the necessity of these specific nutrients for oogenesis and for improving the nutrient quality of crabs. In addition, we found an increasing tendency of carotenoid content and phosphatidylcholine in phospholipid in the ovary from the pre-developmental stage to the proliferative stage, but not in the hepatopancreas and muscle, which highlights the possible involvement of carotenoids during the rapid oocyte development process. Our study may provide valuable information for developing a suitable broodstock diet that promotes the ovarian maturation of adult P. trituberculatus and ensures high-quality larval production. [ABSTRACT FROM AUTHOR]

The insulin-like androgenic gland hormone is a crucial sexual regulator that is involved in the masculine sexual differentiation of crustaceans. As an insulin-like peptide, the insulin-like androgenic gland hormone has been proposed to act through the insulin receptor–mediated pathway. The present study cloned and characterized two insulin receptors (PtIR1 and PtIR2) from the swimming crab Portunus trituberculatus hallmarked with a conserved intracellular tyrosine kinase catalytic domain and several other typical insulin receptor domains in their deduced amino acid sequences. Both insulin receptors were predominately expressed in the testis and the insulin-like androgenic gland hormone–producing organ androgenic gland. Their testicular expression during the annual cycle suggested that they may play critical roles in spermatogenesis. By using the protein colocalization analysis in HEK293 cells, interactions of PtIAG with the two PtIRs were further confirmed. In addition, the insulin receptor antagonist was found to attenuate the stimulatory effects of androgenic gland homogenate on the phosphorylated MAPK levels in testis explants, suggesting that the insulin receptor-dependent MAPK pathway may be essential for insulin-like androgenic gland hormone functions. [ABSTRACT FROM AUTHOR]

Morphometric disparities were employed to characterize the geographical variations in and elucidate the phylogeography of Portunus sanguinolentus in East Asia. In this study, a comprehensive assessment was undertaken based on measurements from 833 individual crabs. These crabs were sampled from eight distinct locations, namely Kyushu (KS), Fuzhou (FZ), Yilan (YL), Xiamen (XM), Tainan (TN), Hong Kong (HK), Vietnam (VN), and Singapore (SG). Twelve morphometric measurements were standardized based on size using the allometric method. A cluster analysis and a canonical variate analysis (CVA) were then conducted for a data analysis. Randomization tests were subsequently performed to validate the morphometric differences observed among the groups. The analytical results classified the eight sampled populations into at least two distinct clusters. The first cluster included three samples from China (specifically FZ, XM, and HK), while the second cluster consisted of samples from East Asia (including KS, YL, TN, VN, and SG). The CVA revealed a tripartite division into three groups: the mainland China group (FZ, XM, and HK), the Kuroshio group (KS, YL, and TN), and the Southeast Asia group (VN and SG). The observed morphometric variations between these broad groups were statistically significant for both genders. These differences may be attributed to evolutionary origins, geographical events, or environmental adaptations. This study highlights the effectiveness of morphometric techniques in providing comprehensive insights into species delimitation and philogeographic relationships. [ABSTRACT FROM AUTHOR]

Currently, there is a need to develop an attractor that utilizes solar energy as a renewable and sustainable energy resource, as an alternative to reduce dependency on the use of solar fuel or gasoline for fishing operations. The research objective is to create a prototype design for a solar-powered lighting aid tool for capturing swimming crab (Portunus pelagicus) named SuryaNet as an effort to promote environmental sustainability. The method used in this research was experimental, involving the creation of a prototype design for a solar-powered lighting aid tool for capturing the swimming crabs (Portunus pelagicus) on the gillnet fishing vessel 'SuryaNet' and indepths interview with fishermen as the basis for designing the tool. The prototype design of the solar-powered lighting aid tool for fishing swimming crab (Portunus pelagicus) named 'SuryaNet' can be created as an effort to maintain environmental sustainability and be more environmentally friendly. SuryaNet is a series of components consisting of four parts, namely: (1) the solar panel section, (2) the SuryaNet charging dock, (3) the underwater light and (4) the ship's lighting system that can be placed on fishing vessels, designed to meet the needs of fishermen, and used during fishing operations. [ABSTRACT FROM AUTHOR]

Ammonia‐nitrogen (ammonia‐N) is an important threat factor to the development of the crustacean breeding industry; however, information on nitrogen metabolism remains limited. In this study, effects of ammonia‐N on the metabolic pathways and tissue distribution of nitrogenous wastes were investigated in swimming crabs Portunus trituberculatus. The results showed that ammonia content in the hemolymph of crabs exposed to 1‐ and 5‐mg/L NH4Cl (ammonia‐N concentrations were 1.36 and 5.31 mg/L, respectively) significantly (P < 0.05) increased with time. The expression of xanthine oxidase was significantly up‐regulated in gills and muscles but was significantly down‐regulated in the hepatopancreas of crabs exposed to 1‐ and 5‐mg/L NH4Cl after 6–12 h. The expression of uricase was significantly up‐regulated in gills and muscles at 3 h, whereas it was significantly down‐regulated in hepatopancreas during 6–12 h but up‐regulated again after 24 h. Moreover, the expression levels of carbamoyl phosphate synthetase III and arginase were significantly up‐regulated in gills and muscles but significantly down‐regulated in the hepatopancreas of crabs exposed to 5‐mg/L NH4Cl after 6–12 h. Furthermore, under 5‐mg/L NH4Cl stress, trace amounts of uric acid were detected, which significantly increased in hepatopancreas and hemolymph at 3 h, in muscles at 6–12 h, and in gills at 6–24 h. In addition, similar to hemolymph ammonia, urea was also significantly increased after NH4Cl exposure. Moreover, uric acid was mainly stored in muscles and urea was primarily synthesized in the hepatopancreas. This study provides a theoretical basis for further study on the nitrogen metabolism mechanism in crustaceans. [ABSTRACT FROM AUTHOR]

As recreational fishers act relatively autonomously, management relies heavily on voluntary compliance. Therefore, understanding fishers' views on management options can be beneficial. This study used a two-phase approach of face-to-face interviews and subsequent online questionnaires to evaluate recreational fishers' salient views on issues affecting the Blue Swimmer Crab (Portunus armatus) and Black Bream (Acanthopagrus butcheri) fisheries in Western Australia as well as current and potential management arrangements, including stock enhancement. The strength and heterogeneity of views were also determined. Minimum size limits were mainly considered acceptable or very acceptable, with restricting recreational fishing and spatial closures the least supported management options for both species, in addition to maximum size limits for crabs. These views were not always consistent across fishing locations for each species and among types of crab fishers, indicating heterogeneity in views. Stocking was the most acceptable of the management measures not already utilised for crabs and among the most popular for bream fisheries. Recreational fishers of both species believed stock enhancement could have strong positive outcomes for the abundance of their target species and increase their subsequent catches. They also recognized that some negative outcomes, e.g., increased fishing pressure and environmental issues, might occur but considered them unlikely. [ABSTRACT FROM AUTHOR]