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The document from Crustaceana covers a wide range of research articles on various topics related to crustaceans. It includes studies on genetic diversity, population structure, evolutionary transitions, and new species discoveries among different types of crabs and shrimps. The document also delves into the impact of environmental variables on crustacean populations and provides insights into the phylogenetic relationships and reproductive traits of different species. The research presented in the document contributes to a better understanding of crustaceans and their habitats. [Extracted from the article]

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]

Global climate change has caused rapid temperature changes in marine environments. Understanding how marine organisms respond to temperature changes can help predict their richness of future biodiversity. In this study, we examined the gene expression levels and the difference in the pathways that are responsive to acute temperature stress in low- and high-latitude populations of the shore swimming crab, Charybdis japonica. The two populations of C. japonica were exposed to low- and high-temperature stresses (15°C and 28°C) and used for transcriptome sequencing. Genetic regulatory ability changes were compared to determine the diverse response of the two crab populations to temperature change. The gene expression levels and functional enrichment analysis showed that the low-latitude crab regulated more genes (938) that were mainly enriched in DNA replication and metabolic pathways, whereas the high-latitude crab regulated less genes (309) that were mainly enriched in genetic information processing at low-temperature stress. Furthermore, the low-latitude crab regulated less genes (33) that were mainly enriched in genetic information processing, whereas the high-latitude crab regulated more genes (280) that were mainly enriched in signal transduction and cellular process at high-temperature stress. These results implied that the low-latitude population was more resilient to high-temperature stress, while the high-latitude population was more resilient to low-temperature stress. This study enhances our understanding of how different geographic C. japonica populations respond to varying temperature environments in their living zone, which could be helpful for predicting future biodiversity trends of intertidal crustaceans under global climate change. [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]

ABSTRACT Understanding the pathogenicity of viral infections in aquatic organisms is vital due to their substantial impact on aquaculture and wild populations. This study assessed the pathogenicity of Callinectes sapidus Reovirus 2 in Callinectes danae and its effects on the metabolic, immunological and behavioural parameters. CsRV2‐negative specimens were divided into CsRV2 inoculum (n = 10) and saline injection (n = 15). After 14 days, all the crabs that received the inoculum tested positive for CsRV2. However, 11 crabs from the control group also tested positive and were subsequently considered an additional experimental group. The cumulative mortality in the group challenged reached 70% after 14 days. RT–PCR revealed Callinectes danae Portunibunyavirus 1 presence in CsRV2‐injected crabs, explaining heightened mortality. Ammonia flow remained unaffected, but oxygen consumption was significantly impacted (p < 0.05) by CsRV2 and coinfection, suggesting increased metabolic energy expenditure. The coinfection caused an increase in the proportion of crabs with reflex impairment as a likely consequence of physiological exhaustion. Additionally, there was a trend toward reducing the number of granulocytes in coinfected crabs, indicating that granulocytes may be more affected by coinfection. These findings demonstrate the pathogenicity of CsRV2 in C. danae, with coinfection exacerbating metabolic, behavioural and immunological changes, increasing mortality. [ABSTRACT FROM AUTHOR]

Achelous spinimanus, a species of swimming crab found along the Western Atlantic from the USA to Brazil, inhabits coastal areas up to 90 m deep across various substrates. While these crabs are known to be omnivorous, the extent of their predatory behaviour remains unclear. This note documents the first record of A. spinimanus actively preying on live fish. In the observed interaction, the fish was still alive and moving its operculum and mouth while being eaten. The observation was made during a night dive at Ilha dos Porcos, Arraial do Cabo, Brazil, where a crab was seen preying on a live Malacoctenus zaluari. The behaviour suggests that A. spinimanus may employ sit‐and‐wait strategy, utilizing its strong chelipeds for capturing prey. Such records are crucial for understanding the trophic dynamics and ecological roles of marine species, emphasizing the importance of both scientific and citizen science contributions to biodiversity knowledge. This finding also underscores the importance of further research on the feeding and behavioural ecology of portunids. [ABSTRACT FROM AUTHOR]

The swimming crab (Portunus trituberculatus) is an economically important species in China, and its growth traits show obvious sexual dimorphism. Thus, it is important to study the mechanism of sex determination and differentiation in this species. Herein, we identified 2138 differentially expressed genes and 132 differentially expressed long non-coding RNAs (lncRNAs) using Oxford Nanopore Technology full-length transcriptome sequencing. We predicted 561 target genes of the differentially expressed lncRNAs according to their location and base pair complimentary principles. Furthermore, pathways related to sex determination, differentiation, and reproduction were enriched for lncRNAs according to gene ontology and Kyoto Encyclopedia of Genes and Genomes analyses. This indicated that lncRNAs might play regulatory roles in these pathways. Our results could form the basis for future studies of sex determination and differentiation in P. trituberculatus. [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]

Crustaceans are a valuable resource globally, both ecologically and economically, and investigations into their health are becoming increasingly important as exploitation rises. The microbiome plays a crucial role in crustacean immunity, and understanding its composition and structure can provide insights into the health of an organism and its interactions with various factors. In this study, we investigated the hepatopancreas microbiome of the velvet swimming crab, Necora puber, and compared its composition and structure with several study factors, including two different sampling points and infection with a paramyxid parasite, Paramarteilia canceri. To our knowledge, we provide the first description of a velvet crab microbiome, highlighting the dominance of a single microorganism, Candidatus hepatoplasma. We identified variations in microbiome composition between sampling points and discussed the possible processes affecting microbiome assembly. We also outline a core microbiome for the velvet crab hepatopancreas, consisting of 12 core phyla. Our study adds to the growing literature on crustacean microbiomes and provides a baseline for future investigations into the velvet crab microbiome and the health of this crustacean species. [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]

We aimed to characterize the trophic ecology and test the hypothesis of niche overlap between four sympatric batoid species of the subtropical South Atlantic. Data were collected between 2017 and 2022 from two artisanal fishery communities in southern Brazil. Batoid's stomach contents were identified, separated into categories, and weighed. We calculated the Levins, Pianka's, and Prey-specific index of relative dietary importance (PSIRI) and performed a similarity test using PERMANOVA and the similarity percentage (SIMPER) for niche analysis. We analyzed 229 stomachs of four batoid species, 187 containing foods. All species showed a narrow food niche. The most important diet items for each species were Leptochaela serratorbita and Onuphidae for Dasyatis hypostigma; Nematoda for Pseudobatos horkelii; L. serratorbita, Sicyonia dorsalis and Portunidae for Rioraja agassizii and Achelous spinicarpus and fish for Sympterygia bonapartii. The analyses showed dissimilarity among the species' diets without significant niche overlap. Our results detected the absence of significant niche overlap among batoid species, suggesting other types of niche partitioning and spatiotemporal habitat variation. This information could be considered for local management plans. [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]

Dietary supplementation with synthetic β‐carotene was investigated in this study to assess its impact on gonad development, antioxidant status, color parameters, and carotenoid composition in adult female swimming crab (Portunus trituberculatus). Four diets, designated as Diet 1 to 4, were formulated to contain 3.07, 53.78, 103.23, and 205.22 mg/kg dry diets of synthetic β‐carotene. The findings revealed the following: (1) No significant differences in body weights or feed utilization were observed, indicating that β‐carotene did not significantly enhance the growth of adult P. trituberculatus. (2) The inclusion of 50–100 mg/kg β‐carotene in the diets led to improvements in antioxidant capacity indicators (T‐AOC, MDA) and immune‐related parameters (AKP, ACP) in both hepatopancreas and hemolymph. (3) Notably, the redness of ovaries and hepatopancreas increased significantly with higher dietary β‐carotene supplementation for color enhancement. In conclusion, incorporating β‐carotene into the diet enhanced the antioxidative capability, nonspecific immunity, and tissue carotenoid contents in adult female P. trituberculatus, and the optimal level of dietary synthetic β‐carotene supplementation for adult female P. trituberculatus was suggested to be around 100 mg/kg. [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]

Since 2014, the provision of the aquatic ecosystem services has been gradually affected due to the biological invasion of Callinectes sapidus (Rathbun, 1896, Crustacea, Decapoda, Portunidae), commonly known as Atlantic blue crab, across several lagoon-like locations in Italy. In addition, this serious aquatic invasive species, native of North American coasts, has already inflicted economic damage of about EUR 100 million to the Italian fishing and farming communities over the past year. To counter their severe and rapid spread, the Italian Government has encouraged the fishing communities to catch as many as possible and commercially exploit them for human consumption in an attempt to manage their expansion. Since there is an ongoing promotion for the consumption of blue crab by forging novel food businesses in Italy, this paper aims to predict the public preferences and their willingness to pay (WTP) towards this biological invader. For this purpose, a discrete choice experiment approach is used, by means of a multinomial logit model (MNL) and latent class model (LCM). The social field survey involves a representative sample of 440 valid respondents in Apulia Region, southern Italy. The descriptive statistics results reveal that 67.50% of the local citizens interviewed know about the blue crab invasion, while 29.09% of them have already consumed this seafood species. In addition, the MNL results show that the most appreciated attributes of the blue crabs by respondents are freshness and large size. Further, the LCM findings reveal two representative classes of Apulian consumers; the first group of citizens (70.9% of total respondents) expresses positive appreciation for consuming blue crabs, while the second group (29.1% of total respondents) is not willing to pay a premium price regarding this potential commercial activity. Furthermore, the econometric results show that the average value that Apulian's (i.e. those belonging to Class/Group I of respondents) WTP for blue crabs' consumption is about EUR 18 per kilogram. In this regard, this research has public and private implications and may reasonably promote the commercial exploitation of blue crabs, enhancing the reduction of its population density through human consumption as a promised management control strategy and forging a novel profitable business mainly for local small-scale artisanal fisheries. [ABSTRACT FROM AUTHOR]

This study aimed to analyze the socio-economic aspects of crab fisheries in Maginti Island, West Muna Regency. Data collection was carried out from March 2021 to December 2023. The data collected were the socio-economic aspects of crab fisheries, including the level of community education, the number of fishermen, income from crab fishing, crab production 2017 - 2023, crab prices during 2017-2023, and the crab trade supply chain. Data were obtained through in-depth interviews with stakeholders, including 62-74 fishermen, three local collectors, and two district-level collectors. Interviews were directly conducted with an open-ended question system based on data needs. Data analysis was carried out with a descriptive-quantitative approach. The study results showed that in the social aspect, crab fishermen's education is dominated by elementary school (S.D.) graduates, namely 61.29% in 2017 and 60.81% in 2023. In the economic aspect, most fishermen have a net income ranging from 1,000,000 - 2,000,000 IDR/month, which was affected by fluctuations in BSC prices. Crab prices from fishermen to collectors tend to fluctuate throughout 2017-2023. The average price of crabs per kg was 32,083.33 IDR in 2017, 36,166.67 IDR in 2018, 30,750 IDR in 2019, 23,750 IDR in 2020, 64,666.67 IDR in 2021, 31,083.33 IDR in 2022, and 44,791.67 IDR in 2023. Price fluctuations occurred since BSC fisheries in Maginti Island are part of the global fisheries supply chain that reaches the international market to America, China, and others. Fluctuations in the global BSC prices not only affected the prices locally but could increase fishermen's income by up to 11.25% which is >2,000,000 IDR/month from 2017-2023. The increase in income indicates that BSC fisheries in Maginti Island have supported the implementation of the sustainable development goals (SDGs), specifically SDGs-1, namely no poverty. [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 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]

The Atlantic blue crab Callinectes sapidus (Decapoda, Portunidae) Rathbun, 1896 is native to the east coasts of North and South America and has recently expanded its distribution in the non-native range into the Gulf of Cadiz (SW Iberian Peninsula, Europe). Considering the impacts caused by this invasive species in numerous estuarine ecosystems and its generalist feeding behavior, this study aims to provide the first account of the Atlantic blue crab diet on the East Atlantic coast. We studied the species' feeding habits using stomach content analyses to predict food web interactions and putative impacts. Samples were obtained in the Guadalquivir estuary (SW Spain, Europe), which was colonized in 2017. The main food items identified on their stomach were, fish (49.9%), mollusks (44.4%) and crabs (32.3%). They also consumed plant material (27.2%), and the sediment (32.3%) in their digestive tract was likely the result of secondary ingestion. The Atlantic blue crab exhibited the same omnivorous behavior as in the native area. There was no sexual variation in diet composition or feeding activity in general, but there was a seasonal variation in the diet composition of females. The decrease of the caramote prawn Penaeus kerathurus (Forskål 1775) observed in the Guadalquivir estuary since 2021 is likely not due to the Atlantic blue crab because they seldomly eat this prey. Overall, our study provides clear baseline information to expand the knowledge about the ecological roles of the Atlantic blue crab in non-native ecosystems. [ABSTRACT FROM AUTHOR]

The taxonomy of the setose brachyuran crabs Ser fukiensis Rathbun, 1931 and Litocheira amoyensis Gordon, 1930 , both described based on material from Fujian, China, have been poorly understood for decades.. The monotypic genus Ser Rathbun, 1931 had been placed under Carcinoplacinae H. Milne Edwards, 1852 and Rhizopinae Stimpson, 1858 by subsequent authors. Examining type lots of both species and recently acquired material, we find the holotype of L. amoyensis is an immature male but this name represents a senior synonym of Ser fukiensis. The genus Ser is re-diagnosed and hereby placed under Pilumninae Samouelle, 1819. It is here considered to contain three species: the type species, Ser fukiensis (= S. amoyensis comb. nov.); S. sasekumari (Serène, 1971) comb. nov. ; and S. mikawaensis (Sakai, 1969) comb. nov.. Comparisons are made between Ser and morphologically similar genera: Rhizopoides Ng, 1987 , Cryptocoeloma Miers, 1884 , Pseudolitochira Ward, 1942 , Bossacarcinus Števčić, 2011 , and Heteropilumnus De Man, 1895. It is also apparent that Heteropilumnus is a morphologically heterogeneous group, and that its type species, H. stormi De Man, 1895 , is quite distinct from other species currently included in the genus. We discuss the implications of this finding, especially as it pertains to Ser. [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]

Several species from the genus Callinectes are economically important, yet the number of species and their geographic distributions remain unclear. Recently, one of the American species, Callinectes larvatus , was synonymized with one of the African species, C. marginatus , making C. marginatus the only species of the genus regarded to be amphi-Atlantic in distribution. However, there was no formal taxonomic study to support this taxonomic change, which was in contradiction to earlier studies that had provided morphological characters to support the taxonomic separation of the eastern Atlantic species from those of western Atlantic distribution. Callinectes maracaiboensis has also been questionably resurrected. Here we present a molecular based analysis for all species of Callinectes , using the two common mitochondrial genes 16S and 12S. Our molecular data support the presence of three eastern Atlantic, three eastern Pacific, and nine western Atlantic species. Historically, it appears that the separation of Africa and South America with the opening of the Atlantic basin gave rise to sister species distributed on opposite sides of the Atlantic Ocean. In a second isolation event, the emergence of the Panamanian isthmus resulted in pairs of geminate species distributed in eastern Pacific and western Atlantic waters. [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]

Diatoms are among the most common epibionts and have been recorded on the surfaces of various living substrates, either plants or animals. However, studies on them are still scarce in view of the many substrata available. In this study, epibiotic diatoms living on Callinectes bellicosus were identified for the first time from a subtropical coastal lagoon in Northwest Mexico. We tested the null hypothesis that the diatom flora living on the carapaces of C. bellicosus would not be similar to that recorded for mangrove sediments, its typical habitat. The epibiotic diatoms were brushed off from the carapaces of two specimens, acid-cleaned, mounted in synthetic resin, and identified based on frustule morphology. This way, 106 taxa from 46 genera were recorded, including 25 singletons, and 6 new records for the Mexican northwest region. The best-represented genera were Nitzschia (10 taxa), Mastogloia (9), Diploneis (8), Navicula (7), Amphora (5), Cocconeis (5), Tryblionella (4), and Gyrosigma (4). Species composition included 93% of local taxa, thus refuting the proposed hypothesis and supporting the alternate one. Although the estimated species richness was lower than that in sediments, it deems the green crab carapace a favorable substrate for the growth of benthic diatoms. [ABSTRACT FROM AUTHOR]

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Marine Protected Areas limit fishing to protect a broad range of species and enhance biodiversity. Consequently, closures may not benefit species equally and species‐specific assessments are required to determine the impact of closures.Relative abundance and size of Giant Mud Crab (Scylla serrata) was compared across no‐take and fished zones in Port Stephens‐Great Lakes Marine Park, on the temperate east coast of Australia (32.45°S). In addition, passive acoustic telemetry was used to estimate daily space‐use areas.Similar abundances were observed between no‐take and fished zones; however certain no‐take sites had higher abundances than others. In addition, crabs were 9.9 mm larger in no‐take zones on average. Daily crab space‐use varied widely (~4 to 1000 m2), and generally increased with water temperature and conductivity.These patterns indicate that recruitment processes interact with marine park protection to shape crab abundances across estuaries. However no‐take zoning appears to primarily limit fishing mortality on legal size crabs (i.e., carapace length >85 mm) resulting in larger crabs within no‐take zones. This may mean no‐take zones enhance reproductive output of crab populations since larger individuals are likely to be more fecund. [ABSTRACT FROM AUTHOR]

The blue swimming crab (Portunus pelagicus) is an economically important crustacean with increasing consumption demands, while wild stock is declining. Therefore, a crab bank project has been initiated to restore crab resources. The crab bank, which has been operating for at least 10 years, collects berried females, hatches their eggs to the zoea stage, and release them into the sea. However, the project’s success has not been evaluated. This study investigates the genetic diversity of berried females from the crab bank project and wild crabs in Trang and Krabi provinces. The nucleotide sequences within the mitochondrial DNA control region of P. pelagicus were analyzed. We found that 65.72% of wild crabs in Trang and 39.72% in Krabi shared haplotypes with berried females from the crab bank project. This indicates a division within the P. pelagicus population, forming two distinct groups corresponding to Trang and Krabi. The demographic history analysis suggests a period of population expansion. Based on these genetic diversity findings, we propose management strategies for the crab bank projects in both areas. However, this study is preliminary, and further research incorporating additional genetic markers from the nuclear genome and more samples from areas beyond Trang and Krabi is recommended. [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]

The neighbor-stranger response difference, which serves as a fundamental social network relationship, plays a crucial role in establishing and expanding complex social networks. However, the underlying causes of this phenomenon have received limited attention in controlled indoor settings. This study focused on Portunus trituberculatus, a representative crustacean species in the Western Pacific Ocean. We analyzed the behavioral responses of crabs towards intruders of varying familiarity and threat levels. Additionally, we quantified various parameters such as territory size, behavior quantification, time allocation, and territorial behavior score. The results showed that with increased familiarity, there was a decrease in the frequency of occupiers' aggressive dash and aggressive wave. As the threat from the intruder decreased, occupiers displayed fewer territorial behaviors and engaged in fewer bouts, while the success rate in fights improved and the territorial behavior score declined. The results indicate a clear dear-enemy effect in the territorial defense of P. trituberculatus, and demonstrates that crabs adjusted the defense strategy according to the relative threat level of intruders. We verified the formation hypothesis of dear-enemy effect in crabs. In the future, we will expand the research from individuals to populations, analyze crustacean social networks from the perspective of group decision making, and provide more support for population dynamic analysis and decision evolution research of crustaceans. Significance: The dear-enemy effect is considered as a potential driving force in the formation and evolution of social structures. However, the reasons behind the dear enemy effect, have seldom been investigated in controlled indoor settings. This study focused on Portunus trituberculatus to explore their territorial behavior and neighbor-stranger response difference. By analyzing the behavioral responses of crabs towards intruders of varying familiarity and threat levels, we discovered a clear dear-enemy effect in the territorial defense of P. trituberculatus. The finding sheds light on the recognition and evaluation rules towards intruders and provides a behavioral foundation for understanding the social networks of crustaceans. Our research lays the groundwork for further exploration of crustacean social networks, from individual behaviors to population dynamics and decision-making processes. [ABSTRACT FROM AUTHOR]

In this study, we report the first occurrence of Callinectes sapidus in the rivers of ‘Oued Tani’ (Martil) and ‘Oued Negro’ (Fnideq), based on 127 individuals of the blue crab caught from November 2022 to August 2023. Additionally, we were able to determine the potential consequences of C. sapidus on the indigenous species as well as the socioeconomic implications on artisanal fisheries activities. This research highlights further data that reinforces recent findings on recorded blue crab from various locations along the Moroccan coastline.

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]

The present work has compiled a total of 389 brachyuran crab species belonging to 188 genera and 38 families to be present in mangrove forests across 122 countries/territories in 10 sub-regions of two global hemispheres viz., Indo-West Pacific (IWP) and Atlantic East Pacific (AEP). The mangrove crabs are highly diverse in the IWP as compared to AEP. They exceed 100 species in nine countries of the IWP viz., Indonesia, India, Japan, Thailand, Australia, Singapore, Philippines, Malaysia, and China. The least number of mangrove crab species (> 10) are found to be present in 38 countries under the AEP. Four countries/territories do not have any record of mangrove crabs. Sesarmidae is the predominant family of mangrove crabs, followed by Ocypodidae and Portunidae. The present work also has brought out 818 synonyms, which otherwise interfere with the preparation of a checklist for an exact number of crab species. It is a matter of necessity to conserve the crabs, which are keystone species of the mangrove ecosystems. [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]

The aim of this study was to determine the relationship carapace width and body weight, condition factor, sex ratio, stage of gonad maturity, first sizesexual maturity, and fecundity in the Kolono Bay. Crab samples were obtained using folding trap fishing gear. The resultas of this study were that distribution of carapace width and body weight of male and ovigerou female T. crenata tended to be greater than that of females. While thecarapace width and body weight of female T. crenata tended to be smaller than body size of thecorrelation between carapace width and body weight of T. crenatashows a very shows a strong andpositive relationship with negative allometric growth patterns. . Male condition factors were significantlydifferent (p <0.05) from ovigerous females and females. Male and female condition factors weresignificantly different (p <0.05) indicating that the male was greater than the female. Overall sex ratiowas significantly different (p <0.05) from the 1: 1 ratio, except in the period July and August. Gonadmaturity stages based on sex and ovigerous females were found to vary during research but weredominated by the mature of gonads. The carapace width of the first sexual maturity this crab, male and female, were 55.39mm and 49.53 mm, respectively with fecundity ranged from 32.741 to 257.798. [ABSTRACT FROM AUTHOR]

The crabs in the subfamily Polydectinae (family Xanthidae) have adapted a defence behaviour in which living invertebrates are used as protection from predators. The polydectine crabs carry a living invertebrate, a sea anemone or nudibranch, in each claw, which is positioned in front of the body and waved to scare off attackers. In an attempt to trace the origin of this behaviour, we sequenced the complete mitochondrial genome of 19 crabs (encompassing 12 genera) from museum samples. The complete mitochondrial genomes were included in a larger dataset with previously published sequences and analysed using maximum likelihood and Bayesian inference. The divergence times of the polydectine crab radiation were estimated using the mitochondrial dataset and fossil calibration points. Our results show that the anemone-carrying polydectine crabs consist of at least three deep evolutionary lineages that evolved in the Late Eocene. All three lineages share the unique behaviour suggesting that it emerged in the ancestor to Polydectinae nearly 40 million years ago and has persisted in all living species. [ABSTRACT FROM AUTHOR]

The current invasion of the Mediterranean Sea by the Atlantic blue crab Callinectes sapidus requires the implementation of effective strategies of control and management. In native areas, the species is highly appreciated as a hard- and soft-shell seafood, and hard-shell fisheries are developing in a number of invaded countries. Here, to verify alternative approaches for enhancing the commercial value of the species, we carried out a pilot experiment to test a flow-through system for the production of soft-shell blue crabs. Fifty crabs were collected in the Lesina lagoon (Adriatic Sea, Italy) and inspected for the coloration of the line on the distal edge of the fifth pereiopod. Accordingly, they were grouped into three groups showing no, white, and red lines, symptomatic of the progression of the pre-molt phase, and maintained for 31 days in a flow-through pond system. The overall mortality rate determined during the trial was similar across the three groups and ranged between 10 and 20%, indicating that the flow-through system was effective for rearing the crabs. In addition, the molting rate was 10%, 65%, and 85% for individuals at an early, intermediate, and advanced pre-molt stage, confirming that the line coloration can be used as an effective indicator of the advancement of the molting process. Our study provides the first contribution towards the introduction in the Mediterranean fishery sector of novel procedures and practices for the production of soft-shell blue crabs, which may represent a cost-effective strategy to enhance the capture and commercialization of this invasive species as a high-quality and valuable shellfish product. [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]

The brachyuran crab Charybdis hellerii is originally from the Pacific; nevertheless, the species has been introduced to tropical waters globally. Its initial sighting in the Western Atlantic was documented in 1990 based on specimens collected in Cuba in 1987. In this paper, we present findings of C. hellerii from two localities in eastern Cuba: Santiago de Cuba and Taco bays. Up to this point, the species has solely been documented in estuaries in Cuba, and it likely exists throughout the entire archipelago. Given its feeding behaviour and extensive distribution, encompassing areas within the National Park Alejandro de Humboldt, this species can be key in the formulation of conservation plans for Cuban marine ecosystems. [ABSTRACT FROM AUTHOR]

Reductions in the size of mature blue crabs, Callinectes sapidus , which are commercially harvested, are of concern to the aquaculture industry. Through their role in the production of viable offspring, aquaculturists focus their attention in particular on female crabs, although the phenomenon will, of course, also affect the males. Meanwhile, decreases in size at maturity throughout the crab population may be the result of temperature alterations, at present also due to global climate change. Temperature-based shifts in growth can lead to changes in reproductive efficiency, as well as in size and age at maturity. In this study, the effects of temperature on the moulting frequency of blue crabs were investigated and survival rates have been calculated. The purpose of this study was to investigate the temperature dependence of survival and of the moulting processes for blue crab larvae, and to determine the effect of increasing temperature on moulting. The stages from zoea-1 to zoea-5 were examined at 16, 22, 26 and 30°C. The results show that there is a significant difference in growth and moulting, depending on the rearing temperature. As the temperature increases, the interval between moulting days can be seen to be shortened, and increasingly so with the progress in the growth of the crabs. Moulting-interval days became less with the growth of the crabs. The effect of a rise in temperature on growth per moult is also significant, and along the temperature range tested the optimum temperature was found to be 26°C. A reduction in the length of the intermoult period was observed from the lowest to the optimum temperature, while a sudden, sharp increase in the intermoult period above 26°C was observed as well. [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]

We report some brachyuran crabs from the late Miocene of Dar Pahn unit, Makran Province, Iran. The studied specimens have been assigned to Ixoides MacGilchrist, 1905, with I. miocenicus n. sp. (Leucosiidae Samouelle, 1819) and Persianus arcuatus n. gen., n. sp. (Portunidae Rafinesque, 1815). Ixoides miocenicus n. sp. represents the first fossil representative of the genus, enlarging its stratigraphic range to the Miocene. Persianus arcuatus n. gen., n. sp. represents the first report of a portunid crab from the Miocene of Iran. We also report an indeterminate majoid crab, representing the first report for the Majoidea from the Miocene of Iran. Finally, one portunid crab is compared with Persianus n. gen. based on some similar morphological characters. [ABSTRACT FROM AUTHOR]

Scylla mud crabs are economically important portunid species for aquaculture in many countries. However, mass production of mud crabs as a supply of seafood is still difficult up-to-date. This review aimed to provide an overview of the major constraints faced in the grow-out farming of mud crabs, and the potential solutions were discussed. The major constraints in the Scylla mud crabs' grow-out culture are (1) inadequate seed supply, (2) cannibalism, (3) disease outbreaks, and (4) no commercial formulated feed that is specifically designed for mud crabs. The inadequate wild mud crabs seed supply can be solved through artificial seed production seed in the hatcheries, but the knowledge of mud crab requirements at early life stages is needed to improve the rearing techniques and production. Cannibalism in the grow-out culture of mud crabs is manageable, provided that the farmers are knowledgeable about the basic prevention methods (shelter provision, size grading, monosex culture) and they are practicing it. On the disease outbreaks, research into discovering new alternatives to antibiotics and prevention methods should be prioritized. Finally, the commercial formulated grow-out diet that is specific for the Scylla mud crabs should be developed to replace the use of natural products for feeding. [ABSTRACT FROM AUTHOR]