Portunus Pelagicus Research Articles

Larval Dispersal Modelling of the Blue Swimming Crab Portunus pelagicus (Linnaeus, 1758) from the Crab Banks along the Coast of Trang Province, Southern Thailand

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.

Blue swimming crab (Portunus pelagicus, Linnaeus 1758) capture fisheries practices in northern Bohol, Philippines

Blue swimming crab (Portunus pelagicus, Linnaeus 1758) capture fisheries practices in northern Bohol, Philippines

Nutritional evaluation of edible swimming crabs Portunus pelagicus (Linnaeus, 1758) and Portunus sanguinolentus (Herbst, 1783) from coastal area of Bangladesh

Edible crabs of different species are well-known as rich sources of protein and minerals. The present study evaluated the nutritional profile of Portunus pelagicus and Portunus sanguinolentus crabs collected from the coastal Cox’s Bazar district of Bangladesh. The meat and shell parts of both male and female crabs were analyzed for moisture, protein, fat and ash/minerals. The meats contain significantly higher amount of protein (12.72-19.25%), fat (2.78-4.06%), moisture (74.71-79.81%) and lower amount of ash (1.06-2.01%) compared to the shells (0.94-1.55% protein, 0.87-1.33% fat, 47.59-51.01% moisture and 20.99-24.48% ash). Among the minerals, calcium, iron and phosphorus are significantly higher in the shells (6567.11-9463.03 mg/100g, 10.36-31.72 mg/100g and 97.76-127.67 mg/100g, respectively) than in the meats (23.33-233.09 mg/100g, 4.22-8.34 mg/100g and 51.88-63.28 mg/100g, respectively). The findings of the present study suggest that the meat and shell of these crabs could be considered for consumption as excellent sources of protein and minerals essential for infants, young children, adults, pregnant and lactating women.

Legal Protection of Portunus Pelagicus: An International Fisheries Law Perspective in the Republic of Indonesia's Fisheries Management Area 713

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.

The Shadow Blue Economy: Optimizing non-target Catch of the Blue Swimming Crab Fisheries in North Coast of Central Java, Indonesia

Blue Economy is the concept of sustainable use and management of resources, including small-scale blue swimming crab (BSC) fisheries. The coastal area of Pati District is one of the BSC landing bases on the north coast of Central Java (part of Indonesian Fisheries Management Area/IFMA 712). However, there has been no study of non-target composistion as a complement to exploratory analysis to better understand the complexity of the social-ecological systems in the BSC fisheries in this region. The purpose of this study is to identify of economically non-target species, Correlation between economically non-target with target species and trend of their proportions, optimizing non-target catch value during Covid-19 pandemic. The biological data was collected from the daily logbooks of BSC middleman, which included catches from 368 individual fishers from January 2019 - March 2021. The socio-economic data was obtained by structured interviews and group discussion. The analytical methods were used such as identification, correlation and trend analysis, and descriptive analysis. The economically non-target species found include Scylla serrata, Charybdis feriatus, squid and cuttlefish (cephalopods), Charybdis afinis, Podopthalmus vigil, Portunus sanguinolentus, and Babylonia spirata (mollusc). Significant correlation between BSC catches decreased, while the catch of Scylla serrata and Charybdis feriatus are increased. The trend of economically non-target BSC fisheries decreased for sale during the Covid-19 pandemic and shadow economic occurred with the changed of fishermen behaviour who were previously commercial fishers to be subsistence fishers. The other shadow blue economy also occurred since mud crab were frequently caught as the non-target species.

Supply chain pattern of blue swimming crabs in the north coast of Java, Indonesia

The blue swimming crabs (BSC) fishing industry in Indonesia is heading towards an imbalance between demand and sustainability of its resources, a factor in supply. The mismanagement of traceability data and information in the supply chain is suspected to be one of the causes adding to the complexity of recent BSC fisheries management. This research aimed to identify BSC supply chain patterns and their issues, especially on two coastal regencies on the North Coast of the Java Sea. The research was conducted during June and December 2023 in Cirebon Regency and Rembang Regency. The study enlisted 70 participants, comprising fishermen, traders, processors, and exporters, with data acquisition facilitated through surveys, interviews, and focus group discussions. Respondent selection employed purposive sampling, while snowball sampling identified pertinent informants within the supply chain. Data analysis encompassed qualitative description and Likert-type scale perception analysis. The findings show that the BSC fishing industry on the North Coast of the Java Sea operates as small-scale fisheries (SSF), with unique vessel types, gear, and socioeconomic conditions crucial for livelihoods. Fishermen prioritize sustainability by using small vessels and traditional gear despite limited education. The BSC supply chain involves stakeholders offering high-value products, yet by-product utilization potential is untapped, requiring improved coordination and innovation. Challenges include export standards, market fluctuations, and product safety, addressed through regulatory support and collaboration. Government regulations, fishermen groups, and data traceability enhance market transparency and sustainability. Therefore, collective action and innovative approaches are vital for long-term economic prosperity and environmental stewardship in the BSC supply chain.

FISHING PRACTICES OF BLUE SWIMMING CRAB IN NORTHERN CATANDUANES, PHILIPPINES: IMPLICATIONS TOWARDS SUSTAINABLE MANAGEMENT

Fishermen in Northern Catanduanes rely heavily on Blue Swimming Crab (BSC) as a source of income. The goal of this study was to characterize the BSC fishery in the maritime environments of Viga, Panganiban, Pandan, and Bagamanoc. A survey was conducted to gather data on the BSC fishery in Northern Catanduanes from February to May 2023. The results revealed that the income of crabbers and their families was well below the poverty threshold. This was worsened by the lack of formal education among crabbers, which restricted their options for finding alternative sources of income. The primary fishing gears utilized by fishers were bottom set gill nets, crab pots, and crab lift nets with 55.77%, 14.90% and 15.38%, respectively. The peak fishing season for most municipalities occurred between May and July while the lean season varied from October to February. About 95.19% of the crab fishers violated regulation on the implementation of the minimum carapace width of 10.2 cm for blue swimming crabs allowed for catching, collecting and trading. The sustainability of the BSC fishery in Northern Catanduanes is under threat. It is critical to put in place efficient management strategies to deal with the issues causing the BSC stocks to decrease. In order to ensure sustainable fishing methods, these actions should prioritize lowering fishing pressure, keeping an eye on and informing crab fishermen, offering substitute revenue streams, and launching education and awareness initiatives.

Genetic Diversity of Blue Swimming Crab (Portunus pelagicus) from a Crab Bank Project and Wild Crabs in Trang and Krabi Province, Thailand Using mtDNA Control Region Sequences

Genetic Diversity of Blue Swimming Crab (Portunus pelagicus) from a Crab Bank Project and Wild Crabs in Trang and Krabi Province, Thailand Using mtDNA Control Region Sequences

POPULATION PARAMETERS OF BLUE SWIMMING CRAB PORTUNUS PELAGICUS IN THE TIWORO STRAIT, SOUTHEAST SULAWESI

The blue swimming crab (Portunus pelagicus) has a wide distribution in the fishing ground waters for fishermen's activity in the Tiworo Strait. The coastal area of Tiworo Strait has quite a lot of crab potential. Therefore, it is used as one of the pilot locations for sustainable crab management projects of the Indonesian Blue Swimming Crab Association (APRI). Growth, total mortality, natural death, fishing mortality, and the exploitation rate were the population parameters of crabs that need to be known so that management can be carried out in a sustainable manner of fisheries. A study on the population parameters of crabs has been conducted in the Tiworo Strait, based on carapace width frequencies data collected from Juli to December 2021 and analyzed using FISAT (FAO-Iclarm Stock Assessment Tool) II. The total sample is 7,809 samples, where the number of male blue swimming crabs is 3,295 samples and 4,514 females. The average size of the blue swimming crab carapace width caught was 107.57 mm for males and 110.65 mm for females. The results of the study showed that the growth rate (K) was 1.01/year, the total mortality rate (Z) was 0.67/year, the natural death rate (M) was 1.25/year, and the fishing mortality rate was 0.58/year. The exploitation rate (E) of blue swimming crab was 0.86, which showed symptoms of over–exploitation, so the management of crabs in these waters must be carried out more carefully to sustain the availability of crab resource stocks. 
 Keywords: blue swimming crab, width, weight, Tiworo Strait

BLUE SWIMMING CRAB ENLARGEMENT TECHNIQUE: INSIGHT FROM SMALL-SCALE FISHERY IN THE SOUTH COAST OF PAMEKASAN, MADURA ISLAND

Pagagan Village, Pademawu District, and especially members of the "Berkah Capit Biru" fishermen, had the potential to carry out the sustainability of blue swimming crab because of the abundant crab fisheries. The purpose of this research was to encourage fishermen to not always carry out crab fishing activities in nature so nature remained sustainable and to increase the potential of natural and human resources who were enthusiastic about crab enlargement in Pagagan village. This research was conducted from January to May 2022. The crab breeding location measured 8x10 meters, had a substrate of muddy sand, and was in a coastal area bordering a mangrove ecosystem. Wooden stakes woven with bamboo with a netting around them were set higher than the wave. This enlargement technique did not use aeration in the form of wheels but only utilized tidal conditions so that periodic water changes occurred at the site. The stages in the crab enlargement technique are 1) site selection, 2) construction, 3) spreading seeds, 4) feeding, 5) controlling, and 6) harvesting. This enlargement technique is a solution for crab fishermen to meet market stocks. 
 Keywords: blue swimming crab, enlargement technique, small-scale fishery

Catch assemblages in the small-scale trap fishery with relation to hydrographic features of a tropical bay in the Gulf of Thailand.

Catches from the small-scale trap fishery in Bandon Bay, Suratthani, Thailand, were monitored from 14 sites around the Bay, then disturbance to aquatic communities and catch assemblage were examined. At the same time, the hydrographical features of the bay were surveyed. The study was conducted throughout 2019 except in December, when a tropical cyclone made sampling impossible. In total, 17,373 animals from 118 species or species groups of aquatic animals were collected. The main target of the fishery, blue swimming crab Portunus pelagicus, contributed about 10% of the total catch in terms of number; meanwhile, another crab, Charybdis affinis, was the most dominant species (41% of total). W-statistics of Abundance-Biomass Comparison curves ranged between -0.025 and 0.031, indicating light disturbance to the communities in this fishing ground. The catch assemblage, based on number in catch composition, were divided into three main clusters and six sub-clusters by using the self-organizing map (SOM) technique. The SOM results showed that the catch assemblages differed based largely on temporal variation. The hydrographic features of Bandon Bay at times exhibited a layered structure and had strong spatial variation. The bay's current system was governed by motion of tidal currents; meanwhile, the circulation was governed by monsoonal wind and freshwater discharges. Tidal current was strong and ranged between approximately 0.6 m to 2.2 m. Water within the bay was always warmer than the outer sea. High water temperature was observed two times during the year: during monsoon transition 1 (April to May) and transition 2 (October). Salinity showed great spatial and temporal variation, differing by more than 5-10 ppt horizontally. It was possible to use these dynamic hydrological features of Bandon Bay to explain assemblage patterns of the trap-net catches.

Effects of eco-friendly fishing gears on fishermen's welfare and sustainable fisheries: Lessons learned from Indonesia

The eco-friendly fishing gears (EFFGs) have been widely suggested as fishing gears for sustainable blue economy development. This study aims to examine the effects of the utilization of the EFFGs of blue swimming crab (BSC) on fishermen's welfare and sustainable fisheries by taking Indonesia as a case study. The number of fishermen randomly sampled was 647. The method used to analyze the data was the Endogenous Switching Regression model. The results showed that factors that have significant positive effects on fishermen's decision to adopt the EFFGs are the membership of fishermen in fisheries groups, credit access to financial sources, decision synchronization, financial capability, and fishers' perception of environmental uncertainty. Meanwhile, the complexity of fishing gears and buyer pressure have significant negative effects on fishermen's decisions to adopt EFFGs. The results also confirmed that the welfare of BSC's fishermen is better off and received positive benefits for the preservation and regeneration of resources by using the EFFGs compared to the non-EFFGs. Therefore, the application of the EFFGs for BSC fisheries supports the sustainable blue economy development goals and needs to be recommended for other coastal areas in developing countries.

Blue Swimming Crab’s Conservation Area Determination in The North of Java Sea Using Reproductive Indicator

Despite being operated on a small scale, Blue Swimming Crab (BSC), Portunus pelagicus fishery substantially contributes to Indonesia's fisheries as the country's third-largest export commodity after tuna and shrimp. The high of BSC’s demand led to pressure on its stock. Hence a conservation area is needed to be set up, in this study, was proposed using reproduction indicators. with the case study of BSC Stock in Keboromo Waters, Pati Regency, North Central Java. The samples were collected from 38 sampling points at a distance of 2-12 miles from the coastline during November-December 2022 using collapsible crab traps. A reproduction observation on female crabs was carried out on their carapace width and gonad maturity stage. The data then were analyzed for the percentage of egg-berried females (EBF), size at first maturity (Lm) and first captured (Lc), and their spawning potential Ratio (SPR). This study found that the mature crabs (GMS2) in November and December were higher than in other stages while the proportion of ovigerous females (EBF) in December was higher than in November. At several sampling points, the size at first captures (Lc) was higher than that at first maturity (Lm) indicating a decrease in resource stocks due to a delay in the recruitment process. SPR of 19% showed that reproductive potential should be maintained before recruitment is limited, therefore based on the existence of EBF in particular sampling points it is recommended three conservation areas as a temporary no-take zone in BSC fishing ground in Keboromo Watres, Pati Regency.

Population structure, stock assessment, and fisheries management of blue swimming crab Portunus pelagicus, Linnaeus 1758, in the eastern Mediterranean Sea

Population structure, stock assessment, and fisheries management of blue swimming crab Portunus pelagicus, Linnaeus 1758, in the eastern Mediterranean Sea

Sampling technique to pool genetic materials of microorganism communities in blue-swimming crab processing plant industry

The crab and seafood processing industry must fulfill standard requirements for sanitation, hygiene, and good manufacturing methods to ensure the safety of the products and free from foodborne bacteria. However, equipment and processing unit surfaces are challenging to clean optimally, which can cause persistent bacteria to emerge. Eliminating persistent bacteria is the latest challenge in the fish processing industry for optimal disinfection, preventing cross-contamination, and controlling foodborne outbreaks. Microbiological testing in industry has been limited to selective culture-media techniques; thus, a rapid, sensitive, accurate, and routine applicable analytical method is urgently needed. The significant reduction in the costs of high-throughput sequencing technologies supports the possibility of routine applications in the industry. This study aimed to determine the profile of the microbial community on the surface of the production room and blue-swimming crab processing unit equipment using short-read metagenomic techniques. The analysis included the stages of sampling, bacterial incubation, bacterial DNA isolation, sequencing, and bioinformatics analysis. The first important step to increase the possibility of routine adoption in the seafood industry is to reduce the cost, complexity, and time required to complete the analysis. Therefore, in this protocol, we generate a scalable, flexible, cost-effective, and auditable workflow.•Collection of bacterial samples by swabbing the surface of the equipment using a sterile cotton swab and sterile cloth, which is easy to apply and follow in the blue-swimming crab processing plant industry.•Effective and efficient sample-pooling is an important step in identifying bacterial communities by metagenomic analysis.

Comparison of lipid content and fatty acid profile of fresh and frozen blue swimming crab Portunus Segnis

The blue swimming crab Portunus segnis has a great economic interest in local and foreign fishing markets and is in high demand by consumers. The aim of the present work was to evaluate the change in total lipid (TL), fatty acids composition and nutritional quality indices (NQI) of the meat of blue swimming crab Portunus segnis after freezing at -18◦C for 15, 30, 60 and 90 days. The comparison of fresh and frozen crabs showed that freezing had significant effects on the nutritional quality of this marine product. Lipid peroxidation was enhanced during the freezing process. Total lipid content decreased significantly as a function of days of storage, especially from 30 days. A significant change was also observed in the fatty acid composition of frozen crab meat. During the freezing process, saturated fatty acids (SFA) increased significantly, while polyunsaturated fatty acids (PUFA) and monounsaturated fatty acids (MUFA) decreased. We can conclude that storage of blue crab P. segnis at -18◦C was not efficient enough for long preservation, as it has a strong effect on the deterioration of the nutritional quality of the meat over time. Frozen crabs should preferably be consumed within 15 days of storage. Our research targets both domestic and international consumers of this crab, with a specific focus on restaurants and hotels that incorporate this item into their menus. We recommend that consumers of this product exercise increased caution regarding the advantages and drawbacks associated with the freezing techniques employed.

The Complete Genome Sequence of Portunus pelagicus (Portunidae, Decapoda), the Blue Swimming Crab.

Portunus pelagicus is a large crab found in the Indo-Pacific. We present the whole genome sequence of this species. Illumina paired-end reads were assembled by a de novo method followed by a finishing step. The raw and assembled data are publicly available via GenBank: Sequence Read Archive (SRR25655135) and assembled genome (JAWWMC000000000).

EVALUATING POTENTIAL BIODEGRADABLE TWINE FOR USE IN THE BLUE SWIMMING CRAB COLLAPSIBLE POTS

This study addresses the global issue of lost fishing gear, specifically traps and pots, which rank second regarding gear lost in marine environments. These traps often contain synthetic fibers that decompose slowly, producing long-lasting ghost fishing. To mitigate this problem, the study explores using biodegradable materials in trap construction. The research focuses on assessing biodegradable materials' physical and mechanical properties and how immersion affects them. Field surveys and sample immersion were conducted at Kejawanan Fishing Port Cirebon, with subsequent testing at IPB University. The study compared three natural materials: cotton, agel, and hemp twines. The cotton twine stood out with its soft texture compared to the rougher agel and hemp twines. Regarding elongation, cotton 20.76% outperformed agel 13.70% and hemp 4.42%. Sequential breaking strength tests revealed cotton's superior strength at 9.84 kgf over agel at 3.61 kgf and hemp at 2.72 kgf, even after immersion. These findings indicate that cotton twine is a viable biodegradable alternative to synthetic twines in blue swimming crab pot fishing. By adopting such materials, fishermen can reduce the environmental impact of lost gear and contribute to more sustainable fishing practices.

Analysis of calcium levels in the carapace of rajungan crab (<i>Portunus pelagicus</i>)

This research aims to determine differences in calcium levels in small crabs (Portunus pelagicus) in three parts, namely carapace/shell, claw feet and abdomen. This research was conducted from May to June 2023 at UD. Bumi Nusantara Pattiro Sompe, Sibulue, Bone Regency, South Sulawesi. The research method used is an experimental method. with three types of samples (abdomen, claw feet and carapace/shell), calcium level parameters with two repetitions. Data were analyzed using T-test. Based on the research results, it shows that the highest calcium levels are in the carapace/shell (46.77%), followed by the claws (41.91%), while the lowest are in the abdomen (40.76%). The conclusion of this study is that there is a significant difference in levels calcium between the carapace/shell and the abdomen and claw legs but did not differ significantly between the abdomen and claw legs.

RNA/DNA Ratio Performance of Blue Swimming Crab (Portunus pelagicus) Fed with Natural Food Phronima sp. and Artemia salina in Juvenile Phase

The availability and quality of fry is a major problem in blue swimming crab aquaculture, with the high mortality at the larval stage. RNA/DNA ratio is one of the parameters that can be used to evaluate the quality of crab fry, including health, nutrition, and growth conditions. This study aims to analyze the effect of Phronima sp. as a substitute feed for Artemia salina on the RNA/DNA ratio performance of blue swimming crab in juvenile phase (crablet 5) during rearing before cultivation in aquaculture ponds. This research was conducted at the Crab Hatchery Unit of the Brackish Water Aquaculture Fisheries Center (BPBAP) Takalar in February 2023. The study used a quantitative experimental completely randomized design (CRD) with five treatments and three repetitions. The ratio of Phronima sp. and Artemia sp. used were: Treatment A 100% Phronima sp; Treatment B 100% Artemia sp; Treatment C 75% Phronima sp and 25% Artemia sp; Treatment D 25% Phronima sp and 75% Artemia sp.; and E: Phronima 75%+Artemia salina 25%. The results showed that Artemia salina combined with Phronima sp. increased the RNA/DNA ratio of the crab compared to a single feed (100% Phronima sp. or Artemia salina 100%). The feed combination with the highest RNA/DNA ratio was shown in treatment E (Phronima sp. 25% + Artemia salina 75%) with an RNA/DNA ratio of 2.02 +0.032 ng/µL.