Blue Swimming Crab Portunus Pelagicus Research Articles

Growth, Development and Survival Rate of The Blue Swimming Crab (Portunus pelagicus) Cultured using Different Larvae Feeds

Blue swimming crab (Portunus pelagicus) is one of the most important commodities of softshell industry. Besides mud crab its demand as feed is increasing day by day. As a coastal dominant country, Bangladesh has a great feasibility of this species in culture, production, use and export. However, the production contribution from Bangladesh is still from natural sources and far behind in terms of farming, culture and production. Optimization of larval rearing techniques is therefore important to develop intensive hatchery rearing technique for this species. So, this study is aimed to develop larvae production technique of Portunus pelagicus with a better survival rate. Newly hatched first zoeal of Portunus pelagicus were reared using three different diets till second zoeal stage: (Treatment 1= Artemia franciscana umbrella + Rotifer (Brachionus rotundiformis); Treatment 2= Rotifer (B. rotundiformis) and Treatment 3= Artemia franciscana umbrella). Then, Artemia franciscana nauplii were used for all three treatments till they metamorphosed to crab instar. Regularly, water quality parameters were monitored and maintained and the survival and molting to next stages was observed. The result showed that, all the hatched zoea of P. pelagicus could successfully turns into crab instar stage under all the treatment applied, but the highest survival rate 6.08% was found in case of treatment 2 followed by 0.58%, 0.91%, respectively in treatment 1 and 3. In terms of metamorphosis, it took more than 15 and 14 days respectively from zoea 1 to metamorphose into megalopa for treatments 1 and 3, whereas metamorphosis from zoea 1 to megalopa in treatment 2 finished at the 12th day with a higher Larval Stage Index (LSI) value which was 4.9. Finally, at the 15th day larvae were metamorphosed into crablet for treatment 2 and 18 and 16 days required for metamorphosis into crablets for treatment 1 and 3, respectively. However, the larval feed showed a significant effect on growth and survival of P. pelagicus larvae, whereas the earlier larval stage of P. pelagicus rearing with Rotifer (B. rotundiformis) is found as the most suitable diet.

Karakteristik Biologi dan Kelimpahan Rajungan (Portunus pelagicus) di Sekitar Perairan Sumenep

The high demand for the crab export market has resulted in the crab commodity experiencing a decline and leading to exploitation. Prediction of crab stocks in Sumenep Regency is minimal due to a need for further information regarding crab data. This study aims to determine the biological characteristics of the blue swimming crab (Portunus pelagicus), limiting blue swimming crab (Portunus pelagicus), and water quality characteristics around Sumenep. Research methods is observation methods or directly contact fishermen. Data collection included blue swimming crab biology, including morphometric aspects, which consisted of measurements of carapace width, carapace length, weight, and level of gonadal maturity. Data collection for water quality parameters used the insitu method at each research location. The results of this study were variations in the morphometric characters of the crabs in the distribution of the carapace width of the male crabs found in class 121-138 mm, as many as 137 individuals, while the female crabs were found in class 121-138 mm as many as 136 individuals, the distribution of size class based on the length of the female crab in class 60 .42-68.42mm as many as 112 people. The size class distribution of male crabs was mainly found in the 51.42-59.42mm class of 96 individuals; the distribution of size classes based on the weight in male crabs in the 126-157 gram class was 65 individuals. The size class of female swimming crabs was found in the 158-189 gram class; as many as 67 individuals applied for crabs around Sumenep. Based on the crab data collection at the first location, Talango was 289 ind/700 cm2, the second location was Tanjung Saronggi, 65 and/700 cm2, and in the third location, Gili Genting, there was as much as 104 ind/700 cm2. The waters of Tanjung Saronggi are a location that has more male crabs than female crabs. The air quality characteristics around Sumenep waters are categorized as optimal for blue swimming crab habitat.

Assessing the sustainability of the blue swimming crab (Portunus pelagicus) on the Eastern Coast of Lampung: a holistic approach to conservation and resource stewardship

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 118.69 mm, 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 long-term ecological health of BSC populations in the study area.

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

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

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.

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

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.

Effect of different chilled storage method and ozone treatment on the quality of steamed whole blue swimming crab (Portunus pelagicus)

Pasteurized canned blue swimming crab (Portunus pelagicus) meat is an important export fisheries product from Indonesia. Ozone treatment in food is known to kill bacteria and other microorganism. The purpose of this study was to determine the effects of ozone treatment in chilled storage on the quality of steamed whole blue swimming crab. A total of four combinations of chilled storage with ozone treatment were tested: storage in cool box with ice (CBI), storage in cool box with ice and ozone treatment (CBI-O), storage in refrigerator with ozone treatment (REF-O), storage in refrigerator (REF). Steamed whole blue swimming crab were stored in each storage for 6 days. Melted ice was replaced every 12 hrs. Samples were taken every day for central temperature measurement and sensory analysis. Water holding capacity (WHC), total volatile base nitrogen (TVBN), moisture, pH, and total plate count (TPC) analysis were carried out every 3 days. The results showed that whole steamed blue swimming crab were rejected after 3 days in CBI, after 4 days in cool box with ozone treatment CBIO and after 6 days were still accepted in both refrigerated storages. Ozone treatment could prolong the freshness of steamed blue swimming crab but reduce the typical aroma.

Life history and spawning potential of blue swimming crab Portunus pelagicus (Linnaeus, 1758) in Pamekasan, Madura Island, Indonesia

Blue swimming crab is one of Indonesia’s most valuable marine crustaceans, experiencing high fishing pressures for export, which could lead to the depletion of stocks. Knowledge of blue swimming crab spawning potential is imperative for understanding the stock’s status. This study aimed to estimate the spawning potential of blue swimming crab (Portunus pelagicus) based on their life history parameters. Fourteen thousand five hundred thirty-three crab samples were collected from fishers caught using the collapsible traps from January to December 2021 in Pamekasan. The biological data, including carapace width, weight, sex, and maturity level, were measured. Length-based spawning potential ratio method was used to estimate the spawning potential ratio. Results showed the growth parameters, CW∞= 179.55 mm, K = 0.98 year−1, and tmax=3 years. Size at first maturity was estimated at 102 mm carapace width, while the size at first capture was 112-121 mm. Egg-berried female crabs were observed throughout the year, with two distinguishable peaks occurring in Jan-Feb and Aug-Sep. The overall estimates of the SPR met the reference point limit. This study gave insights that the stock status of BSC in Pamekasan was not at risk of recruitment impairment, but management actions should be initiated for stock rebuilding.

Improving size and selectivity of blue swimming crab (Portunus pelagicus) by using collapsible trap with escape vents in Pamekasan, Madura Island

Blue Swimming Crab (Portunus pelagicus) is high export value product from Indonesia that usually exported as pasteurized crabmeat in cans, and has high consumer demand. Blue swimming crab production still depends on wild catch, so that it will threaten the existence of them in the sea. The use of traps will cause almost all sizes of blue swimming crabs to be caught (accidentally) including those that are still small (not suitable for catching). This study aims to analyze the effectiveness of the escape vent in collapsible traps to reduce small catches of blue swimming crabs in the Pamekasan area. This research was carried out from August 2021 - January 2022 in the southern waters of Pamekasan. The method used is descriptive analysis and the effectiveness analysis of collapsible traps with a size (length x width) of escape vents is 4,5 x 3,5 cm. The study carried out 106 females and 85 males with a total weight of 22,908 kg and the carapace width ranged from 9,7 to 15,8 cm. The effectiveness of escape vents is 98,65%, which is the higher value (closer to 100%) the more benefits it will give to sustainability of blue swimming crabs in the Pamekasan area.

Seasonal comparison of catch abundance and size of blue swimming crab (Portunus pelagicus) in Rembang, Central Java

Considering the blue swimming crab (Portunus pelagicus) was exported as pasteurized crab meat, the quality of fresh meat (stock and size) could have been influenced by the season and needed to be considered. This study aimed to analyse the effect of the season on the crab’s abundance and size in Rembang Water, Central Java. The study period includes four seasons, namely west monsoon, first transition, east monsoon, and second transition from July 2021 to June 2022. The crab samples from the fishermen were analysed in term of the fishing trips, weight, and carapace width at the fishing ground location. Descriptive statistics and univariate one-way ANOVA was used to analyze the data. The average abundance, weight, and size of crabs caught in Rembang waters during the year were 1,8 kilograms per trip a day (one-day fishing). The abundance of crabs in the west monsoons was greater than in the east monsoons. The pattern of crabs caught was higher at the beginning of the west monsoon (December–January), then it decreased in February until the start of the first transition (March), then gradually increased in April before decreasing again in June until the end of the second transition (October). The ANOVA test showed that the size of crabs in every season had significant differences. It was clearly shown on the boxplot that the catch in the west monsoon and the first transition was smaller than the east monsoon and second transition. These results can provide insightful information for fishers, managers, and policy makers as a basis for developing sustainable fisheries management.

Diversity of non-targeted species on blue swimming crab Portunus pelagicus gillnet fishery in Grogol, Cirebon

Non-targeted Species (NTS) data and research is needed in the management and development of the blue swimming crab fishery ecosystem. The NTS were divided into two groups, namely the retained and the discarded. This study aims to explain the diversity of NTS caught by blue swimming crab fishermen that used gillnet in the Cirebon Regency. This study uses exploration and enumeration methods to analyze the catch of NTS catched by blue swimming crab fishermen for 7 months in 2021. Shannon-Wiener diversity, Evenness, and Simpson’s dominance index were further analyzed. Results showed the diversity of NTS caught by blue swimming crab fishermen with gillnets in Cirebon Regency consisted of 29 species from 23 families (9 fish, 16 crustaceans, and 4 mollusc species). The highest diversity index was observed in December (2.16) and the lowest was October (1.29). The highest population uniformity or evenness was observed in September (0.83) and the lowest in October and November (0.59). The dominance index had the highest value in August at 0.41 and the lowest in July at 0.15. The non-target species biodiversity of P. pelagicus fishery in Cirebon was classified as moderate diversity category, moderate to high evenness, and low dominance. These results provide information for fishermen to reduce catches of non-targeted species which requires fishermen to return and release the non-targeted species within 5 minutes and maintain the diversity of marine biota.

The impact of mangrove environmental conditions on the growth rate of juvenile blue swimming crab (Portunus pelagicus) in Polagan Beach, Pamekasan, Madura Island

Mangrove forests have essential ecological functions, especially for coastal areas, one of which is as a shelter for small crab species at the juvenile stage. The research was conducted in Polagan Beach, Pamekasan Regency in November 2020-January 2021. The methods were divided into three sequential parts: pre-survey (processing of mangrove density data through Sentinel 2 satellite imagery), survey (calculating water quality and mangrove density parameters) and post-survey (determining each point/station that was used to support the continuity of the research). Data used in analysis are primary data (field) and secondary data (satellite image). The satellite image used in this research was acquired from Sentinel 2 satellite. The result concluded that temperature and salinity affect the growth rate of juvenile blue swimming crabs, but it does not occur significantly. The pH and heavy metal levels affect the survival rate of juvenile blue swimming crabs. Optimal temperature and salinity levels that can produce maximum juvenile growth are temperatures around 28-32°C and salinity around 32-34ppt. The level of mangrove density affected the water quality parameters (temperature and salinity).

Kegiatan Produksi Benih Rajungan (Portunus pelagicus) Sebagai Upaya Penyediaan Stok di Alam

Blue swimming crab (Portunus pelagicus) is one type of crustacean that has great potential to be cultivated. Crab seed production activities are carried out to support the availability of crab seeds so as to reduce fishing activities in nature. Data collection during observation using the survey method, namely by making observations in the field. Seed production activities were carried out since container preparation, preparation of rearing media water, broodstock selection, broodstock rearing, egg hatching, larval rearing, feed management, water quality management, pest and disease management and harvesting. Egg fecundity of 750,000 eggs, egg fertilization rate of 83.60%, egg hatching rate of 76% and larval survival rate of 36.55% were obtained.
  
  

A Concept of Open-Closed Season Approach for Indonesian Blue Swimming Crab (Portunus Pelagicus) Management on the North Coast of Java

The open-closed season approach has not been widely used in fisheries management in Indonesia, including blue swimming crab (BSC) fisheries that created ecological and economic balance. This research aims to illustrate the characteristics of BSC fishers, examine the application of the concept of the open-closed season in blue swimming crab fisheries, and predict the sustainability of fishermen's livelihoods. Data collection was conducted in 2020 and 2022 in four regencies: Rembang, Demak, Cirebon, and Lampung. However, Lampung is excluded in 2022. The primary data were obtained from structured questionnaires sent to 520 fishermen and 63 mini plants and collectors, then analysed by descriptive analysis, Likert scale, and business sustainability index. The findings showed that blue swimming crab fishing characteristics at four research sites showed different conditions. Working as fishermen cannot contribute sufficiently to improving the household economy. The factor influencing the blue swimming crab fishing business is the size of the fishing boats. The open-closed season (OCS) policy is worthy of short-term goals consisting of fishermen's welfare and business justice in business actors and long-term goals, namely the sustainability of blue swimming crabs. Institutional schemes are proposed for the OCS model to maintain the sustainability of resources and businesses.

Bioaccumulation of zinc by Portunus pelagicus: Nuclear application techniques that use radiotracer 65Zn to study influence of concentration of Zn in seawater

Zinc (Zn) is an essential trace metal, but also a potential toxicant to aquatic organisms. Zinc is one of the toxicants from various industrial and domestic activities whose waste is directly discharged into water. One of the marine organisms used as an indicator of pollution is the blue swimming crab (Portunus pelagicus). Bioaccumulation studies of Zn in Portunus pelagicus from Jakarta Bay were conducted in a radiotracer laboratory. Laboratory experiments were done to study the uptake and release of 65Zn radioisotope in Portunus pelagicus. The experiments conducted were biota collection, acclimatization, bioaccumulation, and elimination. This study was to determine the relationship between the amount of 65Zn released into the aquatic environment and its effect on Zn bioaccumulation ability and radiation dose received by Portunus pelagicus. Biokinetics parameters, such as concentration factors CF, uptake rate constant ku, elimination rate constant ke, and concentration factor steady state (CFss) were investigated. The results showed that an increase in concentration would decrease the rate of absorption and rate of elimination, and that the concentration factor CF values ​​varied from 7.82 - 60.62 ml.g-1 in Portunus pelagicus. The concentration factor at steady-state Zn was 25.55-59.47 ml.g–1, which is influenced by the concentration after 6 days of exposure. The depuration rate was observed to be high, with a value of retention 34.33 - 78.88 % of 65Zn absorbed by Portunus pelagicus, which was absent 7 days after exposure. Highlights Laboratory experiments lasting 14 days showed that Portunus pelagicus has the ability to accumulate the heavy metal zinc (Zn) from the environment and release it back into the water The highest bioaccumulation kinetics of zinc (Zn) metal in Portunus pelagicus during the 7-day experiment occurred at a contaminant concentration of 0.5 ppm with an absorption constant (ku) value of 0.7838 d-1 and a release constant value (ke) of 0.0892 d-1 Portunus pelagicus concentration factor (CF) has a moderate value and the smallest uptake constant (ku) and elimination constant (ke) value compared to other biota

Sensory Value, Proximate Analysis, Amino Acid and Fatty Acid Profile of Steamed and Boiled Blue Swimming Crab (Portunus pelagicus)

Whole blue swimming crab (Portunus pelagicus) is usually steamed or boiled before taking the meat for canning. The choice of the cooking process between steaming or boiling can determine the characteristics of blue swimming crab (Portunus pelagicus) meat. This study aims to determine and compare the flavor profile of blue swimming crab cooked by steaming and boiling. Whole blue swimming crab were steamed and boiled for 15 minutes at 100°C respectively. The cooked blue swimming crab meat was then tested for yield, sensory value, proximate analysis, amino acid and fatty acid profile. The results showed that the steaming process gave higher yields and sensory value than boiled blue swimming crab.

Microplastics in the Gastrointestinal Tract of Blue Crab (Portunus pelagicus) Caught by Bandaran, Bangkalan Fishermen at Different Sizes

Microplastics are plastic waste that is degraded into small sizes that float in water bodies and can be ingested by aquatic biota. This study aims to determine the shape, color, and abundance of microplastics in the digestive tract of blue swimming crab (Portunus pelagicus) caught by fishermen in Bandaran Village, Bangkalan at different sizes. Swimming crab sampling was carried out 3 times with different sizes, namely small, medium, and large. Identification of microplastics using a solution of H2SO4 and H2O2 with a concentration of 30% with a ratio of 3:1. Microplastic forms found include fiber, fragments, and films. The highest abundance of microplastics was found in large crabs with a value of 3.13 particles/g. The simple regression test results obtained a relatively small R² value of 0.0003 meaning that the size of the crab has a very small correlation with the abundance of microplastics in the digestive tract.