Blue swimming crab Portunus pelagicus, Linnaeus, 1758 in Pare Pare Bay, South Sulawesi, Indonesia: Study of reproduction and breeding potential

Blue swimming crab Portunus pelagicus is one capture fisheries commodity which offers promising prospects in Pangkep Regency, South Sulawesi, Indonesia. This study aimed to determine the fishery management of blue swimming crab based on spatial zoning areas. The research was conducted between April-November 2016 and May-November 2017 in the coastal waters of Pangkep Regency. Primary and secondary data were collected and analysed for water suitability and zonation using mapping and geographic information system analysis (GIS). The water quality parameters were: dissolved oxygen (1.5-11.0 mg/L), temperature (31-37 °C), salinity (9.0-31.0 ppt) and pH (6-8). The fishery management of blue swimming crab was classified into two integrated zoning area types: conservation zone (56,855 Ha) and commercial blue swimming crab fishery zone (36,153 Ha). However, the conservation zones are opened to the commercial fishery at certain times outside the critical periods for blue swimming crab reproduction. These critical periods are the zoea, megalopa and juvenile crab phases which occur from May to October, with an annual spawning peak in August. Fishing is not allowed in the conservation zone during the critical periods in order to accommodate sustainable exploitation. The findings were based on data analysis of water quality suitability, existing environmental conditions, fishing grounds, and the life cycle of blue swimming crab, overlaid on the 2013 zoning plan for the coastal area and small Islands in Pangkep Regency.

Blue swimming crab (Portunus pelagicus) is the important world fishery resource, but the crab larval rearing faces high mortality problem. The aim of the research was to compare survival and growth rate of larvae resulted from wild and domesticated broodstock blue swimming crab. Domesticated and wild broodstock were used to produce larvae. Domesticated broodstock was selected from repeated reared crab until third generation. Selection of the broodstock mainly based on the survival and growth rate. The wild broodstock was collected from Makassar Strait Sea. Larvae from the two sources of broodstock were reared in the conical tanks with density of 50 zoeas per liter. After reaching megalopa phase, then, the larvae were transfered into concrete tank completed with shelter and it were reared until crab phase. Crab phase was reared for 18 days, then these seed were released into the brackishwater pond for further domestication step. Larva from zoea to crab were fed with rotifer, artemia, fresh small shrimp and diet. The result showed that domesticated broodstock produced higher survival rate (P<0.05) larvae, faster larval stage changes (P<0.01) and uniform larval growth compared to the larvae from wild broodstock. It is clearly shown, the use of domesticated broodstock of blue swimming crab produced better larva quality and quantity than the wild broodstoock crab. Keywords : blue swimming crab, larvae, domestication, broodstock selection, faster growth

After absorption of heavy metals in the tissues of aquatic organisms in aqueous solution accumulate and enter the human body through the food chain and proportional to the concentration of toxic metals absorbed, clinical effects observed. The objective of this study was to evaluate and compare the concentration of heavy metals, lead, nickel, iron and copper in muscle tissue of blue swimming crab Portunus plagicus in three regions (Qeshm, Khamir port and Laft port) was conducted in the Hormozgan Province. Sampling was conducted in summer and winter 1394. After the captured biometric sample 180, were isolated muscle tissue. The preparation and analysis of samples was performed according to standard methods MOOPAM. The results show that the studied concentration in muscle tissue of blue swimming crab (Portunus pelagicus) at sample locations statistically significant difference shows. Also studied in terms of concentration in the muscle tissue of blue swimming crab in the study area between summer and winter statistically significant difference was observed ( p<0/05). As both in summer and winter concentrations of lead, nickel, iron and copper in muscle tissue of blue swimming crab in Qeshm is greater than the other two regions. Meanwhile, the results of the study compared concentration in muscle tissue showed blue swimming crab with international standards. The studied concentration in muscle tissue of blue swimming crab in Qeshm, Khamir port and Laft port international standards is less than the limit. Which indicates that the health of aquatic ecosystems contamination is not a problem.

Species identification of the blue swimming crab Portunus pelagicus in Thai waters using mtDNA and RAPD-derived SCAR markers

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.

The basic information on genetic diversity and population structure is essential for the construction of appropriate management schemes leading to sustainable fisheries of the blue swimming crab (Portunus pelagicus). Here, genetic heterogeneity of P. pelagicus (N=174) was examined by single-strand conformational polymorphism (SSCP) analysis of mitochondrial cytochrome c oxidase subunit I (PpCOI270). Seven SSCP genotypes were found across all investigated samples. The average genetic distance between pairs of geographic samples was 0.0014-0.7247. Significant geographic heterogeneity (P&lt;0.05) and restricted levels of female gene flow between paired samples (0.03-1.60 individuals per generation) were observed except between Chanthaburi - Prachuap Kriri Khan and Ranong - Krabi (P&gt;0.05; 6.54 and 16.17 individuals per generation) located in the same coastal regions. Therefore, the gene pool of P. pelagicus in Thai waters was genetically differentiated to different stocks even though it is biologically regarded as a potential dispersal species. Five geographic samples of P. pelagicus in Thai waters could be differentiated to three genetic stocks; Chanthaburi and Suratthani (stock A), Prachuap Khiri Khan (stock B) and Ranong and Krabi (stock C).

Blue swimming crabs Portunus pelagicus occupied Tiworo Strait waters has been experiencing heavy pressure due to high exploitation and damaging its habitat caused by conversion to be a port or jetty particularly in the intertidal and subtidal zones closed to mangrove areas and river mouth. Those zones constitute main habitats of BSCs. The study aimed to analyze temporal sex ratio (SR), growth patterns and condition factor (CF) of BSCs in Tiworo Strait waters which was conducted in June–December 2018. The BSC samples were taken monthly using collapsible pot. Each sample taken was identified its sex, measured its CW and weighed its BW. Monthly SR of male and female was counted, while BW–CW relationship was analyzed using a simple linear regression. Growth patterns and CF were derived and analyzed from BW–CW regression. The results of study showed that monthly BSC SR of male and female showed females preponderated over males, except in November. The growth pattern of male and female was negative allometric (b 3). Data of BSCs CF were mostly influenced by growth coefficient (b), namely the higher b the lower CF. This condition is frequent happening in BSC population dominated by juvenile and mature stages. This study showed most BSCs found in this location were juvenile which indicated as their nursery ground in the intertidal zone dominated by sand substrate closed to mangrove forest.

The blue swimming crab (Portunus pelagicus) is one of the endangered species due to overexploitation. The development of hatchery technology is expected to be a solution in overcoming this problem. However, until now the availability of seeds is not stable due to high mortality, especially in the larval stage which is often caused by poor quality of broodstock. This study aims to assess the reproductive performance of small crab crabs from various small crab production centers in South Sulawesi to find quality broodstock sources. The sampling locations included 3 areas, namely Bone Regency, Maros Regency and Takalar Regency, South Sulawesi Province, Indonesia. The reproductive performance measured was the length and width of the carapace as well as body weight, fecundity, egg diameter and number of larvae produced by each broodstock and assessing the development of egg diameter based on embryo development. The results obtained, namely the value of fecundity, egg diameter and number of larvae were different from each region. The highest body size, fecundity, egg diameter and embryo development and number of larvae were obtained from Takalar while the lowest was from Maros (P <0.05). The aquatic environment affects reproductive performance. This can be seen from the infestation of octolasmis and barnacles found in nearly 90% of bone broodstock which is thought to have an effect on reproductive performance. From this research, it is obtained an illustration that the broodstock of Takalar is better used as the source of broodstock.

Abstract. Hidayani AA, Fujaya Y, Trijuno DD, Rukminasari N, Alimuddin A. 2020. Genetic diversity of blue swimming crab (Portunus pelagicus Linnaeus 1758) from Indonesian waters (Sunda and Sahul Shelf, Wallacea region): Phylogenetic approach. Biodiversitas 21: 2097-2102. Blue swimming crab is one of the exploited fisheries commodities in Indonesia. This condition has contributed to the decline of their genetic diversity. The information on genetic diversity assumes importance for the conservation and the cultural purposes of species. The study aimed to determine the genetic diversity of blue swimming crabs from Indonesian waters using phylogenetic analysis. We conducted sampling of crab from several Indonesian waters, such the Aceh and Semarang (representing Sunda Shelf), Barru, South Sulawesi, and Maumere, Flores (representing Wallacea region) and Sorong, Raja Ampat and Kaimana (representing Sahul Shelf). Genetic diversity in this study using mitochondrial DNA (mtDNA) by implementing the method of Cytochrome c Oxidase Subunit I (COI). According to the findings, the blue swimming crabs from our study sites had a high genetic diversity variation. Three groups of crabs were determined using phylogenetic tree which formed three different unique clades. There was the same haplotype of crab observed from different locations, barring a sample from the Sahul Shelf which has a unique haplotype. There was no genetic speciation of crab samples from the Sunda Shelf and the Wallacea region were observed, except samples from the Sahul Shelf. Hybridization might occur between species of the crabs due to the finding of a cryptic species.

Abstract. Yuliana E, Winata A, Setijorini LE, Yani DE, Hewindati YT, Djatmiko WA. 2024. Ecosystem approach for blue swimming crab (Portunus pelagicus) sustainability in Bekasi District, West Java, Indonesia. Biodiversitas 25: 4117-4126. There is concern that the sustainability of blue swimming crab (BSC) (Portunus pelagicus Linnaeus 1758) resources is threatened by ever-increasing consumption. This has led to increased BSC fishing pressure, which can result in over exploitation. The study aims to analyze BSC sustainability based on the indicators of the ecosystem approach for fisheries management (EAFM) and to determine the follow-up in the form of management tactical steps. The study site was the waters of Segara Jaya Village, Taruma Jaya Sub-district, Bekasi District, West Java, Indonesia. The sampling location was the mudflats around the mangrove ecosystem. Data on BSC were collected from fishermen’s catches; the crabs’ carapace width (CW) and weight were measured, and their sex was identified. The fishermen data were collected from the entire population of Segara Jaya fishermen (40 people). We analyzed BSC sustainability using the CW-based stock assessment. The life-history parameters consisted of growth parameters, mortality, and exploitation rate estimated using the “TropFishR” package in RStudio; the rest used descriptive analysis. The results indicated that the BSC caught had an average CW of 7.25 cm (not compliant with the government policy) and an average weight of 29.24 g. There was overexploitation, with the exploitation rate value being 0.94 for males and 0.85 for females. The results of the water quality measurements were in accordance with seawater quality standards for marine biota. To properly educate fishermen, several counseling and motivational approaches are needed to build the fishermen’s awareness. Regarding fishing techniques, educating fishermen to catch BSC larger than the minimum size set by the government (CW of &gt;10 cm) is needed. Motivation-building to fishermen so that they are invested in conserving BSC resources is also needed in the socio-economy domain.

Seaweed cultures in marine coastal waters provide providing microhabitats, shelter, and food sources to fish and invertebrate. The availability of blue swimming crab (Portunus pelagicus) in seaweed culture area was conducted from October to December 2019 in the south coastal waters of Bulukumba Regency, South Sulawesi, Indonesia. The purpose of the study was to assess the catch, size, and sex distribution of the blue swimming crab in the area. The crabs were caught by set bottom gillnets with 4 inches of mesh sizes and 300 m of a length. The carapace width (CW) and sex for each crab individual were recorded. The results of the study show that the total catch of 21 trips during 3-month fishing operation was 539 crabs that consist of 260 male (48.24 %) and 279 females (51.76 %). The (CW) of males ranged from 53.6 to 143.6 mm, while females ranged from 58.3 to 142.8 mm. There were 38 breeding crabs or 13.62 % from the female total. The carapace width of breeding crab ranged from 92.2 to 138.6 mm. Moreover, it needed to study in the area intensively.

Abstract. Supmee V, Sawusdee A, Sangthong P, Suppapan J. 2020. Population genetic structure of Blue Swimming Crab (Portunus pelagicus) in the Gulf of Thailand. Biodiversitas 21: 4260-4268. The Blue Swimming Crab (Portunus pelagicus) is an important commercial fishery product in the Gulf of Thailand. To provide a strategy for management, information on genetic features is needed. In our study, the population genetic structure and demographic history of the P. pelagicus living in the Gulf of Thailand were analyzed based on the variation of the nucleotide sequence of the mitochondrial DNA in the control region (mtDNA CR). Ninety-seven samples were collected from 5 sampling sites: Rayong, Chonburi, Chumphon, Surat Thani, and Nakhon Si Thammarat provinces in the Gulf of Thailand. Forty-nine haplotypes were identified and 39 private haplotypes were found. An AMOVA showed no genetic structure among populations. The pairwise FST also indicated no statistically significant difference between all possible regional combinations. The topology of a minimum spanning network revealed a star-like topology that was not separated by geographic structure. The historical demographic analysis revealed a stable population size for a long period and followed by a very recent expansion. An absence of a population structure of the P. pelagicus was possibly caused by a high level of gene flow. The results of this study differ from previous studies that used genetic markers in nuclear DNA. Thus, to clear the genetic structure information of P. pelagicus in the Gulf of Thailand, we suggested that more sensitive markers to detect genetic structure should be used in further analysis.

Ghost fishing in the pot fishery for blue swimmer crabs Portunus pelagicus in Queensland, Australia

The Blue Swimming Crab (BSC) is the main export commodity of Indonesia and one of the BSC agribusinesses in the coastal waters of the Pangkep Regency. However, in recent years, BSC agribusiness in this region has been estimated to be unsustainable. The purpose of this study is to formulate the management of BSC (Portunus pelagicus) resources with the Ecosystem Approach to Fisheries Management (EAFM) in the coastal of the Pangkep Regency. The average value score in the BSC management domain is in the medium category (resource, habitat, economic, and institutional domains); the fishing techniques domain is in the good category, while the social domain is in the poor category. In general, the status of BSC fisheries management is categorized as medium (value = 194.25), therefore it can still be developed and improved. To repair the BSC fisheries management for gradually, tactical decisions were made to enhance the indicator conditions. To make the fishery activities sustainable, recommendations to improve the condition of the BSC fisheries in the Pangkep Regency include strengthening the supervision, improving the seagrass cover, improving coordination among institutions on the BSC fisheries management, and increasing stakeholder participation in the effort to manage the BSC fisheries.

Uhlmann, S. S., Broadhurst, M. K., Paterson, B. D., Mayer, D. G., Butcher, P., and Brand, C. P. 2009. Mortality and blood loss by blue swimmer crabs (Portunus pelagicus) after simulated capture and discarding from gillnets. – ICES Journal of Marine Science, 66: 455–461. Two laboratory experiments were carried out to quantify the mortality and physiological responses of juvenile blue swimmer crabs (Portunus pelagicus) after simulated gillnet entanglement, air exposure, disentanglement, and discarding. In both experiments, all but control blue swimmer crabs were entangled in 1-m2 gillnet panels for 1 h, exposed to air for 2 min, subjected to various treatments of disentanglement ranging between the forceful removal of none, one, two, and four appendages, then “discarded” into individual experimental tanks and monitored for 10 d. In Experiment 1, mortalities were associated with the number of appendages removed and the occurrence of unsealed wounds. In Experiment 2, live blue swimmer crabs were sampled for blood at 2 min and 6, 24, and 72 h post-discarding to test for the effects of disentanglement and appendage removal on total haemocyte counts, clotting times, protein levels (by refractive index), and blood ion concentrations. Compared with blue swimmer crabs that had sealed or no wounds, those with unsealed wounds had lower total haemocyte counts, protein, and calcium concentrations and increased clotting times and magnesium and sodium levels. Induced autotomy, as opposed to the arbitrary, forceful removal of appendages has the potential to minimize the mortality and stress of discarded, juvenile blue swimmer crabs.