Stock assessment of blue swimming crab under the fishery improvement project (FIP) was conducted from January to December 2018. Sample was collected by using collapsible crab trap. The result of population dynamic by using monthly sampling of size distribution of crab was analyzed by FiSAT II program software found that growth parameter of male crab was L∞ = 12.78 cm; K = 0.25 per year while the growth parameter of female crab was L∞ = 11.87 cm; K = 0.19 per year. Total mortality of male and female crab were indicated by 0.52 and 0.41 per year, respectively.
The recruitment period occurred all year round with one peak during January to June.
The exploitation rate was 0.36. The result of population structure of crab was found that sex ratio between male and female was 1 : 0.73. The relationship between carapace width (CW) and weight (W) were W = 0.0012CW 2.3731 and W = 0.0042CW 2.0658 in male and female crab, respectively. Size distribution of carapace width was ranged from 8–9 cm. The average of carapace width was 8.48±3.04 cm. Highest abundance was found in pelagic area (station I) while lowest abundance was found in seagrass bed (Enhalus acoroides, station D). Abundance of crab was highest in November and lowest in September. The proportion of juvenile and adult male crab by using collapsible crab trap were 25% and 75% while the proportion of juvenile and adult female crab were 40% and 60%, respectively. The relationship between abundance of crab and physical factor was correlated with transparency depth and dissolved oxygen (P< 0.05).
Comparative in effective of mesh size of collapsible crab trap to blue swimming crab fishery in Kung Krabaen Bay, Chanthaburi Province using four mesh sizes of trap. The size of trap in the bottom was varied three size, 2.00 inch, 2.50 inch and 3.00 inch. And the last size of trap was 2.50 inch in every side. The objective of this study was used for local fishery improvement project in collapsible crab trap adaptive measurement. Sampling was conducted four times in March, June, September and December 2018. The result found that mesh size of trap 2.50 inch in every side can harvested crab in highest was quantity. The average weight was 225.03 g whereas Catch per Unit and Effort (CPUE) was 7.50 g/trap. The mesh size of trap 2.50 inch in the bottom harvested highest many species of by catch (21 species). The highest proportion was found in Clibanarius infraspinatus (43.08%). The sex ratio between male and female was 1:1.74. The result also found that size distribution of crab in each mesh size (2.00 inch, 2.50 inch, 3.00 inch and 2.50” inch) was found in highest range 81-90 mm, 61-70 mm, 51-60 mm, 81-90 mm and 71-81 mm, respectively.
Size distribution of blue swimming crab (Carapace width) fishery in Kung Krabaen Bay was conducted and found highest in range 91-100 mm (30.45%). The result also showed that crabs which were lower size than 60 mm, they were still continuously harvesting (1.92%). The reproductive biology of female blue swimming crab was conducted from January to December 2018. These data aimed to use for making regulation in forbidden harvested female blue swimming crab in spawning season. The result found that ovary development in stage 3 and 4 was highest from June to September. The value were 40.00, 58.63, 56.67 and 40.00, respectively. Gonad somatic index was 2.38% to 4.41%. The result also showed two high peaks in March (4.06%) and September (4.41%). First size at maturity was 109 mm. Abundance of female crab in each station and season was significantly different (P<0.05). Female crabs were most found in pelagic area. And highest and abundance was also found in dry season (71.98%) than wet season (28.02%). Moreover, the relationship between abundance of female crab with physical factors was no correlated (P>0.05).
The genetic study of 29 marine crab specimens was determined using DNA barcording by analyzing the nucleotide sequences of Cytochrome oxidase I (COI) gene. The Identity of all sequences was determined by comparing with GeneBank and BOLD genetic databases. The results found that 11 species were identified with high genetic similarity (98-100%). The Scylla mud crabs were genetically identified in this study and 3 species was found as S. paramamosain, S. tranquebarica and S. olivacea.
This research has isolated the actinomycetes from gills and innards of some marine crabs in Kung Krabaen Bay, Chanthaburi Province. All 50 isolates of actinomycete were isolated from humic acid vitamin (HV) agar and International Streptomyces Project-2 (ISP-2) agar that prepared by seawater. The cross steak method was used to test against some pathogenic microorganism, Bacillus cereus TISTR 2372, Staphylococcus aureus ATCC 25923, Pseudomonas aeruginosa ATCC 28753, Escherichia coli ATCC 25922 and Candida albicans ATCC 90028. The results showed that the 5 isolates of actinomycete could inhibit B. cereus TISTR 2372 and S. aureus ATCC 25923. The inhibition distance of their activity were in the range 14.00 - 22.78 mm and 10.44 - 32.67 mm, respectively. Isolate API01 was the best actinomycete that against the test microbes. Its inhibition distance that against B. cereus TISTR 2372 and S. aureus ATCC 25923 were 22.78 ± 1.86 mm and 32.67 ± 1.80 mm, respectively. API01 was cultured in ISP-2 agar for extraction of crude extracts and ethyl acetate was used as solvent. The crude extract was dark red viscous, weighing 0.5827 g. Broth microdilution method and streak plate method were used to determine the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of crude extract. The MIC and MBC values of crude extracts against B. cereus TISTR 2372 was 512 µg/ml, but the MIC and MBC values against S. aureus ATCC 25923 was more than 1,024 µg/ml. The colony characteristics of the 5 active isolates were white, yellow and gray. The old colony of the API01 isolate was gray. It was found that all 5 isolates of the actinomycetes were characterized as long strands of the small hyphae with broken into small pieces and twisted in a short spiral at the apex, while API01 had a direct spore shape and had a slightly flexuous curve called rectiflexibiles. Data analysis of nucleotide sequences of 16S rRNA genes and phylogenetic tree formation were studied. The results showed that the isolates API01, API03, ACI05 and ATG02 were similar to St. atriruber NRRL B-24165T (99.15%), St. gramineus JR-43T (99.59%),
St. coelicoflavus NBRC 15399T (100 %) and St. sclerotialus DSM 43032T (99.10%), respectively.
This research was collected the timeline database of the blue swimming crab (BSC) status at Kung Krabaen Bay since 2013-2019 and relevant data. Seven database of BSC was divided 1) population dynamic and population structure of BSC including reproductive biology 2) Comparative of effective of mesh size in collapsible crab trap 3) DNA barcoding of BDC and some fish 4) the status of seagrass bed 5) microorganism from BSC and other marine crab 6) ecological modelling of BSC and bycatch and 7) Ability conservation and sustainable management data of BSC at Kung Krabaen Bay. This database will be effected to make decision and create an important measurement or policy in the local and national level. Moreover, these findings could be results in community participation and community opinion, including other stakeholders, in local policy decision-making in the knowledge management of this crab. In addition, it is vital helping people be aware of their valuable roles in community to facilitate the achievement of sustainable development.
