Abstract:The diversity and abundance of marine crabs from a collapsible crab trap fishery at Kung Krabaen Bay, Gulf of Thailand, were observed from August 2012 to June 2013 using 10 sampling stations. The results showed that there were seven families, 11 genera and 17 species (two anomuran and 15 brachyuran crabs). The two anomuran species were Clibanarius virescens (1,710 individuals) and Clibanarius infraspinatus (558 individuals). For brachyuran crabs, Portunidae was the most common family, including 10 species. The dominant species of brachyuran crabs included Thalamita crenata (897 individuals), Portunus pelagicus (806 individuals), Charybdis affinis (344 individuals), Scylla sp. (201 individuals), and Charybdis anisodon (100 individuals). The abundance of crabs was affected by the habitat type. Anomuran crabs had the highest abundance in Halodule pinifolia seagrass beds, whilst brachyurans had the highest abundance in Enhalus acoroides seagrass beds. The dominant brachyuran species were found in pelagic areas near the bay mouth, such as P. pelagicus, P. sanguinolentus, C. feriatus, C. helleri, C. natator, C. affinis, and M. hardwickii. Lastly, reforested mangroves were important habitats for Scylla tranquebarica and C. anisodon. Seasonal and physical factors influenced the abundance of some crabs, for example, the abundance of C. virescens was correlated with temperature, and the abundance of T. crenata was correlated with transparency depth. Our results revealed that Kung Krabaen Bay serves as the home to many marine crab species; however, our results also revealed that 49% of the harvested crabs (2,308 out of 4,694 individuals) were simply discarded and subsequently died. Moreover, our research noted that eight non-target species will become target species in the near future. Therefore, research on the reproductive biology of some marine crabs and an improved understanding of the importance of marine crabs by local fishermen are necessary to prevent biodiversity degradation and loss in this area.

Zooplankton dynamics were assessed, including the relationships between crab larvae, other zooplankton and ecological factors, and an appropriate approach to the management of blue swimming crab in Kung Krabaen Bay, Chanthaburi Province was explored. Sixteen stations were selected for bimonthly sample collection during 2004 and 2005 and these revealed 40 groups of zooplankton from 15 phyla. Among these, four economically important groups were recorded, including shrimp larvae, fish larvae, bivalve larvae and brachyuran larvae (crab larvae). The distribution and density of these four groups were different in relation to the influence of the monsoon season and the specific habitat in the bay where they were found. In particular, brachyuran larvae density was highest (1.4×105 to 3.8×103 ind/100 m3) during the south-west monsoon (May- October), which had a negative correlation with fish larvae and a positive correlation with Acetes spp. The study results indicated that the highest distribution and density of brachyuran larvae were found at the seagrass habitat and the bay mouth. The density and distribution of brachyuran larvae also corresponded to the study of the gonad somatic index, which found two peaks of the spawning of berried female blue swimming crab in September and January. Spawning of female crab showed a relationship with the peak density of brachyuran larvae in November. Both crab larvae and young blue swimming crab use the seagrass bed as a refugium and nursery habitat. With regards to the specific characteristics of this bay, the blue swimming crab is a dominant economic species, which has supported the livelihood of local fishing communities. Blue swimming crab production has declined from 120 t in 2002 to 80 t in 2004 and 62 t in 2005, which is clearly related to over-crabbing in this bay using small mesh size (3.50 cm) collapsible crab traps. Average catching size has also reduced from 11.22 cm in 1999 to 7.31±0.42 cm in 2005, with pre-reproductive females representing 70% of the catch. An appropriate management approach for the blue swimming crab fishery that enhances survival would include: (i) conserving seagrass beds by prohibiting crabbing during the northeast monsoon when berried female blue swimming crab and brachyuran larvae are at their highest density; (ii) enlarging the mesh size of collapsible crab traps to not less than 6.50 cm to avoid catching young crab; (iii) banning the capture of berried females; (iv) promoting crab restocking and culture; and (v) educating and publicizing sustainable crabbing to fisher communities, as well as other stakeholders.

The blue swimming crab, Portunus pelagicus (Linnaeus, 1758), is one of the most economically important crustaceans in Thailand. In order to gather more in-country data on its biological aspects, a comprehensive observation of the annual reproductive cycle of female P. pelagicus, which were gathered each month from Kung Krabaen Bay, Thailand, from October 2017 to September 2018 was undertaken. The ovarian structure, gonadosomatic index (GSI) and histological description of P. pelagicus were observed during this time. It was revealed that six distinct stages-I (immature stage), II (early maturing stage), III (late maturing stage), IV (early matured stage), V (middle matured stage) and VI (late matured stage)-occur during the annual reproductive cycle of the females. Moreover, the percentage of the oogenic proportion of P. pelagicus appeared continuously throughout the year. The ovarian development was exclusively found in stage VI, during October 2017 to December 2017, with the highest peak in November 2017 (39.96%) in relation to the high GSI. From October 2017 to February 2018, stage I was also observed, especially during October 2017 (49.5%), implying its important involvement in supporting oogenic production. It would be suggested that the successive spawning season of the P. pelagicus population clearly occurred during October-December each year. Therefore, this would be the best time to support hatchery seed production, during which P. pelagicus collection should be avoided.

The aims of this study were to investigate the biodiversity and functional distribution of macrofungi within the Plant Genetic Conservation Area of Rambhai Barni Rajabhat University, Chanthaburi Province, Thailand, and to identify the macrofungi by sequence analysis of their internal transcribed spacer (ITS) regions. One hundred and eighty-five macrofungi samples were collected from the survey routes in 2021. The macrofungi with different morphologies were selected to perform molecular identification by sequence analysis of ITS. A total of 41 samples of representative macrofungi were classified into 2 phyla, 5 classes, 11 orders, 21 families, and 34 genera. The macrofungi were found to be in the phylum Basidiomycota (35 taxa, 85.4%), the family Polyporaceae (10 taxa, 24.4%), and Microporus xanthopus was the most frequently found species in every month of samples collection. Their role in the ecosystem was saprotroph (40 taxa, 97.6%), symbiotroph (7 taxa, 17.0%), and pathotroph (4 taxa, 9.8%). In addition, there was no published information about the edibility of many of the macrofungi (29 taxa, 70.7%); however, some edible (8 taxa, 19.5%) and poisonous macrofungi (4 taxa, 9.8%) had previously been reported. Interestingly, some macrofungi samples need more investigation for further identification, and additional genes may be required for the study.

The objective of this study was to investigate the mixed culture of Bacillus subtilis, B. licheniformis and B. megaterium to control acute hepatopancreatic necrosis disease (AHPND) or EMS (Early Mortality Syndrome) in white shrimp Litopenaeus vannamei as a model. The infected shrimps with Vibrio parahaemolyticus AHPND strain were divided into tanks and different feeding of either B. subtilis, B. licheniformis, B. megaterium or all Bacillus strains. The infected shrimps that were fed with a mixed culture of Bacillus showed significantly highest survival rate and revealed lower percent detection of V. parahaemolyticus AHPND strain by Polymerase Chain Reaction (PCR) (57.14%) with a small amount of viability count in their hepatopancreas. In contrast, the infected shrimps that were fed with each of B. subtilis, B. licheniformis or B. megaterium, revealed the spread of V. parahaemolyticus AHPND strain in all tissue by PCR detection (86.67%–100%) with a large amount of viability count (3.53 – 4.24 × 103 CFU/g). This study indicated that the mixed culture of Bacillus subtilis, B. licheniformis and B. megaterium could control the dissemination of V. parahaemolyticus in shrimps, especially in hepatopancreatic that is the target tissue of AHPND in white shrimp (L. vannamei). The result of this study revealed the efficiency and mechanism of the mixed culture of B. subtilis, B. licheniformis and B. megaterium to control the virulence of AHPND and support the application of this mixed culture in aquaculture of shrimp farms to avoid chemical and antibiotic treatment by using it as a biological control.