Molting Of Crab Research Articles

Mangrove crab is one of the leading export commodities in the fisheries sector which has a fairly high selling price at the farmer level. This commodity has great potential to be cultivated in the Asia-Pacific region. However, mangrove crab production in Indonesia is currently still dominated by wild catches because its cultivation activities have not developed optimally. to determine the effect of feeding trash fish and brown mussels on the growth and survival of Mangrove Crabs (S. paramamosain). This study was conducted for 90 days from December 2024 to March 2025. The research location was in the ponds of Candi Manik Village, Sekotong District, West Lombok Regency, West Nusa Tenggara. The research method used 2 treatments, namely trash fish and brown mussels, each of which was repeated 20 times so that 40 experimental units were obtained according to the number of crabs, the treatments tested were trash fish (R) and brown mussels (K). The research data were analyzed using statistical analysis at a real level of 5%. the analysis used to test the results of the experiment was the t-test. The data tested t is the Specific Growth Rate (SGR) value, absolute weight growth, relative weight growth, and crab molting frequency using the mhen withny test while the survival rate (SR) data is analyzed descriptively. The results of the study showed that the absolute, relative, specific weight growth of crabs, molting frequency and survival given feed using brown mussels were higher than those given feed using trash fish. Feeding brown mussels resulted in better absolute, relative, specific growth, molting frequency and survival compared to feeding trash fish on the growth of mangrove crabs. Water quality measurements were within the normal range for the life of mangrove crabs. Keywords: Trash Fish, Mangrove Crabs, Brown Mussels, Molting, Growth

Efficacy of plant extracts in enhancing growth and molting of crab (Scylla serrata) in a traditional pond system

Shape memory polymers (SMPs) are deformable materials capable of recovering from a programmed temporary shape to a permanent shape under specific stimuli. However, shape recovery of SMPs is often accompanied by the evolution of materials from a stiff to soft state, leading to a significant decrease in strength/modulus and thereby impacting their practical applications. Although some attempts are made to pursue the SMPs with self-stiffening capability after shape recovery, the modulus increase ratio is much limited. Inspired by the recrystallization process of CaCO3 during crab molting, a novel and universal strategy is developed to construct water-free self-stiffening SMPs by using a single thermal stimulus through harnessing the polymer melting-recrystallization. The shape recovery is achieved through the melting of polymer primary crystals, followed by the self-stiffening via polymer recrystallization at the same recovery temperature, in which the modulus increase rate and ratio can be programmed in a wide range. Additionally, conceptual applications of these self-stiffening SMPs as artificial stents with self-enhancing supporting function are successfully demonstrated. This work is believed to provide new insights for developing the advanced shape memory devices.

Key species drive community and functional stability of segment‐specific gut microbiomes after the swimming crab molting

The Scylla serrate mangrove crab is one of the leading fisheries commodities in terms of exports, only behind shrimp, tuna and shellfish. Crabs have a fairly high price in foreign markets and most of the mud crabs obtained from wild catches are soft shell crabs. In terms of price, cultivating soft shell crabs is quite profitable, but most cultivators have several problems such as long maintenance periods and inconsistent molting times so that they do not experience business continuity. Applying herbal extracts via injection is an effective method because all the substances that trigger molting directly enter the body. Physiological engineering is needed to speed up the molting phase and get the same molting time. This research aims to identify the ecdysterone content in purslane leaves and determine the optimum dose of purslane leaf extract which can encourage skin molting in mud crabs. This research used a Randomized Block Design (RBD). The in silicons test results show that the compound that has the smallest binding affinity is ecdysone, namely -6.80 kcal/mol. Based on analysis of variance, the best molting percentage occurred in treatment B at 55.50%. The fastest molting period occurred in treatment C, namely on days 4 to 29 after injection. Treatments B and C had the highest survival rate, namely 100%, while in terms of increasing body weight and carapace width, the effect of all treatments was not significantly different. The water quality results for all groups were still within the optimum value, temperature 26.40 – 33.80ºC; pH 6.83 – 7.20; salinity 20.70 – 26.70 ppt and dissolved oxygen 4 – 4.52 ppm

This study investigates the potential of natural stimulants, specifically ecdysteroids, in accelerating the molting process in mangrove crabs. The research was conducted by analyzing various plants containing ecdysterone and their effects on the crabs. The results indicate that forest fern leaves and mulberry leaves are effective sources of ecdysterone in stimulating molting and growth in crabs. The use of such natural stimulants has the potential to enhance productivity and reduce reliance on synthetic hormones in crab cultivation. However, further research is needed to determine the optimal dosage and to understand the mechanisms of ecdysterone action in crabs in more detail. The main challenge in implementation is adjusting the dosage and frequency of natural stimulant administration to achieve optimal results without disrupting the balance of the cultivation ecosystem. This approach offers an environmentally friendly alternative for the sustainable development of crab farming.

Impact and accumulation of calcium on soft-shell mud crab Scylla paramamosain in recirculating aquaculture system

Metabolomic and transcriptomic analysis reveals immune and hormone modulation at the molting stage of juvenile mud crabs challenged with Staphylococcus aureus and Vibrio alginolyticus

One of the factors in aquaculture activities that affect the production and growth process of mud crab is molting. Several techniques have been developed to accelerate the molting of mud crabs, namely ablation, mutilation, and supplementation. One form of supplementation is through the use of fermented mulberry leaves in mud crab feed. Therefore, this study aimed to analyze the effect of adding fermented mulberry leaves (Morus spp.) in feed to stimulate the molting of mud crabs (S. serrata). This research was carried out in traditional ponds in Bugis Village, Sape District, Bima Regency, for 60 days. The method used was an experimental method with a completely randomized design (CRD) consisting of five treatments and three replications, namely control treatment/trash fish (P1), 20% Mulberry Leaf Fermentation (P2), 25% (P3), 30% (P4), and 40% (P5). Research parameters comprise frequency and percentage of molting, absolute growth, specific growth rate, feed utilization efficiency, feed conversion ratio, survival rate, and water quality. The results showed that the combination test feed of fermented mulberry leaf (Morus spp.) in the mud crab (S. serrata) diet did not affect all the parameters measured. The provision of mangrove crab feed formulation with a concentration of 25% mulberry leaf fermentation (P3) and control treatment (P1) gave a faster initial molting, which was the first 10 days of the rearing period with the highest average frequency and percentage of molting of 37 and 41%, respectively.

The molecular mechanisms underlying the dynamic process of crab molting are still poorly understood at the individual level. We investigated global expression changes in the mud crab, Scylla paramamosain, at the transcriptome level and revealed a cascade of sequential expression events for genes involved in various aspects of the molting process using whole-body sequencing of juvenile crabs. RNA-sequencing (RNA-seq) produced 139.49 Gb of clean reads and 20,436 differentially expressed genes (DEGs) among different molting stages. The expression patterns for genes involved in several molecular events critical for molting, such as cuticle reconstruction, cytoskeletal structure remodeling, hormone regulation, immune responses, and metabolism, were characterized and considered as mechanisms underlying molting in S. paramamosain. Among these genes, we identified 10,695 DEGs in adjacent molting stages. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses showed that significantly enriched pathways included structural constituents of cuticle, binding and chitin metabolic processes, steroid hormone biosynthesis, insulin resistance, and amino sugar metabolic processes. The expression profiles of 12 functional genes detected via RNA-seq were corroborated via real-time RT-PCR assays. The results revealed gene expression profiles across the molting cycle and identified possible activation pathways for future investigation of the underlying molecular mechanisms.

There are several techniques that have been developed to accelerate the molting of mud crabs, namely ablation, mutilation and supplementation. One form of supplementation is through the use of fermented spinach leaves on mud crabs. This study aimed to analyze the use of fermented spinach (A. spinosus L) leaves in feed to stimulate the molting of mud crab (S. serrata). This research was conducted for 60 days. The experimental method used in a Completely Randomized Design (CRD) consisting of five treatments and three replications, namely trash fish (P1), Spinach Leaf Fermentation (FDB) 20% (P2), 25% (P3), 30% (P4), and 40% (P5). The results showed that the combination test feed of spinach leaf fermentation had a significant effect on absolute weight and length, specific growth rate (SGR), and feed utilization efficiency, but had no significant effect on feed conversion and survival. Treatment of feed with additional fermented of spinach leaf 30% gave a faster initial molting, which is in the first 10 days with a total of 6 molting crabs and a molting percentage of 40%. Feeding with the addition of 30% and 40% spinach leaf fermented concentrations can provide the best growth and feed efficiency for mangrove crabs.

Perisesarma eumolpe, the dominant species living in the damaged area caused by Durian storm in the Can Gio mangrove forest, had the role of changing the sedimentary structures for easier plant regeneration, contributing to the growth and development of the small soil organisms and playing role in the natural process of mangroves. This paper presented the ecological population structure, seasonal structural changes, growth and development of this species. The investigation based on the size distribution, density, biomass, sex ratio, and reproductive rate of the population and restoration of the forest ecosystem were evaluated. These recorded a P. eumolpe total population of 6169 individuals, including 3749 males (accounting for 60.77%) and 2420 females (accounting for 39.23%). The ratio of male to female individuals was 1: 0.65. August was the month when the most egg-bearing females was recorded. The first time-egg-bearing female had a carapace with the size of 9 mm. The moulting of crabs took place at every month of the year where the highest molting rate was from October to March, and the lowest was in April. The carapace size of individuals in the intact forest area was larger than those in the damaged one (D2F > D1F > D2Hcut > D1Hcut > D1Hnat). The crab density ranged from 268 individuals (in September) to 639 individuals (June) per month. The crab biomass ranged from 504.09 g per month to 1161.03 g per month. The highest biomass was recorded in June (1161.03 g/month), followed by in August (1139.56 g/month), and in May had a total biomass of 1074.4 g/month. The population growth and the development had the tendency of early maturation at smaller sizes and increased individual density in fractured habitats. This was the way that the species adapt to the conditions of a natural forest regeneration.

Observations of the mating behavior of Portunus trituberculatus and the role of shelters in its mating process

Vitamin D3 (vit-D3), as an indispensable and fat-soluble nutrient, is associated with skeletal mineralization and health in mammals. However, such associations have not been well studied in economically important crustaceans. Six levels of vit-D3 with isonitrogenous and isolipidic diets were used to feed Eriocheir sinensis. The range of optimal vit-D3 requirements is 5685.43-10,000 IU/kg based on growth. The crabs fed 9000 IU/kg vit-D3 showed the best growth performance. This vit-D3 dose significantly increased antioxidant capacity in the hepatopancreas and intestine and was optimal for molting and innate immunity via quantitative polymerase chain reaction analysis. Transcriptomics analyses indicate that vit-D3 could alter protein processing in the endoplasmic reticulum, steroid biosynthesis, and antigen processing and presentation. As shown by the enzyme-linked immunosorbent assay, vit-D3 could improve vitamin D receptor, retinoic acid receptor, and C-type lectins concentrations. The 1α,25-dihydroxy vit-D3 content in serum was significantly higher in 3000-9000 IU/kg vit-D3. The study suggests that dietary vit-D3 and its metabolites can regulate molting and innate immunity in crabs.

The world market demand for soft-shell crabs is increasing due to their delicate taste and ease of eating. However, the current production methods of soft-shell crabs (mutilation / limb autotomy) is either considered unethical or the waiting period for molting is too long. Thus, this research assessed the effect of mutilation (removal of all appendages except swimming legs), using herbal extract (Vitomolt TM ) as a stimulant for moulting, and without stimulation (control) on growth (body size and weight increment), molting period, molting percentage and survival. It was observed that mutilation method stimulated faster molting in crabs compared using herbal extracts and naturals, however, with a significantly lower increase in body size and weight. Molting rate was highest in crabs subjected to mutilation (92%), followed by those injected with than Vitomolt TM (73%) and control (52%). The survival rate of crabs subjected to Vitomolt TM was the highest (94.8%) compared to mutilation group (91.7%) and control (89.6%). Based on these results, mutilation is not recommended for soft-shell crab production due to their lower body size and weight increment (lesser profit for farmers). The use of herbal extract (Vitomolt TM ) has huge potential as a stimulant for molting in soft-shell crab production as its usage increased survival and molting rate in S. olivacea .

Hepatopancreas transcriptome analysis reveals the molecular responses to different dietary n-3 PUFA lipid sources in the swimming crab Portunus trituberculatus

Moulting in crabs can be accelerated by adding moulting hormone. Phytoecdysteroids are an active compound found in certain plants, for example amaranthus, that are analogous to the moulting hormone in crustaceans. The aim of this study was to determine the effect of phytoecdysteroid administration through injection and artificial feed on moulting and growth of mud crabs (Scylla olivacea). Mud crabs with carapace width 61–62 mm and weight 50–51 g were reared in individual crab boxes with dimensions 25×20×20 cm. The selected crabs were injected with amaranthus extract at a dose of 1 mL/crab (I), then placed in the crab boxes and kept in a pond. Amaranthus leaves were dried in an oven at 60°C for 24 hours, ground using a hammer mill, and mixed with other feed ingredients. Different doses of amaranthus flour were applied: 0% (control), 10%. 12.5%, 15%, 17.5% and 20%. Moulting and growth data were analysed for a variance. The results showed that the administration of phytoecdysteroids from amaranthus by injection and through artificial feed had no effect on the percentage of mud crabs moulting, survival rate, growth, and feed conversion value. The mud crabs were not able to take full advantage of the artificial feed provided because of the inappropriate size of the feed and the fragile structure that cause wasted and uneaten feed.

One of the fishery commodities in the mangrove forest area that has the potential to be cultivated in the mangrove crab (Scylla serrata). The local and international market demand for soft shell mud crab from year to year tends to increase. Most of the efforts to meet the needs of softshell crab still rely on catches from nature where availability is uncertain. The purpose of this study was to identify the effect of the long molting time of mud crab (Scylla serrata) fed trash feed and feed fed with spinach extract using natural methods and popeye. This research is experimental using a completely randomized design. The treatments consisted of the natural method with trash feed, the natural method with spinach extract feed, the popeye method with trash feed, and the popeye method with spinach extract feed. The crabs used are mud crabs with the hard carapace. The test parameter is the length of time for mud crab molting, which is calculated starting from the hard-shelled crab to molting. The data obtained in the form of differences in the length of time for mud crab molting using various treatments were analyzed descriptively quantitatively. The results of this study indicate that the popeye method with spinach extract feed is the treatment that produces the best molting time, which is 14-21 days compared to other treatments.

An improved YOLOv3 algorithm to detect molting in swimming crabs against a complex background

Mud crabs (Scylla serrata) are one of the coastal fisheries commodities, especially in mangrove forests. This study was proposed to determine mangrove ecosystems service to produce molting of mud crab (S. serrata). This research on mangrove crab molting using a completely randomized design with four levels of treatment, namely ablation, autotomy, ablation + autotomy and control with three replications. The highest growth rate was ablation (molting percentage 80.95%, and 100% survival, growth 12.51%/day) and lowest ablation + autotomy (growth 4.95%/day, molting percentage 19.05%, growth 4.95% of the day). The differences in molting stimulation affect the percentage of molting.