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Giant mud crab (Scylla serrata sp.) shell prepared through pyrolysis at various temperatures without any modification were characterized for physicochemical properties and methyl violet (MV) removal potential. Hence, this paper investigated the performance and mechanism of biochar derived from giant mud crab shell as adsorbent in the removal of methyl violet as well as the potential for regenerating adsorbents via hot water regeneration. The results show that CSB500 (produced through pyrolysis at 500 °C) exhibits a surface area of 59.73 m2/g and mesopore size of 31.3 nm, favorable for methyl violet removal at 3139 mg/g. The equilibrium adsorption data agreed well with Langmuir and Redlich-Peterson isotherm models, indicating a monolayer adsorption of MV. The kinetics data fitted better with both pseudo-first-order and pseudo-second-order models. The intraparticle diffusion and Boyd's models revealed that both film and pore diffusion may be involved in the adsorption process. In hot water regeneration studies, CSB500 shown superior regeneration performance when using water with temperature of 70 °C rather than 30 °C for 9th regeneration cycles, with retained to achieve >90 % MV removal for 6th regeneration cycles. Biochar derived from giant mud crab shell has shown significant promise as a low-cost, effective, and ecologically friendly with reasonably good adsorption capacity and reusability for dye removal, and it can be considered as an environmental sustainability strategy in wastewater treatment. [Display omitted] [ABSTRACT FROM AUTHOR]

Hemocyanins are large extracellular respiratory proteins distributed within the hemolymph of arthropods, molluscs and larval stages of certain insects. In the present study, we characterized the humoral immune functions of cation specific antibacterial hemocyanin (Ab-Hcy) from mud crab, S. serrata . The bacteriolytic activity of Ab-Hcy was against pathogenic and non-pathogenic to crustaceans which includes, Bacillus sp. N1, B. flexus N3, E. coli , P. aeruginosa , V. harveyi , V. parahaemolyticus and V. vulnificus and also expressed bacteriostatic activity against E. coli , B. flexus N3 and V. harveyi . The agglutination activity of Ab-Hcy ranged from 4-16 against B. flexus N3, E. coli , V. harveyi and V. vulnificus and Ab-Hcy also agglutinated with rat and human O erythrocytes (HA titer: 2). The Ab-Hcy lysed the panel of mammalian erythrocytes and strong hemolytic activity of 1.40, 1.28 and 1.22 units·min − 1 ·mg protein − 1 against human A, B and O erythrocytes respectively. It was also found that the Ab-Hcy possess phenoloxidase (PO) activity by oxidizing L-DOPA. These results suggest that Ab-Hcy from the serum of mud crab, S. serrata , is capable of performing multiple humoral immune functions in addition to oxygen transportation. Statement of relevance This manuscript deals with the humoral immune functions, particularly antibacterial property of hemocyanin in crustacean. In this paper we report the different type of antibacterial activity and other humoral immune functions of a hemocyanin isolated from the serum of mud crab, Scylla serrata . This work will help to understand the role of respiratory molecule in immune system, also will be helpful improve disease free crustacean aquaculture industry. And we also state this research work is relevant and suitable to publish in the Journal “Aquaculture”. [ABSTRACT FROM AUTHOR]

Abstract: Competent larvae of most benthic marine invertebrates including brachyuran decapod crustaceans can delay their settlement and metamorphosis in the absence of suitable environmental cues. This however may carry significant costs for the post-larval performance and fitness of early benthic juveniles. In this paper, we examined in the laboratory whether delayed larval metamorphosis affects early juvenile performance of the mangrove crab Ucides cordatus, measured as survival and growth through the first five juvenile crab stages (JI–JV). We further investigated whether ‘carry-over’ effects of an extended larval period vary intraspecifically among juveniles from three different hatches (F1–F3). Ucides megalopae were cultivated in two treatments. In the first one, the control, megalopae were cultivated continuously in exposure to conspecific crab odours (adult-conditioned seawater=ACSW) until moulting to the first juvenile crab stage. In the second, the delay-treatment, settlement-competent megalopae were kept for 20days in pure filtered seawater without metamorphosis-triggering odours. From day 21 onwards, megalopae were transferred to ACSW to induce larval moult. The results showed that delayed metamorphosis affects early juvenile survival and growth of U. cordatus. In the delay-treatment, survival rates of juveniles (JI–JV) from F1–F3 were 11–31% lower and intermoult development periods 1.5–4.2days longer than in the control. Delayed juveniles (F1–F3) exhibited 9.2–14.1% smaller body sizes (carapace width) and 1.4–3.9% lower growth rates mostly in the first two moulting events compared to specimens derived from non-delayed megalopae. Most of the detrimental effects were observed in almost all five crab stages studied, indicating that the costs of delayed metamorphosis may persist throughout early juvenile development. Juvenile morphology, however, was not affected. Our study also showed that carry-over effects of delayed larval moult vary intraspecifically among offspring produced by different females. This plasticity in phenotypic effects could relate to differences in the nutritional state, health or age of the females, to stressful environments during embryogenesis or to genetic differences. The observed carry-over effects of delayed settlement on early juvenile performance may affect the overall recruitment success and population dynamics of U. cordatus. In the field, such a situation would appear when new mangrove areas void of conspecific crabs are colonized or when degraded sites are re-populated by larvae originating from elsewhere populations. [Copyright &y& Elsevier]

Abstract: In this paper, we analyzed population genetic diversity of Scylla paramamosain in Hainan Island of China based on COI gene sequence. Totally 92 individuals were collected from six localities: Haikou, Wenchang, Wanning, Sanya, Dongfang and Danzhou. A 761 bp fragment was sequenced, defining 32 different haplotypes. H4 was the most frequent haplotype, existing in all six localities, while the majority of haplotypes were rare ones, existing in only one or two individuals. Haplotype diversity (h) and nucleotide diversity (π) ranged from 0.625 to 0.914 and from 0.001 to 0.003, with an average of 0.841 and 0.002, respectively. Genetic distance ranged from 0.001 to 0.003 within localities and from 0.002 to 0.003 between localities. The AMOVA analysis indicated a low level of genetic differentiation among six localities (F ST = 0.0176, P > 0.05). Neutrality tests and mismatch analysis implied a potential population expansion event for this crab species. [Copyright &y& Elsevier]

Abstract: Reliable estimates of growth and mortality parameters are crucial for understanding how populations of exploited species may respond to shifts in fishing pressure. Results of previous studies on growth of the ecologically and economically important mangrove crab Ucides cordatus in Brazil differ strongly and age estimates for minimum legal capture size (60mm carapace width) range between less than 1 and 6–10years. These discrepancies are probably due to inherent problems of the applied methods, namely laboratory based observations and cohort-analyses. The present paper takes a new approach by measuring individual growth increments of U. cordatus in situ. Crabs were measured, tagged, released into 100m² field enclosures and periodically recaptured. There was no indication of an enclosure effect and 209 growth increments were obtained from specimens measuring 20.5 to 89.5mm in carapace width (CW). For improving the size coverage of the von Bertalanffy growth curve, first instar juveniles were reared in the laboratory up to an age of six months. Their average percent size increase (PI) was 22.57±6.75% during biweekly measurements, resulting in a CW of 7.8 to 11.5mm after six months. Average PI of the enclosure crabs ranged between 10.87±1.17% (indiv.<40mm CW) and 1.43±0.87% (indiv.>80mm CW) per moult and two large females had moulted without growing. Growth analysis revealed a larger asymptotic size in males than in females (89mm versus 72mm) while the growth parameter K of the von Bertalanffy growth function (VBGF) was lower in males (0.17 versus 0.25), resulting in similar growth performance of the two sexes (males: 1.16; females: 1.10). Age at legal minimum capture size estimated by the inversed VBGF was 6.13years in males and 7.38years in females, corroborating the mid to upper range of earlier growth estimates. Mortality parameters (Z, M and F) were calculated using length converted catch curves. Z in males was higher than in females (0.69 versus 0.49), as expected from the male-biased fishery. M, F and the exploitation rate E were estimated for three different scenarios taking into account the uncertainty of the age/size of functional maturity. Our study provides key information for the sustainable management of the U. cordatus fishery and confirms that the species is relatively slow growing and long-lived (>10years), suggesting a high vulnerability to overfishing. [Copyright &y& Elsevier]

Abstract: Brazilian legislation defines coastal zone as a national patrimony – the geographic space of interaction of air, sea and land formed by the counties directly influenced, but not necessarily by those located in the coastline; also included are those distant until 50km from the coastline, holding activities of great impact for the coastal zone or its ecosystems. The definition includes also the territorial sea of 12 nautical miles. Coastal management is conducted by a national plan legally enforced, complemented by states and counties plans, and a coastal ecologic-economic zoning limited to small portions of the coastal zone. A resolution of the “Environmental National Council” defines as “permanent preservation areas”, of very restricted use, coastal ecosystems as mangroves, sand dunes, and reproduction sites of wild fauna. One could expect that the Brazilian coast should be more protected and properly managed than other countries where a national management plan is lacking (Argentina) or where the guidelines exist but are not yet legally enforced (South Africa). Notwithstanding, we note today in Brazil an intensification of conflicts opposing small-scale vs. industrial fishermen; shrimp farming vs. mangrove crab harvesting; resorts installation vs. native communities; oil and gas activities vs. NGOs; and conflicts on environmental permit between federal and state governmental agencies. This paper evaluates the possible reasons for the failure of the complex legal suite available in Brazil and suggests that participatory management and concerted actions with relevant stakeholders are the key elements for the successful cases. [Copyright &y& Elsevier]

Abstract: Chemical pollution such as chromium and phenol in the sea water has been increasing in recent years in China sea. At the same time, marine shellfish such as prawn and crab are sensitive to this pollution. β-N-Acetyl-d-glucosaminidase (NAGase, EC.3.2.1.52) catalyzes the cleavage the oligomers of N-acetylglucosamine (NAG) into the monomer. In this paper, the effects of phenol on the enzyme activity from green crab (Scylla serrata) for the hydrolysis of p-nitrophenyl-N-acetyl-β-d-glucosaminide (pNP-NAG) have been studied. The results showed that appropriate concentrations of phenol could lead to reversible inhibition on the enzyme and the inhibitor concentration leading to 50% activity lost, IC50, was estimated to be 75.0±2.0mM. The inhibitory kinetics of phenol on the enzyme in the appropriate concentrations of phenol has been studied using the kinetic method of substrate reaction. The time course of the enzyme for the hydrolysis of pNP-NAG in the presence of different concentrations of phenol showed that at each phenol concentration, the rate decreased with increasing time until a straight line was approached. The results show that the inhibition of the enzyme by phenol is a slow, reversible reaction with fractional remaining activity. The microscopic rate constants are determined for the reaction on phenol with the enzyme. [Copyright &y& Elsevier]

As an important step toward development of a formulated diet for hatchery culture of the mud crab, Scylla serrata, this paper reports on laboratory experiments to assess the potential of a microbound diet (MBD) as a replacement for Artemia nauplii fed to megalopal larvae of S. serrata. The effects of different proportions of dietary MBD and Artemia on survival and moulting success of megalopa to the crab stage were investigated. In the first experiment, megalopae were reared communally and fed either 100% MBD, 100% Artemia or different combinations of the two (75%:25%, 50%:50%, 25%:75%). The experiment was terminated when all larvae had either metamorphosed or died. Larvae fed a combination of 25% MBD and 75% Artemia consistently showed the highest survival among all treatments throughout the experiment. Survival of larvae fed 100% MBD was the lowest early in the experiment but improved to become the second highest toward the end of the culture period. Overall survival of larvae fed 100% MBD did not differ significantly from that of larvae fed 100% Artemia. Moulting to the crab stage began on day 7 for larvae in the treatment receiving a 50%:50% combination of MBD and Artemia. On day 8, all larvae in treatments receiving greater than 25% MBD had some first stage crabs. Larvae fed Artemia only were the last to moult to the juvenile crab stage, but moulting occurred simultaneously on day 10. Because of cannibalism observed in the first experiment, a second experiment was conducted where megalopae were reared individually and fed either 100% Artemia or 100% MBD. Ninety percent of larvae from both treatments successfully moulted to the crab stage. Again, megalopae fed MBD began moulting 1 day ahead of those fed Artemia. The results of these studies show that the MBD used contained all necessary nutrients to sustain successful moulting of S. serrata megalopae to the crab stage. The acceptability of MBD by S. serrata larvae suggests significant potential for using the MBD in future experiments to investigate larval nutritional requirements of this commercially important crab species. Indeed, the more rapid moulting of larvae fed MBD in both experiments suggests that the MBD may have contained certain beneficial nutrients that were not provided by Artemia alone. The fact that no significant differences in survival between megalopae fed 100% MBD and those fed 100% Artemia in both communal and individual rearing experiments suggests that total replacement of Artemia with MBD is possible for S. serrata megalopae. This could result in substantial savings in operating costs for S. serrata hatcheries. [Copyright &y& Elsevier]

This paper reports on experiments to determine particle size preference and optimal ration for the various larval stages of the mud crab, Scylla serrata, fed microbound diets (MBD). All experiments used 14C-labelled rotifers as components of MBD, and ingestion was determined by assessing the 14C content of S. serrata larvae after feeding on the MBD. Five size ranges of MBD (<150, 150–250, 250–400, 400–600 and 600–800 μm) were used to assess ingestion by Zoea I, Zoea III, Zoea V and Megalopa. All were fed a ration equivalent to twice the equivalent dry weight of live foods provided to each larval stage under standard rearing conditions (standard ration). MBD particle size preference increased with increasing larval development. Highest ingestion rates by Zoea I, Zoea III, Zoea V and Megalopa were found for particle size ranges of <150, 150–250, 250–400 and 400–600 μm, respectively. MBD within these particle size ranges were used in subsequent experiments to assessed optimum rations for each of the four larval stages. Larvae were fed rations based on multiples or fractions of the standard ration (100%): 12.5%, 25%, 50%, 100%, 200% and 300%. There were no significant increases in ingestion, for any of the four larval stages, when ration was increased above 100%. For Zoea I, Zoea III and Zoea V larvae, there was no significant difference in the rate of MBD ingestion when ration was reduced to 50%; however, a 25% ration brought about a significant decrease in ingestion. There was no significant decrease in the rate of ingestion by Megalopa when ration was reduced from 100% to either 50%, 25% or 12.5%. The results suggest that rations currently used for larval rearing of S. serrata may be excessive. Little is currently known of the feeding behaviour and nutritional requirements of S. serrata larvae, and the results of this study are a significant development in this field. [Copyright &y& Elsevier]