Female Crabs Research Articles

The Feasibility of a Claw‐Only Fishery for the Red Rock Crab, Cancer productus

ABSTRACTThe red rock crab, Cancer productus, is primarily harvested by a recreational fishery, with a small commercial harvest in California. Although relatively large, meat yields are low because the legs are small, and meat is largely confined to the claws. We investigated the potential for a claw‐only harvest for this species. Although hand removal is used in the stone crab fishery, it caused > 90% post‐harvest mortality in red rock crabs. Inducing autotomy by inserting a spike into the arthrodial membranes or by cutting into the autotomy plane resulted in a high post‐harvest survival. We recommend a minimum harvest size of 35 mm claw height to produce a claw size similar to medium‐sized stone crabs and standard‐sized brown and Jonah crabs and to ensure that severed claws are unlikely to have come from female crabs, which is important for regions that mandate a male‐only harvest.

Comparative study on growth performance and nutritional quality of Eriocheir sinensis between Liaohe River strain and Yangtze River strain under rice field culture environment

This study investigated the similarities and differences in catch rates, growth performance, proximate composition, amino acid content, and fatty acid profiles between the Yangtze River crab and the Liaohe River crab in rice aquaculture systems in northern China. A three-month culture experiment was conducted for the Yangtze River crab and the Liaohe River crab in a rice located at longitude 124.82° and latitude 43.50°. The results revealed that Liaohe River crab had higher catch rate and faster growth rates than Yangtze River crab, and the female crab had earlier ovaries. The edible tissues of Liaohe River crabs contain higher crude protein and fat contents, featuring a more reasonable amino acid composition and structure. Meanwhile, the gonads of male and female Yangtze River crabs had higher PUFA content. In conclusion, under the conditions of this experiment, the Liaohe River crab demonstrated a significant growth advantage.

Mating behaviour and cholesterol nutritional strategies promoted ovarian development of female swimming crab (Portunus trituberculatus).

Female crabs enter a stage of rapid ovarian development after mating, and cholesterol is a substrate for steroid hormone synthesis. Therefore, in this experiment, an 8-week feeding trial was conducted to investigate the effects of mating treatments (mated crab and unmated crab) and three dietary cholesterol levels (0·09 %, 0·79 % and 1·40 %) on ovarian development, cholesterol metabolism and steroid hormones metabolism of adult female swimming crab (Portunus trituberculatus). The results indicated that crabs fed the diet with 0·79 % cholesterol significantly increased gonadosomatic index (GSI) and vitellogenin (VTG) content than other treatments in the same mating status. Moreover, mated crabs had markedly increased GSI and VTG content in the ovary and hepatopancreas than unmated crabs. The histological observation found that exogenous vitellogenic oocytes appeared in the mated crabs, while previtellogenic oocytes and endogenous vitellogenic oocytes were the primary oocytes in unmated crabs. The transmission electron microscopy analysis showed that when fed diet with 0·79 % cholesterol, the unmated crabs contained more rough endoplasmic reticulum and mated crabs had higher yolk content than other treatments. Furthermore, mating treatment and dietary 0·79 % cholesterol level both promoted cholesterol deposition by up-regulation of the mRNA and protein expression levels of class B scavenger receptors 1 (Srb1), while stimulating the secretion of steroid hormones by up-regulation of the mRNA and protein expression of steroidogenic acute regulatory protein (Star). Overall, the present results indicated that mating behaviour plays a leading role in promoting ovarian development, and dietary 0·79 % cholesterol level can further promote ovarian development after mating.

Feeding Behavior and Bait Selection Characteristics for the Portunidae Crabs Portunus sanguinolentus and Charybdis natator

Understanding the feeding behavior of Portunidae crabs with different baits can improve bait selection and is crucial for improving the effectiveness of crab fishing gear. This study, conducted in indoor experimental tanks, used trajectory tracking software and two types of natural baits (mackerel (Scomber australasicus) and squid (Uroteuthis chinensis)) to understand the behavior of Portunus sanguinolentus and Charybdis natator. Spatial distribution results showed that P. sanguinolentus was frequently present in the starting area (S1) and bait area (S3) in the control and treatment groups. However, C. natator was frequently present and concentrated in the S1 area compared to the middle areas S2 and S3, and only in the mackerel treatments were they observed to move to the S3 areas. The spatial distribution results indicate that P. sanguinolentus shows a stronger willingness to explore its surroundings, while C. natator is generally in a stationary, wait-and-see state. The swimming speeds of P. sanguinolentus and C. natator showed different trends. P. sanguinolentus showed continuous movement with no fixed speed when no bait was present in the control groups. However, when treated with mackerel and squid, the average swimming speed of P. sanguinolentus was faster (>5 cm/s) in the first 10 min and showed a more stable movement speed when searching for the baits. C. natator showed a stationary or low movement speed when no bait was present in the control groups. However, when C. natator perceived the presence of the baits in the treatment groups, their movement speed increased in the first 10 min. In addition, there was no significant difference between male and female crabs of P. sanguinolentus and C. natator in movement speed in the control and treatment groups. Compared to C. natator, P. sanguinolentus might be more sensitive to natural baits, as shown by its movement from S1 to S3. The results indicate that the species of Portunidae crabs show different bait selections. Natural baits (mackerel and squid) are recommended for catching P. sanguinolentus in crab fisheries.

Stock assessment of the mud crab (Scylla olivacea) collected from the terrestrial edge of the Sundarbans mangrove forest, Bangladesh

We estimated mud crab (Scylla olivacea) population parameters to determine recruitment patterns, asymptotic carapace width (CW∞), growth coefficient (k), mortality rate (Z, M, and F), exploitation rate (E) and relationship between body weight and carapace width (BW - CW) in the terrestrial edge of the Sundarbans mangrove forest, Bangladesh. Baited long lines and traps were used to collect crab samples from the terrestrial edge of the mangroves (up to 10 km inside of the Sundarbans mangroves) monthly for a year (Jan 2021–Dec 2021). These CW frequency data were utilized to determine population characteristics. Based on the BW × CW relationship, male S. olivacea crabs increased their BW faster (b = 2.89, R2 = 0.86) than females (b = 2.29, R2 = 0.82). Crabs displayed negative growth allometry, b significantly differed from the isometric growth (b = 3). Both male and female CW∞ was estimated to be 126.00 mm and 113.40 mm, with k values of 0.50 yr−1 and 0.48 yr−1, respectively. The total mortality (Z), natural mortality (M), and fishing mortality (F) of male and female crabs were 1.89 yr−1 and 1.84 yr−1, 0.79 yr−1 and 0.80 yr−1 and 1.10 yr−1 and 1.04 yr−1 respectively. Both sexes were recruited using a bimodal recruitment strategy, with a significant peak from March to June. However, young crabs were present year-round. The virtual population analysis (VPA) shows that males and females are caught at smaller sizes (60–90 mm). The estimated exploitation rate (E) exceeds (0.58 for males and 0.57 for females) the optimum exploitation level (E = 0.50) and E values were close to the projected maximum yield per exploitation rate (Emax = 0.655 for males and 0.647 for females) which indicated over-exploitation of the mud crabs from the territorial edge of the Sundarbans mangrove forest of Bangladesh and hence suggested for proper management.

Molecular Evaluation of the Mating Dynamics of Snow Crab (Chionoecetes opilio) in the Eastern Bering Sea

ABSTRACTSnow crab (Chionoecetes opilio) in the eastern Bering Sea (EBS) supports a valuable crab fishery that harvests large males. To better understand the potential impact of the presence of snow‐Tanner hybrids (C. opilio × C. bairdi) on snow crab mating dynamics, the maternal lineage of hybrids was evaluated using single nucleotide polymorphisms (SNPs). Contrary to results from a previous study that indicated hybrids result only from crosses between Tanner crab (C. bairdi) males and snow crab females, results from this study showed hybrids result from bidirectional parental crosses. SNP and microsatellite markers were used to evaluate the species and number of males detected as mates in female sperm reserves acquired during mating and as sires among embryos in brooded clutches. The incidence of interspecies mating between female snow crab and Tanner crab or hybrid males was low (2%), suggesting interspecies mating is not currently a pressing fishery management concern. Most females had stored sperm from either a single mate (59%) or two mates (32%), which reflects fewer mates than observed for other snow crab populations. Few females were observed with either no stored sperm (5%) or sperm from three to four mates (4%). Single (82%) or dual (18%) paternity was found among embryos in brooded clutches. Sperm from some mates appeared to be fully utilized for fertilization of the brooded clutch for 35% of females. In contrast to findings for other snow crab populations, no significant differences were detected in the numbers of mates or sires between primiparous and multiparous females. The low extent of polyandry observed may suggest that female snow crab in the EBS have limited mating opportunities, potentially leading to insufficient sperm reserves to fertilize subsequent clutches without remating.

Effects of dietary supplementation with medicinal plant mixtures and immunostimulants on the immune response, antioxidant capacity, and hepatopancreatic health of Chinese mitten crab (Eriocheir sinensis).

This study aimed to evaluate the efficiency of tea polyphenols (TP) and medicinal plant mixtures (Astragalus membranaceus + Lonicera japonica, Rheum officinale Bail + Scutellaria baicalensis + Platycladus orientalis) combined with astaxanthin (AST), benzoic acid (BA), and yeast complex on the health status of Eriocheir sinensis. A total of 630 crabs (male crabs: 41.51 ± 1.63 g; female crabs: 47.27 ± 0.79 g) were randomly distributed into seven groups with three replicates (male: female, 1:1). These crabs were fed as follows for 8 weeks: basal diet (M1), M2 (M1 + 100 mg/kg TP), M3 (M1 + 2.0 g/kg A. membranaceus + 20 g/kg L. japonica), M4 (M1 + 2.5 g/kg R. officinale Bail + 1.5 g/kg S. baicalensis + 1.0 g/kg P. orientalis), and M5, M6, M7 (M2, M3 and M4 with 600 mg/kg AST +1.0 g/kg BA + 20 mg/kg yeast complex added, respectively). The results showed that the activities of acid phosphatase (ACP), alkaline phosphatase (AKP), and lysosome (LZM) in the hemolymph were significantly increased in M5, M6, and M7 (P < 0.05), and the highest phagocytosis index (PI) and LZM activity were observed in M7 of female crabs. Moreover, the antioxidant indicators superoxide dismutase (SOD), glutathione (GSH), glutathione peroxidase (GPx), and catalase (CAT) of hepatopancreas were also significantly improved in M5, M6, and M7 (P < 0.05), while the malondialdehyde (MDA) contents showed an opposite trend. Furthermore, a morphological examination also showed the improved histological structure of hepatopancreas in M7, especially as seen in the clear lumens, no vacuolation, and integrity of the basal membrane of the hepatopancreatic tubule. Taken together, these results suggested that 2.5 g/kg R. officinale Bail, 1.5 g/kg S. baicalensis, and 1.0 g/kg P. orientalis in combination with 600 mg/kg AST, 1.0 g/kg BA, and 20 mg/kg yeast complex could improve the non-specific immunity, antioxidant capacity, and hepatopancreatic health of E. sinensis.

Food composition and trophic niches of blue swimming crab (Portunus pelagicus, 1758) in Madura Strait, Pamekasan, East Java

Abstract Blue swimming crab (Portunus pelagicus) is the main fishery commodity in the Madura Strait, Pamekasan Regency. The sustainability of the crab depends on the suitability of the habitat and the availability of food in the waters. This study aims to analyze the food composition and trophic niches of blue swimming crab in the Madura Strait, Pamekasan Regency. Sampling was conducted using the simple random sampling technique. The analysis included composition of the collection based on length frequency distribution, gastric fullness index, trophic niche area, food niche overlap, crab food composition, and growth (carapace width-weight relationship, and condition factor). The results of the index study showed that the index of stomach content of the female was generally greater than that of the male. Blue swimming crab is classified as a carnivore with the main food being fish. The overlap of the niches of male and female crabs of 0.9328 indicates a high level of competition for food. The male crab has a negative allometric growth pattern, while the female crab has a positive allometric growth pattern. The condition of the crab factor in each month of observation is greater than 0.5 indicating the availability of food and water conditions suitable for crab life.

Impact of steaming and peeling on the weight loss in blue swimming crabs in Pangkajene Islands, South Sulawesi

Abstract The blue swimming crab (Portunus pelagicus) is an important fishery resource in Indonesia because it has a high value and involves a lot of human resources. The pasteurized crab goes through several main stages, namely steaming, stripping, and canning. Steamed crabs will experience weight loss and produce a yield of meat in a certain amount and composition after peeling. This study aims to determine the weight loss during crab steaming and stripping processes on different sizes of crabs. The crabs were classified into three categories, namely small crab (carapace width &lt;10 cm), big crab (carapace width &gt;10 cm), and egg-berried female crabs. Technically, crabs were steamed for 20 minutes after the water boils with temperature of steaming of 80–90 °C. Steaming process wereallowed to stand for 60 minutes, followed by. peeling process where crab meat were separated from the skin. Weight measurements were taken on fresh, warm (shortly after steaming), and cooked crab (adjusted to room temperature) to calculate weight loss due to steaming while considering temperature adjustments and total loss. Results revealed the weight decrease about 16.75% during steaming, 19.61% during relaxation, and 27.47% during overall process. The highest meat yield was obtained from small crab by 30.64%, followed by large crab by 27.25%, and egg berried female by 24.39%.

Distance of fishing ground against blue swimming crab (Portunus pelagicus) catches using a gillnet in Gresik, East Java, Indonesia

Abstract Information on fishing grounds is crucial in efforts to manage blue swimming crab capture fisheries. The further away the fishing location, the higher cost risk. The purpose of this study is to determine differences in catches and biological characteristics of crabs caught by the crab fishermen using gillnets on 0–2 miles and 5-7 miles from November 2022 to January 2023 in the waters of Mengare Island, Bungah District, Gresik Regency, East Java Province. Descriptive analysis and multivariate analysis of variance (MANOVA) were used to explain the biological characteristics of the blue swimming crabs and differences in the effect of fishing ground distance on crab catches. The results showed that the total yield of 2478 female crabs and 4360 male crabs with details at a distance of 0–2 miles was 1701 males and 925 females, while at a distance of 5-7 miles, there were 2659 males and 1553 females. Most crabs with mature level were found at 0–2 miles and 5-7 miles. The distance to the fishing ground affects the average width, average weight, and number of male crabs. Distance and fishing ground differences can affect the diversity of crab biological characteristics.

The effectiveness of crab apartment to shelter egg berried female of blue swimming crab (Portunus pelagicus) in Rembang, Central Java, Indonesia

Abstract Blue swimming crab is an Indonesian fishery commodity with high economic value for export to America, Asia, and Europe. The increase in crab fishing activities every year results in diminishing stocks in nature, in addition to predator attacks around spawning areas. The purpose of this study was to determine the growth of blue swimming crabs and identify types of fish in the crab apartment shelters in Rembang Regency, Central Java Province, from March to May 2023. The egg berried female crabs were put in a floating apartment for three months and monitored every 2 weeks to determine the growth of the hatched crab eggs. Our observations showed as many as 50 egg berried female crab with with an average size of 8–10 cm and a weight of 40–65 g. There were other marine organisms found in the shelter, including rabbit fish, shrimp, small crabs, and therapon-perch. Rabbit fish and therapon-perch often result in reduced juveniles. Therefore, add and installing shelter is highly recommended to the entry of these fish. This study found crab apartment brings positive impacts on the survival of hacthing crabs and protected them from the threat of predatory fish.

The analysis of natural forage of blue smimming crab (Portunus pelagicus Linnaeus, 1758) on the east coast of Pangandaran, West Java

Continuous use of blue swimming crab (Portunus pelagicus) without any control can cause population decline which leads to damage to the stability of the marine ecosystem, especially in East Coast Pangandaran, therefore cultivation is needed. In aquaculture, it is necessary to provide the right feed by knowing its natural diet. This study aimed to determine the natural diet of blue swimming crabs. The method used was descriptive analysis. The parameters observed were carapace width, gastric weight, the composition of natural diet. The relationship between the carapace width and gastric weight was analyzed by simple regression while the main type of natural diet was known by calculating the percentage of food composition. The relationship between carapace width and gastric weight was positive. Based on the composition found in crab gastric, there were 5 types of natural foods consisting of crustaceans (28.35%), meat (25.37%), mollusk (18.65%), fish (15.67%), and undefined material (UM) (4.47%). It is revealed that crabs are carnivores and scavengers, pose significant relationship between their size and gut content weight. It was also found that the composition of female crab feed was generally higher than that of males.

Size distribution and growth parameters of blue swimming crab (Portunus pelagicus, Linnaeus 1758) in Awur Bay, Jepara

Blue swimming crab (Portunus pelagicus) is a fishery commodity that has important economic value. One of the catch landings in Teluk Awur, Jepara is blue swimming crab. Intensive crab catching carried out with small sizes has an effect on decreasing crab stocks in the waters. This study aims to determine the size distribution, the relationship between carapace width and weight, growth parameters and recruitment patterns. The research was conducted in May, June, July and August 2022 in the waters of Teluk Awur, Jepara. Sampling using systematic sampling method. The data collected is carapace width (mm) and crab weight (grams). Data analysis was performed using FiSAT II software. The results of the analysis of the relationship between carapace width and weight showed that the growth of the male crab was positive allometric and the growth of the female crab was isometric, with the equation of the male crab W = 0.0000214cW3.251 and the female crab W = 0.0000232cW3.220. The growth parameters obtained by the equation of the male and female crabs were cWt = 158,55(1- e(-1,2(t+0,083))], and cWt = 158.55(1 – e(-0.67(t+0.152) ))). The peak of male crab recruitment was in October at 22,71%, while the female crab was in May at 13,52%, indicating that in that month new crab individuals were added. Based on these results, the stock of crab resources in Jepara's Awur Bay must always be considered and always support the recruitment process of crab. Beside that, the goverment can enforce management of crab fishing.Keywords: Allometric; Carapace Width; Crab; Recruitment

The regulatory effects of arginine on ovary development in the Chinese mitten crab Eriocheir sinensis

This study aimed to investigate the effects of arginine (Arg) on the vitellogenesis and ovarian maturation of Chinese mitten crab. Six isonitrogenous and isolipidic diets (1.83, 2.52, 3.26, 3.96, 4.81 and 5.52 % Arg) were fed to adult female Chinese mitten crab (60.05 ± 4.33 g). The feeding period lasted for eleven weeks. The results showed that gonadosomatic index of crabs increased with increasing dietary Arg concentrations from 1.83 % to 2.52 % and significantly decreased from 2.52 % to 5.52 %. The quadratic regression analysis based on gonadosomatic index estimated that the optimal Arg requirement for adult female crabs was 2.60 %. Dietary supplementation with 2.52 % Arg significantly increased the crude protein concentration in the ovary. A dose of 2.52 % Arg significantly decreased the vitellogenesis-inhibiting hormone (VIH) content in the hemolymph. Arg (2.52 %) significantly upregulated the Vg and protein kinase A (PKA) gene expressions and increased the cyclic adenosine monophosphate (cAMP) concentration in the hepatopancreas. Moreover, dietary supplementation with 2.52 % Arg significantly decreased the cyclic guanosine monophosphate (cGMP) concentration and downregulated protein kinase G (PKG) and p38 mitogen-activated protein kinase (p38 MAPK) gene expression. Arg at 2.52 % significantly increased hemolymph Vg content and the gene expression of the vitellogenin receptor (VgR). In conclusion, Arg at 2.52 % improved vitellogenesis and ovarian maturation by reducing the VIH content and regulating Vg expression via the cGMP/cAMP pathway.

Identification of ETH receptor and its possible roles in the mud crab Scylla paramamosain

Ecdysis-triggering hormone (ETH) is a neuropeptide hormone characterized by a conserved KxxKxxPRx amide structure widely identified in arthropods. While its involvement in the regulation of molting and reproduction in insects is well-established, its role in crustaceans has been overlooked. This study aimed to de-orphanise a receptor for ETH in the mud crab Scylla paramamosain and explore its potential impact on ovarian development. A 513-amino-acid G protein-coupled receptor for ETH (SpETHR) was identified in S. paramamosain, exhibiting a dose-dependent activation by SpETH with an EC50 value of 75.18 nM. Tissue distribution analysis revealed SpETH was in the cerebral ganglion and thoracic ganglion, while SpETHR was specifically expressed in the ovary, hepatopancreas, and Y-organ of female crabs. In vitro experiments demonstrated that synthetic SpETH (at a concentration of 10−8 M) significantly increased the expression of SpVgR in the ovary and induced ecdysone biosynthesis in the Y-organ. In vivo experiments showed a significant upregulation of SpEcR in the ovary and Disembodied and Shadow in the Y-organ after 12 h of SpETH injection. Furthermore, a 16-day administration of SpETH significantly increased 20E titers in hemolymph, gonadosomatic index (GSI) and oocyte size of S. paramamosain. In conclusion, our findings suggest that SpETH may play stimulatory roles in ovarian development and ecdysone biosynthesis by the Y-organ.

Ngan mayla gen. et sp. nov, a new blind potamid cave crab from Borneo, Kalimantan (Crustacea: Decapoda: Brachyura: Potamoidea, Potamidae), and three other unidentified cave crabs from the same region

We here report on freshwater cave crabs of the families Potamidae and Gecarcinucidae in East Kalimantan, Sarawak, Indonesia in Borneo. A new genus and species of potamid crab, Ngan mayla, is described from Lubang Gedung Cave in the Merabu Karst. With its bullet-shaped eyes, Ngan mayla gen. et sp. nov. is totally blind and also displays the characters associated with an obligate cave-dwelling life, namely that it is dolichopod and fully depigmented. The closest genus and species is Cerberusa caeca Holthuis, 1979, from northern Sarawak. Highly modified, Ngan mayla gen. et sp. nov. proves to be among the most troglobitic of the known subterranean potamids, of which there were currently only seven in the Old World, with only four simultaneously being completely blind, entirely depigmented and dolichopod (Cerberusa caeca Holthuis, 1979, Diyutamon cereum Huang, Shih &amp; Ng, 2017 and Phasmon typhlops Huang, Ahyong &amp; Shih, 2020, to which must be added today Ngan mayla gen. et sp. nov.). Ngan mayla gen. et sp. nov. is easily distinguished from other potamid genera by its chelipeds bearing numerous acute teeth, spines (some horn-tipped) and short simple setae or spine-like setae on all articles. Two young female crabs collected in 2010 at the same area (Merabu Karst) but from a different cave, the Lubang Tebot Cave, could not be identified to specific level: an Isolapotamon sp., and a gecarcinucid with very long legs, pale colouration and slightly modified but black-pigmented eyes, close to Balssiathelphusa Bott, 1969, could possibly belong to a new genus. Some information on New World troglobitic crabs is provided.

Sex-bias of core intestinal microbiota in different stocks of Chinese mitten crabs (Eriocheir sinensis)

The differences in intestinal microbiota composition are synergistically shaped by internal and external factors of the host. The core microbiota plays a vital role in maintaining intestinal homeostasis. In this study, we conducted 16S rRNA sequencing analysis to investigate the stability of intestinal microbiota and sex-bias of six stocks of Chinese mitten crabs (105 females; and 110 males). The dominant phyla in all six stocks were Proteobacteria, Tenericutes, Bacteroidetes and Firmicutes; however, their relative abundance differed significantly. Twenty-seven core operational taxonomic units (OTUs), corresponding to 18 genera, were screened. Correlation analysis revealed that OTUs of four stocks in the Yangtze River system play important roles in maintaining the stability of intestinal microbiota. Additionally, the core intestinal microbiota was significantly sex-biased, and the top three genera in terms of relative abundance (Acinetobacter, Vibrio, and Candidatus_Hepatoplasma) were significantly dominant in female crabs. Network structure analysis also confirmed gender differences in the association pattern of intestinal microbiota. The intestinal microbiota of male crabs has a higher degree of functional enrichment. This study provided a theoretical basis for further investigating exploring the shaping effect of gender and geographical factors on the intestinal microbiota of Chinese mitten crabs.

MORFOMETRI KEPITING BAKAU (Scylla paramamosain) DI KAWASAN MANGROVE PANTAI PULAU SANTEN BANYUWANGI

Mangrove crab (Scylla paramamosain) is one of crab species that live in mangrove area. The purpose of this research was to obtain the morphometric and alometric of mangrove crab in mangrove area in santen island Banyuwangi. The sample of this research were taken by used transek methode by divide the area in to 3 stations. The first station was located in upper course of mangrove, the second station in down stream of mangrove, and the third station in the middle of mangrove zone. This research was measure about carapac length (CL), carapac width (CW), abdoment leng (AL), abdoment width (AW), hand bite length (HBL), hand bite width (HBW), frontal length (FL), and frontal width (FW). The alometric was observed about relation of morphometric measurement and bodymass in female and male of crab. The result of this research showed 3 species from all of the stations. But the focus of measurement was in one species called Scylla paramamosain. The result of male morphometric measurement minimal CL: 6,5 cm, CW: 8,5 cm, AL: 4 cm, AW: 1,5 cm, HBL: 10 cm, HBW: 1,5 cm, FL: 1 cm, FW: 2 cm, Body mass: 200 gram. Maximum CL: 9 cm, CW: 10 cm, AL: 4 cm, AW: 2 cm, HBL: 8,25 cm, HBW: 2,75 cm, FL: 1,5 cm, FW: 3 cm, Body mass: 500 gram. Al though in female measurement minimal CL: 5 cm, CW: 7,5 cm, AL: 3 cm, AW: 2,5 cm, HBL: 2 cm, HBW: 1,5 cm, FL: 1 cm, FW: 2 cm, Body mass: 200 gram. Maximum CL: 7,5 cm, CW: 11 cm, AL: 3 cm, AW: 5 cm, HBL: 4 cm, HBW: 5 cm, FL: 2 cm, FW: 4 cm, Body mass: 300 gram. The alometric result of male crabs was 0,98, that means negative alometric because it was less than 3 point. The negative alometric also happen in female crabs. The conclusion of the measurement is produce a negative growth pattern in male and female crabs

Morphometric relationships of blue swimming crab (&lt;em&gt;Portunus pelagicus&lt;/em&gt;, Linnaeus, 1758) caught in Negombo coastal waters in Sri Lanka.

Length-weight relationships provide information about the blue swimming crab (Portunus pelagicus) population for successful stock management. Morphometric measurements of Two hundred fifty (250) crab samples were obtained from April to November 2019, of which 128 were males, and 122 were females, showing a sex ratio of 1:1. Chi-square test indicated that the sex ratio was not significantly different from the expected value of 1:1 at 5% level of significance (χ2cal = 0.144, χ2tab = 3.84). Carapace width (CW) was measured at the nearest 0.001 cm using a vernier calliper, and total body weight (W) was measured at the nearest gram (g) using a digital scale. The carapace width of males ranged from 7.28 - 15.7 cm, whereas it varied from 3.06 - 15.8 cm in females. The body weight of male crabs varied from 22.45 - 334.6 g, and females had a range from 23.0 - 275.35 g. Length-weight relationships for male and female crabs were W=0.0495CW3.0469 (R2=0.8526) and W=0.063CW2.9428 (R2=0.8179) respectively. Student’s t-test showed that the growth of male crabs was positive allometric (t = 5.64, p&lt;0.05) and negative allometric (t = -8.21, p&lt;0.05) for females. The mean condition factors for males and females were 5.68±0.12 and 5.65±0.12, respectively, indicating no significant difference between males and females (p=0.882) by two-sample t-tests. Providing baseline data, the present study recommends further studies for successful utilization, development and management of this crab species as it has been recognized as a commercially valuable species with a high market demand.

Comparison of Body Characteristics, Carotenoid Composition, and Nutritional Quality of Chinese Mitten Crab (Eriocheir sinensis) with Different Hepatopancreas Redness.

In this study, we investigated the body characteristics, carotenoid composition, and nutritional quality of Eriocheir sinensis with different hepatopancreas redness (a*). We distributed the crabs into two groups based on the hepatopancreas a* values and compared their body characteristics, chroma, carotenoid composition, and protein, lipid, total sugar, amino acid, and fatty acid content via paired t-test. The results revealed that the relationships between hepatopancreas a* values and crab quality are sex specific. In female crabs, the differences in nutritional characteristics were evident mainly in the hepatopancreases and ovaries. In the redder hepatopancreases, the content of zeaxanthin and β-carotene increased, and the levels of C22:6n3 and C20:5n3 decreased (p < 0.05). In the ovaries, the content of astaxanthin, canthaxanthin, β-carotene, umami, and sweet amino acids were lower in the redder hepatopancreas crabs (p < 0.05). In male crabs, there were positive relationships between hepatopancreas a* and amino acid and fatty acid content. The content of leucine, arginine, and total umami amino acids in muscles and of unsaturated fatty acids and n-6 polyunsaturated fatty acids in hepatopancreases and testicles increased with increasing hepatopancreas a* values (p < 0.05). Therefore, the redder the hepatopancreas, the higher the nutritional quality of male crabs.