scholarly journals Gonad development and size at maturity of the male mud crab Scylla paramamosain (Forsskål, 1755) in a tropical mangrove swamp

2013 ◽  
Vol 1 (1) ◽  
pp. 7 ◽  
Author(s):  
Md. Sherazul Islam ◽  
Hisashi Kurokura

The reproductive traits and size at sexual maturity of the male mud crab Scylla paramamosain were investigated in Pak Phanang mangrove swamps, Thailand. Samples were taken seven times from the local middlemen mud crab traders during June 2006 to January 2008. Gonad development was determined based on histological appearance that was classified into three stages: 1) Immature (Spermatogonia), 2) Maturing (Spermatocytes) and 3) Mature (Spermatids and Spermatozoa). Among the sample population, the highest 72% was under gonad development stage I, whereas mature stage III was only 12%. The size at first maturity was estimated by the external allometric growth and histological observation of gonad. The size at which 50% of individuals attain sexual maturity was estimated by the two mathematical models such as probit analysis and logistic curve. The mean size at first sexual maturity and 50% maturation of male S. paramamosain were 96 mm and 109 mm internal carapace width (ICW) which revealed that 88% individuals were immature. The present result suggested that the minimum legal size of male S. paramamosain capture should be >110 mm ICW.

2021 ◽  
Vol 8 ◽  
Author(s):  
Wenxiao Cui ◽  
Shaobin Fang ◽  
Ligang Lv ◽  
Zhi Huang ◽  
Fei Lin ◽  
...  

In order to uncover the sexual difference in morphology and how early they appear during the development stage of mud crab Scylla paramamosain, we measured, observed, and biostatistically analyzed morphological traits related to sex. For unveiling the morphological differences between sexes, morphological traits involving abdomen width (AW), carapace length (CL), and carapace width (CW) were first measured during the crablet development stage of S. paramamosain in the present study. The correlation analyses and path analyses exhibited that sexual dimorphism in the third abdomen width (AW3) and fourth abdomen width (AW4) could be used for sex identification from stage C VI (stage VI of crablet). Based on the stepwise discriminant analysis and standardized traits, a sex discriminant equation was constructed, which is capable for sex identification in crablets from stage C VI. Observations for secondary sexual traits and abdomen morphology (shape and pleopods) using a dissecting microscope or scanning electron microscope indicated that sexes are easily identified at stage C VIII according to the abdomen shape; meanwhile, at stage C II based on pleopod difference, and at stage C I by the presence or absence of gonopores. The findings in this study contribute greatly to the accuracy of sex identification of S. paramamosain during the early development stage, which promotes the understanding of the morphological differentiation mechanism of sex.


2019 ◽  
Vol 66 (1) ◽  
Author(s):  
C. Viswanathan ◽  
M. Pravinkumar ◽  
T.V. Suresh ◽  
V. Elumalai ◽  
S.M. Raffi

The present study was conducted to assess the size distribution, sex ratio, size at first sexual maturity, fecundity and spawning season of the commercially important orange mud crab Scylla olivacea (Herbst, 1796) in Pichavaram mangroves in south-east India. This study is the first contribution to the knowledge of reproductive biology of S. olivacea from the Indian coast. Size distribution analysis in the fishery revealed the irrational exploitation of undersized S. olivacea. The estimated sex ratio deviated from equality, being 1:0.87, revealing a male domination. Size at first sexual maturity was determined to be 87 mm in carapace width (CW) in females. Fecundity ranged from 1.16 to 3.53 million in females of 76 to 135 mm CW. Breeding takes place year-round with a peak in pre-monsoon, indicating that it is a prolific breeder. Results revealed that immature individuals of S. olivacea contributed significantly to the catches and thus an effective management of the resource by framing minimum legal size is crucial so that the females are allowed to spawn at least once prior to capture.


2021 ◽  
Vol 13 (3) ◽  
pp. 9-16
Author(s):  
Thanh Phuong Nguyen ◽  
Tinh Em Nguyen ◽  
Thi Kim Ha Nguyen ◽  
Quoc Viet Le ◽  
Thi Thanh Huong Do

This study aimed to evaluate the effects of temperature on the growth and survival of mud crab (Scylla paramamosain) larvae in two stages including zoea-1 to megalopa (the first experiment) and megalopa to crablet-1 (the second experiment). Each experiment was conducted in a completely randomized design with four temperature levels (27, 30, 33, and 36℃) in triplicate. Stocking density of 200 ind./L for the first experiment and 4 ind./L for the second experiment. Fiberglass tanks of 500-L (containing 300-L and 250-L of 25‰ water for the first and second experiment, respectively) were used in the experiments. The results showed that S. paramamosain larvae at zoea-3 and zoea-4 died at 33℃ or above, while the highest survival rate of this stage was found at 27℃ (11.5%). The growth and larval stage index during the zoea to megalopa stage were significantly higher in 30℃ (p<0.05) compared to those in the 27℃ treatment. In the second experiment, the survival rates of crablet-1 were highest (72.9%) at 27℃ and lowest (34,7%) at 36℃. The growth rate of crablets at this stage increased with increased temperature. The highest carapace width and weight (3.41 mm and 0.030 g, respectively) were recorded at 36℃. The findings of this study suggested that mud crab larvae should be reared at the temperature range of 27-30℃ to maximize their production.


2015 ◽  
Vol 224 (3) ◽  
pp. 273-287 ◽  
Author(s):  
Jie Gong ◽  
Haihui Ye ◽  
Yinjie Xie ◽  
Yanan Yang ◽  
Huiyang Huang ◽  
...  

In arthropods, it is known that ecdysteroids regulate molting, limb regeneration, and reproduction through activation of the ecdysone receptor (EcR). However, the ecdysteroid signaling pathway for promotion of ovarian development in crustaceans is still unclear. In this study, three cDNA isoforms of EcR were cloned from the mud crab Scylla paramamosain. qRT-PCR revealed that the SpEcR mRNA was abundant in the eyestalk, ovary and epidermis. During ovarian development, the SpEcR transcripts increased from stage I (undeveloped stage) and reached a peak at stage IV (late vitellogenic stage) before dropping to a lower level at stage V (mature stage). Meanwhile, levels of 20-hydroxyecdysone (20E) in the hemolymph, detected by HPLC-MS, displayed a similar pattern of increase with ovarian development. Results from in situ hybridization indicated that SpEcR mRNA was present in the follicular cells during vitellogenesis. Results from in vivo experiments revealed that 20E at 0.2 μg/g body weight significantly stimulated the expression of SpEcR and vitellogenin (SpVg) in female crabs during the early vitellogenic stage but not during the previtellogenic stage. This was confirmed by results from in vitro experiments which indicated that SpEcR and SpVg expression levels were significantly upregulated in early vitellogenic ovarian explants incubated with 5.0 μM 20E at 3 and 6 h but not in previtellogenic ovarian explants. Finally, results from in vitro gene silencing experiments indicated that the expression of SpEcR and SpVg in the ovary was significantly inhibited by SpEcR dsRNA. All these results together indicated that in S. paramamosain, 20E, and SpEcR, located in the follicular cells, play important roles in the promotion of ovarian development via regulating the expression of SpVg.


2017 ◽  
Vol 12 (1) ◽  
pp. 65 ◽  
Author(s):  
Ong Moc Quy ◽  
Ravi Fotedar ◽  
Ho Thi Truong Thy

The study evaluated the effects of extended dietary inclusions of rotifers (Brachionus plicatilis) on the survival, metamorphosis rate, growth and development time in the larvae of mud crabs (Scylla paramamosain). The five most commonly published feeding regimes of mud crab (S. paramamosain) larvae were selected and tested by including rotifers onto them. Mud crab larvae in the first feeding regime were fed exclusively with Artemia nauplii (control or regime A), while those in feeding regimes 2, 3, 4 and 5 were fed rotifers starting from zoea 1 (Z1) to various development stages of mud crab larvae whereas feeding with Artemia nauplii was commenced from the Z2 stage until the end of the trial (megalopa stage). The results of the larval feeding trial for 24 days of culture showed the progressive decrease in survival of the larvae in all feeding regimes. Extended inclusion of rotifer feeding until Z5 stage resulted in significantly higher survival than in the control from 18 day after hatching onwards. Larval survival was negatively correlated (R2 from 0.78 to 0.90) with the rearing time; however, different feeding regimes had no significant effect on this correlation. Extending inclusion of rotifer feeding until the Z3, Z4 and Z5 stages resulted in higher percentages of megalopa metamorphosis than in regime control, but did not significantly impact development time, carapace width, body length and wet weight of megalopa. 


2006 ◽  
Vol 8 (1) ◽  
pp. 101
Author(s):  
Muhammad Marzuqi ◽  
Ibnu Rusdi ◽  
Nyoman Adiasmara Giri ◽  
Ketut Suwirya

The purpose of this experiment was to know lipid sources requirement for growth of mud crab (Scylla paramamosain) juvenile. The experiment used ninety of juveniles reared in 30 l of seawater with flow-throught water system and aeration. Initial average body weight and carapace width of juveniles were 0.21 g and 1.05-1.07 cm, respectively. Juveniles were stocked individually using a supernet material in each tank. Five isoprotein and isoenergy formulated diet with dry pellet form containing different proportion of squid oil and soybean oil as lipid sources i.e. 12%:0%, 9%:3%, 6%:6%, 3%:9% and 0%:12%. Feed were given twice a day in the morning and afternoon. The results showed that proportion of dietary squid oil and soybean oil as lipid sources had significant effects on final body weight, weight gain, carapace width, feed efficiency and essential fatty acid of mud crab (P


2021 ◽  
Vol 111 ◽  
Author(s):  
Isabela Chellegatti ◽  
Rogério Caetano da Costa ◽  
Antonio L. Castilho ◽  
Isabela R. R. Moraes ◽  
Daphine R. Herrera ◽  
...  

ABSTRACT The marine crab Xanthodius parvulus (Fabricius, 1793) is naturally distributed in the Western Atlantic, being commonly found in the northeastern Brazilian coast. However, this species has been also recorded in the southeastern coast, especially in São Paulo State, on islands located close to harbors, which are becoming a place of occurrence for exotic species. This study aimed to estimate the morphological sexual maturity (relative growth) of X. parvulus the functional biological patterns of the species in a No-take marine reserve. The crabs were sampled at the Marine State Park of Laje de Santos, an important protected area from São Paulo that is located close to the largest Brazilian harbor, Santos, using an artificial substrate and active search methods (scuba diving). The morphological sexual maturity of females was estimated in 7.28 mm, according to the Abdomen Width vs. Carapace Width relationship, while for males this value was 8.83 mm based on the Gonopod Length vs. Carapace Width relationship, the females presented an increase in abdominal growth, even during the mature stage in order to achieve higher reproductive success, since the abdominal structure is used to protect the embryos. The Gonopod Length vs. Carapace Width relationship showed that males copulate with different sized females, since a non-exaggerated growth of the gonopods keeps them adequate to the size of the female genital pore, i.e., juveniles exhibited negative allometry and adults presented isometry. Thus, estimating the size of the sexual maturity of a species requires the development of a model to acknowledge its biological and reproductive pattern, being an important tool to increase the knowledge about the behavior of this species and one of the parameters to evaluate its conservation status.


2006 ◽  
Vol 49 (2) ◽  
pp. 239-248 ◽  
Author(s):  
Daniela da Silva Castiglioni ◽  
Maria Lucia Negreiros-Fransozo

The gonad development of Uca rapax was studied to achieve the size at onset of its sexual maturity. Crabs were sampled from April/2001 to March/2002 in the Itamambuca and Ubatumirim mangroves in Ubatuba, São Paulo, Brazil. The specimens were grouped in 10 size classes. Juveniles and adult crabs frequencies were assessed for each class. The size of carapace width in which 50% of males and females were considered mature was 14.8 and 12.1 mm (Itamambuca) and 13.6 and 11.4 mm (Ubatumirim), respectively for males and females. Males matured at higher sizes than females, probably due to a major investment in their somatic growth, while females spend their energy in the reproductive process, saving energy for eggs' production.


2020 ◽  
Vol 9 (1) ◽  
pp. 55-64
Author(s):  
Shofi Firda Safitri ◽  
Sunaryo Sunaryo ◽  
Ali Djunaedi

 ABSTRAK: Kepiting Bakau (Scylla sp.) merupakan sumberdaya kelautan penting di Indonesia dan permintaan terhadap komoditi Kepiting Bakau cenderung meningkat, baik di pasar lokal maupun mancanegara. Peningkatan permintaan Kepiting Bakau dapat menyebabkan terganggunya populasi kepiting di alam. Penelitian ini bertujuan untuk mengkaji biomorfometrik Kepiting Bakau (Scylla sp.) yang meliputi ukuran lebar karapas Kepiting Bakau, hubungan lebar karapas dan berat, nisbah kelamin, faktor kondisi dan tingkat kematangan gonad Kepiting Bakau di perairan Bandengan Kendal pada November 2018 sampai Februari 2019. Penelitian menggunakan metode deskriptif eksploratif. Hasil penelitian menunjukkan, bahwa jumlah Kepiting Bakau yang diamati sebanyak 1914 ekor, terdiri atas 897 betina dan 1017 jantan, terdapat empat spesies Kepiting Bakau yang tertangkap di perairan Bandengan Kendal, yaitu Scylla serrata, Scylla tranquebarica, Scylla paramamosain dan Scylla olivacea, perbandingan betina dan jantan 1:1,19. Ukuran lebar karapas berkisar antara 43,75-165,5 mm dengan berat berkisar antara 23-660 g. Hubungan lebar karapas dengan berat bersifat allometrik negatif. Nilai faktor kondisi yang didapatkan berkisar 1,66–1,189. Tingkat kematangan gonad kepiting betina didominasi oleh TKG I dan II, pada bulan November 2018 – Februari 2019 di perairan Bandengan Kendal belum terjadi masa puncak pemijahan.  ABSTRACT: Mud crabs (Scylla sp.) are important marine resources in Indonesia and demand for mud crabs tends to increase, both in local and foreign markets. Increased demand for Mangrove Crabs can cause disruption to the population of crabs in nature. This study to examine the morphometrics of Mud Crabs (Scylla sp.) Which include the size of the width of the Mud Crab carapace, the relationship between carapace width and weight, sex ratio, condition factors and the level of maturity of the Mud Crab in Bandengan Kendal waters from November 2018 to February 2019. The descriptive explorative methods was used in this research. The results showed that the number of mud crabs caught from November 2018 to February 2019 was 1914, consisting of 897 females and 1017 males, there were four species of mud crabs caught in Kendal Bandengan waters, namely Scylla serrata, Scylla tranquebarica, Scylla paramamosain and Scylla olivacea, comparison of females and males 1: 1,19. Carapace widths range from 43.75 - 165.5 mm with weights ranging from 23 - 660 g. The relationship between carapace width and weight are negative allometric. The obtained condition factor values range from 1.66 - 1.189. The maturity level of female crab gonads are dominated by TKG I and II, thus it is suspected that in November 2018 - February 2019 in the waters of Bandengan Kendal, the spawning peak has not yet occurred.


2021 ◽  
Author(s):  
Ardavan Farhadi ◽  
Shi Xi ◽  
Yin Zhang ◽  
Huaiping Zheng ◽  
Shengkang Li ◽  
...  

Abstract Background: We previously discovered a potential sex-specific single nucleotide polymorphism (SNP) locus named SNP1888 in mud crab (Scylla paramamosain). Methods: In this study, we first verified SNP1888 to be truly a female-specific locus and then we identified a novel imprinted gene (designated as Sp-Pol) at the upstream of SNP1888 (SNP1888 is located at the 3’-UTR of Sp-Pol). Moreover, SNP1888 together with Sp-Pol were mapped on LG32 of a high-density genetic map. Results: Phylogenetic analysis showed that Sp-Pol may need to be classified as a new gene family due to the very low sequence identity with other known genes. Sp-Pol was expressed at a higher level in gonads compared to other tissues and its expression level in the testis was much higher than in the ovary. Coincidentally, mono-allelic expression was observed in the ovary. Moreover, Sp-Pol exhibited sex-biased expression with approximately 3- to 4-fold higher in males than in females at fifth (C5) and sixth (C6) crablet stages. During the zoeae development, Sp-Pol had the highest expression at the zoea I stage. After unilateral eyestalk ablation, the expression level of Sp-Pol significantly increased in testis and hepatopancreas in males, while it was downregulated in the hepatopancreas of females. Fluorescence in situ hybridization (FISH) assay revealed that Sp-Pol transcripts were strongly localized in the epithelia of seminiferous tubules of the testis and in the ovary it was detected in the oogonium cells.Conclusion: These results demonstrated that Sp-Pol may play important roles in the sexual development of S. paramamosain.


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