Carapace Width Weight Research Articles

Carapace Length-weight, Carapace Width-weight Relationships, Condition Factor and Sex Ratio of Freshwater Crab Sartoriana spinigera (Wood-Mason, 1971) from the River Burhi Gandak, North Bihar, India

Background: The Burhi Gandak river origins in the Chautarwa Chaur region near Bisambharpur in the West Champaran district of Bihar and flows through the East Champaran, Muzafarpur, Samastipur and Begusarai districts. It falls into the river Ganga near Khagaria district. Its coordinates are 25°51'40''N latitudes and 85°48'36''E longitudes. The total area of catchment is 12500 sq. km in size overall, of which 9601 sq. km are in Bihar and the rest in Nepal. The study will be helpful for stock estimation, developing conservation and choosing appropriate species for aquaculture. The present data can be used to develop conservation plans while providing biological data needed for an effective management of this fishery. Methods: The carapace length-weight, carapace width-weight relationship, condition factor and sex ratio of freshwater crab Sartoriana spinigera (n=663) collected from River Burhi Gandak, North Bihar, between July 2020 to June 2021. In the present investigation, freshwater crabs were collected from different types of techniques, including hand-picking, digging, setting traps and taking them from their nest. Result: Total of 663 specimens of Sartoriana spinigera (Wood-Mason, 1971) of both sexes (male and female) were collected in which 363 female and 300 male. The carapace length-weight of Sartoriana spinigera females were calculated as W = 0.9122.521 with R2 = 0.875, male W = 0.43102.505 with R2 = 0.853 and length-weight of combined sex (male and female) were calculated as W = 0.6612.701 with R2 = 0.954. The carapace width-weight of female were calculated as W = 0.5542.331 with R2 = 0.831, male W = 0.7912.421 with R2 = 0.802 and carapace length-weight of combined sex (male and female) were calculated as W = 0.18122.601 with R2 = 0.900. From this study showed it could be stated that crabs have allometric growth pattern. The Fulton’s condition factor (Kn) value were calculated as 1.10 and sex ratio calculated was 1:1.49. This paper provides information.

Carapace Length–Weight, Carapace Width–Weight Relationships and Relative Condition Factor of Four Portunid Crab Species of the Gulf of Mannar, Southeast Coast of India

Carapace Length–Weight, Carapace Width–Weight Relationships and Relative Condition Factor of Four Portunid Crab Species of the Gulf of Mannar, Southeast Coast of India

Morphometrics, length-weight relationship and relative condition factor in Charybdis (Archias) omanensis septentrionalis Türkay & Spiridonov, 2006 (Brachyura, Portunidae) from the Arabian Sea

Abstract Charybdis (Archias) omanensis septentrionalis Türkay & Spiridonov, 2006, has recently been recorded from the Arabian Sea, while the first record of the species was from the Red Sea. The specimens were collected in a shrimp trawl from a depth of 65-68 metres from the southwest coast of the Arabian Sea, off Kerala, India. The species size ranged between 17 and 37 mm carapace width, from 11 to 22.5 mm carapace length and in total weight between 0.39 and 5.53 g. The interrelationships between various morphometric characters, viz., carapace width and length and chelar propodus length and height in males, as well as carapace width and length and abdominal width and length in females, were estimated for the species and it was found that most relationships are positive and highly significant. In the carapace width/length-weight relationship, the estimated b values for carapace width-weight in males, females and pooled, were 2.674, 2.719 and 2.783, respectively, and for carapace length-weight they were 2.601, 2.588 and 2.681, respectively. The results show a significant deviation from an isometric growth pattern. An analysis of covariance indicated that there is a significant difference between sexes with respect to the carapace width/length-weight relationship. The relative condition factor values estimated in males and females were 0.9794 ± 0.16 and 1.1280 ± 0.26, respectively, also recording a significant variation () between sexes.

Population dynamics and reproductive biology of Scylla serrata (Forskål, 1775) on the shores overlooking the mangrove forest of the Persian Gulf

Size frequency distribution and reproductive biology of Scylla serrata (Forskål, 1775) collected by gill net in the tidal zone of the northern Persian Gulf were studied in May 2019 and then from November 2019 to September 2020. A biometric data of 165 mud crabs showed that males are larger compared to females. The populations of male and female crabs were dominated by adult crabs (CW > 100 mm) from winter to mid-spring (December to May). The juvenile crabs were dominant from late spring to mid-summer (May to August). The sex ratio of male:female was 3:1, with 75.2% being male. This species could spawn continuously throughout the year and its peak occurs in winter and spring. The size of the first-maturity of females and LM50% were recorded in the carapace width of 82 mm and 99.4 mm, respectively. The carapace width–weight relationship showed positive allometric growth in male crabs and negative allometric growth in female crabs with a b value calculated to be 3.43 and 2.97 for males and females, respectively.The parameters CW ∞, K, and t0 were estimated at 217 mm, 1.5 Y−1, −0.61 y−1 for males and 198 mm, 1.1 Y−1, −0.86 y−1 for females, respectively. The φ index was estimated at 4.85 in males and 4.63 in females. Total, natural, and fishing mortality rates were estimated at 3.50, 1.32, and 2.18 Y−1 for males and 1.46, 1.10, and 0.36 Y−1 for females, respectively. The exploitation ratio was calculated to be 0.62 for males and 0.24 for females.This findings state of knowledge on the population biology of mud crabs will act as a baseline to propose suitable management strategies for the S. serrata stocks on the Iranian coast as well as for future research to support the development of sustainable mud crab aquaculture and fisheries.

Carapace width/length-weight relationships for portunid crabs (genus Callinectes Stimpson, 1860) in northern Brazilian mangrove estuaries

Carapace width-carapace length (CW/CLRs), carapace width-weight (CW/WRs), and carapace length-weight (CL/WR) relationships are presented for the portunid species Callinectes bocourti A. Milne Edwards, 1879, Callinectes danae Smith, 1869, and Callinectes ornatus Ordway, 1863 from the northern coast of Brazil. A total of 85 crabs were collected between May and October 2015 in intertidal zones of the Caeté, Pirabas and Salinas estuaries. All species had strong relationships between measurements with a coefficient of determination (r 2) ranging between 0.97 and 0.99. The variable most strongly related to CW was CL with 99 % of the variability provided by C. ornatus. These relationships are a useful tool for field ecologists to estimate length and/or mass of portunid species, and it is not necessary to euthanize the organism to collect body measurements. Additionally, this study describes the first reference of CW/CLRs and CL/WRs for these portunid species in the region. The Callinectes species in Amazon estuaries are still poorly studied, and there is a need for monitoring their stocks due to its importance for artisanal fishery. The present data are important for supplying biological information required for an adequate management of this fishery.

Size-weight relationships and condition factor of the invasive Atlantic blue crab Callinectes sapidus Rathbun, 1896 (Decapoda: Brachyura: Portunidae) from northern Tunisia: a preliminary investigation

Abstract We determined the condition factor and relative growth patterns of the newly established invasive Atlantic blue crab Callinectes sapidus in the Ghar El Melh Lagoon, northern Tunisia, central Mediterranean Sea using two biometric relationships: carapace width-weight and carapace length-weight. Crabs were sampled during winter and summer 2020. Growth coefficient (slope b) for width-weight relationship ranged from 2.037 to 3.008 according to sex and seasons, indicating an isometry to negative allometry growth patterns. Length-weight relationship, however, demonstrated isometry growth patterns, with the exception of the summer sample, which displayed a positive allometry. The allometry seems to be not affected by seasons, but sex demonstrated a strong effect for the width-weight relationship, as indicated by ANCOVA. The Fulton’s condition factor, however, showed significant variation between seasons, but not between sexes.

Fishery of mud crab Scylla serrata of Kotania Bay, Western Seram District: potency, stock status and sustainable management

Study on the fishery of mud crab Scylla sp. of Portunid crab at Kotania Bay of Western Seram District was conducted between March and August 2018. The objectives of this study were to analyze biological parameters, the potency, stock status, sustainability, and to propose a sustainable management plan for this fishery. A total of 592 individual mud crab sample were collected from local fisher for biological parameters analysis. Historical catch data from local fisher, mud crab collector and fishery enumerator were used to analyze stock biomass, fishing intensity and stock status using Graham-Schaefer dynamic model. Rapfish analysis was used to analyze the sustainability of the stock. The carapace width ranged from 7.80 - 23.50 cm with an average of 13.68 cm (±2.25). There was a strong relationship between carapace width-weight (r = 0.9405) with overall growth pattern of isometric. The estimated stock biomass of mud crab of Kotania Bay was 130,000 t with BMSY of 22,425 t.yr−1, and mud crab fishery was under overfishing status. The overall sustainability was 46.92% and was considered as less sustain according to the ecosystem approach to fisheries management. Most sensitive attributes affecting sustainability were catching before maturity, consumer attitude towards sustainability, gear side effect, just governance, and government quality. Law enforcement, education and training on ecosystem approach to fisheries management, mud crab pot with escape gab, community based fishery management as well as monitoring and reporting should be conducted for mud crab sustainability.

Body Weight, Carapace Length and Width Relationship and Condition Factor of the Mud Crab Scylla serrata (Forskal) in Mangrove Ecosystem

The relationship of length-weight and width-weight of the carapace and the relative condition factor of mud crab Scylla serrata from Coringa Wildlife Sanctuary (Andhra Pradesh, India) was the subject of present study. Significant difference in both males and females was observed between carapace length-weight, carapace width-weight with a linear relationship. The regression values of both the sexes were found to be statistically significant. The regression equations calculated for length-weight were W= 0.00000178 L 3.1139 (r= 0.95) for males, W= 0.00000520 L 2.8056 (r=0.94) for females and for sexes combined it was W = 0.0000297 L 2.9891(r= 0.94). In case of carapace width-weight relationship of males, females and sexes combined the regression equations were W= 0.00000121 CW 3.0426 (r= 0.92), W= 0.00000178 CW 2.775 (r=0.93) and W = 0.00000204 CW 2.9210(r= 0.92) respectively. The male crabs showed positive allometric growth whereas female had negative allometric growth. Analysis of covariance confirmed remarkable difference between males and females in the growth pattern. The mean relative condition factor (Kn values) of both males and females and of the pooled sexes ranged from 0.680 (April) to 1.029 (November). A gradual raise in Kn values was observed from small- to big- sized crabs in both the sexes. Peak values were observed in 12.0-13.9 cm size group in November.

Body Measurements and Proximate Analysis of Freshwater Crab (Sudanonautes aubryi) of Asejire Reservoir, Ibadan, Nigeria

In this study, the interrelationships between various morphometric characters, viz., carapace width and length and chelae propodus length in males, as well as carapace width and length and abdominal width and length in females, were estimated using a total of 97 freshwater crabs (Sudanonautes aubryi). The allometric relationships between the characters of this set suggest that most relationships are positive and highly significant. The ‘b’ values for carapace width-weight in males and females were 3.008 and 2.973 respectively, and for carapace length-weight they were 2.908 and 2.74, respectively. The results show a significant deviation from an isometric growth pattern in female S. aubryi. Other interrelationship between characters such as left and right chelae; abdominal length and abdominal width; carapace length and abdominal width; and other interrelationship showed significant correlation. The sex ratio was also determined with male as the dominant sex. The samples were subjected to proximate analysis. The moisture content recorded on the body fluid of S. aubryi are at an average of 76.45% in male and 75.08% in female, the crude fat which has a relatively low value of 13.57% for male and average of 14.55% in female, the ash contents obtained were very low with an average of 1.16% in male and 0.398% in female, the crude protein reported on the fluid of both male and female S. aubryi are 4.5% for male and 4.62% for female, Carbohydrate percentages available in S. aubryi has a relatively high value with an average of 3.83% for male and 5.36% for female.

Carapace width-weight relationship, age, growth and longevity of the mud crabScylla olivacea(Herbst, 1796) in the Pichavaram mangroves, south-east India

The present study provides novel information on carapace width-weight (CWR) relationship and growth parameters of the mud crabScylla olivacea(Herbst, 1796) inhabiting the Pichavaram mangroves, east coast of India based on length frequency data sets during June 2010 to May 2012. CWR revealed linear regression between carapace width and weight in both sexes, and overall CWR exponent (b) values acquired for males and females are 3.035 (r2= 0.962) and 2.925 (r2= 0.933) respectively. The growth parameters, CW∞,Kandtoderived for males and females were 148.05, 0.762 year−1and −0.637 and 138.80 mm, 0.856 year−1and −0.681 respectively. The growth ofS. olivaceawas assessed through various methods in such a way that the outcome of one method functions as a rider, check and control over the other.

Age, growth, mortality and sex ratio of the inshore population of the edible crab, Cancer pagurus (Linnaeus 1758) in South Wales (UK)

Age, growth, and mortality of the edible crab, Cancer pagurus, were determined for the native population in South Wales (UK). Sampling was carried out on a monthly basis between February 2001 and September 2002. Carapace width ranged between 10.4 and 163 mm. Based on the carapace width frequency distribution, the Swansea and Gower population was composed mainly of males belonging to the first and second age-class (1 and 2), and of females belonging to the third and fourth age-class (3 and 4). Sex ratio was 1.126 ± 0.27 in favour of males. Carapace width frequency distributions and weight-at-age data were used to estimate the von Bertalanffy growth equation parameters. For the population as a whole, these were: L∞ = 199 mm, W∞ = 1179.56 g, K = 0.24 year−1, t0 = −0.1004 years. The overall carapace width–weight relationship was: W = 0.38(CW2.69). Analysis of covariance indicated a significant difference in the carapace width–weight relationship between males and females in the study area. Total mortality Z and natural mortality M rates for combined sexes were 1.245 year−1 and 0.567 year−1, respectively. The exploitation ratio E was estimated to be 54.43%.

Morphometrics and Length-Weight Relationship in the Blue Swimmer Crab, Portunus Pelagicus (Linnaeus, 1758) (Decapoda, Brachyura) from the Mandapam Coast, India

In this study, the interrelationships between various morphometric characters, viz., carapace width and length and chelar propodus length and height in males, as well as carapace width and length and abdominal width and length in females, were estimated using a total of 980 crabs, Portunus pelagicus. The carapace width/length — weight relationship was studied in both sexes on a total of 1188 crabs using the allometric growth equation of Von Bertalanffy. The allometric relationships between the characters of this set suggest that most relationships are positive and highly significant. The 'b' values for carapace width-weight in males and females were 3.607 and 3.293, respectively, and for carapace length-weight they were 3.049 and 2.774, respectively. The results show a significant deviation from an isometric growth pattern. An analysis of covariance indicates that there is a significant difference between sexes with respect to the carapace width-weight relationship.