Carapace Width-weight Relationship 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.

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-weight relationship and condition factor of Austruca annulipes in mangroves of Penang Island

Carapace width-weight relationship and relative condition factor (Kn) of Austruca annulipes were estimated from 2086 individuals comprising 1503 males and 583 females. Crabs were sampled from mangroves of Teluk Tempoyak and Pulau Betong during the study period of March 2017 to February 2018. Monthly sampling of crabs was conducted using hand catch method (catch per unit effort (CPUE)) with captured crabs counted as number of crabs/15 min/4 m². Data recorded was analysed in four categories; sex, dry and wet months, five size classes and sampling site. The carapace width-weight relationship of male and female crabs was significantly positive for the four categories with overall samples indicating positive allometric growth, except for males in the size class of 1.70 – 1.99 cm, and females in the size class of 0.80 – 1.09 cm that were characterized by negative allometric growth. The values of mean relative condition factor (Kn) of A. annulipes was higher than 1 indicating that mangrove in Penang Island provide favourable habitat condition for the growth of A. annulipes.

Carapace length-weight and width-weight relationships of Scylla serrata in Bulungan District, North Kalimantan, Indonesia

Widigdo B, Rukisah, Laga A, Hakim AA, Wardiatno Y. 2017. Carapace length-weight and width-weight relationships of Scylla serrata in Bulungan District, North Kalimantan, Indonesia. Biodiversitas 18: 1316-1323. The mud crab, Scylla serrata lives associated with mangrove ecosystems and is widely distributed in the Indo West-Pacific. The present work was aimed to reveal the carapace length/width-weight relationships of Scylla serrata in two mangrove ecosystem area of Bulungan District, North Kalimantan- Indonesia, i.e. Kahayan Delta and Tibi Island. The crabs were collected by using ambau pancang (trap) for two months from November to December 2016. A total of 522 individuals were collected and their carapace length, carapace width, and weight were measured. The sex ratio of total collected samples (male to female) was 1:0.79. Carapace length and width of S. serrata caught in these two study area ranged from 40 to 89 mm for male; 32 to 91 mm for female and 59 to 128 mm for male; 53 to 122 mm for female, respectively. The carapace length-weight relationships of total samples showed logarithmic equations as follow: W = -3.2194 + 2.9725 Log CL for male and Log W = -2.2010 + 2.3750 Log CL for female. While the carapace width-weight relationships are as follow: W = -3.9162 + 3.1012 Log CW for male and Log W = -2.6001 + 2.3968 Log CW for female. The b values of carapace width-weight relationship indicated that the growth pattern of male was positive allometric and female was negative allometric. Size frequency of crab population is also presented.

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.

Short Communication: Population structure of mangrove crab Scylla oceanica in mangrove ecosystem of Tanjung Lesung, Banten, Indonesia

Pudiawati T, Patria MP. 2017. Short Communication: Population structure of mangrove crab Scylla oceanica in mangrove ecosystem of Tanjung Lesung, Banten, Indonesia. Biodiversitas 18: 813-817. The mangrove crab Scylla oceanica is one of the dominant crabs in the mangrove ecosystem at Tanjung Lesung Beach, Banten, Indonesia. The aim of the study was to determine the temporal distribution, carapace width-weight relationship and condition factors of S. oceanica. The crabs were collected by using traps for four months from August to November 2015. It was observed that the carapace was larger in male crabs (9.97 cm) than in female crabs (9.34 cm) and the average weight of the males (206.08 g) was higher than that of the females (183.83 g). b value of male (1.955) and female (2.123) crabs were significantly different (P < 0.05). Both of them have a negative allometric growth pattern. The result of the distribution analysis was a Morisita spread index Id of 1.5176; this indicates the crabs have clustered distribution patterns and their distribution was allegedly associated with the reproductive cycle.

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.

Size at Maturity, Sex Ratio and Variant Morphometrics of Blue Swimming Crab Portunus segnis (Forskal, 1775) from Boushehr Coast (Persian Gulf)

Size at maturity, sex ratio and variant morphometrics of blue swimming crab Portunus segnis was studied for one year along the Persian Gulf coasts, Iran. Sex ratio during a year of study was M:F=0.92:1 which should be the relative frequency of females. Male blue crabs have a V-shaped abdomen and female have an abdomen broad and rounded. The carapace width/length- weight relationship was studied in both sexes of crab. The allometric relationships between the characters of this set suggest that most relationships are positive and highly significant. An analysis of covariance indicates that there is a significant difference between sexes with respect to the carapace width-weight relationship. The crab’s carapace widths ranged were from 75 to175 mm for males and 70 to170 mm for females. The crab’s carapace lengths were from 35 to 80 mm for male and 30 to 80 mm for female. The results of this study show that at the same size, weight and the parameters of carapace length and carapace width male of Portunus segnis are higher than females in Persian Gulf coasts.

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%.

영광 칠산도 주변해역 꽃게, Portunus trituberculatus (Miers, 1876)의 생물자원학적 특성

Frequency distribution of carapace width, relative growth, sex ratio and fecundity of blue crab Portunus trituberculatus in Younggwang adjacent water were investigated. A total number of individuals collected for this study were 658(Males : 305 and females : 353). Water temperature and salinity of the study areas varied from 5.9 to and 28.1 to 31.6 psu, respectively. The carapace length-width and carapace width-weight relationship was calculated and the equations obtained are; For males; CL

Population structure of the crab Callinectes ornatus Ordway, 1863 (Brachyura: Portunidae) bycatch in shrimp fishery in northern Rio de Janeiro state, Brazil

This study provides the first data on the population structure of swimming crab Callinectes ornatus Ordway, 1863 bycatch from coastal shrimp fishing in northern Rio de Janeiro State, Brazil (21º 30'-21º 50' S and 41º 05'-41º 07' W). Crabs were collected monthly from April 2006 to March 2007. A total of 5,611 specimens were analyzed, of which 3,951 were males and 1,660 ovigerous and non-ovigerous females. The overall sex ratio (2:1) differ significantly from the expected 1:1 proportion, being the mature males significantly predominant as bycatch in this fishery. The specimens' carapace width and weight varied from 27 to 126 mm (mean: 77.3 ± 12.3 mm) and 1.2 to 128.2 g (mean: 31.0 ± 14.4 g) for males, and 30 to 101 mm (mean: 63.4 ± 9.3 mm) and 1.7 to 66.0 g (mean: 16.4 ± 7.4 g) for ovigerous and non-ovigerous females. Seasonal comparisons did not reveal differences between the number of specimens captured in dry and rainy periods considering both sexes and maturity stages. The size at first maturity was 79 mm for males and 65 mm for females, and the carapace width-weight relationship indicated an alometric pattern for both sexes. The bycatch swimming crabs are locally used as bait, but the capture tendency for a specific sex/age-group can affect this population structure over time.

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.