Width-weight Relationships Research Articles

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.

Morphometry and length-weight relationships of the freshwater pearl mussel Parreysia corrugata (Muller 1774) (Bivalvia: Unionidae) from Daya River, Odisha, India

Allometry in the freshwater mussel Parreysia corrugata was studied from east-flowing riverDaya, Bhubaneswar, India. The results indicated that shell length (SL)-shell height (SH) andshell length-shell width (SW) relationships for P. corrugata were SH = 0.876 + 0.932SL andSW = 0.625 + 0.898SL. Greater correlation was found between SL and SW than between SLand SH. The length-weight, height-weight and width-weight relationships of P. corrugata wereestablished as TW = 0.00038SL2.80, TW = 0.0006SH2.95 and TW = 0.0023SW2.97 respectively.The t-test value of b indicated an isometric growth pattern in the width-weight and theheight-weight relationships. The highest r2 value was obtained for shell length-total weightand shell height-total weight equations. Present study will be helpful in strengthening theknowledge on interrelationship between the morphometric variables of P. corrugata and alsoin comparing with the earlier studies to know the existence of spatial or temporal variabilityin the morphometry of this species. This information can also be used to better understandthe biology of P. corrugata and to improve the management of this species. Keywords:Conservation, Daya River, Length-weight relationships,Morphometry

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

Samara length–weight relationships in the endangered Cedro (Cedrela montana Moritz ex Turcz)

ABSTRACT Cedrela montana Moritz ex Turcz, a ‘nearly threatened’ tree species in Colombia, produces a samara (fruit) that has not been classified in the literature. This article focusses on exploring the length–weight and width–weight relationships in samaras collected in Bogotá City, Colombia, to provide morphological guidelines for identifying C. montana from their samaras. A total of 101 samaras were collected from 12 C. montana trees in an urban forest and were weighed and measured. The average weight of the samaras was 4.86 g, the average width was 19.44 mm, and the average length was 54.53 mm. However, the length of the samaras ranged from 38.72 to 73.35 mm, with widths from 15.32 to 24.03 mm and weights from 2.08 to 9.54. Length–weight relationships showed a moderate to strong correlation of 0.63. Width–weight relationships had a moderate to strong correlation of 0.71. These allometric relationships could be used for identification and conservation purposes.

Distribution and Growth Patterns of Crab (P. pelagicus) Based on Environmental Characteristics in Candi Waters, Pamekasan Regency, East Java Province

Blue swimming crab (BSC) is a fishery commodity with high economic value and great demand in domestic and foreign markets. P. pelagicus swimming crabs are commonly found in Indonesian sea waters, one of the largest contributors to the country's foreign exchange after shrimp and tuna. The high demand for blue crab resources will trigger an increase in fishing efforts. If this is done continuously, it is feared that it could endanger the population structure. Moreover, disrupting the sustainability of blue swimming crab resources in the waters, this study examines the morphometric distribution and growth pattern of P. pelagicus crabs based on environmental characteristics in Candi waters, Pamekasaan Regency. Census sampling was carried out using the census method; the census method was carried out by taking all crab samples caught by fishermen. The results obtained found 33 individual crabs, which were divided into three classes, namely small (<10 cm), medium (>10 cm), and large (>12 cm) size classes. Male crabs dominated the research locations with wider straps than female crabs. The analysis results show that the width-weight relationship's b values are 1.47 (males) and 2.00 (females). In addition, male and female crabs have a positive allometric growth pattern. Blue swimming crabs are often found in habitats with a substrate of dusty mud, high salinity and organic matter.

Density and width-weight relationship of blue swimming crab (Portunus pelagicus) in Letman Waters, Southeast Maluku

Blue swimming crab (Portunus pelagicus) is a fishery commodity with a fairly high selling value, both as a local commodity and as an export commodity. The high level of utilization and trade of blue swimming crabs is not matched by knowledge of how to conserve these resources which can result in a decrease in blue swimming crab resource stocks. Sampling was carried out in November 2021 using a selected random sampling method. The density of the male blue swimming crab is 94,118 ind/km2 and the female is 58,824 ind/km2. The results of the analysis of the width-weight relationship of the blue swimming crab showed the nature of the blue swimming crab growth was negative allometric with a b value of 2.579.Keywords: density, width-weight relationship, blue swimming crab, Letman

Density and width-weight relationship of blue swimming crab (Portunus pelagicus) in Letman Waters, Southeast Maluku

Blue swimming crab (Portunus pelagicus) is a fishery commodity with a fairly high selling value, both as a local commodity and as an export commodity. The high level of utilization and trade of blue swimming crabs is not matched by knowledge of how to conserve these resources so that it can result in a decrease in blue swimming crab resource stocks. Sampling was carried out in November 2021 using a selected random sampling method. The density of the male blue swimming crab is 94,118 ind/km2 and the female is 58,824 ind/km2. The results of the analysis of the width-weight relationship of the blue swimming crab showed the nature of the blue swimming crab growth was negative allometric with a b value of 2.579.Keywords: blue swimming crab; density; Letman; width-weight relationship

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.

ABUNDANCE AND MORPHOLOGICAL CHARACTERIZATION OF WEST AFRICAN FRESHWATER CRAB (SUDANOUNTES AFRICANUS) ALONG LOWER RIVER BENUE, MAKURDI, BENUE STATE NIGERIA

The abundance and morphological characterization of freshwater crab (Sudanountes africanus) were determined in Makurdi along the Lower River Benue. 160 Sudanountes africanus were collected from August-November, 2016. The highest percentage (35.63%) S. africanus was obtained in August while the lowest (12.50%) was obtained November. The mean total length, body weight, carapace width, carapace length, length of the teeth, abdominal length, number of legs and diameter of the eye socket of male S. africanus were 3.38±0.03, 38.52±0.84, 4.67±0.83, 1.44±0.18, 3.51±0.06, 2.91±0.06, 8.00±0.00 and 0.69±0.01, respectively while the female counterpart had 3.40±0.07, 37.63±1.77, 4.71±0.10, 1.43±0.15, 3.26±0.08, 2.72±0.08, 8.00±0.00 and 0.64±0.01, respectively. There was no significant difference (p>0.05) between mean total length, body weight, carapace width, carapace length, abdominal length and the diameter of the eye socket. Female S. africanus had better “b” value (16.56) and mean condition factor (36.18±1.22) than the male with 7.13 “b” value and 7.16±4.77 condition factor. From the width weight relationship, female S. africanus had better “b” value (11.22) and mean condition factor (9.20±2.09) than the male with 2.00 “b” value and 1.07±4.45 condition factor.

Growth parameters of the invasive blue swimming crab Portunus segnis (Forskål, 1775) (Crustacea) in the North-Eastern Mediterranean, Türkiye

The blue swimming crab, Portunus segnis, is a Lessepsian and the most abundant and economically significant crab species on the Mediterranean Sea coast of Türkiye. However, there are a few studies on the growth of P. segnis in Türkiye. Our objective is to determine the allometry, and growth parameters of P. segnis in Iskenderun Bay, the Northeastern Mediterranean. Blue swimming crabs were sampled using a bottom trawl net from July 2014 to June 2015. Totally 320 specimens were caught. The carapace width (CW) varied from 38.1 to 163.17 mm (mean: 109.88±27.56 mm) and the total weight (TW) was measured at a minimum of 3.46 and a maximum of 324.36 g. The width (CW)- weight (TW) relationships of the crabs were estimated as log(TW)=2.9028CW-9.0664 (R2=0.7452) for the females and log(TW)=2.9773CW-9.3842 (R2=0.8433) for the males. The carapace width-weight relationships of both sexes indicated that the growth pattern is allometric (p<0.05). The von Bertalanffy growth parameters were computed as CW∞=166.00 mm, K=1.2 year-1, t0=-1.62 years, C=0, WP=0.20, and Φ´=4.519 for all crabs. The von Bertalanffy growth parameters of P. segnis were determined on the coasts of Türkiye, for the first time.

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.

Saros Körfezi’nde (Kuzey Ege Denizi) Kahverengi Vatozun (Raja miraletus Linnaeus, 1758) Biyolojik Yönleri

The present study reports the age, growth, and reproduction parameters of 52 brown rays (Raja miraletus) captured from the Saros Bay (Northern Aegean Sea) between September 2006 -2008. The males and females accounted for 44.2% and 55.8% of the sample, respectively. The males measured 10.5-53.5 cm (disc width, 6.5-32 cm) and the females ranged 25.5-47.7 cm (disc width, 18-30.5 cm) in total length (TL). The equations TW=0.0017*TL3.27 and TW=0.0017*DW3.38 were used to describe the total length-weight and disc width-weight relationships, respectively. The length-at-age data on vertebrae were used to estimate the von Bertalanffy growth equation: L∞ = 62.43 cm, K = 0.28 year−1, t0 = −0.54 year. The maximum age was found to be 4 years for both the males and females.

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 width-weight relationships of blue swimmer crab Portunus armatus (A. Milne-Edwards, 1861) (Crustacea: Brachyura: Portunidae) in southwestern Australia: influences of sex, decadal change, environment, and season

AbstractThe relationship between carapace width (CW) and weight (W) of the blue swimmer crab Portunus armatus (A. Milne-Edwards, 1861) was determined for southwestern Australian populations using measurements collected over two decades from a range of nearshore marine and estuarine environments. A strong and significant positive linear relationship occurred between the natural logarithm (ln) of CW and ln(W) for both sexes overall and individually for males and females (R2 = 0.985–0.987; P < 0.001). The relationships were: overall ln(W) = −10.2262 + 3.1708 ln(CW); males ln(W) = −10.4641 + 3.234 ln(CW), and females ln(W) = −10.0595 + 3.1246 ln(CW). Significant differences in the relationship were detected between sexes, decadal sampling periods, environments, and seasons (P < 0.001), with sex and decadal period being most influential. Males were heavier than females at any given CW, which was most apparent at larger (>100 mm CW) sizes. Crabs were also generally heavier at CW in a recent sampling period (2014–2019) than historically (1995–2000), with the greatest decadal differences occurring in the estuarine environment. These relationships have direct applicability for use in stock assessments of this valuable fishery species. Moreover, observed changes in the CW-W relationships over time highlight the importance of regularly reviewing biological parameters used in fisheries assessments, particularly in response to climate change as in the case of southwestern Australia.

LENGTH-WEIGHT, WIDTH-WEIGHT AND HEIGHT-WEIGHT RELATIONSHIPS OF CULTURED FRESHWATER PEARL MUSSEL LAMELLIDENS MARGINALIS (LAMARCK, 1819)

Lamellidens marginalis (Lamarck, 1819) is one of the important candidate species for freshwater pearl production in India. In the present study, the length-weight, width-weight and height-weight relationships of L. marginalis maintained in the farm were examined from January 2015 to September 2016. Monthly sampling was carried out and a total of 1015 specimens were analysed for the study. The length-weight, width-weight and height-weight relationships derived were W = 0.0003L2.712, W = 0.0018L2.708 and W = 0.0.0293L2.210 and the value of r2 was estimated as 0.776, 0.619 and 0.597 respectively. The values of b indicated the relative growth in body weight and superior physiological condition of the mussel. The length-weight, width-weight and height-weight relationships were found to be positive allometric and better correlation was observed in length-weight and width-weight relationships.

Allometry, condition factor and growth of the swimming blue crab Portunus segnis in the Gulf of Gabes, Southeastern Tunisia (Central Mediterranean)

The blue swimming crab Portunus segnis (Forskål, 1775) is one of the earliest Lessepsian invaders of the Mediterranean Sea, and is recorded since decades in various areas of the Mediterranean. Its presence in the southeastern Tunisian coasts (Gulf of Gabes) is, however, very recent. Allometry, condition factor and growth of P. segnis were studied along the Gulf of Gabes coasts. Sampling was performed by artisanal fishing gears as well as trawl net during a one-year period (October 2015 to September 2016) as processed 4971 crabs were collected. The crab carapace width (CW) ranged from 45 to 168 mm for males and 50 to 159 mm for females. The crab carapace length (CL) was 22.02-89.20 mm and 38.70-85.28 mm, respectively for males and females. The carapace width-carapace length, carapace width- front, carapace width-carapace height and carapace width-weight relationships were studied in separate sexes of crab. The covariance analysis indicates a significant difference between the two sexes with respect to the carapace width-carapace length and the carapace width-weight relationships. The condition factor ranged between 0.0042 and 0.0118 with a mean of 0.0078. The condition factor decreased with increasing crab size. The Von Bertalanffy growth parameters CW∞, K and t0 were estimated on the basis of Length-frequency modal progression analysis methods. The mean values of L∞ (mm), K (year-1) and t0 would be, respectively, 206.48 mm, 1.34 and -0.130 for males; 183.89 mm, 1.42 and -0.127 for females and, 190.60 mm, 1.02 and -0.177 for combined sexes.

Comparative analysis of growth performance between female and male mud crab Scylla paramamosain crablets: Evidences from a four-month successive growth experiment

Mud crab (Scylla paramamosain) is an economically important crustacean species for fisheries and aquaculture industry in China and other Southeast Asian countries. In this study, the sex ratio, morphological dimorphism, and the characteristics of morphological traits between female and male S. paramamosain juveniles at three different pond-culture stages were determined. The sex ratio skewed towards female crablets as growth and development proceeded. Three growth traits exhibited significant differences between sexes when the crablets were at two months of pond-culture stage, however, the number of growth traits with significant differences increased to seven when the crablets were at three and four months of pond-culture stages. Further, significant positive correlations were detected among all the 190 trait-pairs, irrespective of the pond-culture stages of the crablets. Apart from this, the path coefficients and determination coefficients varied between sexes among the three pond-culture stages, suggesting that the growth traits have different effects on body weight (BW) of female and male crablets during different pond-culture stages. The effect of growth traits on BW in both sexes at different pond-culture stages was determined by constructing six multiple regression equations. Analysis of the width-weight relationship revealed that male crablets had positive growth allometry whereas the females had isometric growth. In addition, an obvious sexual dimorphism in cheliped size and abdomen width was observed with growth and development. A discriminant function equation was successfully constructed for sex identification based on morphological indexes, with a high accuracy of 90.4%.

Biological aspects of the common torpedo, Torpedo torpedo (Linnaeus, 1758) (Elasmobranchii: Torpedinidae), in the central Mediterranean Sea (Sicily, Ionian Sea)

Data on the biology of Torpedo torpedo from the Ionian Sea are absent, and in the Mediterranean Sea, most of the published works focus on the reproductive biology of the species and are not recent. Several biological and ecological aspects of Torpedo torpedo were investigated between March and May 2019 on the coast of Sicily (Ionian Sea) between Avola and Marzamemi. Morphological (disc width–weight relationships, total length-disc width relationships), population (size-frequency distribution, sex ratio, fecundity), and ecological (habitat, diet) characteristics were studied. Stomach content analysis revealed that T. torpedo is a generalist piscivore, feeding on a wide variety of benthic and benthopelagic fish: Levin’s index value (Bi) was 0.82. The analysis of the sex ratio showed a higher proportion of males vs. females. Females were, on average, larger than males. Fecundity showed a positive correlation with body size, with the smallest mature female being 14.9 cm in disc width and 24.8 cm in total length. The ovarian fecundity ranged from 3 to 20 eggs. In the study area, both adults and juveniles of the species were caught in considerable numbers with trammel nets. We also provide data from some specimens of Torpedo marmorata caught during the study period.

Some biological aspects of juveniles of the rough ray, Raja radula Delaroche, 1809 in Eastern Sicily (central Mediterranean Sea)

Several biological aspects of juvenile specimens of Raja radula were investigated from February to May 2017 in the central Mediterranean Sea. Diet, sex ratio, disc width-weight relationships, and size-frequency distribution were analyzed. Stomach content analysis of 127 collected specimens showed that juveniles of R. radula actively feed on small benthic crustaceans, particularly on amphipods and isopods (Idotea balthica) (%IRI values of 62.74% and 12.39%, respectively). Although the Levin's index value (Bi = 0.44) indicated that juveniles of R. radula are a moderately stenophagous feeders, active mostly on crustaceans, the analysis of the prey-specific (Pi) biomass of the main preys vs. the frequency of their occurrence (%F) showed no clear dominance. The analysis of the sex ratio showed no significant difference in sex distribution. However, there were significant differences in mean size between sexes: females were, on average, larger than males, and also the b value (slope of the curve) of the disc width-weight relationships was higher in females.