scholarly journals The relative growth and sexual maturity of the freshwater crab Dilocarcinus pagei (Brachyura, Trichodactylidae) in the northwestern region of the state of São Paulo

2013 ◽  
Vol 103 (3) ◽  
pp. 232-239 ◽  
Author(s):  
Daphine R. Herrera ◽  
Thiago M. Davanso ◽  
Rogerio C. Costa ◽  
Fabiano G. Taddei
Keyword(s):  
Sexual Maturity ◽  
Sao Paulo ◽  
Minimum Size ◽  
São Paulo ◽  
Freshwater Crab ◽  
Relative Growth ◽  
Stage Of Development ◽  
Gonadal Maturity ◽  
Size At Sexual Maturity ◽  
Dilocarcinus Pagei

The aim of the present study was to determine the size at sexual maturity in the freshwater crab Dilocarcinus pagei Stimpson, 1861, from a population located in Mendonça, state of São Paulo, Brazil. The crabs were sampled monthly (July 2005 to June 2007), at Barra Mansa reservoir. The specimens were captured manually or in sieves passed through the aquatic vegetation. The crabs were captured and separated by sex based on morphology of the pleon and on the number of pleopods. The following dimensions were measured: carapace width (CW); carapace length (CL); propodus length (PL); and abdomen width (AW). The morphological analysis of the gonads was used to identify and categorize individuals according to their stage of development. The morphological maturity was estimated based on the analysis of relative growth based on the allometric equation y = ax b. The gonadal maturity was based on the morphology of the gonads by the method CW50 which indicates the size at which 50% of the individuals in the population showed gonads morphologically mature to reproduction. The biometric relationships that best demonstrated the different patterns of growth for the juvenile and adult stages were CW vs. PL for males and CW vs. AW for females (p<0.001). Based on these relationships, the estimated value to morphological sexual maturity was 21.5 mm (CW) in males and 19.7 mm (CW) in females. The determination of the size at sexual maturity and the adjustment of the data based on the logistic curve (CW50) resulted in a size of 38.2 mm for males and 39.4 mm for females (CW). Based on the data obtained for sexual maturity for D. pagei, we can estimate a minimum size for capture of 40 mm (CW). This minimum size allows at least half of the population to reproduce and retains the juveniles and a portion of the adults in the population.

scholarly journals Size at sexual maturity of female crabs Sesarma rectum Randall (Crustacea, Brachyura) and ontogenetic variations in the abdomen relative growth

2005 ◽  
Vol 22 (2) ◽  
pp. 433-437 ◽  
Author(s):  
Maria H. de A. Leme
Keyword(s):  
Sexual Maturity ◽  
Carapace Width ◽  
Analysis Of Covariance ◽  
Northern Coast ◽  
Growth Phases ◽  
Differential Growth ◽  
Relative Growth ◽  
Gonadal Maturity ◽  
Body Sizes ◽  
Size At Sexual Maturity

The aim of the present study was to ascertain the size at sexual maturity in females of the crab Sesarma rectum Randall, 1840 by comparing gonadal maturity to morphologic maturity (using abdomen-width data). The relative growth of the abdomen was analysed for all growth phases (for each 3-mm carapace width size class), and the slopes of the separate allometric relationships were compared through analysis of covariance (ANCOVA) from log e-transformed data to detect changes in the level of allometry during ontogeny. The physiological size at maturity (gonadal criteria) was determined through a logistic curve, indicating the size at which 50% of females presented mature gonads (M50 = 17.4 mm CW). The highest allometric levels occurred in growth phases 2 and 3 (body sizes ranging from 15 to 21 mm CW), indicating faster growth of the abdomen during those phases. Phases 1 (< 15 mm CW) and 4 and 5 (size classes above 21 mm CW) showed isometric growth. In the study area, a mangrove on the northern coast of the state of São Paulo, Brazil, individuals of S. rectum began to reach sexual maturity from 15 mm CW onward, when the slopes of the relationship of abdomen width to carapace width became positively allometric, indicating a differential growth rate. A gradual decrease in the slope, tending to isometry, occurred during ontogeny, as the animals became larger (older).

scholarly journals Relação peso/largura da carapaça e fator de condição em Dilocarcinus pagei Stimpson (Crustacea, Trichodactylidae), em São José do Rio Preto, São Paulo, Brasil

2005 ◽  
Vol 22 (4) ◽  
pp. 825-829 ◽  
Author(s):  
Marcelo A. A. Pinheiro ◽  
Fabiano G. Taddei
Keyword(s):  
Sao Paulo ◽  
São Paulo ◽  
Dilocarcinus Pagei

A biologia de caranguejos de água doce tem sido pouco enfocada na literatura carcinológica, especialmente em relação à Dilocarcinus pagei Stimpson, 1861. Este estudo visa analisar a relação peso/tamanho e variações temporais/sazonais do fator de condição, comparando com a biologia da espécie. Os exemplares foram coletados mensalmente na Represa Municipal de São José do Rio Preto (São Paulo), durante um período bianual (outubro/1994 a setembro/1996). Foram obtidos 962 espécimes (534 machos e 428 fêmeas), que foram mensurados (LC = largura do cefalotórax) e pesados (PE = peso úmido total). Os pontos empíricos da relação PE/LC foram analisados para cada sexo e submetidos à análise de regressão pela função potência (y = ax b) e representadas por: PE Machos = 0,0002LC3,º8 e PE Fêmeas = 0,0005LC2,82. O fator de condição foi calculado mensal e sazonalmente, sendo o das fêmeas cerca de 2,5 maior que o dos machos, possivelmente devido ao maior tamanho/peso das gônadas. De modo geral o verão foi caracterizado pela menor média de fator de condição (época reprodutiva), contrastando com a maior verificada no inverno (reorganização gonadal). Os resultados obtidos são enfocados pela primeira vez na literatura carcinológica, sendo de grande valia no manejo populacional e preservação desta espécie, que vem sendo intensamente explorada e usada como isca na pesca esportiva.

scholarly journals Patterns of temporal variation in growth rate from a mainland population of Anolis nebulosus (Squamata: Dactyloidae), in the Mexican Pacific Coast

2017 ◽  
Author(s):  
Aurelio Ramírez Bautista ◽  
Uriel Hernández-Salinas ◽  
Raciel Cruz Elizalde
Keyword(s):  
Growth Rate ◽  
Food Availability ◽  
Sexual Maturity ◽  
Pacific Coast ◽  
Growth Patterns ◽  
Dry Forest ◽  
Minimum Size ◽  
Von Bertalanffy ◽  
Mexican Pacific ◽  
Size At Sexual Maturity

In this study we used three nonlinear regression models: Von Bertalanffy, logistic-by-length, and logistic-by-weight to describe the pattern of growth of hatchling, juvenile, and adult of the lizard Anolis nebulosus in a tropical dry forest near of the Mexican Pacific coast during a period of 1989 and 1990. Von Bertalanffy and logistic-by-length models showed the best fit to the growth data for males and females of three age classes from marked and recaptured lizards in these years. The characteristic parameter of growth (r) and asymptotic growth (A1) extracted from these models indicated that males grow faster than females, but the latter reach a slightly larger size than males. The growth curves revealed that males reach minimum size at sexual maturity at 35 mm in snout-vent length (SVL), at an age of seven months, while females reach sexual maturity at 37 mm of SVL at nine months. Comparisons of growth rate between wet and dry seasons and years revealed that hatchlings and juveniles of both sexes had higher growth during the wet season for both years. Although there was no significant variation between measured environmental variables or in the food availability, the weight of evidence suggests that environmental variation has an influence on the growth of A. nebulosus of this population. Results indicate that variation on growth patterns observed may result from a combination of environmental factors, such as food availability, predation pressure and some reproductive characteristics as size at sexual maturity and size of hatchlings at birth.

scholarly journals Crescimento do caranguejo de água doce, Dilocarcinus pagei Stimpson (Crustacea, Brachyura, Trichodactylidae)

2005 ◽  
Vol 22 (3) ◽  
pp. 522-528 ◽  
Author(s):  
Marcelo A. A. Pinheiro ◽  
Fabiano G. Taddei
Keyword(s):  
Sao Paulo ◽  
São Paulo ◽  
Dilocarcinus Pagei

A biologia de caranguejos de água doce tem sido pouco enfocada na literatura carcinológica, especialmente em relação ao crescimento das espécies da família Trichodactylidae. Este estudo visa determinar as curvas de crescimento em tamanho e peso, bem como a longevidade e a idade na muda pubertária dos caranguejos de água doce Dilocarcinus pagei Stimpson, 1861. As amostras foram obtidas mensalmente na Represa Municipal de São José do Rio Preto (São Paulo), de outubro/1994 a setembro/1996. Os indivíduos tiveram o sexo determinado, sendo também mensurados (LC = largura do cefalotórax) e pesados (PE = peso úmido). O crescimento dos indivíduos foi determinado pelo método de distribuição dos exemplares em classes de tamanho, sendo utilizado o programa FiSAT para a determinação das curvas através do ajuste não linear dos dados pelo modelo de Bertalanffy. Foram analisados 962 exemplares (534 machos e 428 fêmeas) e as curvas de crescimento em tamanho foram expressas pelas equações LC Machos = 61,7[1-e-0,97(t+0,041)] e LC Fêmeas = 57,1[1-e-1,41(t+0,031)], enquanto o crescimento em peso foi melhor representado por PE Machos = 65,2[1-e-0,97(t+0,041)]3,08 e PE Fêmeas = 44,9[1-e-1,41(t+0,031)]2,82. O tamanho assintótico dos machos (61,66 mm) foi pouco superior ao das fêmeas (57,09 mm), ocorrendo o inverso para a longevidade, estimada em 2,4 e 2,7 anos, respectivamente. O tamanho máximo estimado com base em 95% do tamanho assintótico foi de 58,6 mm para os machos e 54,2 mm para as fêmeas, valores muito próximos dos maiores tamanhos registrados na natureza para cada sexo (55,8 mm). A muda da puberdade dos machos ocorreu com idade superior à das fêmeas (tMachos = 1,2 anos e tFêmeas = 0,9 anos). Os resultados obtidos neste trabalho são inéditos na literatura carcinológica, sendo de grande valia no manejo populacional e preservação desta espécie, que vem sendo intensamente explorada e usada como isca na pesca esportiva.

Relative Growth of the Speckled Swimming Crab Arenaeus Cribrarius (Lamarck, 1818) (Brachyura, Portunidae), Near Ubatuba, State of São Paulo, Brazil

Crustaceana ◽  
1993 ◽  
Vol 65 (3) ◽  
pp. 377-389 ◽  
Author(s):  
Marcelo Antonio Amaro Pinheiro ◽  
Adilson Fransozo
Keyword(s):  
Carapace Width ◽  
B Value ◽  
Sao Paulo ◽  
São Paulo ◽  
Western Atlantic ◽  
Positive Allometry ◽  
Relative Growth ◽  
Maturation Phase ◽  
Length Width ◽  
Independent Variable

AbstractArenaeus cribrarius is a mainly tropical crab that occurs in the Western Atlantic Ocean, Brazil being its type-locality. The species ranges from Vineyard Sound, Massachusetts, USA to La Paloma, Uruguay. Information about this species is scarce. The relative growth ofA. cribrarius was analyzed, based on some morphometric relations, where the carapace width, excluding lateral spines (CW), was used as an independent variable. A total of 403 specimens (189 males and 214 females), was collected in Ubatuba, State of São Paulo, Brazil, with otter-trawls. The animals were sexed and sorted to maturation phase (juvenile or adult). Some measurements were made: carapace (length and width excluding lateral spines), abdomen (greatest width of the fifth somite in females and the sixth in males) and major chela (greatest length, width and height, dactylus length). This study was made by the application of the power function (y=a.xb) which was fitted to the data and the pattern of growth established for each parameter by the "b"-value (constant of allometry), as positive allomctry (b>1), negative allometry (b<1) or isometry (b=1). The morphometric relations of the carapace showed a tendency to isometry. In females, the abdominal width grew in positive allometry, higher in juveniles (b= 1.33) than in adults (b=1.18). In this case, an overlap and discontinuity was noticed between the phases over a carapace width range of 55 to 70 mm, where the puberty molt occurs. The majority of relationships showed that the major chela of the males grew in positive allometry, however, the greatest allometric difference between the phases was observed towards the propodus length with 1.09 as juvenile and 1.26 as adult "b"values. In the males, this variable showed an inflection between the CW range of 45 to 55 mm, where the transition to the maturation phase occurs. The relative growth of this species is similar to those of previously studied species. This indicates, that the propodus length and the abdominal width are the morphometric variables most appropriate to estimate the size at the beginning of the sexual maturity for males and females of this species, respectively.

scholarly journals Relative growth and reproduction in Achelous spinicarpus (Crustacea: Portunidae) on the south-eastern continental shelf of Brazil

2012 ◽  
Vol 93 (3) ◽  
pp. 667-674 ◽  
Author(s):  
André L. Pardal-Souza ◽  
Marcelo A.A. Pinheiro
Keyword(s):  
Continental Shelf ◽  
Sexual Maturity ◽  
Developmental Stages ◽  
Carapace Width ◽  
Gravimetric Method ◽  
Tropical Region ◽  
The South ◽  
Relative Growth ◽  
South Eastern ◽  
Size At Sexual Maturity

This investigation aimed to study the relative growth, morphological sexual maturity and fecundity of the swimming crab Achelous spinicarpus in a tropical region, on the south-eastern continental shelf of Brazil (25°S). Biometry of all specimens was conducted, including measurements of the cephalothorax, cheliped, abdomen and gonopods. Relative growth was described based on the equation for allometry (y = axb), and size at sexual maturity was determined from inflections in relations involving the cheliped, gonopods (males), and abdomen (females), as dependent variables, related to the cephalothorax width (independent variable). Fecundity was estimated by the gravimetric method. The relations of the length of the chelar propodus and carpal spine to the carapace width without the lateral spines (CW) showed positive allometry in both sexes, with a significant variation in the constant ‘b’ for males between the developmental stages (juvenile and adult) and the size at maturity estimated at 37 mm CW. In females, the abdomen was most appropriate for the estimate of morphological maturity, which occurred at a smaller size (32 mm CW), with a change in the growth pattern between the stages, passing from isometric (juveniles) to positive allometric (adults). The gonopods also showed different growth rates between developmental stages, in synchrony with the variables of the cheliped. Mean fecundity for the species was 53,984 eggs, with a positive correlation between the number of eggs exteriorized and the size of the female; the equations allowed interconversion between these variables, due to the adjustment of the power function (r2 ≥ 86%).

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