Size at sexual maturity and body size composition of mud crabs Scylla spp. caught in Don Sak, Bandon Bay, Gulf of Thailand

2010 ◽  
Vol 77 (1) ◽  
pp. 49-57 ◽  
Author(s):  
Katsuyuki Hamasaki ◽  
Naohiro Matsui ◽  
Makoto Nogami
Keyword(s):  
Body Size ◽  
Sexual Maturity ◽  
Size Composition ◽  
Gulf Of Thailand ◽  
Size At Sexual Maturity ◽  
Mud Crabs

Comparative life history features of the western spotted frog, Rana pretiosa, from low- and high-elevation populations

1975 ◽  
Vol 53 (9) ◽  
pp. 1254-1257 ◽  
Author(s):  
Lawrence E. Licht
Keyword(s):  
British Columbia ◽  
Life History ◽  
Body Size ◽  
Sexual Maturity ◽  
High Elevation ◽  
The Body ◽  
Female Fecundity ◽  
Size At Sexual Maturity ◽  
Rana Pretiosa

Comparisons are made of life history features of the western spotted frog, Rana pretiosa pretiosa, living at 70 m in southwestern British Columbia, and 2600 m in Yellowstone Park, Wyoming.Lowland tadpoles remain longer as larvae and transform at twice the body size as highland tadpoles.Growth rates of juveniles and adults are rapid in the lowland population and the same amount of growth achieved by them in 2–3 years takes 8–10 years for highland frogs.Body size at sexual maturity is the same for frogs from both populations, but B.C. frogs breed at half the age of Wyoming frogs. Female fecundity, the number of eggs at spawning, is the same, but lowland females breed annually, while high-elevation females breed only every 2 or 3 years.Various explanations are put forth to account for observed differences.

Maturation génitale des varans du nil mâles (Varanus niloticus) dans trois populations du Sahel

1999 ◽  
Vol 77 (2) ◽  
pp. 222-232 ◽  
Author(s):  
Vivian de Buffrénil ◽  
Jacques Castanet ◽  
Frédérique Rimblot
Keyword(s):  
Body Size ◽  
Sexual Maturity ◽  
Morphometric Study ◽  
Lake Chad ◽  
Breeding Stock ◽  
Size At Sexual Maturity ◽  
Monitor Lizards ◽  
Mature Spermatozoa ◽  
Accurate Indicator

Genital maturation of male monitor lizards, a subject poorly documented up to now in spite of the heavy exploitation of these animals, was studied on a sample of 211 Nile monitors (Varanus niloticus) from Chad (Lake Chad), Mali (central delta of the Niger), and Nigeria (Hadejia-N'Guru wetlands). Snout-vent lengths (LC) in the sample ranged from 15.6 to 85.5 cm. After a morphometric study of the monitors, their testes were sampled, weighed at ±0.01 g and fixed for histology. The age of each specimen was estimated by skeletochronology. The testes of monitors less than 36 cm LC (Malian specimens) or 40 cm LC (Chadian and Nigerian individuals) do not contain mature spermatozoa, whereas the testes of larger specimens do. Most Malian monitors aged 18 months (1.5 years) have mature spermatozoa. Conversely, in Chadian and Nigerian individuals, mature gametes appear only in specimens aged 30 months (2.5 years). These data indicate that genital maturity in the Nile monitor is reached at 36-40 cm LC and 1.5-2.5 years according to the populations. The growth in mass of the testes, compared with LC, is an accurate indicator of body size at sexual maturity, and confirms the precocity of Malian specimens. Conversely, testis growth is poorly related to age. These results are discussed with reference to the possible accommodation of Nile monitor populations to heavy exploitation by means of precocious recruitment of the male breeding stock.

Importance of reproductive biology of a harvest lizard, Tupinambis merianae, for the management of commercial harvesting

2015 ◽  
Vol 42 (8) ◽  
pp. 697 ◽  
Author(s):  
Sergio Naretto ◽  
Gabriela Cardozo ◽  
Cecilia S. Blengini ◽  
Margarita Chiaraviglio
Keyword(s):  
Body Size ◽  
Clutch Size ◽  
Sexual Maturity ◽  
Biological Information ◽  
Specific Information ◽  
Central Argentina ◽  
Management Plans ◽  
Size At Sexual Maturity ◽  
Tupinambis Merianae ◽  
The Relationship

Context Management of the exploitation of resources requires biological information on exploited species. The skins of large reptiles have a commercial value as luxury leather items and Tupinambis lizards from southern South America have historically been exploited for this purpose. Argentina implemented management plans for Tupinambis lizards since 1988 that established a minimum capture size based on the width of dried skins, but this prescription has not been linked to local reproductive attributes of species. Aim In this study, we aim to determine the reproductive parameters of Tupinambis merianae and evaluate which class sizes of individuals are susceptible to commercial trade in central Argentina to generate local and species-specific information to improve available management tools. Methods We determined the relationship between the width of dried skins and live body sizes. We identified size at sexual maturity in males and females. Moreover, we determined status of reproductive individuals by body size and characterised gonadal development and seasonal reproductive events in central Argentina. We evaluated the relationship between female body size and clutch size. Key results Reproduction of T. merianae in central Argentina is markedly seasonal, with both sexes concentrating their reproductive activities between October and December. Size at sexual maturity was smaller for males than females, and the percentage of reproductive females was lower than males. In both sexes, the frequency of reproductive individuals was low in smaller lizards, and bigger females had bigger clutch size. The width of dried skins was positively related to body size. Conclusions Size at sexual maturity, and reproductive period, should be taken into account when management plans are designed to minimise any negative impacts of harvesting. Implications In central Argentina, the breeding season coincides with hunting periods set by national legislation. The results of our study have prompted local authorities to impose hunting closures for part of December and to raise the minimum catch size. Further, we offer an equation that can be used as a monitoring tool for estimating snout to vent length of live animals from skins. Studies like ours should be replicated in different areas and extrapolated to other models.

WEIGHT AT MENARCHE: SIMILARITY FOR WELL-NOURISHED AND UNDERNOURISHED GIRLS AT DIFFERING AGES, AND EVIDENCE FOR HISTORICAL CONSTANCY

PEDIATRICS ◽  
1972 ◽  
Vol 50 (3) ◽  
pp. 445-450
Author(s):  
Rose E. Frisch
Keyword(s):  
Genetic Variation ◽  
Body Size ◽  
Causal Relationship ◽  
Sexual Maturation ◽  
Sexual Maturity ◽  
Historical Evidence ◽  
Critical Weight ◽  
Size At Sexual Maturity ◽  
The Mean

The mean weight at menarche of 30 undernourished Alabama girls did not differ from that of 30 well-nourished controls, although the undernourished girls attained menarche two years later than controls and at a significantly greater height. This supports the hypothesis that a critical weight triggers menarche. The weight-dependency of menarche, irrespective of a causal relationship, reduces variation in body size at sexual maturity by delaying or advancing the age of sexual maturation as a compensation for environmental or genetic variation. Recent and historical evidence indicates that the mean weight at menarche of Caucasian girls has been about 46 kg. for over a century.

scholarly journals Associations between Childhood Body Size, Composition, Blood Pressure and Adult Cardiac Structure: The Fels Longitudinal Study

PLoS ONE ◽  
2014 ◽  
Vol 9 (9) ◽  
pp. e106333 ◽  
Author(s):  
Roy T. Sabo ◽  
Miao-Shan Yen ◽  
Stephen Daniels ◽  
Shumei S. Sun
Keyword(s):  
Blood Pressure ◽  
Body Size ◽  
Longitudinal Study ◽  
Size Composition ◽  
Cardiac Structure

scholarly journals Use of otoliths to estimate size at sexual maturity in fish

2000 ◽  
Vol 43 (4) ◽  
pp. 437-440 ◽  
Author(s):  
Carlos Sérgio Agostinho
Keyword(s):  
Sexual Maturity ◽  
Line Segments ◽  
Alternative Method ◽  
Straight Line ◽  
Size At Sexual Maturity

The viability of an alternative method for estimating the size at sexual maturity of females of Plagioscion squamosissimus (Perciformes, Sciaenidae) was analyzed. This methodology was used to evaluate the size at sexual maturity in crabs, but has not yet been used for this purpose in fishes. Separation of young and adult fishes by this method is accomplished by iterative adjustment of straight-line segments to the data for length of the otolith and length of the fish. The agreement with the estimate previously obtained by another technique and the possibility of calculating the variance indicates that in some cases, the method analyzed can be used successfully to estimate size at sexual maturity in fish. However, additional studies are necessary to detect possible biases in the method.

scholarly journals A comparison of the allometric growth in Uca leptodactyla (Crustacea: Brachyura: Ocypodidae) from two subtropical estuaries

2004 ◽  
Vol 84 (4) ◽  
pp. 733-735 ◽  
Author(s):  
Rosana Carina Flores Cardoso ◽  
Maria Lucia Negreiros-Fransozo
Keyword(s):  
Growth Pattern ◽  
Sexual Maturity ◽  
Carapace Length ◽  
Brazilian Coast ◽  
Allometric Growth ◽  
Size At Sexual Maturity ◽  
Subtropical Estuaries ◽  
Habitat Similarity

The allometric growth of Uca leptodactyla from two distinct subtropical estuaries on the Brazilian coast was evaluated concerning its growth pattern and size at onset of sexual maturity. Females attained maturity at similar sizes in both sites (4·1 mm of carapace length in Indaiá and 4·2 mm in Ubatumirim), while males differed slightly. They reached the size at sexual maturity of 5·3 mm of carapace length in Indaiá and 4·6 mm in Ubatumirim. Growth pattern is usually similar among crabs from distinct sites while size at sexual maturity is frequently different. However, in the case of U. leptodactyla it did not occur, probably due to the strong habitat similarity and intrinsic features of this species.

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