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.

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.

scholarly journals ISOMETRY OF EGG SIZE IN A TEXAS POPULATION OF THE TURTLE STERNOTHERUS ODORATUS THAT EXHIBITS A NEARLY FIXED CLUTCH SIZE

2020 ◽  
pp. 13-17
Author(s):  
Peter V. Lindeman
Keyword(s):  
Body Size ◽  
Clutch Size ◽  
Egg Size ◽  
Female Body Size ◽  
Competing Demands ◽  
Sternotherus Odoratus ◽  
Central Texas ◽  
Relationship Of ◽  
The Relationship ◽  
Anatomical Constraints

In evaluating optimal egg-size theory and the effects of anatomical constraints on egg size in turtles, pivotal questions concern the significance of the relationship of egg size to female body size and whether the relationship is isometric or hypoallometric. In a central Texas population of the kinosternid turtle Sternotherus odoratus in which clutch size of a sample of turtles was nearly fixed (seven of eight females had two eggs while the largest female had three eggs), there was an isometric increase in egg width with body size among the females with two-egg clutches and significantly reduced egg width in the largest female’s three-egg clutch. Allometric analyses of populations that exhibit little variation in clutch size, as well as analysis of modal clutch sizes in populations with more variable clutch sizes, both have the potential to further illuminate the competing demands of increasing egg size vs. increasing clutch size as females grow larger, enabling them to optimize their reproductive output as it increases with body size.

Reproductive characteristics of three small-bodied cuttlefish in subtropical waters

2018 ◽  
Vol 69 (3) ◽  
pp. 403
Author(s):  
Amanda L. Beasley ◽  
Karina C. Hall ◽  
Coral I. Latella ◽  
Peter L. Harrison ◽  
Stephen G. Morris ◽  
...  
Keyword(s):  
Seawater Temperature ◽  
Reproductive Mode ◽  
Gonadal Development ◽  
Specific Information ◽  
Potential Fecundity ◽  
Reproductive Characteristics ◽  
Eastern Australia ◽  
Management Plans ◽  
Size At Sexual Maturity ◽  
Species Specific

Life history information for many commercially important cuttlefish is lacking, and thus the effects of long-term harvest remain unknown. The present study investigated the reproductive mode and seasonality of three small-bodied cuttlefish (Sepia opipara, S. plangon and S. rozella) in subtropical eastern Australia. Monthly samples were collected over 2 years and examined for gonadal development, size at sexual maturity, potential fecundity, size of mature oocytes and spermatophores, and temporal variation in maturity stages and gonadal weight relative to seawater temperature. All species showed reproductive characteristics consistent with a terminal multiple spawning mode, with S. opipara and S. rozella likely to be intermittent batch spawners, whereas S. plangon spawned continuously. Spawning occurred year round for all species, but S. opipara and S. rozella showed greater seasonality than S. plangon, peaking in autumn–spring. The biggest species, S. opipara, matured at a larger size than the others, had the greatest potential fecundity (the highest documented for any cuttlefish) and the largest spermatophore sizes. In contrast, S. rozella and S. plangon had much larger mature oocytes than S. opipara. These results further highlight the diversity of reproductive characteristics in cuttlefish, and the need for species-specific information for fishery and conservation management plans.

scholarly journals Morphometric sexual maturity and allometric growth of the crab Sesarma rectum Randall, 1840 (Crustacea: Sesarmidae) in an impacted tropical mangrove in northeast Brazil

2017 ◽  
Vol 41 (2) ◽  
pp. 361-368
Author(s):  
Felipe Bezerra Ribeiro ◽  
Helena Matthews Cascon ◽  
Luis Ernesto Arruda Bezerra
Keyword(s):  
Sexual Maturity ◽  
Inflection Point ◽  
Carapace Width ◽  
Northeast Brazil ◽  
Allometric Growth ◽  
Catch Per Unit Effort ◽  
Crab Population ◽  
Size At Sexual Maturity ◽  
Left And Right ◽  
The Relationship

The size at sexual maturity and the allometric growth of the semi-terrestrial crab Sesarma rectum were studied in an impacted tropical mangrove in northeast Brazil. Crabs were monthly collected during spring low-tide periods, from October 2009 through September 2010. A catch-per-unit-effort (CPUE) technique was used to sample the crab population, with two-hour sampling periods, by two people. A total of 492 crabs were obtained, being 262 males and 230 females. The specimens were measured at carapace width (CW), the left and right propodus length and height (RPL, RPH, LPL and LPH), and the gonopod length of males (GL), and abdomen width (AW) of females. In males, the inflection point was at 27.14 mm CW in the relationship between CW and the length of right propodus (LRP), considering the morphological size at the onset of maturity. Based on the relationship between CW and AW, the size at sexual maturity in females was 22.97 mm. In spite of living in an impacted area, this population attained the maturity onset at a bigger size than other localities.

scholarly journals Female reproductive cycle of the snaked-eyed Lizard Ophisops elegans Ménétriés, 1832 (Reptilia: Lacertidae) from Lebanon

2019 ◽  
Author(s):  
Fida Nassar ◽  
Souad Hraoui-Bloquet
Keyword(s):  
Body Size ◽  
Clutch Size ◽  
Reproductive Cycle ◽  
Sexual Maturity ◽  
Reproductive Activity ◽  
Male Adult ◽  
Female Body Size ◽  
Significant Difference ◽  
Ophisops Elegans ◽  
Female Reproductive Cycle

We studied the female reproductive cycle of a population of Ophisops elegans lizard from the herpetology collection of the Natural History Museum of the Lebanese University. Females collected during spring and summer showed vitellogenesis in their ovaries with oviposition occurring from May to July followed by a subsequent quiescent period. They produced up to two clutches. Mean clutch size was 3.2 ± 1, range 2-5 eggs. Clutch size was independent of female body size. The smallest female attaining sexual maturity had a snout vent length of 45 mm. Sexual maturity can be attained within one year of age. We found no significant difference in body size between female and male adult lizards. Seasonal variations in the reproductive activity of females were well synchronized with those of males. 

The relationship between maternal body size and clutch size, development time and egg mortality in Euchaeta norvegica (Copepoda: Calanoida) from Loch Etive, Scotland

1977 ◽  
Vol 57 (3) ◽  
pp. 723-733 ◽  
Author(s):  
C. C. E. Hopkins
Keyword(s):  
Body Size ◽  
Clutch Size ◽  
Body Length ◽  
Development Time ◽  
The Body ◽  
Regression Analyses ◽  
Maternal Body ◽  
Egg Mortality ◽  
The Relationship ◽  
Personal Research

Analyses of the relationship between the size and the number of eggs per female in various decapods, isopods, cumaceans and mysids were made by Jensen (1958) based upon personal research and information from available literature. Regression analyses indicated that the number of eggs per female is related to the cube of the body length.

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.

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