scholarly journals Growth and reproduction in harbour porpoises (Phocoena phocoena) in Icelandic waters

2003 ◽  
Vol 5 ◽  
pp. 195 ◽  
Author(s):  
Droplaug Ólafsdóttir ◽  
Gísli A Víkingsson ◽  
Sverrir Daníel Halldórsson ◽  
Jóhann Sigurjónsson
Keyword(s):  
Body Size ◽  
Sex Ratio ◽  
Coastal Waters ◽  
Sexual Maturity ◽  
Phocoena Phocoena ◽  
Age Classes ◽  
Present Collection ◽  
Growth And Reproduction ◽  
Exact Timing ◽  
Icelandic Waters

A total of 1,268 harbour porpoises were obtained from fishing nets in Icelandic coastal waters from September to June in the years 1991 to 1997. Foetal sex ratio was 1.2:1 (male:female). The bias towards males increased further among older animals in the present collection. The modal year classes were 0 and 1 years but the oldest porpoise was a female estimated at 20 years of age. Length at birth was estimated as approximately 75 cm, and females grew faster and attained larger sizes than males. Asymptotic length was 149.6 cm for males and 160.1 cm for females. Estimated age and length at sexual maturity was 1.9 to 2.9 years and 135 cm for males and 2.1 to 4.4 years and 138 to 147 cm for females. Immature individuals were significantly shorter than pubertal and mature animals in both sexes in age classes 1 to 3. Testes weight increased only slightly with body size in immature males but increased rapidly around maturity. Pronounced seasonality was alsoobserved in testes weight, indicating a peak in testes activity in summer. Lack of data from the summer makes the exact timing of parturition and mating unknown. Births do, however, most likely peak in June and July and lactation lasts at least 7 to 8 months. Ovulation and pregnancy rates were 0.98.

scholarly journals Reproductive Biology of Round Sardinella (Sardinella Aurita) (Valenciennes, 1847) in Senegalese Coastal Waters

2018 ◽  
Vol 9 (1) ◽  
pp. 31
Author(s):  
Ismaïla NDIAYE ◽  
Alassane SARR ◽  
Alioune FAYE ◽  
Modou THIAW ◽  
Malick DIOUF ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Reproductive Biology ◽  
Coastal Waters ◽  
Sexual Maturity ◽  
Reproductive Parameters ◽  
Monthly Variation ◽  
Relative Fecundity ◽  
The Mean ◽  
Sardinella Aurita ◽  
Somatic Index

In this study, a total of 1068 specimens Sardinella aurita of which 553 females and 515 males were examined. The objectif of this study was to determine the reproductive parameters of Sardinella aurita. The sex ratio was significantly in favor of females (55%). The size at first sexual maturity was estimated at 18.9 cm for females and 18.0 cm for males. The monthly variation of sexual maturity stages and gonado-somatic index (GSI) allowed to locate the reproduction periods from February to June and from September to December. The mean absolute fecundity was estimated at 110.794 ± 7582 oocytes whereas relative fecundity was about 422 ± 26 oocytes per gram of female.

Changes in Growth and Reproduction of Harbour Porpoises, Phocoena phocoena, from the Bay of Fundy

1990 ◽  
Vol 47 (11) ◽  
pp. 2158-2163 ◽  
Author(s):  
Andrew j. Read ◽  
David E. Gaskin
Keyword(s):  
Sexual Maturity ◽  
Prey Availability ◽  
Simultaneous Increase ◽  
Bay Of Fundy ◽  
Commercial Fisheries ◽  
Phocoena Phocoena ◽  
Pronounced Change ◽  
Younger Age ◽  
Incidental Mortality ◽  
Growth And Reproduction

Changes in the growth and reproduction of harbour porpoises from the Bay of Fundy are described by comparing samples collected in 1969–73 and 1985–88. The most pronounced change was an increase in the length of calves, from 92.1 cm (SE 1.6) in 1969–73 to 108 cm (SE 1.3) in 1985–88. Females in 1985–88 attained sexual maturity at a significantly younger age (3.44 yr) and shorter length (143 cm) than females from the older sample (3.97 yr and 147 cm). These changes may be attributable to an increase in prey availability to individual porpoises. This presumed increase in prey availability may have resulted from a decrease in porpoise density caused by incidental mortality in commercial fisheries, a simultaneous increase in prey abundance, or a combination of these factors.

scholarly journals Reproductive aspects of the flyingfish, Hirundichthys affinis from the Northeastern coastal waters of Brazil

2015 ◽  
Vol 75 (1) ◽  
pp. 198-207 ◽  
Author(s):  
MR. Oliveira ◽  
MM. Carvalho ◽  
NB. Silva ◽  
ME. Yamamoto ◽  
S. Chellappa
Keyword(s):  
Sex Ratio ◽  
Coastal Waters ◽  
Sexual Maturity ◽  
Total Body Length ◽  
Gonadal Development ◽  
Biological Information ◽  
Gonad Maturation ◽  
Fishery Resource ◽  
Maturation Stages ◽  
Total Body

The epipelagic flyingfish, Hirundichthys affinis is a major artisanal fishery resource from the Northeastern coastal waters of Brazil. However, biological information about this species has been poorly documented. This paper presents data on the length-weight relationship, sex ratio, length at first sexual maturity, gonadal development and fecundity of H. affinis sampled from the coastal waters of Rio Grande do Norte, Brazil. The total body length and weight for both sexes ranged from 23.4 to 29.4 cm and from 89 to 188g, respectively. The allometric coefficient of males was 2.208 and that of females was 2.985, indicating negatively allometric growth. The sex ratio was 1M:1.6F thus differing from the expected ratio of 1:1 (χ2 = 18.63). The total length at first sexual maturity was estimated at 27.3 cm for males and 27.1 cm for females. The macroscopic characteristics of the gonads indicated four maturation stages. Histological studies of gonads of H. affinis showed seven phases of oocyte development and four phases of spermatocyte development. The mean absolute fecundity was 9092 vitelogenic oocytes. Spawning occurred during the months of March to July. The microscopic descriptions of the stages of gonad maturation indicate that the study area is an important spawning ground of H. affinis.

scholarly journals Estructura de la población del cangrejo rojo de manglar, Goniopsis cruentata (Decapoda: Grapsidae) bajo diferentes impactos de pesca: Implicaciones para la gestión de los recursos.

2015 ◽  
Vol 63 (2) ◽  
pp. 443 ◽  
Author(s):  
Gustavo L. Hirose ◽  
Laize S. Souza ◽  
Sonja L. R. Silva ◽  
Douglas F. R. Alves ◽  
Maria Lucia Negreiros-Fransozo
Keyword(s):  
Body Size ◽  
Sex Ratio ◽  
Sexual Maturity ◽  
Abiotic Factors ◽  
Mangrove Ecosystem ◽  
The Body ◽  
Sediment Surface ◽  
Brazilian Coast ◽  
Catch Per Unit Effort ◽  
Fishery Resource

<p>The red mangrove crab, <em>Goniopsis cruentata,</em> influences the recruitment and composition of plant species in the mangrove ecosystem and it is an important fishery resource. Nevertheless, no current management and conservation plans are available for this species for the Brazilian coast. This investigation evaluated the population structure and reproductive biology in populations of <em>G. cruentata</em> under contrasting fishery pressures. The sampling program was carried out in two mangroves, Vaza-Barris and Sergipe River, from January through December 2011. Crabs from both mangroves were randomly collected by a professional fisherman during daytime low tide periods, using a fishing rod baited with pieces of a locally abundant gastropod, <em>Pugilina morio</em>, during 20min/area (catch per unit effort). Monthly measurements of air, sediment surface layer and water temperatures were obtained with a digital thermometer and salinity with an optical refractometer. Both crab populations were compared concerning their abundance, body size, sex ratio, size at onset of sexual maturity and fecundity (FI). Abiotic factors (air, water and mud temperature; and salinity) showed no significant differences between sampling localities. A total of 4 370 crabs were sampled, 2 829 from the Sergipe River and 1 541 from the Vaza-Barris River. The abundance and body size of crabs were compared between mangroves, and statistically significant differences were found. The sex ratio for both populations differed from the expected 1:1 ratio, and a significant deviation in favor of juvenile males was obtained, while adults showed a bias toward females. The estimated size at onset of sexual maturity for both sexes was similar in both populations. However, the populations differed significantly in the number and volume of eggs: a higher FI was obtained in females from the Sergipe River, while a higher egg volume was observed in females from the Vaza-Barris River mangrove. These results indicated a tendency to decrease the body size, the abundance of crabs and the reproductive potential of the species, with higher fishing intensities, reinforcing the need to develop a management plan as well as to establish conservation units for <em>G. cruentata</em> in the Northeastern Brazilian coast. Habitat loss in conjunction with long-term overfishing can have irreversible consequences, which can impact not only the populations of commercially exploited crabs, but the dynamics of virtually the entire mangrove ecosystem.</p>

Age, growth, and reproduction in Hector's dolphins

1991 ◽  
Vol 69 (6) ◽  
pp. 1689-1700 ◽  
Author(s):  
Elisabeth Slooten
Keyword(s):  
Life History ◽  
Body Size ◽  
Sexual Maturity ◽  
Fishing Gear ◽  
Male And Female ◽  
Pulp Cavity ◽  
Traditional Procedure ◽  
History Of ◽  
Growth And Reproduction ◽  
Beach Cast

Data are provided on the reproductive biology and life history of Hector's dolphin, Cephalorhynchus hectori, a species found only in New Zealand waters. Samples were taken from 60 dolphins found beach-cast or killed incidentally in fishing gear. Male and female reproductive tracts were examined macroscopically and histologically, and tooth sections provided an age estimate for each individual. The traditional procedure for preparing dolphin teeth was simplified by using a faster stain and more readily available embedding and sectioning equipment. An important advantage of this method is that it facilitates the cutting of thinner sections, increasing the chances of obtaining a section through the centre of the pulp cavity. Sectioning revealed an open pulp cavity in all the teeth examined. The maximum observed age was 19 years for females and 20 years for males. Females reach a larger body size than males, and are apparently larger than males at any given age. Males appear to reach sexual maturity between 6 and 9 years of age, whereas females give birth to their first calf at 7–9 years of age. Mature males have extremely large testes relative to their body size. The largest male found in this study weighed 41.5 kg, with testes (including epididymides) totalling 1.21 kg.

Sex ratio and life history traits at reaching sexual maturity in the dioecious shrub Fuchsia parviflora: field and common garden experiments

2021 ◽  
pp. 1-6
Author(s):  
Jessica S. Ambriz ◽  
Clementina González ◽  
Eduardo Cuevas
Keyword(s):  
Natural Population ◽  
Sexual Maturity ◽  
Sex Ratios ◽  
Natural Populations ◽  
Common Garden ◽  
Common Garden Experiment ◽  
Trade Offs ◽  
Reproductive Biomass ◽  
Common Garden Experiments ◽  
Growth And Reproduction

Abstract Fuchsia parviflora is a dioecious shrub that depends on biotic pollination for reproduction. Previous studies suggest that the male plants produce more flowers, and male-biased sex ratios have been found in some natural populations. To assess whether the biased sex ratios found between genders in natural populations are present at the point at which plants reach sexual maturity, and to identify possible trade-offs between growth and reproduction, we performed a common garden experiment. Finally, to complement the information of the common garden experiment, we estimated the reproductive biomass allocation between genders in one natural population. Sex ratios at reaching sexual maturity in F. parviflora did not differ from 0.5, except in one population, which was the smallest seedling population. We found no differences between genders in terms of the probability of germination or flowering. When flowering began, female plants were taller than males and the tallest plants of both genders required more time to reach sexual maturity. Males produced significantly more flowers than females, and the number of flowers increased with plant height in both genders. Finally, in the natural population studied, the investment in reproductive biomass was seven-fold greater in female plants than in male plants. Our results showed no evidence of possible trade-offs between growth and reproduction. Despite the fact that female plants invest more in reproductive biomass, they were taller than the males after flowering, possibly at the expense of herbivory defence.

scholarly journals Morphological determinants of jumping performance in the Iberian green frog

2019 ◽  
Vol 66 (4) ◽  
pp. 417-424
Author(s):  
Gregorio Moreno-Rueda ◽  
Abelardo Requena-Blanco ◽  
Francisco J Zamora-Camacho ◽  
Mar Comas ◽  
Guillem Pascual
Keyword(s):  
Body Size ◽  
Body Mass ◽  
Fluctuating Asymmetry ◽  
Hind Limb ◽  
Limb Length ◽  
Age Classes ◽  
Jumping Performance ◽  
Hind Limbs ◽  
Selective Forces ◽  
Pelophylax Perezi

Abstract Predation is one of the main selective forces in nature, frequently selecting potential prey for developing escape strategies. Escape ability is typically influenced by several morphological parameters, such as morphology of the locomotor appendices, muscular capacity, body mass, or fluctuating asymmetry, and may differ between sexes and age classes. In this study, we tested the relationship among these variables and jumping performance in 712 Iberian green frogs Pelophylax perezi from an urban population. The results suggest that the main determinant of jumping capacity was body size (explaining 48% of variance). Larger frogs jumped farther, but jumping performance reached an asymptote for the largest frogs. Once controlled by structural body size, the heaviest frogs jumped shorter distances, suggesting a trade-off between fat storage and jumping performance. Relative hind limb length also determined a small but significant percentage of variance (2.4%) in jumping performance—that is, the longer the hind limbs, the greater the jumping capacity. Juveniles had relatively shorter and less muscular hind limbs than adults (for a given body size), and their jumping performance was poorer. In our study population, the hind limbs of the frogs were very symmetrical, and we found no effect of fluctuating asymmetry on jumping performance. Therefore, our study provides evidence that jumping performance in frogs is not only affected by body size, but also by body mass and hind limb length, and differ between age classes.

scholarly journals Phthalate metabolites in harbor porpoises (Phocoena phocoena) from Norwegian coastal waters

2020 ◽  
Vol 137 ◽  
pp. 105525 ◽  
Author(s):  
May Britt Rian ◽  
Kristine Vike-Jonas ◽  
Susana Villa Gonzalez ◽  
Tomasz Maciej Ciesielski ◽  
Vishwesh Venkatraman ◽  
...  
Keyword(s):  
Coastal Waters ◽  
Phocoena Phocoena ◽  
Phthalate Metabolites ◽  
Harbor Porpoises

II.—Hidden Divergence in Laboratory Strains of Drosophila pseudo-obscura

1944 ◽  
Vol 62 (1) ◽  
pp. 9-19 ◽  
Author(s):  
Rowena Lamy
Keyword(s):  
Body Size ◽  
Sex Ratio ◽  
Genetic Constitution ◽  
Low Grade ◽  
Testis Size ◽  
Hybrid Female ◽  
Back Cross ◽  
Pure Race ◽  
Range Of Variation

The Race A/Race B hybrid females of D. pseudo-obscura have a high percentage of fertility, comparable with that of females of pure race. The number and viability of their offspring, however, are largely affected by the genetic constitution of the hybrid female as well as by that of the male to which she is mated in the backcross. Hence the performance of any given hybrid is determined in the first instance by the actual strains of the pure races which are used in making the P1 racial cross. Generally speaking the results are of the same order whenever the same strains are used. The progenies of hybrid females of different genetic constitution may differ in three main aspects: (1) The total number of offspring may be comparable with that usually obtained in a pure race cross; it may be reduced to any extent; in certain matings it is consistently at zero. (2) The sex ratio may be completely normal or male-deficient or female-deficient in any degree; completely uni-sexual progenies are sometimes obtained. (The above observations are mainly in agreement with reports of earlier writers; cf. Lancefield, 1929, Dobzhansky, 1936, Mampell, 1941, Sturtevant, 1937.) (3) “Viability characters,” i.e. those affecting general vigour and physical normality, may be of a high or a low grade; some progenies are comparable in this respect with the pure race, the only exception being that they show a much greater range of variation in body-size of both sexes, and in the testis size of males, abnormalities which are common to all back-cross progenies whatever the genetic constitution of the mother or father. Some progenies show in addition deformities of a peculiar type usually affecting the abdomen and occasionally the legs and wings.

Variation in Weight, Size, and Sex Ratio of Coccinellid Adults (Coleoptera: Coccinellidae)

1966 ◽  
Vol 98 (6) ◽  
pp. 639-644 ◽  
Author(s):  
B. C. Smith
Keyword(s):  
Body Size ◽  
Sex Ratio ◽  
Water Content ◽  
Food Supply ◽  
Sexual Differences ◽  
Intraspecies Variation ◽  
Food Scarcity ◽  
Food Requirement ◽  
Males And Females

AbstractThe weight and size of coccinellid adults varied with species, sex, and feeding. Intraspecies variation in weight was generally similar in the eight species studied. Females were more variable than males in body size. Females of some species were heavier and larger than males, and species can be classified on a basis of difference in the weight and size of the sexes.An increase in the food supply after a period of food scarcity affected the sex ratio, as the minimum food requirement of females was greater than males. Females increased in weight more rapidly than males after feeding. The availability of food in the field affected the weight and size of some species. Adult water content was influenced by feeding but not by sex or the quantity of food given to the larva.Males were more abundant in species with small sexual differences in weight and size. The degree of difference in weight and size between males and females may be used as a criterion to select species that are best adapted to survive when food is scarce.

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