scholarly journals Morphohistological studies of the gonads of hybrid polyploid loach cobitis from the Lower Dniester

2021 ◽  
Author(s):  
Nina Fulga ◽  
◽  
Laurentia Ungureanu ◽  
Dumitru Bulat ◽  
Denis Bulat ◽  
...  
Keyword(s):  
Germ Cells ◽  
Gonadosomatic Index ◽  
Spawning Season ◽  
Relative Mass ◽  
Breeding Period ◽  
Water Basin ◽  
Asynchronous Development ◽  
Hybrid Complex ◽  
Cobitis Taenia

In the lower Dniester, polyploid females of the hybrid complex Cobitis taenia are a portion spawning species with asynchronous development of germ cells during the entire breeding period. The spawning season in this water basin begins in the second decade of May and ends in July. In the population, in parallel with females, hermaphrodite individuals are also present, in which the ovary zone is functional, and the testis zone is sterile. A decrease in the relative mass of the gonads of subsequent generations was noted, which leads to a consistent decrease in the value of the gonadosomatic index, in females, before the second and third spawning.

scholarly journals Clonal gametogenesis is triggered by intrinsic stimuli in the hybrids germ cells but is dependent on sex differentiation

2021 ◽  
Author(s):  
Tomas Tichopad ◽  
Roman Franek ◽  
Marie Dolezalkova Kastankova ◽  
Dmitrij Dedukh ◽  
Anatolie Marta ◽  
...  
Keyword(s):  
Stem Cells ◽  
Germ Cells ◽  
Sex Differentiation ◽  
Asexual Development ◽  
Triploid Hybrid ◽  
Intrinsic Signals ◽  
Gonadal Tissue ◽  
Hybrid Complex ◽  
Cobitis Taenia ◽  
Regular Meiosis

Interspecific hybridization may trigger the transition from sexual reproduction to asexuality, but mechanistic reasons for such a change in a hybrids reproduction are poorly understood. Gametogenesis of many asexual hybrids involves a stage of premeiotic endoreduplication (PMER), when gonial cells duplicate chromosomes and subsequent meiotic divisions involve bivalents between identical copies, leading to production of clonal gametes. Here, we investigated the triggers of PMER and whether its induction is linked to intrinsic stimuli within a hybrids gonial cells or whether it is regulated by the surrounding gonadal tissue. We investigated gametogenesis in the Cobitis taenia hybrid complex, which involves sexually reproducing species (Cobitis elongatoides and C. taenia) as well as their hybrids, where females reproduce clonally via PMER while males are sterile. We transplanted spermatogonial stem cells (SSCs) from C. elongatoides and triploid hybrid males into embryos of sexual species and of asexual hybrid females, respectively, and observed their development in an allospecific gonadal environment. Sexual SSCs underwent regular meiosis and produced normally reduced gametes when transplanted into clonal females. On the other hand, the hybrids SSCs lead to sterility when transplanted into sexual males, but maintained their ability to undergo asexual development (PMER) and production of clonal eggs, when transplanted into sexual females. This suggests that asexual gametogenesis is under complex control when somatic gonadal tissue indirectly affects the execution of asexual development by determining the sexual differentiation of stem cells and once such cells develop to female phenotypes, hybrid germ cells trigger the PMER from their intrinsic signals.

scholarly journals Analysis of reproductive biology and spawning season of the pink ear emperor Lethrinus lentjan, from marine ecosystem

2020 ◽  
Vol 37 ◽  
pp. 1-10
Author(s):  
Elsayed M. Younis ◽  
Nasser A. Al-Asgah ◽  
Abdel-Wahab A. Abdel-Warith ◽  
Mohamed H. Gabr ◽  
Fozi S. Shamlol
Keyword(s):  
Fish Species ◽  
Gonadosomatic Index ◽  
Marine Ecosystem ◽  
Local Population ◽  
Spawning Season ◽  
Monthly Basis ◽  
Population Sampling ◽  
Maturation Rate ◽  
Maturation Index ◽  
One Year

A total of 593 samples of Lethrinus lentjan (Lacepede, 1802) were collected from the Red Sea, Jeddah, Saudi Arabia, to study their productive biology and spawning season of the local population. Sampling was carried out on a monthly basis for a period of one year. The monthly sex ratios indicated that females were dominant throughout the study period, with an overall male:female sex ratio of 1:7.98, although males were larger than females. The highest monthly performance maturation index (PMI), as well as the male and female gonadosomatic index (GSI) and ovarian maturation rate (OMR) were observed in February and March. Histological examination of the gonads confirmed the process of sexual transformation in this fish species, wherein individuals mature first as female, and then change sex to male (protogynous hermaphroditism). Histological sections also showed that the sexual maturation of males of L. lenjtan comprised three main stages, while the sexual development of females could be classified into four main stages. Extended spawning in the form of batches released during different months throughout the year were recorded for this fish species, with the main spawning season in February and March, and an additional, shorter spawning season in September.

scholarly journals Seasonal variations in the population biology of Salmostoma bacaila (Cyprinidae) from a tributary of the Payra River, Bangladesh

2019 ◽  
pp. 113-119
Author(s):  
Ahamed Ahamed ◽  
Faruque Ahmed Zoarder ◽  
Jun Ohtomi
Keyword(s):  
Sex Ratio ◽  
Seasonal Variations ◽  
Population Biology ◽  
Sexual Maturity ◽  
Condition Factor ◽  
Gonadosomatic Index ◽  
Spawning Season ◽  
Frequency Distributions ◽  
Size At Sexual Maturity ◽  
Management And Conservation

Some biological parameters of Salmostoma bacaila – including sex ratio, length-frequency distributions (LFDs), size at sexual maturity, spawning season, length-weight relationships (LWRs) and condition factor – were studied. Samples were collected seasonally during June 2017 to May 2018 from a tributary of the Payra River. The overall sex ratio was significantly different from the expected value of 1:1 (p < 0.001), in favour of male specimens. Females were significantly larger than males. Size at sexual maturity was estimated at 7.6~7.7 cm total length. Seasonal variations in the gonadosomatic index (GSI) indicate that the main spawning season is from spring to summer. The LWRs showed negative allometric growth in both sexes, but with clear seasonal variation. Fulton’s condition factor varied in both sexes and was attributed to variations in GSI with maturity. The fin¬dings of this study will be helpful for management and conservation of S. bacaila populations.

Gonadal cycle of the blue crab Portunus segnis (Forskål, 1775) (Decapoda, Portunoidea) in the Mediterranean Sea off Alexandria, Egypt

Crustaceana ◽  
2021 ◽  
Vol 94 (1) ◽  
pp. 1-27
Author(s):  
Ibrahim Gaber ◽  
Mauro Luisetto ◽  
Oleg Latyshev
Keyword(s):  
Mediterranean Sea ◽  
Germ Cells ◽  
Vas Deferens ◽  
Gonadosomatic Index ◽  
Sex Ratios ◽  
Stage Iv ◽  
Hepatosomatic Index ◽  
Chi Square ◽  
The Mediterranean ◽  
Portunus Segnis

Abstract Adults of Portunus segnis were captured from Ras el Tin beach on the Mediterranean Sea at Alexandria, Egypt, from January to December 2017. Male crabs are present in higher density in the sea during fall and winter, while female crabs are more common during spring and summer. Sex ratios were calculated as follows: number of males or females/total number of crabs. The calculated sex ratios were subjected to a Chi-square test according to the equation: , where O represents the observed frequency and E the expected frequency. One-way analysis of variance shows differences in the carapace size (length and width) and the weight of males and females during the four seasons. The hepatosomatic index of male crabs ranges from 9.1-9.25 in winter months, 8.7-7.9 in fall, being lower, 3.12-2.25, in spring and 5.96-4.13 in summer. The hepatosomatic index of female crabs is 8.9-3.9 in spring, 9.2-7.9 in summer, shifts lower to 5.1-3.2 in fall and to 4.2-1.5 in winter. The gonadosomatic index of female crabs is 0.12-8.2 in spring, 0.20-13.9 in summer and decreases to 0.66-7.8 in fall and 0.18-4.7 in winter. Ovaries and testes were isolated, fixed, and prepared for histological examination. The testicular lobes are surrounded by simple epithelium with haemolymph filling the interspaces. Seminiferous ducts are inserted in the testicular lobes. Spermatogenesis and spermiogenesis are described. The vas deferens is usually filled with spermatophores. Spermatophore formation begins in the testis near the vas deferens. Near the base of the penes there is glandular tissue. This study proposes the classification of the ovarian maturation into five stages: Stage I, Immature ovary with primary and secondary oogonia; Stage II, early maturing ovary with germ cells in different maturation phases; Stage III, mature ovary with vitellogenic oocytes and germ cells; Stage IV, maturing ovary with oocytes I, II and fully mature oocytes; and Stage V, ovary in regeneration. The wall of the spermatheca consists of a stratified squamous epithelium.

Sexual Maturity, Spawning Periodicity and Fecundity of Obtuse Barracuda Sphyraena obtusata (Cuvier, 1829) along Karnataka Coast, Southeastern Arabian Sea

2021 ◽  
Author(s):  
M.M. Meshram ◽  
Mridula Rajesh ◽  
K.M. Rajesh ◽  
N.K. Suyan
Keyword(s):  
Gonadosomatic Index ◽  
Management Strategies ◽  
Gravimetric Method ◽  
Reproductive Traits ◽  
Breeding Period ◽  
Southeastern Arabian Sea ◽  
Spawning Periodicity ◽  
Gravid Females ◽  
First Maturity ◽  
Management And Conservation

Background: The success or failure of spawning in any population affects the fishery. Hence, studies on spawning, maturation, fecundity and length at first maturity become essential in drafting management strategies. The detailed information on reproductive traits of Sphyraena obtusata will be helpful in sustainable management and conservation in the study area. Methods: Three hundred and fifty five specimens of S. obtusata were collected fortnightly from Mangaluru and Malpe fishing harbors during August 2019 to March 2020. Maturity of gonads was examined by macroscopic and histological investigations. Spawning periodicity was worked out based on maturity stages and seasonal gonadosomatic index. Gravimetric method of analysis was employed to evaluate the fecundity from randomly collected samples of gravid females. Result: Overall sex ratio revealed that the population had significantly higher (p less than 0.05, X2 test) proportion of females than males. The length at 50% maturity (Lm50) for females and males was estimated at 21.1 and 21.5 cm respectively. The gonadosomatic index (GSI) and the availability of matured individuals for both the sexes in various percentage indicated a prolonged breeding period from October to March with peaks in November and December. The absolute fecundity varied from 91,942 eggs (20.0 cm TL) to 1,34,445 eggs (27.0 cm TL) with an average of 1,12,878 ± 2,984 hydrated oocytes per female.

Gonadal Maturation and Histological observations of S. curvifrons in River Jhelum Kashmir

2018 ◽  
Author(s):  
Sauliheen Qadri ◽  
Tasaduq H Shah ◽  
M. H. Balkhi ◽  
Bilal A. Bhat ◽  
F. A. Bhat ◽  
...  
Keyword(s):  
Gonadosomatic Index ◽  
Gonadal Development ◽  
Spawning Season ◽  
Gonadal Maturation ◽  
Maturity Stages ◽  
Preparatory Phase

The objective of the present study is to describe the phases of gonadal development and determine the spawning season of Schizothorax curvifrons in River Jhelum Kashmir. A total of 298 fish specimen were studied to analyse the gonadosomatic index and maturity stages of S. curvifrons. Five maturity stages namely Immature phase, Preparatory phase, Maturing phase, Ripe/spawning phase and Spent phase were observed in the gonads. Based on GSI values and gonadal conditions, April to June appears to be the spawning season for S. curvifrons

The sexuality and spawning of Manx Pectinids

1962 ◽  
Vol 42 (3) ◽  
pp. 683-703 ◽  
Author(s):  
Kosaraju Reddiah
Keyword(s):  
Comparative Study ◽  
Germ Cells ◽  
Large Scale ◽  
Life Time ◽  
Sex Reversal ◽  
The Other ◽  
Breeding Cycle ◽  
Breeding Period ◽  
Short Period ◽  
Spawning Periods

The results of a comparative study of the breeding biology of the Manx pectinids with special reference to Chlamys varia, C. distorta, C. tigerina, C. striata and C. furtiva are presented.It is shown that C. varia and C. distorta are protandric hermaphrodites with separate sexual phases similar to those of oysters, and evidence is presented on the possibility of sex reversal. The other species, C. tigerina, C. striata and C. furtiva, are truly dioecious, possessing at no stage germ cells of both sexes in the same gonad and as most individuals produce only one brood, the possibility of sex reversal is excluded.C. distorta has two large-scale or peak spawning periods, once in summer and for the second time in autumn, although some spawning occurs as a rule in most months of the year. The breeding behaviour of this species is intermittent and therefore the breeding period is prolonged.C. varia has two mass spawnings in a year, once in June and for the second time during September and October and the breeding period is not markedly different from that observed in French waters. Spawning is usually completed within a short period. C. tigerina and C. striata spawn only once annually in June and August respectively and most individuals have only one breeding cycle during their life time. C. furtiva however, may have two spawnings in a year, but the material available was inadequate to confirm this.

Reproduction and growth of the spiny lebbeid shrimp, Lebbeus groenlandicus (Fabricius, 1775) (Caridea, Hippolytidae) in the East Sea of Korea

Crustaceana ◽  
2014 ◽  
Vol 87 (11-12) ◽  
pp. 1430-1446 ◽  
Author(s):  
Ho Jin Bae ◽  
Chul-Woong Oh
Keyword(s):  
Gonadosomatic Index ◽  
Growth Function ◽  
East Sea ◽  
Breeding Period ◽  
Female Ratio ◽  
Von Bertalanffy Growth Function ◽  
Significant Difference ◽  
Male Female Ratio ◽  
Regression Slopes ◽  
Egg Stages

Reproduction and growth of the spiny lebbeid shrimp, Lebbeus groenlandicus (Fabricius, 1775), were investigated based on samples in the East Sea of Korea [= Sea of Japan], from January 2012 to April 2013. We collected 2964 shrimp samples during the study period, which included significantly more females than males (male : female ratio, 1.0 : 1.17). The females were generally larger than the males, and significant differences in the linear-regression slopes of carapace length (CL) versus body weight between the sexes indicate sex-specific differences in allometric growth. The gonadosomatic index (GSI) varied monthly, reaching a maximum in November 2012 (10.28) and a minimum in March 2013 (2.15). The proportion of ovigerous females varied from month to month. The highest values of the GSI coincided with the breeding period, and there was a significant difference between the mean GSI of females with non-eyed and those with eyed eggs, indicating that L. groenlandicus is a consecutive breeder. There was a significant correlation between CL and the number of eggs (EN) in the early egg stages. There was also a significant difference in the slopes of the regressions of CL versus EN between females carrying non-eyed and eyed egg stages. Based on the dry weights in the early egg stages, reproductive output was determined to be 0.18 ± 0.006. The Von Bertalanffy growth function parameters were CL∞ = 38.80 mm, year−1, , and WP = 0.4 for males, and CL∞ = 43.64 mm, year−1, , and WP = 0.6 for females. The growth performance index () was 2.86 for males and 2.89 for females.

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