Reproductive cycle of the common guitarfish, Rhinobatos rhinobatos (Linnaeus, 1758), in Alexandria waters, Mediterranean Sea

1993 ◽  
Vol 44 (3) ◽  
pp. 507 ◽  
Author(s):  
SH Abdel-Aziz ◽  
AN Khalil ◽  
SA Abdel-Maguid
Keyword(s):  
Embryonic Development ◽  
Mediterranean Sea ◽  
Reproductive Cycle ◽  
Egg Size ◽  
Gonadosomatic Index ◽  
Maximum Size ◽  
Reproductive Rate ◽  
Gestation Period ◽  
Monthly Basis ◽  
The Common

The common guitarfish, Rhinobatos rhinobatos, is an ovoviviparous fish having a gestation period of about nine months and a mean reproductive rate of 8 to 14 progeny per pregnancy. Data on gonadosomatic index, maximum ovum diameter, size frequency of ova, and ovarian and uterine contents for 438 specimens (236 females and 202 males), analysed on a monthly basis, indicated a distinct seasonal reproductive cycle for R. rhinobatos. Females reached a maximum size of 181 cm and 20 kg, whereas the maximum size of males was 172 cm and 16 kg. Lengths at which 50% of specimens were mature were 87 and 70 cm for females and males, respectively. Ovarian egg size and male gonadosomatic index both peaked in July and August, indicating that mating occurred in summer. Uterine eggs were present from late February through July, but no embryonic development was evident. Females with full-term embryos were observed in late August, and parturition was followed immediately by ovulation. Ovarian fecundity ranged from 8 to 27 (mean 18) eggs per fish, whereas uterine fecundity ranged from 8 to 14 (mean 12) eggs or embryos per fish.

scholarly journals Reproductive biology of the crab Munida subrugosa (Decapoda: Anomura: Galatheidae) in the Beagle Channel, Argentina

2002 ◽  
Vol 82 (4) ◽  
pp. 589-595 ◽  
Author(s):  
Federico Tapella ◽  
Gustavo A. Lovrich ◽  
M. Carolina Romero ◽  
Sven Thatje
Keyword(s):  
Embryonic Development ◽  
Reproductive Cycle ◽  
Carapace Length ◽  
Gonadosomatic Index ◽  
Maximum Size ◽  
Average Diameter ◽  
Female Size ◽  
Physiological Maturity ◽  
Beagle Channel ◽  
Maximum Value

Munida subrugosa was sampled monthly from November 1997 to November 1999 in the Beagle Channel by means of an epibenthic trawl. The reproductive cycle started in May, reflected by the occurrence of ovigerous females. Maximum size of oocytes, maximum value of gonadosomatic index in females (16·8 g mm carapace length [CL]−1) and males (1·6 g mm CL−1), and the proportion (∼70%) of ovigerous females with full egg-clutches occurred in June. Since the proportion of ovigerous females in October was ∼5% and the planktonic larvae reportedly hatch in September, the embryonic development lasted ∼90–120 days. Females and males attained physiological maturity at 9·9 and 8·0 mm CL respectively, and males reached morphometric maturity at 24·4 mm CL. Fecundity was correlated with female size (r=0·85) and was between 124 and 10,750 eggs per female. Average diameter of recently extruded eggs was 0·69 mm (SD±0·06 mm). At the beginning of the reproductive cycle, ovigerous females had partial broods of ∼300 eggs, which represented <5% of complete clutch.

Observations on the biology of the common torpedo (Torpedo torpedo, Linnaeus, 1758) and marbled electric ray (Torpedo marmorata, Risso, 1810) from Egyptian Mediterranean waters

1994 ◽  
Vol 45 (4) ◽  
pp. 693 ◽  
Author(s):  
SH Abdel-Aziz
Keyword(s):  
Reproductive Biology ◽  
Breeding Season ◽  
Reproductive Cycle ◽  
Strong Correlation ◽  
Maximum Size ◽  
Size At Maturity ◽  
Torpedo Marmorata ◽  
Food Items ◽  
The Common ◽  
Males And Females

The reproductive biology and diets of Torpedo torpedo and T. marmorata from Egyptian Mediterranean waters are described. Males and females reached a maximum size of 39.1 and 40.8 cm total length (TL), respectively, in T. torpedo and 38.6 and 61.2 cm TL, respectively, in T. marmorata. The size at maturity of males of T. torpedo and T. marmorata is 18 and 25.5 cm TL, respectively, and of females, is 22 and 35.5 cm TL, respectively. Both species exhibit aplacental viviparity. T. torpedo has a restricted breeding season, and individual females appear to breed annually, whereas T. marmorata females appear to have a more extended reproductive cycle (probably breeding every two years). In both species, males are capable of mating every year. In T. torpedo, mating occurs between December and February, ovulation in March-April, and parturition in late August and September after five to six months of gestation. Individuals of T. marmorata mate between November and January, ovulate between December and February, and give birth the following December after 10-12 months of gestation. Mean embryos sizes are 7.3 cm TL (range 4.6-8.2 cm TL) for T. torpedo and 8.5 cm TL (range 5.8-10.1 cm TL) for T. marmorata. Observations in Egyptian Mediterranean waters show a strong correlation between ovarian and uterine fecundity and the length of the mother in both species. Fish are an important component of the diet of the two species, as, to a lesser extent, are crustaceans for T. torpedo and cephalopods for T. marmorata. Juveniles eat a wide variety of food items, whereas adults feed only on fish.

scholarly journals Permanent germinal epithelium and reproductive cycle of tropical gar Atractosteus tropicus males (Lepisosteiformes: Lepisosteidae), Tabasco, Mexico

2016 ◽  
Vol 64 (4) ◽  
Author(s):  
Otilio Méndez Marin
Keyword(s):  
Reproductive Cycle ◽  
Gonadosomatic Index ◽  
Basic Knowledge ◽  
Germinal Epithelium ◽  
Seminiferous Tubules ◽  
Class Iii ◽  
Wild Populations ◽  
Monthly Basis ◽  
Early Maturation ◽  
Tropical Gar

Tropical gar A. tropicus plays an important ecological role, as a regulator of other fish stocks, in the water bodies of Mexico but their wild populations are being reduced. One conservation alternative is breeding which requires the study of germ and somatic structures of testis to characterize the reproductive cycle, basic knowledge required to create exploitation and conservation models. Three sexually mature males were captured on a monthly basis (N=24), in wild populations of Pomposu lagoon, municipality of Jalpa de Mendez (18°19'59" N - 93°01'12" W), Tabasco, Mexico. The capture technique was trawl net; they were transported live to the Tropical Aquaculture Laboratory, DACBiol, UJAT. Males were sacrificed by decapitation; testis fragments from all of the specimens collected were processes using a routine histological procedure, that consisted of dehydration for ascending etanol series, xylol, and inclusion in paraffin, with a sliding microtome 7µm thick cuts, and were dyed with hematoxylin-eosin (HE). The diameter of 20 seminiferous tubules (Tse), height of germinal epithelium (Egl), gonadosomatic index (GSI) and gonad volume (Gv) were determined on a monthly basis, as well as the gonadosomatic index GSI=PG/PT(100) and the gonad volume vG=4/3 pa2.b. Morpho-physiological characteristics of the testis show that it consists of a network of tubules anastomosed with non-restricted cystic spermatogenesis, and a permanent germinal epithelium. As far as we are concerned, this is the first time that this type of epithelium is reported in Holostei (Lepisosteiformes: Lepisosteidae). Five reproductive classes were identified: Class I Recrudescence, Class II Early Maturation, Class III Intermediate Maturation, Class IV Advanced Maturation, Class V Regression, that when contrasted with the monthly value of the "GSI, GV, Tse" sexual indicators it shows a variation pattern: January-February shows low values with empty testis, with discontinuous germinal epithelium in regeneration; in March spermiogenesis increased and spermatogenesis decreased. Generally speaking, these variations show that at a population level they do not mature synchronously, but with an annual seasonal reproductive cycle with spermatogenesis throughout the year, where temperature and precipitation seem to play an important role as a factor that stimulates reproductive activity and therefore spermiation.

scholarly journals Identifikasi dan siklus hidup chydoridae (Cladocera) di Perairan Sulawesi Utara

2018 ◽  
Vol 6 (3) ◽  
Author(s):  
Henneke Pangkey ◽  
Revol D. Monijung ◽  
Rose Mantiri ◽  
Sartje Lantu
Keyword(s):  
Life Cycle ◽  
Embryonic Development ◽  
Egg Production ◽  
Egg Size ◽  
Maximum Size ◽  
Adult Size ◽  
Entire Life ◽  
Entire Life Cycle ◽  
Average Size ◽  
Length Of Life

The purpose of this study was to identify chydoridae using conservative way, while the observations of the life cycle was done through a microscope to determine the egg production per parent and length of life. Individual chydoridae acclimatized to reach 10 generations (1 month), and 10 females were isolated for the production of seedlings. Based on literatures review, chydoridae used was derived from subfamily Aloninae (Alona spp.); while studies on the life cycle found: the egg size of chydoridae 150.2 ± 22.4 μm, and neonates have an average size of 291.82 ± 3.06 μm, and reached adult size after 2.3 ± 0.5 days, with an average size of 441.22 ± 10.2 μm. Time of embryonic development occured for 1-2 days. On the entire life cycle, only 2 eggs could be produced per individual. Based on this study, the number of eggs produced by the female during its lifetime ranges between 30-60 eggs. Similarly, the length of life of this organism on average 47.2 ± 11.7 days, with the longest lifespan was achieved 60 days. It was found also the maximum size was 1,037 ± 8.5 mm; while the average size of an organism's body was 800.42 ± 56.3 μm.Keywords: chydoridae, identification, life cycle, Alona spp

Delayed ovulation and parturition in a viviparous alpine lizard (Niveoscincus microlepidotus): morphological data and plasma steroid concentrations

2002 ◽  
Vol 14 (1) ◽  
pp. 43 ◽  
Author(s):  
J. E. Girling ◽  
S. M. Jones ◽  
R. Swain
Keyword(s):  
Reproductive Cycle ◽  
Early Pregnancy ◽  
Post Partum ◽  
Maximum Size ◽  
Morphological Data ◽  
Monthly Basis ◽  
Plasma Progesterone ◽  
Plasma Oestradiol ◽  
Winter Hibernation ◽  
Detailed Picture

The southern snow skink, Niveoscincus microlepidotus, exhibits an unusual biennial reproductive cycle with an extended gestation period of approximately 1 year. Morphological data were gathered on a monthly basis, providing a detailed picture of the reproductive cycle. Vitellogenesis begins in spring, immediately after parturition. Maximum follicular diameter is reached before the winter hibernation period and ovulation occurs the following spring. Embryos are fully developed and reach maximum size by early autumn. Yolk reserves are depleted before winter. Birth of between one and four young occurs the following spring. Plasma progesterone concentrations are low (2.7 ± 0.9 ng mL–1) in post-partum females, begin to rise in autumn in vitellogenic females and peak (38.5 ± 7.9 ng mL–1) in pre-ovulatory females after hibernation. Concentrations are high (15.4 ± 5.9 ng mL–1) in early pregnancy and decline to basal levels before winter and well before birth in spring. Plasma oestradiol concentrations peak during vitellogenesis (1.0 ± 0.3 ng mL–1) and decline to basal levels during pregnancy (0.2 ± 0.03 ng mL–1). A second oestradiol peak occurs before parturition (0.7 ± 0.2 ng mL–1). Thus, functional completion of vitellogenesis and gestation is achieved by autumn in successive years. The mechanisms that defer ovulation and parturition by a further six months are unknown.

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.

Reproduction in the common sheath-tailed bat, Taphozous georgianus (Thomas) (Microchiroptera : Emballonuridae), in Western Australia

1973 ◽  
Vol 21 (3) ◽  
pp. 375 ◽  
Author(s):  
DJ Kitchener
Keyword(s):  
Corpus Luteum ◽  
Western Australia ◽  
Reproductive Tract ◽  
Vas Deferens ◽  
Gestation Period ◽  
Early Winter ◽  
Male And Female ◽  
The Common ◽  
The Right

The reproductive and associated organs of both male and female T. georgianus are briefly described. In females, only the right ovary is functional and pregnancies occur only in the right horn. They are monovular and the corpus luteum occupies most of the ovary and is deeply embedded in its stroma. Females are monotocous and the gestation period is probably about 4 months, young being born from October to February. They are monestrous and there is an autumn and early winter dioestrousanoestrous period. Spermatozoa are not stored in the reproductive tract of females and copulation appears to coincide with the oestrous condition. In males, spermatogenesis proceeds throughout the year and spermatozoa are present in the epididymis and vas deferens in all months that males were collected (no records for December). Spermatozoa are also found in the ampulla of Henle and vesicula seminalis in most months of the year. The position of the testes varies with season: in summer they descend to the scrota1 sacs; in autumn, winter, and spring they are more abdominal.

Zebrafish (Danio rerio) and the egg size versus egg number trade off: effects of ration size on fecundity are not mediated by orthologues of the Fec gene

2010 ◽  
Vol 22 (6) ◽  
pp. 1015 ◽  
Author(s):  
Erin L. Forbes ◽  
Craig D. Preston ◽  
P. Mark Lokman
Keyword(s):  
Danio Rerio ◽  
Egg Size ◽  
Egg Quality ◽  
Quantitative Polymerase Chain Reaction ◽  
Gonadosomatic Index ◽  
Hatching Rate ◽  
Mrna Levels ◽  
Trophic Conditions ◽  
Trade Off ◽  
Ration Size

Few studies have demonstrated plasticity of egg size within the confines of an egg size–number trade-off in response to trophic conditions in fishes. Moreover, the physiological mechanisms that govern this plasticity are not known. Growth differentiation factor 9 (Gdf9) and bone morphogenetic factor 15 (Bmp15) are oocyte-specific factors implicated in follicular growth and ovulation in mammals. In order to investigate whether expression levels of these genes were correlated with ration-dependent changes in fecundity in fish, zebrafish (Danio rerio) were subjected to four different feeding regimens. Counts of spawned eggs or vitellogenic follicles were used to estimate fecundity, whereas quantitative polymerase chain reaction analyses were performed to determine Gdf9 and Bmp15 mRNA levels in response to changes in ration size. Both relative fecundity and gonadosomatic index increased significantly with increased ration size, whereas egg size and hatching rate decreased significantly. No significant differences in Gdf9 or Bmp15 transcript abundance were evident between feeding regimens, suggesting that these growth factors do not govern fecundity in fish. However, favourable trophic conditions markedly affected follicle or egg size and number, with important implications for downstream egg quality and survival.

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