scholarly journals Reproduction of the Brazilian snapper, Lutjanus alexandrei Moura & Lindeman, 2007 (Perciformes: Lutjanidae), off the northern coast of Pernambuco, Brazil

2012 ◽  
Vol 10 (3) ◽  
pp. 587-592 ◽  
Author(s):  
Cezar A. F. Fernandes ◽  
Paulo G. V. de Oliveira ◽  
Paulo E. P. Travassos ◽  
Fábio H. V. Hazin
Keyword(s):  
Sex Ratio ◽  
Sexual Maturity ◽  
Gonadosomatic Index ◽  
Northern Coast ◽  
Batch Fecundity ◽  
Spawning Behavior ◽  
Spermatogenic Cells ◽  
Maturity Stages ◽  
Microscopic Evaluation ◽  
Batch Spawning

Reproductive aspects of the Brazilian snapper Lutjanus alexandrei, were characterized, including a description of the development of oocytes and spermatogenic cells, size at first sexual maturity, and fecundity. A total of 540 fish were analyzed with 250 having their gonads sectioned to allow microscopic evaluation. Six maturity stages were identified for females and males: immature, maturing, mature, spawning, spawned, and resting. Fish standard length (SL) varied from 13.0 to 28.3 cm and sex ratio was 1.6 males: 1.0 females. Monthly distributions of mean Gonadosomatic Index (GSI) and maturity stages suggest that spawning occurs mainly in a protracted period, during the warmer months, from November to March. The size of first sexual maturity was estimated at 17.1 cm SL for females and 16.8 cm SL for males. Oocyte development suggests that L. alexandrei exhibits a multiple batch spawning behavior and batch fecundity varied from 34,000 to 324,000 oocytes.

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.

scholarly journals REPRODUCTIVE BIOLOGY OF THE SPINY EEL MACROGNATHUS PANCALUS HAMILTON, 1822 FROM UPPER ASSAM, INDIA

2020 ◽  
Vol 67 (1) ◽  
Author(s):  
S.K. Abujam ◽  
S.P. Biswas
Keyword(s):  
Sexual Dimorphism ◽  
Sex Ratio ◽  
Reproductive Biology ◽  
Body Shape ◽  
Gonadosomatic Index ◽  
Percentage Distribution ◽  
Relative Fecundity ◽  
Absolute Fecundity ◽  
Maturity Stages ◽  
Fish Samples

Reproductive biology of spiny eel Macrognathus pancalus Hamilton, 1822 was studied from the waterbodies of upper Assam, India. Sexual dimorphism was easily distinguished based on their body shape and colouration. Among the 467 fish samples examined, 312 males and 155 females were identified and the Male:Female (M:F) ratio ranged from 1:0.08 in November to 1:2.17 in June with overall sex ratio of 1:0.5. Five maturity stages were identified in a year and percentage distribution of each stage was calculated. The gonadosomatic index (GSI) ranged from 0.42 to 8.08 for females and from 0.33 to 1.25 for males. The length at 50% of the fishes attained maturity (Lm50) was 9-12 cm in males and at 12-15 cm in females, indicating males matures at moderately smaller size than their female counterparts. Ova diameter ranged from 0.3 to 1.3 mm; absolute fecundity ranged from 765.48 to 1691.96 and relative fecundity from 57.9 to 152.17. M. pancalus spawned once in a year with peak spawning between June and August.

scholarly journals Parámetros biológicos básicos para la conservación de Pseudocurimata lineopunctata (Characiformes, Curimatidae) en el Río Anchicayá, Valle del Cauca, Colombia

2016 ◽  
Vol 65 (1) ◽  
pp. 239
Author(s):  
Sandra Lamouroux-López ◽  
Merling López ◽  
Hector Ricardo Flores Gatica
Keyword(s):  
Sex Ratio ◽  
Sexual Maturity ◽  
Extinction Risk ◽  
Gonadosomatic Index ◽  
Weight Ratio ◽  
Biological Data ◽  
Minimum Size ◽  
Ratio Distribution ◽  
Fish Samples ◽  
June July

Pseudocurimata lineopunctata represents an important nutritional source for local human communities in Colombia and Ecuador. Although the yearly catch of this fish is low (590 kg/year), there are no restrictions on minimum size, and this species is categorized as vulnerable with moderate extinction risk by the Regional Autonomous Corporation of the Cauca Valley (Colombia). To support conservation programs, biological data of the target species are required. Therefore, the aims of this study were to describe the sex ratio, distribution, size to weight ratio, macroscopic stages of reproductive maturity, fecundity, and size at first sexual maturity for P. lineopunctata. For this, fish samples were captured with nets over nine months (February-October) in 2007. The total length (Lt) of the captured fish ranged between 10.7 and 16.5 cm, with total weight (Pt) between 25.0 and 67.5 g. Females represented 52.6 % of the sample group while males represented 47.4 %, and differences in sex ratio were observed in relation to fish size. For all sampled months, the fish captured showed an advanced maturity state. Based on analyses of the gonadosomatic index (IGS), gonadic index (IG), and Fulton’s condition factor (K), and two spawning peaks were determined, one in June-July, and the other in September-October. The size at first sexual maturity was 9.2 cm for females and 10.1 cm for males. Absolute fecundity was estimated as 3 598 oocytes/g♀. It is necessary to carry out additional investigations on the reproduction of this species, to support future repopulation programs.

scholarly journals Population structure and growth of the hermit crab Pagurus brevidactylus (Anomura: Paguridae) from the northern coast of São Paulo, Brazil

2005 ◽  
Vol 85 (1) ◽  
pp. 127-128 ◽  
Author(s):  
F.L. Mantelatto ◽  
R.A. Christofoletti ◽  
W.C. Valenti
Keyword(s):  
Population Structure ◽  
Sex Ratio ◽  
Hermit Crab ◽  
Sexual Maturity ◽  
Scuba Diving ◽  
Northern Coast ◽  
Short Life ◽  
Continuous Reproduction ◽  
Shield Length ◽  
Number Of Males

The hermit crab Pagurus brevidactylus (Crustacea: Anomura: Paguridea) from the infralittoral area of Anchieta Island, Ubatuba, was characterized by population structure (size, sex ratio, reproduction and recruitment) and growth. Animals were collected monthly during 1999 by SCUBA diving. A total of 1525 individuals was collected (633 males and 892 females), 695 of them were ovigerous females. Overall sex ratio was 0·7:1 in favour of females. The crabs showed a unimodal distribution with males significantly larger than females. Ovigerous females were collected during all months and in high percentages from 1·0 mm of shield length, demonstrating intense and continuous reproduction. The longevity was approximately 24 months for males and 18 for females, which showed larger growth rate and reached sexual maturity earlier (two months) than males. The low number of males in this population may be due to the longer life span. Moreover, the sexual dimorphism favours males during the intra- and interspecific fights by shell, food, reproduction and territory. Females demonstrated a short life cycle and intense reproduction.

scholarly journals Reproductive biology of blue swimming crab, Portunus segnis (Forskal, 1775) in Yumurtalık Cove, Northeastern Mediterranean, Turkey

2017 ◽  
pp. 424 ◽  
Author(s):  
CANAN TURELI ◽  
IREM NUR YESILYURT
Keyword(s):  
Sex Ratio ◽  
Reproductive Biology ◽  
Sexual Maturity ◽  
Gonadosomatic Index ◽  
Carapace Width ◽  
Gonadal Development ◽  
Swimming Crab ◽  
Female Population ◽  
Iskenderun Bay ◽  
Portunus Segnis

Blue swimming crab, Portunus segnis is a Lessepsian migrant into the Mediterranean and little is known about the biology of it in Iskenderun Bay, Northeastern Mediterranean, Turkey. In the present study the sex ratio, gonadal development stages, gonadosomatic index, size at first sexual maturity, and the fecundity of P. segnis were examined. The specimens of P. segnis were collected monthly from July 2014 to June 2015 (except February) with trawl net from the Yumurtalık Cove. The crabs were found throughout the year and were abundant between July to October (74%). Carapace width range of all samples was between 38.1-163.17 mm, and body weight ranged from 3.46-324.36 g. The population sex ratio was obtained Male:Female=0.7:1 which showed more abundant female population. Fifty percent of the female crabs attained sexual maturity when they reached the sized of 115-119.99 mm CW. The ovigerous female crabs ranging between 101.39- 154.03 mm CW can produced 139379 to 2745236 eggs. The mean fecundity of P. segnis was 1070425±580978 eggs with a mean carapace width of 130.04±12.77 mm. In Yumurtalık Cove, breeding season of P. segnis were observed throughout the year, except winter. Further studies are needed for assessing the reproductive biology of blue crabs in other locations of Turkey.

Akodon molinae (Rodentia Cricetidae), a new laboratory animal: breeding, management and reproductive performance

1980 ◽  
Vol 14 (2) ◽  
pp. 129-131 ◽  
Author(s):  
Maria Susana Merani ◽  
Marta Susana Lizarralde
Keyword(s):  
Sex Ratio ◽  
Reproductive Performance ◽  
Sexual Maturity ◽  
Laboratory Animal ◽  
Post Partum ◽  
Animal Breeding ◽  
Haemorrhagic Fever ◽  
Sex Ratio At Birth ◽  
Breeding Management ◽  
Laboratory Colony

Akodon molinae, a vole mouse widely distributed in central Argentina, shows remarkable chromosome polymorphisms. It is one of the natural reservoirs of the actiologic agent of haemorrhagic fever, and a laboratory colony could be of great help in investigating this disease. Pregnancy lasted 23 (range 21-25) days. Litters of 4-5 young were born to monogamous breeding pairs about every 30 days, with weaning at 26 days post partum. The sex ratio at birth was 505 males to 500 females: at weaning it was 460 to 440. Sexual maturity was attained at about 16 weeks of age in males and 12-20 weeks in females. Akodon molinae is easy to handle, but fighting and killing or neglect of young are problems.

Reproductive Ecology of The Allied Rock-wallaby, Petrogale assimilis.

1996 ◽  
Vol 19 (2) ◽  
pp. 209
Author(s):  
R. Delaney
Keyword(s):  
Life History ◽  
Sex Ratio ◽  
Sexual Maturity ◽  
Post Partum ◽  
Reproductive Ecology ◽  
Oestrous Cycle ◽  
Embryonic Diapause ◽  
Minimum Age

Petrogale assimilis has a typical life history and reproductive ecology for a macropodid of its size. Both sexes are capable of reproducing continuously; gestation is about the same length as the oestrous cycle (approximately one month); a single young is born and, a post-partum oestrus and embryonic diapause probably occurs. The sex ratio of young is unbiased. Pouch young remain permanently attached to the teat until 110 - 143 days (n=11). Permanent exit from the pouch occurs at 180 - 231 days (mean=201 days, n=25), and weaning occurs between 267 - 387 days (n=5). Sexual maturity occurs at a minimum age of 17.5 months in females and 23 months in males.

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.

scholarly journals Population structure and reproductive characteristics of the silky shark Carcharhinus falciformis (Müller & Henle, 1839) (Carcharhiniformes: Carcharhinidae) off the coast of Oaxaca, Mexico

2017 ◽  
Vol 44 (3) ◽  
pp. 513-524
Author(s):  
María del Carmen Alejo-Plata ◽  
Miguel Ángel Ahumada-Sempoal ◽  
José Luis Gómez-Márquez ◽  
Adrián González-Acosta
Keyword(s):  
Population Structure ◽  
Sex Ratio ◽  
Seasonal Changes ◽  
Sexual Maturity ◽  
Size Structure ◽  
Landing Sites ◽  
Silky Shark ◽  
Oceanic Species ◽  
Carcharhinus Falciformis ◽  
Gravid Females

Carcharhinus falciformis is an abundant oceanic species, which occurs in equatorial and tropical zones, with an important catch in the Atlantic and Pacific coasts of Mexico. Samples were taken from December 2000 to December 2007 in four landing sites of the artisanal fleet on the coast of Oaxaca. During the period of study 1236 specimens (602 females and 634 males) of C. falciformis were registered. Total length (TL) ranged from 49 to 217 cm for females (mean = 111.3 cm) and from 59 to 265 cm for males (mean = 111.7 cm). The sex ratio of females to males was 1:1 ( 2 0.05 = 0.78, P > 0.05). The present data suggest a size at first sexual maturity of about 184.8 cm TL for females and 178.5 cm TL for males. The catches were composed mainly of young. In the 52 gravid females examined, the average number of embryos per female was seven; with a range of 3-14 embryos. Mean TL of embryos ranged from 10 to 66 cm with evidence of seasonal changes in the size structure. Results obtained showed that C. falciformis gives birth most of the year, with the highest proportion of births during the rainy season (May to October).

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