scholarly journals Reproductive biology of a population of Gymnotus aff.carapo (Teleostei: Gymnotidae) from southern Brazil

2006 ◽  
Vol 4 (3) ◽  
pp. 339-348 ◽  
Author(s):  
Diego de Paula Cognato ◽  
Clarice Bernhardt Fialho
Keyword(s):  
Sex Ratio ◽  
Dissolved Oxygen ◽  
Abiotic Factors ◽  
Gonadal Development ◽  
Reproductive Period ◽  
Size Distributions ◽  
Water Conductivity ◽  
Multiple Spawning ◽  
Absolute Fecundity ◽  
The Mean

The reproductive period and its relation with somatic and abiotic factors, the relative and absolute fecundity, spawning type, length of first maturation and sex ratio is describe for Gymnotus aff.carapo from a small lake at Itapuã State Park, Rio Grande do Sul, Brazil. Gymnotus aff. carapo presents a relatively long reproductive cycle extending from November/2003 to March/2004. Decreases in water conductivity and increases in dissolved oxygen are correlated with increased gonadal development in males. In females, seasonal increases in temperature and photoperiod and decreases in dissolved oxygen are correlated with increased gonadal development. The mean absolute fecundity was 915.3 oocytes, and mean relative fecundity 0.20 oocytes/mg body weight. Egg size distributions indicate multiple spawning. The size of first maturation was 141 mm in females and 146 mm in males. The sex ratio was 1:1, with a male bias only in smaller size classes.

scholarly journals Population biology of shrimp Macrobrachium jelskii (Miers, 1778) (Decapoda, Palaemonoidea) at the Grande River at northwest of the state of Minas Gerais, Brazil

2012 ◽  
Vol 24 (3) ◽  
pp. 266-275 ◽  
Author(s):  
Samara de Paiva Barros-Alves ◽  
Ariádine Cristine Almeida ◽  
Vivian Fransozo ◽  
Douglas Fernandes Rodrigues Alves ◽  
José Carlos da Silva ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Frequency Distribution ◽  
Population Biology ◽  
Abiotic Factors ◽  
Mesh Size ◽  
Minas Gerais ◽  
Reproductive Period ◽  
Length Frequency Distribution ◽  
Length Frequency ◽  
Monthly Basis

AIM: The population biology of the freshwater shrimp Macrobrachium jelskii was investigated here emphasizing the length-frequency distribution, sex ratio, reproductive period and juvenile recruitment. In addition, the abundance of individuals was correlated with the abiotic factors. METHODS: Samples were collected on a monthly basis from July 2005 to June 2007 along the river margin in shallow water of Grande River, at Planura region, State of Minas Gerais, Brazil (20º 09' S and 48º 40' W), using a trawl net (1.0 mm mesh size, and 2.0 m × 0.5 m wide). The fishing gear was handled by two people along the marginal vegetation of the Grande River in a course of 100 m, covered for one hour. In the laboratory, the specimens were identified, measured and sexed. RESULTS: A total of 2,789 specimens was analyzed, which corresponded to 1,126 males (549 juveniles and 577 adults) and 1,663 females (1,093 juveniles, 423 adults non-ovigerous and 147 ovigerous). The sex ratio differed significantly in favor of the females of M. jelskii (1:1.48; χ² = 103.95; p < 0.0001). The mean size of carapace length (CL) of females (6.32 ± 1.84 mm CL) was statistically higher than of males (5.50 ± 1.07 mm CL) (p < 0.001). The length-frequency distribution of the specimens revealed an unimodal pattern and non-normal distribution for males and females (W = 0.945; p < 0.01). No significant relationship between the abundance of M. jelskii and the environmental variables was observed (p = 0.799). CONCLUSION: The presence of ovigerous females and juveniles in the population suggests a continuous reproduction pattern and recruitment for M. jelskii at Planura region.

scholarly journals Reproductive biology of weakly electric fish Eigenmannia trilineata López and Castello, 1966 (Teleostei, Sternopygidae)

2009 ◽  
Vol 52 (3) ◽  
pp. 617-628 ◽  
Author(s):  
Júlia Giora ◽  
Clarice Bernhardt Fialho
Keyword(s):  
Sexual Dimorphism ◽  
Reproductive Biology ◽  
Electric Fish ◽  
Abiotic Factors ◽  
Reproductive Period ◽  
Weakly Electric Fish ◽  
Southern Brazil ◽  
Water Conductivity ◽  
Total Length ◽  
Weakly Electric

This study described the reproductive biology of a population of the weakly electric fish Eigenmannia trilineata from southern Brazil, providing the information on the estimation of reproductive period, fecundity, spawning type, first maturation size, and analysis of gonadal morphology and histology of the species, relating these data to alimentary and abiotic characters. The species showed a relatively long reproductive period, a relative fecundity of 0.27 oocytes per mg of total weight and a parcelled spawning type. First maturation size estimated for the females was 80.5 mm and for the males 63.5 mm of total length. Sex ratio did not differ from 1:1 under a X²test (α= 0.01) during all the sampled months. Sexual dimorphism was related to total length, and males had larger total length than females. The abiotic factors photoperiod and water conductivity presented significant correlations with female GSI, while male GSI presented a significant correlation only with photoperiod.

scholarly journals Sexual development and reproductive pattern of the Mutton hamlet, Alphestes afer (Teleostei: Epinephelidae): a dyandric, hermaphroditic reef fish

2011 ◽  
Vol 9 (3) ◽  
pp. 547-558 ◽  
Author(s):  
Simone Marques ◽  
Beatrice Padovani Ferreira
Keyword(s):  
Sperm Competition ◽  
Group Structure ◽  
Maximum Size ◽  
Gonadal Development ◽  
Reproductive Period ◽  
Spawning Season ◽  
Reproductive Pattern ◽  
Multiple Spawning ◽  
Mating Group ◽  
Group Spawning

There is little knowledge on the reproduction of the genus Alphestes. The reproduction of the Mutton hamlet, Alphestes afer, sampled in Pernambuco reefs (Brazil) was studied based on macroscopic analysis during reproductive period and histological analysis of gonad material from March 2008 to October 2009. This study showed that A. afer is a diandric, protogynous hermaphrodite. Sex change followed protogynous mode in two pathways: primary males formed from immature female individuals or secondary males formed from resting, ripe or spent female individuals. The numerical distribution of gonad classes by size indicated that females from 11-18 cm L T were immature while females from 16-25 cm L T and males from 12-22 cm L T were in various stages of gonadal development. Individuals identified as immature bisexual and transitional (presenting both ovarian and sperm tissue) were sized from 16-24 cm L T. Size of first reproduction for females was 18 cm L T and for males was 12 cm L T. Alphestes afer showed multiple spawning, with spawning season period from August to December 2008 and from August to October 2009. The sex-ratio (females: males) in 2008 and 2009 was 0.94:1 during the months of spawning season. Males were smaller than females, reaching maximum size of 22 cm compared to 25 cm observed for females. Males showed a high sperm competition rank (3.8), suggesting intense sperm competition. This latter is a possible indication of a shift in the mating group structure from paired to group spawning. The presence of small males added to high sperm competition index, suggest that this species, while retaining the protogynous pattern, has a reproductive strategy similar to gonochorist epinephelids.

scholarly journals Reproductive cycle of the mangrove oyster, Crassostrea rhizophorae (Bivalvia: Ostreidae) cultured in a macrotidal high-salinity zone on the Amazon mangrove coast of Brazil

2021 ◽  
Vol 51 (2) ◽  
pp. 113-121
Author(s):  
Ícaro ANTONIO ◽  
Ana SOUSA ◽  
Tiago LENZ ◽  
Izabel FUNO ◽  
Rodolf LOPES ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Reproductive Cycle ◽  
Condition Index ◽  
Gonadal Development ◽  
Reproductive Period ◽  
Salinity Zone ◽  
Crassostrea Rhizophorae ◽  
Reproductive Events ◽  
The Tropics ◽  
The Relationship

ABSTRACT This study aimed to establish the reproductive cycle of the mangrove oyster, Crassostrea rhizophorae cultured in the macrotidal estuary of the Paciência River, Maranhão state, on the northeastern coast of Brazil, and its relationship with environmental factors. Oysters were collected monthly throughout 2013 for histological analysis of sex ratio, gonadal development and condition index. The sex ratio was 1:1.39 (M:F) and only 5 specimens presented hermaphroditism. The breeding process was continuous throughout the year and mature (IIIA stage) and spawning oysters (IIIB stage) were present in practically all months. Low variation in temperature seemed to be the main factor for the continuity of the reproductive cycle. Besides temperature, the relationship between rainfall, salinity and primary productivity affected the stimulus and timing of reproductive events. The rainy season, with low values of salinity and high values of chlorophyll a and particulate organic matter, appeared to be the main reproductive period, with release of gametes and production and maturation of new gamete cohorts in the short term. In the tropics, where gamete maturation and release seem to be continuous and concomitant, the condition index does not appear to be the best method to assess reserve accumulation peaks and gonadal repletion.

scholarly journals Reproductive strategy of a non-annual rivulid in a perennial wetland

2015 ◽  
Vol 105 (3) ◽  
pp. 288-296
Author(s):  
Laísa W. Cavalheiro ◽  
Clarice B. Fialho
Keyword(s):  
Sex Ratio ◽  
Reproductive Strategy ◽  
Aquatic Vegetation ◽  
Abiotic Factors ◽  
Gonadosomatic Index ◽  
Rio Grande ◽  
Reproductive Period ◽  
Rio Grande Do Sul ◽  
Reproductive Tactics ◽  
Patos Lagoon

ABSTRACT Atlantirivulus riograndensis (Costa & Lanés, 2009) is a fish registered to the basin of Patos lagoon and the adjacent coastal plains in southern states of Rio Grande do Sul and Santa Catarina, Brazil, found in shallow water courses with that have large quantities of aquatic vegetation and forest edges. The objective of this study was to investigate the reproductive strategy and tactics of this species including the sex ratio, the length at first maturity, spawning type, fecundity and the possible associations among reproduction and abiotic factors. Sampling of specimens occurred in perennial wetlands within the Banhado dos Pachecos wildlife refuge, in the city of Viamão, state of Rio Grande do Sul, Brazil, which is a conservation unit that belongs to an area of environmental protection in the Pampa Biome. The capture of 30 A. riograndensis specimens per month occurred from January to December of 2012. A total of 188 females and 172 males were captured and the total sex ratio was 1:1 in the sampled population. Sexual maturity of the species occurs after 13.59 and 11.92 mm (SL) for females and males, respectively. Both a multiple spawning and a long reproductive period (since August to March) were confirmed by the presence of post-ovulatory follicles that were observed through histological analysis and the values of the gonadosomatic index in females considered spawning capable. The average absolute fecundity of the species is of 19.33 (± 6.18) vitellogenic oocytes in mature ovaries. No significant relationship was found between mean GSI and the abiotic data. Reproductive tactics presented by A. riograndensis indicate a species with an opportunistic reproductive strategy, following the pattern of other species of the Rivulidae family.

scholarly journals Reproductive and feeding biology of Acestrorhynchus pantaneiro Menezes, 1992 (Osteichthyes: Acestrorhynchidae) in areas under the influence of dams in the upper Uruguay River, Brazil

2012 ◽  
Vol 10 (1) ◽  
pp. 159-166 ◽  
Author(s):  
Samira Meurer ◽  
Evoy Zaniboni-Filho
Keyword(s):  
Feeding Activity ◽  
Stomach Contents ◽  
Reproductive Period ◽  
Equal Proportion ◽  
Southern Brazil ◽  
Multiple Spawning ◽  
Feeding Biology ◽  
Gonadal Maturity ◽  
The Mean ◽  
Uruguay River

The reproductive and feeding biology of Acestrorhynchus pantaneiro were studied in the upper Uruguay River, southern Brazil. Fourteen sites were surveyed seasonally between 2000 and 2006. A total of 3,427 fish were caught, being 2,015 females and 1,412 males. The sex ratio was 1.66:1 (female:male) in lentic habitats (p<0.05), but showed equal proportion in lotic and transition habitats. Feeding activity was similar for both sexes and showed little variation along the year. The analysis of stomach contents of 2,401 stomach showed that "fish" was the most consumed resource in all different habitats, corresponding to 99% of the food in the gravimetric analyzes. The species showed a multiple spawning type with a long reproductive period, although the highest intensity of reproduction occurred between the beginning of spring and summer, marked by the highest GSI and advanced gonadal maturity stages. Relative fecundity (mean ± SD) was 139 ± 56 oocytes per mm of total length and 152 ± 66 oocytes per gram of total weight. The mean absolute fecundity was 33,470 ± 19,151 oocytes and the average of the mature oocytes diameter was 897.5 ± 365.4 µm. Acestrorhynchus pantaneiro is more abundant in lentic environments and presents biological characteristics that favor the establishment of the species in dammed rivers.

scholarly journals Age and reproduction of the southern king croaker Menticirrhus americanus in subtropical South Atlantic environments

2021 ◽  
Vol 49 (2) ◽  
pp. 242-257
Author(s):  
Barbara Maichak de Carvalho ◽  
Alejandra Vanina Volpedo ◽  
Luís Fernando Fávaro
Keyword(s):  
Sampling Methods ◽  
Gonadal Development ◽  
South Atlantic ◽  
Subtropical Region ◽  
Beach Seine ◽  
Development Stages ◽  
Multiple Spawning ◽  
Males And Females ◽  
The Mean ◽  
First Maturity

Menticirrhus americanus were sampled (n = 393) from two beaches (P1 is an estuarine beach near the mouth of the Paranaguá Estuarine Complex, and P2 is a beach adjacent to the Paranaguá Estuarine Complex) in the subtropical region of the western South Atlantic waters between August 2015 and June 2016. This study aimed to identify the spawning season and the age structure for M. americanus using two sampling methods. For sampling at the P1 beach, seine, line, and pole were used, while samples from the P2 beach were obtained from the artisanal fishers. Females were numerically dominant in all sampling months at both sites except for February when the males became dominant. The species exhibited a protected reproductive season with multiple spawning peaks between August and December. Males and females were captured at all gonadal development stages and ages between 1 and 6 from both sites. At first maturity, the length of the females was 16.3 cm, and the mean age at first maturity was 1.3 years. Individuals aged between 1 and 3 years were dominant (68%). The results suggested that young and adults of the M. americanus use the same habitats throughout their ontogeny.

scholarly journals Reproductive period, fecundity and histology of gonads of two cheirodontines (Ostariophysi: Characidae) with different reproductive strategies - insemination and external fertilization

2010 ◽  
Vol 8 (2) ◽  
pp. 351-360 ◽  
Author(s):  
Cristina L. C Oliveira ◽  
Clarice B Fialho ◽  
Luiz R Malabarba
Keyword(s):  
Gonadosomatic Index ◽  
Relative Weight ◽  
Gonadal Development ◽  
Reproductive Period ◽  
Total Weight ◽  
Tropical Region ◽  
Temporal Separation ◽  
External Fertilization ◽  
Relative Fecundity ◽  
The Mean

The reproductive period and fecundity of the inseminating cheirodontine Compsura heterura and of the externally fertilizing cheirodontine Odontostilbe pequira, from tropical and subtropical regions of Brazil, respectively, are described. The reproductive period of C. heterura lasted from January to April 2002, while O. pequira showed two reproductive periods, the first during September and October 2001 (spring), and the second between January and February 2002 (summer). Smaller classes of SL of females of O. pequira predominated in the second reproductive period, suggesting individuals born in the first period become shortly sexually mature, participating in the second reproductive period. In C. heterura, from a tropical region, temperature showed significant correlations with the variation in the gonadosomatic index (GSI) for both sexes, and rainfall showed significant correlation with the variation in the GSI only for females. In O. pequira, from a subtropical region, photoperiod was the only factor that showed significant correlations with the GSI variation in both sexes. The mean relative fecundity of C. heterura was 0.55 oocytes per milligram of total weight, similar to that of other cheirodontines with external fertilization, refuting the hypothesis, at least in Cheirodontinae, that insemination provides diminishing energy expenditure for the production of oocytes, due to a greater probability of fertilization. The mean relative fecundity of O. pequira was 0.8 oocytes per milligram of total weight, the largest known among cheirodontines. Spermatozoa were found inside the ovaries of maturating, mature and semi-spent females of C. heterura supporting the hypothesis of temporal separation between courtship and spawning. The largest relative weight of testis and the presence of sperm in maturing ovaries outside the reproductive period in C. heterura support the hypothesis that males of inseminating species make a greater investment in gonadal development than those externally fertilized.

Reproductive biology of the freshwater shrimp Macrobrachium tenellum (Smith, 1871) (Decapoda: Caridea: Palaemonidae) in Mexico

2020 ◽  
Vol 40 (6) ◽  
pp. 746-755
Author(s):  
Ernesto López-Uriarte ◽  
Fernando Vega-Villasante ◽  
Ingo S Wehrtmann ◽  
Edilmar Cortés-Jacinto ◽  
Marcelo U García-Guerrero ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Water Temperature ◽  
Reproductive Biology ◽  
Rainy Season ◽  
Sexual Maturity ◽  
Significant Positive Correlation ◽  
Abiotic Factors ◽  
Reproductive Period ◽  
Female Population ◽  
First Maturity

Abstract We analyzed the reproductive cycle of females of the palaemonid shrimp Macrobrachium tenellum (Smith, 1871) collected in the Ameca River, between the Jalisco and Nayarit states, Mexico. We studied the seasonal occurrence of ovigerous females during the year, their relationship with abiotic factors, and the size of the first sexual maturity. The study included 7,100 specimens of M. tenellum, of which 2,791 (39.3%) were males, 3,559 (50.1%) females, and 750 undifferentiated (10.6%). The sex ratio of the total (male-female) population differed significantly from the expected 1:1 with more females. A total of 309 females carried eggs (8.7% of all collected females). Ovigerous females, which were collected in three of the four sampling sites, were found almost year-round (with the exception of March and December), and their number showed a significant positive correlation with water temperature and rainfall. The size of first maturity (TL50%) for all collected females was 55.7 mm total length (TL), ranging from 64.3 mm TL to 42.7 mm TL. The results revealed that the population of M. tenellum in the Ameca River has a continuous reproductive period associated with the rainy season and increasing water temperature.

COMPORTAMENTO REPRODUTIVO DAS MULHERES RIBEIRINHAS DO AMANÃ

2008 ◽  
Vol 1 (1) ◽  
pp. 31-40 ◽  
Author(s):  
Edila Arnaud Ferreira Moura
Keyword(s):  
Sustainable Development ◽  
Reproductive Health ◽  
Reproductive Behavior ◽  
Reproductive Period ◽  
Health Programs ◽  
Local Conditions ◽  
The Sustainable Development ◽  
Rivers And Lakes ◽  
Pregnancy And Delivery ◽  
The Mean

This work presents the results of a study about the reproductive behavior of riverine women living in the Sustainable Development Reserve Amanã, in the Middle Solimões region, state of Amazonas. The study was done in 2001 with the objective of identify aspects of the reproductive behavior of 83 women, collected through reproductive history methodology. These women live in small localities along the rivers and lakes in the middle of the Amazonian forest. The study identified that these women initialize their reproductive period at the age of 17, in average, and the mean age of their last pregnancy occurs at the age of 42, considering those above 50 years old. 36% of these 83 women had lost one or more of their children before the age of five. Only 16% use contraceptives and 12% are sterilized. They don’t have access to the basic health assistance in a regular basis and the local midwives are extremely important in their assistance during pregnancy and delivery. This study em phasizes the importance of reproductive health programs including those social and cultural local conditions.

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