Estrutura populacional e época de reprodução de Astyanax fasciatus (Cuvier) (Characidae, Tetragonopterinae) do Rio Ceará Mirim, Poço Branco, Rio Grande do Norte, Brasil

Gurgel, Hélio de Castro Bezerra

doi:10.1590/s0101-81752004000100022

Cited by 49 publications

(48 citation statements)

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“…2009) e A. fasciatus (Cuvier, 1819) (CARVALHO et al, 2009), enquanto outros encontraram desova total para as espécies A. schubarti (NOMURA, 1975), A. fasciatus (NOMURA, 1975;GURGEL, 2004) e A. bimaculatus (NOMURA, 1975;SANTOS et al, 1996). Além dessa variação no tipo de desova entre espécies de Astyanax, GARUTTI (1989), estudando populações de A. bimaculatus da bacia do rio Paraná, sugeriu que a espécie exibe desova parcelada e período reprodutivo prolongado em hábitats como riachos e cabeceiras de rios e desova total e período reprodutivo curto em rios com maior volume de água, onde os indivíduos estariam menos expostos a mudanças abruptas.…”

Section: Resultsunclassified

Biologia reprodutiva de Astyanax henseli (Teleostei, Characidae) do curso superior do Rio dos Sinos, RS, Brasil

Dala‐Corte

Azevedo

2010

Iheringia, Sér. Zool.

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ABSTRACT. Reproductive biology of Astyanax henseli (Teleostei, Characidae) in the upper Rio dos Sinos, RS, Brazil. This study describes the reproductive biology of a population of Astyanax henseli Melo & Buckup, 2006 from the upper Rio dos Sinos, Caraá, Rio Grande do Sul, Brazil. A total of 336 specimens was analyzed, comprising 169 males, 154 females and 13 individuals of undetermined sex. The reproductive season lasted approximately five months, from August to December, gonadossomatic index (GSI) peaked of in October, corresponding to the end of winter and the spring in the southern hemisphere. No correlation was found between the GSI and abiotic factors (temperature, rainfall and photoperiod). However, these factors may trigger gonad maturation. Also, no correlation was observed between biotic variables, such as stomach repletion index (RI) and hepatosomatic index (HSI), and GSI. Despite that, high RI values during the reproductive period may indicate that A. henseli maintains its feeding activity throughout the reproductive months, while low HSI values during the peak of GSI suggest a higher energy expenditure of the liver during this period. The sex ratio in the population was 1:1 for the total number of individuals sampled, among different classes of length, and among the different months of the year. The size at first gonadal maturation was 69 mm for males and 60 mm for females. The absolute fecundity mean was 3,038 oocytes and the relative fecundity mean was 0.13 oocytes mg -1 . The oocyte development indicated that A. henseli is a total spawner. KEYWORDS.Reproductive period, small size characid, gonadosomatic index, fecundity, first gonadal maturation. RESUMO. No presente estudo é descrita a biologia reprodutiva de uma população de Astyanax henseli PALAVRAS-CHAVE.Período reprodutivo, caracídeo de pequeno porte, índice gonadossomático, fecundidade, primeira maturação gonadal.

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Section: Resultsunclassified

Biologia reprodutiva de Astyanax henseli (Teleostei, Characidae) do curso superior do Rio dos Sinos, RS, Brasil

Dala‐Corte

Azevedo

2010

Iheringia, Sér. Zool.

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“…In a study about reproductive ecology of Astyanax fasciatus, Gurgel (2004) suggests that differences in sex ratio during the reproductive period are due to the increase in the weight of the gonads of females, which make them more susceptible to capture. However, this idea is not applicable to our study, due to the small mesh size used, and also because the active sampling minimized this possibility.…”

Section: Discussionmentioning

confidence: 99%

Population aspects of Bryconamericus stramineus in streams of the upper Paraná River basin, Brazil

2011

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Abstract:In order to describe some aspects of the population ecology of Bryconamericus stramineus in the Guiraí River basin, upper Paraná River basin, samples were taken bimonthly from October 2006 to August 2007 at seven sites in the basin. A total of 960 individuals, including 532 females, 316 males, and 112 of undetermined sex, were collected. A significant variation in the sex ratio was observed (χ 2 = 32.82; p < 0.001). Females were larger (59.7 mm) than males (58.9 mm); however, males showed a larger angular growth coefficient (b) than females. It was estimated that 50% of females were sexually mature at 36.4 mm. The highest rate of ovary development was observed in October, while in June 2007 no mature females were found. Mean fecundity was estimated at 313 eggs, and the relative fecundity was 184.6 eggs/g. The asymptotic was estimated at 62.8 mm and the growth rate at 0.76. The growth performance index was calculated at 3.47, the longevity at 3.94 years and the mortality (M) at 1.18 years. The recruitment pattern of the species showed peaks concentrated in periods of low rainfall. Keywords: length-weight relationship, mortality, reproductive strategy, sex ratio. Neotrop., vol. 11, no. 2 In which season does reproductive activity of B. stramineus increase in the streams sampled? 5) What is the mean standard length at which females reach first maturation? 6) Is there any relationship between fecundity and the size of females? 7) Are seasonal differences in recruitment patterns for studied population? 8) What are the growth and mortality parameters for B. stramineus in sampled streams? Material and Methods Study siteThe Guiraí River basin (22° 45' S, 54° 30' W and 22° 15' S, 53° 30' W), occupies an area of approximately 2,248 km 2 and includes seven municipal districts. The mouth of the Guiraí River is located at an altitude of 370 m a.s.1., and the river flows for approximately 100 km until it enters the Ivinhema River, at 238 m of altitude. In its lower portion, it forms the boundary of the Parque Estadual das Várzeas do rio Ivinhema. Field and laboratory methodsThe fish samples were taken bimonthly from October 2006 to August 2007 at seven sites in the Guiraí River basin (Figure 1). The streams were selected for their location in the basin and ease of access.The samples were taken during daylight, with a rectangular sieve measuring 1.2 × 0.8 m (2 mm mesh size) and standardized effort (20 throws) at each site, with approximately 100-m long hauls. The equipment was slide to sweep the substrate toward the banks of the stream. This technique was used because of the difficulties of using the electric fishing in these streams, such as low electrical conductivity and high turbidity, and also due to difficult access. The permission for fish retrieval was granted by IBAMA (#13458-1).Specimens were fixed in 10% formalin and preserved in 70% ethanol for subsequent identification. Voucher specimens were deposited at the Coleção de Peixes do Nupelia (NUP/UEM # 9322).In the laboratory, some biometric data were mea...

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“…This ratio is significantly different from 1:1, and may be due to differences in the size of females and males (HARTZ & BARBIERI 1994), or related to the amount of available food, which under optimal conditions, would lead to a higher frequency of females in the population (NIKOLSKII 1969, GURGEL 2004. The sex ratio of this species, with internal fertilization, and morphologic pattern of males with the presence of strong bony hooks on the dorsal and pectorals fins suggest that males compete for mature females as described for Hoplosternum littorale Hancock, 1828 (Callichthyidae) in the swamps of Venezuela (WINEMILLER 1987).…”

Section: 10 11mentioning

confidence: 99%

Diet and reproductive dynamics of Trachelyopterus lucenai (Siluriformes: Auchenipteridae) in subtropical coastal lagoons in southern Brazil

Maia¹,

Artioli²,

Hartz³

2013

Zoologia (Curitiba)

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Estrutura populacional e época de reprodução de Astyanax fasciatus (Cuvier) (Characidae, Tetragonopterinae) do Rio Ceará Mirim, Poço Branco, Rio Grande do Norte, Brasil

Cited by 49 publications

References 1 publication

Biologia reprodutiva de Astyanax henseli (Teleostei, Characidae) do curso superior do Rio dos Sinos, RS, Brasil

Biologia reprodutiva de Astyanax henseli (Teleostei, Characidae) do curso superior do Rio dos Sinos, RS, Brasil

Population aspects of Bryconamericus stramineus in streams of the upper Paraná River basin, Brazil

Diet and reproductive dynamics of Trachelyopterus lucenai (Siluriformes: Auchenipteridae) in subtropical coastal lagoons in southern Brazil

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