“…The values for GSI also began to rise in August/September, peaking in October/November for females and August/September for males. Similar results were found in other Loricariidae in various regions of Brazil, for example, Rhinelepis aspera (Agostinho et al, 1990), Hypostomus commersonii (Agostinho et al, 1991), H. ancistroides (Viana et al, 2008), Rineloricaria latirostris (Barbieri, 1994), Loricariichthys platymetopon (Bailly et al, 2011;Marcucci et al, 2005), L. spixii (Duarte et al, 2007), among others. Males showed distinctly greater condition factor than that of females throughout the study period, probably because of higher energy expenditure of females during the maturation process (Cantanhêde et al, 2007), a feature also reported by Agostinho et al (1990) for Rhinelepis aspera in the rio Paranapanema (state of Paraná).…”
Section: Discussionsupporting
confidence: 81%
“…Studies addressing population and reproductive aspects of this family of fish have been conducted in several Brazilian basins, focusing on several species such as Rhinelepis aspera Spix & Agassiz, 1829 (Agostinho et al, 1987;Agostinho et al, 1990), Hypostomus commersonii Valenciennes, 1836 (Agostinho et al, 1991), Rineloricaria latirostris (Boulenger, 1900) (Barbieri, 1994), Hypostomus ancistroides (Ihering, 1911) (Viana et al, 2008), Pareiorhina rudolphi (Miranda Ribeiro, 1911) (Braga et al, 2009), among others. Studies conducted on the genus Loricariichthys have focused primarily on L. anus (Valenciennes, 1835), L. platymetopon Isbrücker & Nijssen, 1979(Tos et al, 1997Querol et al, 2002;Marcucci et al, 2005;Bailly et al, 2011) and L. spixii (Steindachner 1881) (Duarte & Araújo, 2001).…”
Section: Introductionmentioning
confidence: 99%
“…Studies on reproductive dynamics are important for research on fishing activities in that they provide the necessary support for developing programs aimed at the rational exploitation and conservation of fish species in Brazilian rivers and lakes. In this line of research, studies particularly focus on breeding season, size and age of first gonadal maturity, fecundity, growth rate and type of spawning (Barbieri, 1994).…”
The objective of this study was to analyze population structure (spatial distribution, seasonal distribution and distribution by length classes, sex ratio and length-weight relationship) and aspects of the reproductive biology of Loricariichthys melanocheilus. Fish were sampled bimonthly using gillnets and trammel nets in lentic and lotic environments in the rio Ibicuí, between the years 2000 and 2001. Were collected 410 specimens: 230 females, 164 males and 16 specimens whose sex could not be determined. A greater number of specimens were collected in October/November and December/January and in lentic environments. The greater length classes had a higher amount of females ( p < 0.05) and the sex ratio in all sampling periods was 1.38 females per male. Both males and females showed positive allometric growth (b = 3.299 and b =3.487, respectively). The highest values for gonadosomatic index (GSI) and gonadal condition factor (K) were observed from August/September and peaked in October/November, just like the highest frequencies of females at maturity stage C (mature), which is indicative that the breeding season occurs at this time.O objetivo deste trabalho foi analisar a estrutura populacional (distribuição espacial, sazonal e por classes de comprimento, proporção sexual e relação peso-comprimento) e aspectos da biologia reprodutiva de Loricariichthys melanocheilus. Os peixes foram amostrados bimestralmente com redes de espera e feiticeiras em ambientes lêntico e lóticos no rio Ibicuí, entre os anos de 2000 e 2001. Foram capturados 410 indivíduos: 230 fêmeas, 164 machos e 16 indivíduos que não foi possível determinar o sexo. Foi capturado um maior número de indivíduos em outubro/novembro e dezembro/janeiro e em ambientes lênticos. As classes de comprimento superiores apresentaram maior quantidade de fêmeas ( p < 0.05) e a proporção sexual em todos os períodos amostrados foi de 1,38 fêmeas para cada macho. Tanto os machos quanto as fêmeas apresentaram crescimento alométrico positivo (b = 3.299 and b =3.487, respectivamente). Os maiores valores do Índice Gonadossomático (IGS) e do fator de condição gonadal (K) foram observados a partir de agosto/setembro, com pico em outubro/novembro, assim com as maiores frequências de fêmeas em estádio de maturação C (maduro), indicando que o período reprodutivo se dá nesta época.
“…The values for GSI also began to rise in August/September, peaking in October/November for females and August/September for males. Similar results were found in other Loricariidae in various regions of Brazil, for example, Rhinelepis aspera (Agostinho et al, 1990), Hypostomus commersonii (Agostinho et al, 1991), H. ancistroides (Viana et al, 2008), Rineloricaria latirostris (Barbieri, 1994), Loricariichthys platymetopon (Bailly et al, 2011;Marcucci et al, 2005), L. spixii (Duarte et al, 2007), among others. Males showed distinctly greater condition factor than that of females throughout the study period, probably because of higher energy expenditure of females during the maturation process (Cantanhêde et al, 2007), a feature also reported by Agostinho et al (1990) for Rhinelepis aspera in the rio Paranapanema (state of Paraná).…”
Section: Discussionsupporting
confidence: 81%
“…Studies addressing population and reproductive aspects of this family of fish have been conducted in several Brazilian basins, focusing on several species such as Rhinelepis aspera Spix & Agassiz, 1829 (Agostinho et al, 1987;Agostinho et al, 1990), Hypostomus commersonii Valenciennes, 1836 (Agostinho et al, 1991), Rineloricaria latirostris (Boulenger, 1900) (Barbieri, 1994), Hypostomus ancistroides (Ihering, 1911) (Viana et al, 2008), Pareiorhina rudolphi (Miranda Ribeiro, 1911) (Braga et al, 2009), among others. Studies conducted on the genus Loricariichthys have focused primarily on L. anus (Valenciennes, 1835), L. platymetopon Isbrücker & Nijssen, 1979(Tos et al, 1997Querol et al, 2002;Marcucci et al, 2005;Bailly et al, 2011) and L. spixii (Steindachner 1881) (Duarte & Araújo, 2001).…”
Section: Introductionmentioning
confidence: 99%
“…Studies on reproductive dynamics are important for research on fishing activities in that they provide the necessary support for developing programs aimed at the rational exploitation and conservation of fish species in Brazilian rivers and lakes. In this line of research, studies particularly focus on breeding season, size and age of first gonadal maturity, fecundity, growth rate and type of spawning (Barbieri, 1994).…”
The objective of this study was to analyze population structure (spatial distribution, seasonal distribution and distribution by length classes, sex ratio and length-weight relationship) and aspects of the reproductive biology of Loricariichthys melanocheilus. Fish were sampled bimonthly using gillnets and trammel nets in lentic and lotic environments in the rio Ibicuí, between the years 2000 and 2001. Were collected 410 specimens: 230 females, 164 males and 16 specimens whose sex could not be determined. A greater number of specimens were collected in October/November and December/January and in lentic environments. The greater length classes had a higher amount of females ( p < 0.05) and the sex ratio in all sampling periods was 1.38 females per male. Both males and females showed positive allometric growth (b = 3.299 and b =3.487, respectively). The highest values for gonadosomatic index (GSI) and gonadal condition factor (K) were observed from August/September and peaked in October/November, just like the highest frequencies of females at maturity stage C (mature), which is indicative that the breeding season occurs at this time.O objetivo deste trabalho foi analisar a estrutura populacional (distribuição espacial, sazonal e por classes de comprimento, proporção sexual e relação peso-comprimento) e aspectos da biologia reprodutiva de Loricariichthys melanocheilus. Os peixes foram amostrados bimestralmente com redes de espera e feiticeiras em ambientes lêntico e lóticos no rio Ibicuí, entre os anos de 2000 e 2001. Foram capturados 410 indivíduos: 230 fêmeas, 164 machos e 16 indivíduos que não foi possível determinar o sexo. Foi capturado um maior número de indivíduos em outubro/novembro e dezembro/janeiro e em ambientes lênticos. As classes de comprimento superiores apresentaram maior quantidade de fêmeas ( p < 0.05) e a proporção sexual em todos os períodos amostrados foi de 1,38 fêmeas para cada macho. Tanto os machos quanto as fêmeas apresentaram crescimento alométrico positivo (b = 3.299 and b =3.487, respectivamente). Os maiores valores do Índice Gonadossomático (IGS) e do fator de condição gonadal (K) foram observados a partir de agosto/setembro, com pico em outubro/novembro, assim com as maiores frequências de fêmeas em estádio de maturação C (maduro), indicando que o período reprodutivo se dá nesta época.
“…Los ovarios maduros estudiados presentaron características similares a las de otros loricaridos con ovocitos maduros "grandes" por poseer gran cantidad de vitelo, lo que también explica, como ya se dijo, la baja fecundidad encontrada (MachadoAllison, 1993;Barbieri, 1994;Suzuki, 2000). La distribución de las frecuencias de los diámetros ovocitarios representadas en la figura 1, con dos picos o grupos predominantes de ovocitos, develan un crecimiento ovocitario por grupos de maduración o asincrónico, otros loricaridos también lo presentan Pachyurus bonariensis y Loricariichthys platymetopon (Marcucci et al, 2005).…”
Section: Discussionunclassified
“…Los ovocitos liberados fueron tamizados en malla de nylon de 500 µm de ojo de malla siendo que los retenidos por la malla, considerados como ovocitos "reclutados", esto es en alguna etapa de maduración vitelogénica y que efectivamente pueden ser expulsado en un próximo desove, fueron contados manualmente (Barbieri, 1994). Con la suma de los ovocitos retenidos de los dos ovarios de cada hembra se estableció la Fecundidad.…”
Ortiz -Nuevo método para la cuantificación de la actividad endoglucanasaVolumen 15 -N o 1-Año 2011
RESUMENLa fecundidad en peces, es la estimación de la cantidad de ovocitos que una hembra podría expulsar en un desove, siendo uno de los indicadores más utilizados para evaluar el potencial reproductivo de una especie y sus posibilidades para la piscicultura. Para aportar al conocimiento de este criterio, se estudiaron los ovarios de hembras silvestres maduras, las cuales fueron pesadas individualmente al igual que sus ovarios y calculado el Índice gonadosómatico (IGS). Luego cada ovario fue digerido en solución Gilson durante 20 días y luego tamizado en malla de 500 µm y los ovocitos retenidos fueron contados y obtenida la fecundidad. La fecundidad relativa a peso (FRP) también fue calculada así como los diámetros ovocitarios medidos bajo estereoscopio. Una decima parte de cinco ovarios fueron procesados para histología convencional H & E y una vez analizados, deducido el desarrollo de los ovocitos y el tipo de desove comparando la información obtenida.Se obtuvo una fecundidad de 62 ± 8 ovocitos / hembra y una FRP = 91 ± 10 ovocitos g-¹ peso total, el IGS fue de 13,2 ± 1,1 %, y el diámetro ovocitario de los ovocitos maduros fue de 1.366,5 ± 203,8 µm, siendo que las frecuencias de los diámetros de los ovocitos mayores de 500 µm encontradas en conjunto con las placas histológicas estudiadas, mostraron dos grupos de ovocitos en crecimiento, lo que permite concluir que el desarrollo del ovario es asincrónico y el desove parcial.Palabras clave: desarrollo ovocitario, desove, diámetros ovocitarios, fecundidad relativa, índice gonadosómatico, otocinclo.
ABSTRACTFecundity is the estimated number of oocytes which a female could be expected to expel during one spawning; this is thus one of the most used indicators for evaluating fish species'reproductive potential and their farming potential. The ovaries of mature wild female fish were studied to contribute towards knowledge regarding this criterion. Fish and ovaries were weighted individually and the gonadosomatic index (GSI) was calculated. Each ovary was digested in Gilson's solution for 20 days and then screened through a 500 µm mesh; the retained oocytes were counted (by stereomicroscope) and fecundity was thus estimated. The relative fecundity to weight (RFW) ratio was also calculated and oocyte diameters were measured. Atenth part of five ovaries was processed by conventional histology (haematoxylin and eosion-H&E -stain) to study oocyte development and types of spawning.
Artículo Original /Original Article
Fecundidad de Otocinclus spectabilisOrinoquia 15(1): [41][42][43][44][45][46][47] 2011
The gross morphology of the brain of Rineloricaria heteroptera and its relation to the sensory/behavioural ecology of the species is described and discussed. The sexual and ontogenetic intraspecific variation in the whole brain length and mass, as well as within/between the eight different brain subdivisions volumes, is also examined and discussed. Negative allometry for the whole brain length/mass and relative growth of the telencephalon and optic tecta was observed. Positive allometry was observed for the relative growth of the olfactory bulbs and medulla oblongata. Univariate and multivariate statistical analyses did not reveal significant differences in the brain subdivision growth rates among sexes and/or developmental stages, except for the optic tectum and some portions of the medulla oblongata, with juveniles and males showing more developed optic tecta and medullary subdivisions, respectively. The growth rates for each brain subdivision were relatively constant, and the slopes of the growth equations were almost parallel, except for those of the olfactory bulbs and medulla oblongata subdivisions, suggesting some degree of tachyauxesis of subdivisions against the entire brain. The corpus cerebelli was the more voluminous brain subdivision in most specimens (principally adults), followed by the optic tectum (the more voluminous subdivision in juveniles), hypothalamus, and telencephalon, in that order. Differences in the number of lamellae and relative size of the olfactory organ were also detected among developmental stages, which were more numerous and larger in adults. Based on these results, it is possible to infer an ontogenetic shift in the habitat/resource use and behaviour of R. heteroptera. Vision, primarily routed through the optic tectum, could be fundamental in early stages, whereas in adults, olfaction and taste, primarily routed through the olfactory bulbs and medulla oblongata, play more important roles.
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