Reproduction and fecundity of invader of internal insemination Trachelyopterus galeatus in a Neotropical floodplain

After the formation of Itaipu Reservoir, the invader Trachelyopterus galeatus colonized the upper Paraná River. Light microscopy was used to describe gametogenesis and the reproductive phases of females and males. The following data were verified: diameter of the oocytes, spawning type, batch fecundity by ovary weight, standard length, and total weight of the fish, along with the regions where this species reproduced in the upper Paraná River floodplain. A total of 470 specimens were collected quarterly in 2016, 2018 and 2019, and bimonthly in 2017. The gonads were fixed in a Karnovsky solution, dehydrated, infiltrated, and embedded in historesin. The histological slides were stained using PAS + iron hematoxylin + metanil yellow, analyzed and photographed under an image-capturing microscope. As regards diameter of the oocytes and fecundity estimates, ovaries whose oocytes were measured under a stereomicroscope were sampled. In the oogenesis, undifferentiated and differentiated oogonia, early primary growth oocytes, secondary growth oocytes, full-grown oocytes and maturing oocytes were recorded. In the spermatogenesis, primary and secondary spermatogonia, primary and secondary spermatocytes, spermatids and spermatozoa were recorded. The reproductive phases found for females and males were: immature, early development, late development, spawning/sperm-releasing capable, regression, and regeneration. Trachelyopterus galeatus prefers to occupy and reproduce in the Ventura, Patos, Guaraná, Fechada, Garças, and Pau Véio lagoons. The diameter of the oocytes varied from 0.4 to 2.9 mm. Females spawn, on average, 113 oocytes per batch. Batch fecundity variation shows that the larger the ovary, standard length, and total weight, the larger the number of oocytes to be spawned. This invader possesses reproductive success in the upper Paraná River floodplain, especially in lagoons.

Reproduction and fecundity of invader of internal insemination Trachelyopterus galeatus in a Neotropical floodplain

After the formation of Itaipu Reservoir, the invader Trachelyopterus galeatus colonized the upper Paraná River. Light microscopy was used to describe gametogenesis and the reproductive phases of females and males. The following data were verified: diameter of the oocytes, spawning type, batch fecundity by ovary weight, standard length, and total weight of the fish, along with the regions where this species reproduced in the upper Paraná River floodplain. A total of 470 specimens were collected quarterly in 2016, 2018 and 2019, and bimonthly in 2017. The gonads were fixed in a Karnovsky solution, dehydrated, infiltrated, and embedded in historesin. The histological slides were stained using PAS + iron hematoxylin + metanil yellow, analyzed and photographed under an image-capturing microscope. As regards diameter of the oocytes and fecundity estimates, ovaries whose oocytes were measured under a stereomicroscope were sampled. In the oogenesis, undifferentiated and differentiated oogonia, early primary growth oocytes, secondary growth oocytes, full-grown oocytes and maturing oocytes were recorded. In the spermatogenesis, primary and secondary spermatogonia, primary and secondary spermatocytes, spermatids and spermatozoa were recorded. The reproductive phases found for females and males were: immature, early development, late development, spawning/sperm-releasing capable, regression, and regeneration. Trachelyopterus galeatus prefers to occupy and reproduce in the Ventura, Patos, Guaraná, Fechada, Garças, and Pau Véio lagoons. The diameter of the oocytes varied from 0.4 to 2.9 mm. Females spawn, on average, 113 oocytes per batch. Batch fecundity variation shows that the larger the ovary, standard length, and total weight, the larger the number of oocytes to be spawned. This invader possesses reproductive success in the upper Paraná River floodplain, especially in lagoons.(AU)

Gonadal development and reproductive period of the characin Astyanax aff. bimaculatus (Characiformes: Characidae) in a tropical reservoir in southeastern Brazil

The gonadal development of the characin Astyanax aff. bimaculatus from Funil Reservoir, an impoundment in the middle reaches of the Paraiba do Sul River in southeastern Brazil was analysed through histological, histochemical and histometric techniques, and the spawning season was determined. Unbalanced sex ratio was found, with females outnumbering and reaching larger sizes than males. The following stages of oogenic cell development were identified for females: primary growth, pre-vitellogenic (cortical alveolar) and vitellogenic. In males, the following stages were determined: spermatogonia primary and secondary, spermatocyte primary and secondary, spermatid and spermatozoa. The spawning occurs most of the year, peaking in January-February, as indicated by the gonadosomatic index. In the peak of the spawning period, the condition factor and hepatosomatic indices decreased suggesting use of stored body energy reserves during the reproduction. Spawning in batches, small-sized oocytes and a long reproductive season suggest that Astyanax aff. bimaculatus fits to an opportunist strategy. Such strategy may facilitate the use of a wide range of lentic and lotic body waters in the Neotropical region.

Gonadal development and reproductive period of the characin Astyanax aff. bimaculatus (Characiformes: Characidae) in a tropical reservoir in southeastern Brazil

The gonadal development of the characin Astyanax aff. bimaculatus from Funil Reservoir, an impoundment in the middle reaches of the Paraiba do Sul River in southeastern Brazil was analysed through histological, histochemical and histometric techniques, and the spawning season was determined. Unbalanced sex ratio was found, with females outnumbering and reaching larger sizes than males. The following stages of oogenic cell development were identified for females: primary growth, pre-vitellogenic (cortical alveolar) and vitellogenic. In males, the following stages were determined: spermatogonia primary and secondary, spermatocyte primary and secondary, spermatid and spermatozoa. The spawning occurs most of the year, peaking in January-February, as indicated by the gonadosomatic index. In the peak of the spawning period, the condition factor and hepatosomatic indices decreased suggesting use of stored body energy reserves during the reproduction. Spawning in batches, small-sized oocytes and a long reproductive season suggest that Astyanax aff. bimaculatus fits to an opportunist strategy. Such strategy may facilitate the use of a wide range of lentic and lotic body waters in the Neotropical region.(AU)

Non-seasonal reproduction in inseminating species of Mimagoniates (Characidae, Characiformes) from southern Brazil

Some aspects of reproduction in two species of Mimagoniates, M. microlepis (Steindachner 1877) and M. rheocharis Menezes & Weitzman 1990 are herein described. Samples were taken monthly from January 1998 to February 1999 in two streams in the locality of Maquiné, Rio Grande do Sul, Brazil. Results from the analysis of hundreds of specimens of M. microlepis and M. rheocharis in two investigated sites indicated mature specimens and peaks of the gonadosomatic index (GSI) along the year. There was a negative and significant correlation between M. microlepis males GSI and water temperature. Females of the latter species and both sexes of M. rheocharis, in turn, showed no correlation with any of the tested parameters (relative stomach weight, day length, rainfall). Absolute and relative fecundity are lower than in externally fertilized species of Characidae. Maximum oocyte length was 1.14 mm for M. microlepis and 1.02 mm for M. rheocharis and both species were characterized as total spawners based on the type of oocyte development estimated through oocyte size analysis. Features like non-seasonal reproductive period, low fecundity, and insemination may indicate adaptive advantages, which may enhance the chance of survival even with low energetic investment and improved fertilization.

Non-seasonal reproduction in inseminating species of Mimagoniates (Characidae, Characiformes) from southern Brazil

Some aspects of reproduction in two species of Mimagoniates, M. microlepis (Steindachner 1877) and M. rheocharis Menezes & Weitzman 1990 are herein described. Samples were taken monthly from January 1998 to February 1999 in two streams in the locality of Maquiné, Rio Grande do Sul, Brazil. Results from the analysis of hundreds of specimens of M. microlepis and M. rheocharis in two investigated sites indicated mature specimens and peaks of the gonadosomatic index (GSI) along the year. There was a negative and significant correlation between M. microlepis males GSI and water temperature. Females of the latter species and both sexes of M. rheocharis, in turn, showed no correlation with any of the tested parameters (relative stomach weight, day length, rainfall). Absolute and relative fecundity are lower than in externally fertilized species of Characidae. Maximum oocyte length was 1.14 mm for M. microlepis and 1.02 mm for M. rheocharis and both species were characterized as total spawners based on the type of oocyte development estimated through oocyte size analysis. Features like non-seasonal reproductive period, low fecundity, and insemination may indicate adaptive advantages, which may enhance the chance of survival even with low energetic investment and improved fertilization.(AU)

Reproductive biology of the lambari Hyphessobrycon santae (Eigenmann, 1907) (Pisces: Characidae) in the Fazenda Lagoa do Nado Urban Park, São Francisco river basin, Minas Gerais/Brazil / Biologia reprodutiva do lambari Hyphessobrycon santae (Eigenmann, 1907) (Pisces: Characidae) no Parque Urbano Fazenda Lagoa do Nado, bacia do rio São Francisco, Minas Gerais/Brasil

In order to study the lambari Hyphessobrycon santae reproductice cycle, GSI, spawning, sex ratio and first maturation, a total of 223 individuals (124 females and 99 males) were captured, from November /2006 to October/2007 in the Fazenda Lagoa do Nado urban park, Belo Horizonte/Minas Gerais. Through macro and microscopic gonad features and variations in the GSI values, stages of the reproductive cycle were determined: 1: resting, 2: maturing/mature and 3: spawned for females and spent for males. An analysis of the stages of the reproductive cycle showed reproductively active fish year around, with an GSI peaks in March/April and September/October. Histological characteristics of ovaries containing post-ovulatory follicles next to oocytes in all phases of development indicate that H. santae presents multiple spawning. The smallest spawned females were in the 2.5 to 3.0 cm length class, while the smallest spent males were in the 3.0 to 3.5 cm class. This study can be used as a tool for the conservation of small characids in artificial environments that predominate in the São Francisco river basin, in Minas Gerais state.

Para estudar o ciclo reprodutivo, IGS, tipo de desova, proporção sexual e tamanho da primeira maturação sexual do lambari Hyphessobrycon santae, capturou-se um total de 223 exemplares (124 fêmeas e 99 machos), no período de novembro/2006 a outubro/2007 no parque urbano Fazenda Lagoa do Nado, Belo Horizonte/Minas Gerais. Através de características macro e microscópicas das gônadas e as variações dos valores do IGS determinou-se os estádios do ciclo reprodutivos: 1:repouso, 2:em maturação/maduro e 3: desovado para fêmeas e espermeado para machos. A análise dos estádios do ciclo reprodutivo mostrou peixes em atividade reprodutiva o ano todo, com picos de IGS em março/abril e setembro/outubro. Características histológicas de ovários contendo folículos pós-ovulatórios ao lado de ovócitos em todas as fases de desenvolvimento, indicam que H. santae apresenta desova do tipo parcelada. As menores fêmeas desovadas estavam na classe de comprimento 2,5 a 3,0, já os menores machos espermeados estavam na classe 3,0 a 3,5. Esse estudo pode ser usado como ferramenta para a preservação de pequenos caracídeos em ambientes artificiais que predominam na bacia do rio São Francisco no estado de Minas Gerais.

Reproductive biology of the lambari Hyphessobrycon santae (Eigenmann, 1907) (Pisces: Characidae) in the Fazenda Lagoa do Nado Urban Park, São Francisco river basin, Minas Gerais/Brazil / Biologia reprodutiva do lambari Hyphessobrycon santae (Eigenmann, 1907) (Pisces: Characidae) no Parque Urbano Fazenda Lagoa do Nado, bacia do rio São Francisco, Minas Gerais/Brasil

In order to study the lambari Hyphessobrycon santae reproductice cycle, GSI, spawning, sex ratio and first maturation, a total of 223 individuals (124 females and 99 males) were captured, from November /2006 to October/2007 in the Fazenda Lagoa do Nado urban park, Belo Horizonte/Minas Gerais. Through macro and microscopic gonad features and variations in the GSI values, stages of the reproductive cycle were determined: 1: resting, 2: maturing/mature and 3: spawned for females and spent for males. An analysis of the stages of the reproductive cycle showed reproductively active fish year around, with an GSI peaks in March/April and September/October. Histological characteristics of ovaries containing post-ovulatory follicles next to oocytes in all phases of development indicate that H. santae presents multiple spawning. The smallest spawned females were in the 2.5 to 3.0 cm length class, while the smallest spent males were in the 3.0 to 3.5 cm class. This study can be used as a tool for the conservation of small characids in artificial environments that predominate in the São Francisco river basin, in Minas Gerais state.(AU)

Para estudar o ciclo reprodutivo, IGS, tipo de desova, proporção sexual e tamanho da primeira maturação sexual do lambari Hyphessobrycon santae, capturou-se um total de 223 exemplares (124 fêmeas e 99 machos), no período de novembro/2006 a outubro/2007 no parque urbano Fazenda Lagoa do Nado, Belo Horizonte/Minas Gerais. Através de características macro e microscópicas das gônadas e as variações dos valores do IGS determinou-se os estádios do ciclo reprodutivos: 1:repouso, 2:em maturação/maduro e 3: desovado para fêmeas e espermeado para machos. A análise dos estádios do ciclo reprodutivo mostrou peixes em atividade reprodutiva o ano todo, com picos de IGS em março/abril e setembro/outubro. Características histológicas de ovários contendo folículos pós-ovulatórios ao lado de ovócitos em todas as fases de desenvolvimento, indicam que H. santae apresenta desova do tipo parcelada. As menores fêmeas desovadas estavam na classe de comprimento 2,5 a 3,0, já os menores machos espermeados estavam na classe 3,0 a 3,5. Esse estudo pode ser usado como ferramenta para a preservação de pequenos caracídeos em ambientes artificiais que predominam na bacia do rio São Francisco no estado de Minas Gerais.(AU)

BIOLOGIA REPRODUTIVA DO CANGULO REI (Baliste vetula, LINNAEUS 1758) NO LITORAL DE PERNAMBUCO, BRASIL

A espécie Balistes vetula (LINNAEUS 1758) tem grande valor comercial e é de extrema importância para a pesca artesanal do litoral do estado de Pernambuco. Este estudo teve o objetivo de entender acerca da biologia da espécie é essencial para a sua conservação e para um melhor entendimento da dinâmica dos ecossistemas recifais, fornecendo subsídios para uma melhor gestão de manejo para conservação da espécie através de dados como: proporção sexual, tamanho de primeira maturidade (L50), época e tipo de desova. Um total de 202 espécimes foram analisadas, 139 (64,9%) fêmeas e 75 (31,1%) machos, apresentando uma proporção sexual de 1 macho: 1,8 fêmeas; quando analisados por mês, apresentaram, através do teste do x², diferenças significativas nos meses de fevereiro, abril, julho, agosto, setembro, outubro e novembro (P< 0,05). O comprimento padrão (CP) dos machos variou de 13,5 a 33,2 cm (média ± D.P. 24,9 ± 2,22) e peso (PT) entre 111,51 e 1.262,00g (média ± D.P. 661,08 ± 131,07). Para as fêmeas, o comprimento padrão (CP) variou de 15,3 a 32,8 cm (média ± D.P. 25,2 ± 1,97) e peso total (PT) entre 144,51 e 1.117,00g (média ± D.P. 631,73 ± 1,97). A classe de comprimento mais frequente para os machos foi de 17,7 19,1 cm e para as fêmeas de 19,1 20,5 cm. O coeficiente angular estimado na relação comprimento-peso foi de 2,216 e 2,119 para fêmeas e machos, respectivamente. A partir do teste t podemos afirmar que ambos os sexos apresentam um crescimento do tipo alométrico negativo (b<3), ou seja, o crescimento é maior que o ganho de peso. O tamanho de primeira maturação (L50) para as fêmeas foi estimado em 19,11 cm de comprimento padrão (CP), utilizando um n=131 indivíduos. Para os machos foi estimado em 17,91 cm CP utilizando um n=68 indivíduos. Através da análise do número de fêmeas no estágio maduro e dos valores do índice gonadossomático, observou-se que a desova ocorre durante todo o ano, com um período de maior intensidade nos meses de setembro a dezembro com um pico em setembro. A média da fecundidade foi de 385.741 ovócitos variando entre o valor mínimo de 230.660 ovócitos, onde o ovário pesou 33,15 g e o comprimento total (CT) foi de 31,2 cm, com máximo de 677.876 ovócitos, onde o ovário pesou 78,64 g e o CT do peixe foi de 28,6 cm. Ao analisar o desenvolvimento ovocitário, foi observado que B. vetula possui uma desova através de lotes e sincronicamente, onde os ovócitos são eliminados na desova e alguns em menores quantidades se encontram no estoque reserva denominando uma desova total e sincrônica em dois grupos.

The species Balistes vetula (LINNAEUS 1758) has great commercial value and is of extreme importance for artisanal fishing of the coast of the state of Pernambuco. This study aimed to understand the biology of the species is essential for its conservation and for a better understanding of the dynamics of the reef ecosystems, providing subsidies for a better management of conservation for the species through data such as: sexual ratio, size first maturity (L50), season and type of spawning. A total of 202 specimens were analyzed, 139 (64.9%) females and 75 (31.1%) males, presenting a sexual ratio of 1 male: 1.8 females; when analyzed by month, showed significant differences in the months of february, april, july, august, september, october and november(P <0.05) through the x² test. The standard length (SL) of the males ranged from 13.5 to 33.2 cm (mean ± SD 24.9 ± 2.22) and weight (WT) between 111.51 and 1.262.00g (mean ± SD 661.08 ± 131.07). For females, the standard length (SL) ranged from 15.3 to 32.8 cm (mean ± SD 25.2 ± 1.97) and total weight (WT) between 144.51 and 1.117.00g (mean ± SD 631.73 ± 1.97). The most frequent length class for males was 17.7 19.1 cm and for females 19.1 20.5 cm. The estimated coefficient of the length-weight ratio was 2.216 and 2.119 for females and males, respectively. From the t-test we can affirm that both sexes present a growth of the negative allometric type (b <3), that is, the growth is proportionally greater than the weight gain. The first maturation size (L50) for females was estimated at 19.11 cm of standard length (SL), using n = 131 individuals. For males it was estimated at 17.91 cm CP using n = 68 individuals. Through the analysis of the number of females in the mature stage and the values of the gonadosomatic index, it was observed that spawning occurs throughout the year, with a period of greater intensity in the months of September to December with a peak in September. The mean fecundity was 385,741 oocytes ranging from a minimum of 230,660 oocytes, where the ovary weighed 33.15 g and the total length (LT) was 31.2 cm, with a maximum of 677,876 oocytes, where the ovary weighed 78.64 geo CT of the fish was 28.6 cm. When analyzing oocyte development, it was observed that B. vetula spawns through lots and synchronously, where the oocytes are eliminated in the spawning and some in smaller quantities are in the reserve stock, denominating a total and synchronous spawning in two groups.

Reproductive biology of Bryconamericus iheringii (Ostariophysi: Characidae) from rio Vacacaí, RS, Brazil

In this paper we describe some aspects of the reproduction and development of secondary sexual characters of Bryconamericus iheringii, based on the analysis of 194 females and 210 males collected monthly in the rio Vacacaí (30º21'34"S and 54º18'48"W), from April 2001 to March 2002. The reproductive period occurred from September to January (spring and summer in the Southern Hemisphere), as described for other characids of the same area. The absolute fecundity mean was 933.71 ± 303.10 oocytes, and the relative fecundity mean was 0.36 ± 0.08 oocytes per mg of total weight, being the species a multiple spawner. There was no correlation between the values of GSI and variation of biotic (stomach repletion and hepatosomatic indexes) and abiotic data (rainfall, day length and temperature) but we suggest that these factors can influence the reproduction of the species acting as "starters" of the beginning of gonadal maturation. Fin-ray hooks consist in a sexually dimorphic character of the species. Well developed hooks were found mainly in mature males, during the reproductive period and in the largest individuals.

Neste trabalho são descritos aspectos da reprodução e do desenvolvimento de caracteres sexuais secundários em Bryconamericus iheringii. Foram analisados 194 fêmeas e 210 machos coletados mensalmente no rio Vacacaí (30º21'34"S e 54º18'48"W), de abril de 2001 a março de 2002. O período reprodutivo ocorreu de setembro a janeiro (primavera e verão no hemisfério sul), como descrito para outros caracídeos da mesma região. A fecundidade absoluta média foi de 933,71 ± 303,10 ovócitos e a fecundidade relativa média foi de 0,36 ± 0,08 ovócitos por mg de peso total, sendo a desova do tipo parcelada. Não houve correlação entre os valores de IGS e a variação dos dados bióticos (índices de repleção e hepatossomático) e abióticos (pluviosidade, fotoperíodo e temperatura) mas sugere-se que estes fatores possam influenciar na reprodução da espécie, atuando como desencadeadores do início da maturação gonadal. Ganchos nas nadadeiras ventrais e anal dos machos consistiram em caracteres de dimorfismo sexual da espécie. Ganchos bem desenvolvidos são encontrados principalmente em machos maduros, durante o período reprodutivo e nos maiores indivíduos.

Reproductive biology of Bryconamericus iheringii (Ostariophysi: Characidae) from rio Vacacaí, RS, Brazil

In this paper we describe some aspects of the reproduction and development of secondary sexual characters of Bryconamericus iheringii, based on the analysis of 194 females and 210 males collected monthly in the rio Vacacaí (30º21'34"S and 54º18'48"W), from April 2001 to March 2002. The reproductive period occurred from September to January (spring and summer in the Southern Hemisphere), as described for other characids of the same area. The absolute fecundity mean was 933.71 ± 303.10 oocytes, and the relative fecundity mean was 0.36 ± 0.08 oocytes per mg of total weight, being the species a multiple spawner. There was no correlation between the values of GSI and variation of biotic (stomach repletion and hepatosomatic indexes) and abiotic data (rainfall, day length and temperature) but we suggest that these factors can influence the reproduction of the species acting as "starters" of the beginning of gonadal maturation. Fin-ray hooks consist in a sexually dimorphic character of the species. Well developed hooks were found mainly in mature males, during the reproductive period and in the largest individuals.

Neste trabalho são descritos aspectos da reprodução e do desenvolvimento de caracteres sexuais secundários em Bryconamericus iheringii. Foram analisados 194 fêmeas e 210 machos coletados mensalmente no rio Vacacaí (30º21'34"S e 54º18'48"W), de abril de 2001 a março de 2002. O período reprodutivo ocorreu de setembro a janeiro (primavera e verão no hemisfério sul), como descrito para outros caracídeos da mesma região. A fecundidade absoluta média foi de 933,71 ± 303,10 ovócitos e a fecundidade relativa média foi de 0,36 ± 0,08 ovócitos por mg de peso total, sendo a desova do tipo parcelada. Não houve correlação entre os valores de IGS e a variação dos dados bióticos (índices de repleção e hepatossomático) e abióticos (pluviosidade, fotoperíodo e temperatura) mas sugere-se que estes fatores possam influenciar na reprodução da espécie, atuando como desencadeadores do início da maturação gonadal. Ganchos nas nadadeiras ventrais e anal dos machos consistiram em caracteres de dimorfismo sexual da espécie. Ganchos bem desenvolvidos são encontrados principalmente em machos maduros, durante o período reprodutivo e nos maiores indivíduos.