Gametogenesis and reproduction of the matrinxã Brycon orthotaenia (Günther, 1864) (Pisces: Characidae) in the São Francisco river, Minas Gerais, Brazil

Abstract

The gametogenesis and reproduction of the matrinxã, Brycon orthotaenia in the São Francisco river, Pirapora Region, Minas Gerais, were studied from December, 1998 to November, 1999. The matrinxã B. orthotaenia is an endemic species in the São Francisco river basin in Brazil and important for commercial fishing. The size of the 1 st gonadal maturation, indicated by the total length of the smallest spent males and spawned female, was 32.0 and 40.5 cm respectively. Reproduction occurred from October to January, when high frequencies of females and males at an advanced ripening/mature stage and spawned females were found. The short spawning period and histological characteristics of spawned ovaries containing only oocytes in stages of initial development, along with post-ovulatory and atresic follicles, indicated that Brycon orthotaenia presents total spawning.Keywords: teleost fish, oogenesis, spermatogenesis, reproductive cycle. RESUMO Gametogênese e reprodução do matrinxã Brycon orthotaenia (Günther, 1864) (Pisces: Characidae) do rio São Francisco, Minas GeraisEstudaram-se a gametogênese e a reprodução de Brycon orthotaenia do rio São Francisco, na região de Pirapora, Minas Gerais, no período de dezembro/1998 a novembro/1999. O matrinxã B. orthotaenia é uma espécie endêmica da bacia do rio São Francisco, Brasil e importante na pesca comercial. O tamanho de 1ª maturação gonadal, indicado pelo comprimento total do menor macho espermiado e da menor fêmea desovada, foi de 32,0 e 40,5 cm, respectivamente. A reprodução ocorreu de outubro a janeiro, quando observam-se altas freqüências de fêmeas e machos no estádio maturação avançada/maduro e fêmeas desovadas. O curto período de desova e as características histológicas de ovários desovados, contendo somente ovócitos nos estádios iniciais de desenvolvimento ao lado de folículos pós-ovulatórios e atrésicos, indicam que a desova de B. orthotaenia é do tipo total.Palavras-chave: peixe teleósteo, ovogênese, espermatogênese, ciclo reprodutivo.

Wide reproductive period of a long-distance migratory fish in a subtropical river, Brazil

“…The same relationship between the reproductive period and precipitation was observed for Salminus franciscanus Lima, Britski, 2007, for which the beginning of the reproductive period and an increase in the GSR occur in October, coinciding with the beginning of the rainy season in the São Francisco River Basin (Freitas et al, 2013). In the same watershed, Gonçalves et al (2006) also found that the reproductive period of the migratory fish B. orthotaenia occurs in the same period, between October and January. Salminus brasiliensis (cited as S. maxillosus) from the Upper Paraná River show a reproductive period between October and January (Vazzoler, 1996), similar to that observed for S. franciscanus from the São Francisco River (Freitas et al, 2013).…”

“…In this way, as the condition factor of each fish is also affected by the gonad weight, the presence of individuals at different maturity stages in the same month can cause an increase in the monthly average dispersion of K values. When fish show a short reproductive period, as reported for S. brasiliensis in the Paraná River (Barbieri et al, 2001) and for matrinxã Brycon orthotaenia Günther, 1864 (Gonçalves et al, 2006), it is observed that the GSR increase is directly associated with the condition factor values. A similar situation occurs in fish with a marked seasonality in feeding rate, such as the tambaqui Colossoma macropomum (Cuvier, 1816) (Villacorta-Correa, Saint-Paul, 1999) and the pacu-toba Mylossoma cf.…”

“…The reproductive process constitutes the basis of the knowledge of the species life cycle (Chaves, Vazzoler, 1984) and can exhibit seasonal variations depending on the environment (Winemiller, 1993). In the Neotropical region, the reproductive timing of long-migratory species usually occurs between spring and summer, with greater intensity between November and January (Gonçalves et al, 2006;Boncompagni Junior et al, 2013;Nunes et al, 2015). This period is associated with temperature (Reynalte-Tataje et al, 2012), precipitation, electrical conductivity and water level and flow increase (Welcomme, 1979;Vazzoler, 1996;Fernandes et al, 2009).…”

Influence of a large dam and importance of an undammed tributary on the reproductive ecology of the threatened fish matrinxã Brycon orthotaenia Günther, 1864 (Characiformes: Bryconidae) in southeastern Brazil

“…Species in this genus are among the most threatened in Brazilian rivers and have been since the 1970s (Godoy, 1975). The matrinxã Brycon orthotaenia Günther, 1864, is a benthopelagic, predominantly herbivorous species endemic to the rio São Francisco basin which migrates during its reproductive period (Alvim & Peret, 2004;Gonçalves et al, 2006). Its body weight may reach more than 7 kg, thus it is a very important fish for commercial and sport fishing (Gonçalves et al, 2006).…”

“…The matrinxã Brycon orthotaenia Günther, 1864, is a benthopelagic, predominantly herbivorous species endemic to the rio São Francisco basin which migrates during its reproductive period (Alvim & Peret, 2004;Gonçalves et al, 2006). Its body weight may reach more than 7 kg, thus it is a very important fish for commercial and sport fishing (Gonçalves et al, 2006). In riparian forests in the Neotropics, fruits and seeds is an essential part of the diet of adult Brycon species; and thus these fish play an important role in the dispersal of plants (Azevedo et al, 2011).…”