Spawning induction and embryonic development of Salminus hilarii (Characiformes: Characidae)

Abstract

Summary The present study aimed to evaluate two different methods of artificial reproduction induction, and characterize the embryonic development of Salminus hilarii. Different than observed for other tropical fish species, artificial reproduction induction followed by hand-stripping of gametes was considered unfeasible for S. hilarii, as no gamete fertilization was observed. However, females that were induced and spawned naturally presented a fertilization rate of 65.64 ± 0.54%. With a mean temperature of 26.20 ± 0.90ºC it was possible to clearly distinguish a large perivitelline space at 14 min after fertilization (AF) and at 49 min AF more than 50% of the embryos presented two blastomeres, and these cleavages occurred until 1 h 54 min AF. The gastrula phase was characterized at 3 h 56 min AF, and blastopore closure was observed at 8 h 31 min AF. At 9 h 1 min, organogenesis started, with a clear distinction of the yolk mass, embryonic axis, cephalic and caudal regions; at 11 h 51 min AF the embryos already had advanced segmentation and a free tail. Total hatching occurred at 21 h 17 min and after opening the mouth, which occurred at 33 h 9 min, the larvae of S. hilarii presented a strong and characteristic cannibalism. This information can be considered fundamental to improving S. hilarii production in captivity and for collaboration with a conservation programme in the upper Tietê river basin.

Early development ofProchilodus nigricansSpix & Agassiz 1829 (Characiformes: Prochilodontidae) in captivity

“…After fertilization, rapid hydration and obtaining the ample perivitelline space in Prochilodus eggs is a characteristic related to the reproductive behaviour of migratory fish that present external fertilization and development, without parental care, leaving their offspring free in the water column (Abdo et al, 2015; Arias‐Gallo et al, 2010; Orsi et al, 2016). This characteristic is also observed in other genera of Characiformes with the same reproductive strategy, as in Leporinus piau (Borçato et al, 2004), Piaractus brachypomus (Lima, 2014), Colossoma macropomum (Almeida, 2014), Brycon nattereri (Maria et al, 2017) and Salminus hilarii (Araújo et al, 2020).…”

Efeito da sazonalidade na reprodução de peixes Characiformes em um rio Neotropical

“…Estudos que investigaram o ciclo reprodutivo de tabaranas mostraram que o seu período reprodutivo varia entre os meses de outubro a fevereiro (Godoy, 1975;Villares Junior et al, 2007), mesmo padrão encontrado no presente trabalho e para as espécies de piracema na bacia do Alto Paraná (Vazzoler & Menezes, 1992). Estudo recente realizado por Araújo et al (2020) avaliou a indução da reprodução e caracterizou o desenvolvimento embrionário de S. hilarii, constatando a influência da temperatura da água sobre os eventos reprodutivos da espécie. Para o rio Sorocaba, o maior número de indivíduos nos estádios em maturação e maduros nos meses de novembro e dezembro, indicam um padrão sazonal reprodutivo para as espécies estudadas.…”