Environmental manipulation on Astyanax altiparanae out of season spawning

Abstract

This study aimed to evaluate the effect of manipulating hours of light and water temperature in some important reproductive parameters for Astyanax altiparanae fish farming during winter. The experiment was conducted from July 3 rd to August 28 th 2013 (57 days), and two groups of 32 couples of fish (G1 and G2) were used. On G1, hours of light and water temperature were not controlled; on G2, otherwise, these variables were manipulated in order to achieve similar conditions to those observed in spring. Every 14 days, eight couples of each group were hormonally induced with carp pituitary gland extract, and eggs were collected after semi-natural spawning. The percentage of females from G2 that spawned was higher than G1 (81.25 vs. 9.38%), the same trend was observed for a number of eggs produced per female (G1: 2,976.57 ± 1,085.71; G2: 8,471.14 ± 860.08). The G2 ovaries presented a higher incidence of primary growth oocytes and post-ovulatory follicles whereas G1 ovaries had more atretic follicles. Economic analysis showed that operational profit from eggs and larvae production on G2 was higher than on G1, as well as the gross margin. In conclusion, the results showed that environmental manipulation might improve reproduction management practices extending eggs and larvae production during the natural non-breeding season. Further studies are necessary to determine more appropriate facilities to be used by farmers in large scale, as well as management protocols to ensure the survival of post-larvae.

GnRHa implants and temperature modulate Lambari‐do‐rabo‐amarelo, Astyanax altiparanae (Characiformes: Characidae) induced reproduction out of the reproductive season

“…During the spring‐summer period, when A . altiparanae is normally induced to spawning in captivity, some reproductive data, such as egg size, plasma levels of MIS, and time of spawning and hatching, remained similar to the data obtained in our study (Abreu et al, 2021; Evangelista et al, 2019; Nascimento et al, 2018).…”

“…Astyanax altiparanae females implanted with GnRHa before spawning induction, regardless of the temperature or dose, showed MIS plasma levels that varied from about 10 to 35 ng/ml, while without GnRH supplementation, MIS plasma levels after spawning induction were about 1 to 2.5 ng/ml (Abreu et al, 2021). During the spring-summer period, when A. altiparanae is normally induced to spawning in captivity, some reproductive data, such as egg size, plasma levels of MIS, and time of spawning and hatching, remained similar to the data obtained in our study (Abreu et al, 2021;Evangelista et al, 2019;Nascimento et al, 2018).…”

“…Vitellogenesis and spermiogenesis apparently occur throughout the year in captivity (Jesus et al, 2017), but with a low gamete production. This gamete production, even if it is low, allows this fish to respond to artificially hormonally induced reproduction, outside the reproductive period, in the winter (Brambila‐Souza et al, 2019; Evangelista et al, 2019). This is an important characteristic for captive rearing and commercial aquaculture, allowing juvenile production throughout the year (Duncan et al, 2013), decreasing the off‐season for the producers.…”

Establishing a model fish for the Neotropical region: The case of the yellowtail tetra Astyanax altiparanae in advanced biotechnology

“…The yellowtail tetra adapts easily into aquaria, aquaculture tanks, and ponds, and it can be fed with artificial commercial pellets. The intertidal spawning pattern allows it to be bred year-round, given that the temperature and photoperiod are manipulated ( Machado-Evangelista et al, 2019 ). The yellowtail tetra presents sexual dimorphism as shown in our recent study ( Siqueira-Silva et al, 2020 ), noting that the male presents bony hooks in the anal and ventral fins that are not present in the females ( Figure 1 ).…”