Comparative analysis of the reproductive activity of Leporinus piau (Characiformes: Anostomidae) in lentic and lotic environments

Abstract

In this study, we determined the main reproductive parameters of piau gordura, Leporinus piau, in two sections of the São Francisco River basin. Between May 2015 and April 2016, a total of 573 specimens were captured from a lentic environment (section 1), the Três Marias Reservoir (TMR), and a lotic environment (section 2), downstream of the TMR at the confluence of the São Francisco River (SFR) with the Abaeté River. Analysis of reproductive activity showed that L. piau from both sections reproduced, but females and males from section 1 exhibited higher total length, body weight, Fulton condition factor, and gonadosomatic index values, as compared to section 2. Sexual dimorphism was evident in the species, with females being larger than males. Moreover, males reached first gonadal maturation at a smaller size than females. The peak maturation/mature stage was observed in November/April for females and males in section 1 and in November/December in section 2, coinciding with high temperatures and precipitation in the region. In both sections of the river, L. piau exhibited the typical characteristics of partial spawning, with a prolonged spawning period, and preferential reproduction in lentic environments.

Morphological analysis of the reproductive activity of Curimatella lepidura (Characiformes: Curimatidae)

“…The largest females and males at gonadal maturation were recorded in section 1, which may be related to food availability and differences in environmental conditions between the studied sections (Brandão et al, 2017). The present study found that males reached first gonadal maturation at a smaller size than females, as observed for other species in the SFR (Bazzoli et al, 2019; Nascimento et al, 2020).…”

“…In other studies, a similar sex ratio was also observed in the species Pygocentrus piraya (Ferreira et al, 1996), Serrasalmus brandtii (Bazzoli et al, 2019) and Leporinus piau (Nascimento et al, 2020) in the São Franscisco River. However, the differences in sex ratio found in the different sections may be related to the selectivity of fishing equipment, population stratification, and variation in fish growth rates (Carvalho et al, 2009).…”

“…In C. lepidura, the cells of the spermatogenic lineage were observed in the germinal epithelium, similarly observed in other fish (Santos et al, 2019). (Bazzoli et al, 2019;Ervilha et al, 2022;Nascimento et al, 2020) were observed alongside follicles at all stages of development, confirming that spawning in C. lepidura is of the partial type.…”

“…This is similar to the classifications used for other species by Normando et al (2014) for the SFR basin and Bazzoli et al (2019) for the Jequitinhonha River basin. Fish were found in reproductive activity during most of the year, and spawning females presenting post‐ovulatory follicles (Bazzoli et al, 2019; Ervilha et al, 2022; Nascimento et al, 2020) were observed alongside follicles at all stages of development, confirming that spawning in C . lepidura is of the partial type.…”

“…Hydrological and thermal alterations affect fish reproduction, including species that depend on lotic environments for spawning (Abdo et al, 2018; Brandão et al, 2017). Further downstream, after the confluence with a medium‐sized tributary (Abaéte River, section 3), the SFR has better conditions in terms of water temperature, dissolved oxygen, and flow rate, which favourably influence reproduction (Bazzoli et al, 2019; Nascimento et al, 2020).…”