Reproductive dynamics, age and growth of Astyanax aff. fasciatus in a Neotropical basin

Abstract

Population dynamics provide crucial information for management and conservation. This study analysed the spatial and temporal patterns in reproductive biology, age and growth of Astyanax aff. fasciatus from a Neotropical river. Although located in a priority area for conservation, this river is affected by human activities in the surrounding landscapes. Water and environmental parameters were subjected to principal component analysis (PCA) to characterise the different sampling sites. Length–frequency distributions, gonad development and body indices were used to evaluate maturity and spawning, and to calibrate the von Bertalanffy model to determine the age and growth of A. aff. fasciatus. Reproductive behaviour of the species was not homogeneous along the river, due to geomorphology and human activities in the surrounding areas, with some sites becoming unavailable for breeding. The PCA highlighted the geomorphological, human (first axis) and temporal (second axis) trends influencing the environmental features along the river. Females predominated throughout the basin, and spawning took place from September to June in distinct areas of the river. The species matures at an age of 1–1.5 years, and so tends to be a fast-growing species, with a life span close to 3.5 years. Fish population dynamics should be monitored to support conservation and management, both for the fish species and the aquatic environments.

Diet of Psalidodon aff. fasciatus (Cuvier, 1819) (Teleostei: Characidae) in a neotropical river before reservoir formation

“…The feeding patterns that we found here match the observed by Silva et al (2014) for the same species in Paraná River. Similar results were found by congeneric species such as Astyanax lacustris (Lütken, 1875) (Silva et al, 2012) and Astyanax abramis (Jenyns, 1842) (Leite et al, 2021), which seems to be expected for all species belonging to the Characidae family (Mise et al, 2013;Silveira et al, 2020).…”

Ecomorphology of yellowtail lambari (Characiformes: Characidae) in the neotropical semi-arid region, Brazil

“…In our study, specimens from different localities with distinct environmental characteristics were analyzed, identifying population differences. The difference in size structure between sexes was also observed for other species of the genus in other localities, indicating that females are larger than males (Cordeiro et al, 2019;Pinheiro et al, 2019;Silveira et. al., 2020).…”

Reproductive aspects of an isolated population of Psalidodon aff. fasciatus (Teleostei: Characidae) from southern Brazil

“…fasciatus from Furna 2 showed a male predominance, which contrasts with the typical P. aff. fasciatus female predominance (Carvalho et al, 2009;Silva et al, 2010;Hirt et al, 2011;Silveira et al, 2020), with an exception of Gurgel (2004) who also found a male predominance in a possible oligotrophic environment in the Ceará-Mirim river. The higher number of males found in freshwater fish populations has been linked to oligotrophic environments (Nikolsky, 1969;Gurgel, 2004), which differs from that found in Furna 2 because the environment is stable and the food resource is abundant.…”

“…(A) Relative frequency distribution of males and females of P. aff fasciatus collected in Furna 2 of the VVSP in the period 2019-2020; (B) Posterior distribution of the proportion of females in the naturally-isolated population of P. aff. fasciatus, estimated through the Beta-binomial model using the overall sex ratio captured between February/2019 and January/2020 collected in Furna 2 of VVSP compared with the estimates from the literature(Carvalho et al, 2009;Silveira et al, 2020).…”