Biological aspects of Hypostomus affinis (Siluriformes: Loricariidae) in Brazilian coastal rivers

Tiago Magalhães Da Silva Freitas,Gilberto Nepomuceno Salvador

doi:10.1590/s2179-975x1121

Tiago Magalhães Da Silva Freitas, Gilberto Nepomuceno Salvador

Open Access

https://doi.org/10.1590/s2179-975x1121

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Abstract

Abstract Aim Determine the length-weight relationship (LWR), the period of reproduction, and evaluate the variation of the condition factor (K) of Hypostomus affinis from two coastal drainages in southeastern Brazil, assessing the influence of the rainfall on these biological aspects. Methods fish were sampled quarterly between April 2008 and April 2010 in tributaries of the Doce River basin (DRB) and the Paraíba do Sul River basin (PSRB). Specimens were caught using gillnets. LWR parameters were assessed by location and sex through a t-test. We used the frequency of mature specimens (FM) to evaluate the breeding period. Both FM and K values were assessed by a sinusoidal equation. Results A total of 492 specimens was captured, of which 128 were from the Doce River basin (DRB) and 364 from the Paraíba do Sul River basin (PSRB). In both areas, specimens showed a negative allometric growth type. We collected mature specimens along the studied period in both drainages, with the highest frequency observed at the beginning of the rainy season. We found a positive correlation between the rate of matures and the local rainfall variation. The condition factor (K) was lower for specimens from DRB and did not show a cyclic trend. On the other hand, we observed a cyclic chance of the K values for the individual from the PSRB, peaking in the transitional dry-rainy period. However, it was not possible to correlate it to the rainfall variation. Conclusions LWR parameters of H. affinis were consistent with data already available in the literature. The rainfall may influence the FM but not the K values. In this case, biological characteristics such as reproduction and (or) feeding may be jointly driving a discrete variation of K values. The reduction in K values in the rainy periods suggests a remarkable energetic cost for the reproductive process. In short, our results help us to understand the life cycle of a fish species within a highly modified environment, especially by dams.

Highlights

The Neotropical armored catfish family Loricariidae, commonly known as plecos, is one of the most species-rich fish families on Earth, with almost one thousand valid species (Fricke et al, 2021; Weber, 2003)
Data on the reproductive traits of H. affinis is missing for the Doce River basin, or it is prevenient from decades ago for the Paraíba do Sul River basin (Mazzoni & Caramaschi, 1997)
The length-weight relationship (LWR) residues were biased between sexes for the set of specimens from the Paraíba do Sul River basin (PSRB)

Summary

Introduction

The Neotropical armored catfish family Loricariidae, commonly known as plecos, is one of the most species-rich fish families on Earth, with almost one thousand valid species (Fricke et al, 2021; Weber, 2003). Harboring about 150 species (Dias & Zawadzki, 2018; van der Laan & Fricke, 2021), the genus Hypostomus Lacepède, 1803 is the richness taxa within loricariids, and most of them are endemic to the Brazilian coastal drainages (Camelier & Zanata, 2015) This genus usually fed on detritus (Power, 1984; Salvador Junior et al, 2009) and shows great adaptability to different habitats, from clear running water with rocky-bed to muddy water with soft bottoms (Garavello & Garavello, 2004; Sales et al, 2016). Data on the reproductive traits of H. affinis is missing for the Doce River basin, or it is prevenient from decades ago for the Paraíba do Sul River basin (Mazzoni & Caramaschi, 1997)

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