Reproductive biology of the armored catfish Neoplecostomus microps in a coastal Atlantic Forest stream, southeastern Brazil

Vd Carvalho Alves,Mfg Brito,Ep Caramaschi

doi:10.3354/ab00706

Abstract

This work aims to analyze reproductive attributes of the species Neoplecostomus microps (Steindachner, 1877), a well-known species of the catfish family Loricariidae but little con - templated in ecological studies. We describe the reproductive behavior of the species and compare the patterns identified in 2 different basins. The specimens (117 males and 102 females), collected in the Macae River, did not present a bias in sex ratio during the year. In the largest length classes, males predominated and attained earlier maturity than females. The length−weight relationship showed positive allometric growth for both sexes. The variation of the gonadosomatic index and frequency of maturation stages indicated a reproductive period of 4 to 6 mo, starting in September and reaching a peak in November. The mean absolute fecundity was 43.83 (SD = 7.62) oocytes, ranging from 32 to 55 oocytes. The frequency distribution of oocyte diameter of mature ovaries revealed 3 clutches, suggesting batch spawning. A prolonged reproductive period, low fecundity, large eggs, possible parental care, and repeated spawns recorded for N. microps suggest a strategy that maximizes parental fitness. The population structure and reproductive characteristics of this species indicate a tendency toward equilibrium. The early maturation in females in the Macae River population may favor a more rapid replacement of juveniles in the population as a response to the unstable environmental conditions that the population experiences in the rainy season.

Highlights

Loricariid catfishes are important components of the stream ichthyofauna (Buckup 1999) throughout most of the Neotropics (Ferraris 2003a)
The sex ratio did not differ from 1:1, considering months and localities grouped in total, despite the slight predominance of males over females
Considering sex ratio in the different localities, no significant differences were observed, but differences were found in March 2004 and July 2004, with male predominance

Summary

Introduction

Loricariid catfishes are important components of the stream ichthyofauna (Buckup 1999) throughout most of the Neotropics (Ferraris 2003a). Their representatives typically inhabit lotic environments (Sterba & Mills 1983, Sakurai et al 1993) and consume algae and detritus (Flecker 1992, Power 1984). Distinct from other fish groups, the dispersion of the family occurs almost exclusively at the primary trophic level, with adaptations involving morphology, feeding behavior, Species of the genus Neoplecostomus are distributed in rivers and streams in south-central Brazil (Ferraris 2003b, Buckup 2007, Zawadzki et al 2008). Studies on distribution pattern, sexual dimorphism, nesting sites, and some reproductive attributes were published for populations in the Paraíba do Sul and Macaé River basins (Braga et al 2008, Brito et al 2016)

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