Reproduction and Feeding of the Electric Fish Brachyhypopomus gauderio (Gymnotiformes: Hypopomidae) and the Discussion of a Life History Pattern for Gymnotiforms from High Latitudes

Abstract

The reproductive biology and feeding habits of the electric fish Brachyhypopomus gauderio were studied. The species has seasonal reproductive behavior, with breeding occurring during the Southern Hemisphere spring and summer, and having a positive relation with the photoperiod variation. Brachyhypopomus gauderio was defined as a fractional spawner, with low relative fecundity and high first maturation size. Sexual dimorphism was registered, males undergoing hypertrophy of the distal portion of caudal filament. The results on reproductive biology herein obtained are in agreement with data concerning gymnotiforms from Southern Brazil and Uruguay, pointing to an ecological pattern for the species from high latitudes, differing from species with tropical distribution. According to the analysis of the food items, B. gauderio feed mainly on autochthonous insects, likewise the other gymnotiforms previously investigated, leading to conclude that there is no variation on the diet of the species of the order related to climatic conditions or even to habitat of occurrence.

Resource use by two electric fishes (Gymnotiformes) of the National Forest Saracá-Taquera, Oriximiná, Pará

“…Consumption of benthic prey was reported for several species of gymnotiforms (Winemiller, Adite, 1997;Peretti, Andrian, 1999;Giora et al, 2005;Luz-Agostinho et al, 2006;Rocha et al, 2009;Giora et al, 2012;Tesk et al, 2014), suggesting it is a pattern for this fish order (Giora et al, 2014). However, benthic prey was not the only food category consumed by G. rondoni and G. coropinae: both species consumed prey associated with macrophytes (e.g.…”

“…Moreover, gymnotiforms that inhabit Amazonian streams are important components of the ichthyofauna because they act as linkages between detritivorous arthropods and other components of the aquatic system due to their benthivorous diet composed mainly of autochthonous prey (e.g. Giora et al, 2014).…”

A taxonomic revision of the Neotropical electric fish genus Brachyhypopomus (Ostariophysi: Gymnotiformes: Hypopomidae), with descriptions of 15 new species

“…Reproductive biology and life history: Detailed accounts of the reproductive ecology and life history of Brachyhypopomus are available for B. occidentalis from Panama (Hagedorn, 1986;, and for three species from southern subtropical systems: B. bombilla , B. draco (Schaan et al, 2009), and B. gauderio (Giora et al, 2014;Miranda et al, 2008;Quintana et al, 2004;Silva et al, 2007;Silva et al, 2002; (and see species descriptions herein). The reproductive ecology of Amazon and Orinoco species is largely undocumented, although Alves-Gomes (1997) noted spawning preceding seasonal flooding in the rio Branco system of Roraima, Brazil, and Crampton (1996a) observed spawning coincident with the rising-water period and high water period in species from Amazonian floodplains.…”

“…3'), B. gauderio (Silva et al, 2003), B. occidentalis (Hagedorn, 1988), and B. pinnicaudatus (Kirschbaum & Schugardt, 2002). Fractional spawning has been observed in B. bombilla , B. brevirostris (Kirschbaum et al, 2008), B. draco (Schaan et al, 2009), B. gauderio (Giora et al, 2014;Miranda et al, 2008), B. occidentalis (Hagedorn, 1988), and B. pinnicaudatus (Kirschbaum et al, 2008). Kirschbaum & Schugardt (2002) reported egg diameters of approximately 1.7 mm in B. pinnicaudatus, with hatching on day three after spawning, and exogenous feeding beginning on day eight.…”

“…Westby (1988) reported small aggregations of larval Brachyhypopomus beebei in a coastal stream of French Guiana but these were apparently not attended by a parent. However, Giora et al (2014) reported aggregations of larval B. gauderio near single mature males.…”