Brycon dulcis Lima & Vieira 2017

Rodrigues, Leydiane Nunes, Silva, Juliana Paulo Da, Lima, Flávio César Thadeo, Ingenito, Leonardo Ferreira Da Silva, Duboc, Luiz Fernando, Machado, Débora Ferreira & Sarmento-Soares, Luisa Maria, 2021, The genus Brycon Müller & Troschel (Ostariophysi: Characiformes: Bryconidae) of Espírito Santo State, Brazil: new records and comments on conservation, Zootaxa 5072 (2), pp. 145-156 : 148

Brycon dulcis Lima & Vieira 2017

Local names. Piabanha, biririca.

Distribution and additional records. Brycon dulcis is recorded from the middle and lower rio Doce basin, in the Minas Gerais and Espírito Santo ( Lima 2017). The species was reported specifically from Espírito Santo State only from the Lagoa Juparanã system, with the last record from the state in 1965, from which it was inferred that the species might have been extirpated from the lower portion of the rio Doce basin ( Lima 2017). Somewhat surprisingly, a juvenile specimen was collected in January 2014 in the Lagoa de Juparanã (UMMZ 250042), which demonstrates that, despite the odds, B. dulcis still survives in the lower portion of the rio Doce basin. Recently a single B. dulcis specimen (MBML 13000, figure 2 ) was captured downstream from Cachoeira do Oito hydropower dam, in the Colatina, Espírito Santo, confirming that this species still occurs in the lower section of rio Doce in Espírito Santo. Lima (2017) also commented on a possible previous occurrence of the species in the rio Santa Maria da Vitória, based on some old lots putatively collected from this river basin. João L. Gasparini (pers. comm.) reported that old fishermen from that area mentioned the previous existence of a fish that was very likely a Brycon species at the rio Santa Maria da Vitória, known by them as biririca (a name still employed for B. insignis at the rio Itabapoana ( Lima 2017). So, apparently, Brycon dulcis once had a distribution extending southward into the rio Santa Maria da Vitória.

Habitat and ecological notes. The Lagoa de Juparanã on the lower rio Doce is the largest coastal lake in Brazil ( Sarmento-Soares et al. 2017). Today, the Juparanã is inhabited by numerous allochthonous species, typical of lentic environments of other biomes such as the piranha Pygocentrus nattereri Kner and the tucunaré Cichla kelberi Kullander & Ferreira. The collapse of Lagoa do Juparanã, mainly caused by eutrophication and habitat destruction, changed its fauna composition (E.H. de Barros, pers. comm.), and most of the native species that previously occurred in the lake are now rare. This is the case of Brycon dulcis , an inhabitant of shallow waters and feeding on allochthonous resources, and its populations are possibly vulnerable to predation by the piranhas, and the juveniles, by Cichla kelberi .

Figures

FIGURE 2. Brycon dulcis, MBML 13000, 250,0 mm SL: Brazil, Espírito Santo, rio Doce basin.