Conservation status and bio-ecology of Brycon orbignyanus (Characiformes: Bryconidae), an endemic fish species from the Paraná River basin (Brazil) threatened with extinction

Abstract

Brycon orbignyanus is an endemic species from La Plata basin whose stocks have been presenting significant reductions throughout the Paraná River. Brycon orbignyanus is categorized as an endangered species. This study evaluated aspects of the bio-ecology of this species that may be related to this threat, highlighting its distribution, abundance, and diet as well as the corresponding relationships between its recruitment and flood regimes. Data were obtained from different parts of the upper Paraná River (stretches free and regulated by dams) from 1986 to 2010 with more detailed data collected from the free remnant of this basin. The results indicate that no records for species exist at more than half of the sampling points located in dam-regulated sections of the Paraná River, whereas specimens were collected from 75% sites in the free plain remnant. We observed a remarkable effect of the hydrological regime on recruitment as well as distinct food demands during ontogenetic development, with adults almost exclusively consuming fruits and seeds, revealing that these individuals are supported by riparian vegetation. Thus, it is concluded that changes in the natural flood regime as well as riparian vegetation removal threaten B. orbignyanus populations in the Paraná River basin.

Lista De Especies De Peces De La Cuenca Del Río Queguay, Río Uruguay Bajo

“…personal). También cabe destacar el registro del salmón criollo (Brycon orbignyanus), especie considerada amenazada en toda la cuenca del Plata, cuya depencia trófica de frutos y semillas del monte ripario realza la importancia de la conservación de este tipo de vegetación, en la cuenca y en la región (Tonella et al, 2019). La existencia de especies migradoras es de particular interés ya que representan un gran aporte en el flujo de energía entre diferentes ecosistemas (Willson & Halupka, 1995), lo que resalta la importancia del mantenimiento de la conectividad de los afluentes de la cuenca con los tramos bajos y con el Río Uruguay.…”

Functional DNA annotation from a preliminary de novo genome assembly of Brycon orbignyanus, an endangered Neotropical migratory fish

“…• Brycon orbignyanus, Valenciennes, 1850 (Characiformes: Bryconidae) is an endangered migratory fish, heavily depleted in impounded portions of the Platine Basin in South America, such as the upper Grande River (ROSA; LIMA, 2008;TONELLA et al, 2019). It has been the focus of environmental mitigation initiatives through the practice of hatchery spawning and stocking operations (TONELLA et al, 2019). These programs are still in a relatively early technical-scientific stage, with many unknown variables regarding their real efficiency (e.g.…”