Population genetic structure revealed by a school of the freshwater migratory fish, Brycon hilarii

Abstract

ABSTRACT. It is believed that different genetic populations of migratory fishes can co-exist in a single hydrographic system. Although different populations may occupy and explore the river together, they segregate during the spawning season and consequently the population genetic structuring is maintained. Genetic variation of a Brycon hilarii spawning school and samples from different collection sites in the Miranda River basin were surveyed using seven microsatellites. Population structuring was revealed by a significant differentiation of the spawning school related to the supposed local populations. The genetic differentiation detected may be supported by behavior during the reproductive season that promotes the maintenance of the genetic integrity of different populations. These data may contribute toward the understanding of the behavior and biology of these fish as well as fishery management and species conservation programs. Keywords: Characidae, Bryconinae, neotropical fish, population structuring, microsatellite, Brasil.Estructura genética poblacional revelada por un cardumen del pez migratorio de agua dulce, Brycon hilarii RESUMEN. Se ha documentado que diferentes poblaciones genéticas de peces migratorios pueden coexistir en un único sistema hidrográfico. Diferentes poblaciones pueden ocupar y explorar el río juntas, pero se segregan durante la temporada de desove y consecuentemente la estructuración genética poblacional se mantiene. La diversidad genética de un cardumen reproductivo de Brycon hilarii y muestras de diferentes sitios en la cuenca del Río Miranda fueron analizadas mediante siete microsatélites. La estructura poblacional fue revelada por una diferenciación genética significativa del cardumen reproductivo con las muestras de las poblaciones locales. La diferenciación genética detectada puede ser resultado de un probable comportamiento durante la temporada reproductiva, que promueve el mantenimiento de la integridad genética de las diferentes poblaciones. Estos datos pueden contribuir a la comprensión del comportamiento y biología de estos peces, así como amparar programas de gestión de la pesca y conservación de las especies.

Predicted impacts of proposed hydroelectric facilities on fish migration routes upstream from the Pantanal wetland (Brazil)

“…While there have not been any basin‐wide studies of spawning sites or ichthyoplankton abundance, there have been a handful of localized studies within the basin. These studies report the presence of ichthyoplankton (Ziober et al, ) or actively migrating adults (Lourenço et al, ; Okazaki et al, ; Pereira et al, ; Resende et al, ; Sanches & Galetti, ) at between one and eight sites within the PHB but outside of the Pantanal sub‐basin. These studies have been conducted in streams ranging from first to fourth order, and represent 35% of the 23 migratory fish species in the basin.…”

“…Fish lengths (mm), provided in parentheses, have been compiled from Assumpção et al (2012), Barros, Moraes Filho, and de Oliveira (2006), Britski et al (2007), and Vazzoler, Suzuki, Marques, and Lizama (1997). Spawning and ichthyoplankton studies from the basin have been footnoted by species Sanches and Galetti (2012). c Okazaki, Hallerman, de Resende, and Hilsdorf (2017).…”

Polygynandry and high genetic diversity supported by kinship and population genetics from neotropical catfish ichthyoplankton

“…Such aggregation for spawning in P. maculatus is supported by field observations of mature adults in the lotic portions of the reservoirs (Dei Tos et al, 2002). Aggregations of mature adults have been also detected by molecular markers in other migratory species, such as Salminus brasiliensis (Sanches & Galetti Jr, 2012). Therefore, it is likely that P. maculatus still aggregates breeders for simultaneously spawning even in reservoirs with a small number of tributaries as in the case of Canoas I and Canoas II in the Paranapanema River.…”