Episodic recruitment of young Prochilodus lineatus (Valenciennes, 1836) (Characiformes: Prochilodontidae) during high discharge in a floodplain lake of the River Paraná, Argentina

Abstract

Prochilodus lineatus (Val.) is one of the main target species of South American freshwater fisheries. The following null hypotheses regarding juvenile recruitment of P. lineatus were tested: (a) recruitment is not determined by variations in larval abundance and (b) recruitment is not determined by variations in discharge. For this purpose, variations in abundance of larvae in main channel drift and monthly captures of juveniles in a floodplain lake of the River Paraná were examined weekly between 2009 and 2016. Mean annual abundances of larval densities and CPUE of juveniles were correlated with a set of hydrometric variables. A positive correlation was found between the abundance of juveniles with high and persistent flood pulses. By contrast, larval abundance was not correlated with juvenile abundance. Pronounced contrast was found in the recruitment of P. lineatus between years of high and low discharge, which supports the hypothesis that floods are the main determining factor for recruitment of this species.

Arms as areas for larval development of migratory fish species in a Neotropical reservoir and the influence of rainfall over abundances

“…et al, 2004) Lozano et al (2019). found a positive relationship between the abundance of juveniles of P. lineatus and high and persistent flood pulses in an undammed stretch in the Paraná River, supporting the hypothesis that floods are the determining factor for the recruitment of this species.…”

“…The rates of fish larvae predation are greater in environments with more transparent water, such as that of reservoirs (Agostinho et al ., 2007), and even in the shelter provided by structured environments, such as that of the arms, high predation is still likely to occur. Although catches of larvae in the arms indicate their use for initial development, only with studies that assess recruitment in this structured environment will it be possible to determine the reproductive success of species (Lozano et al ., 2019).…”

“…The coincidence of greater larval densities with periods of greater rainfall suggests that populations of migratory species respond to the same environmental stimuli to reproduction as conspecifics in nondammed environments. The reproduction of migratory fish is directly linked to the hydrological cycle (Agostinho et al, 2004;Harvey & Carolsfeld, 2003;Lozano et al, 2019;Rosa et al, 2018;Vazzoler, 1996), with the rainfall regime described as a trigger for the reproduction of tropical fish (Lopes et al, 2018;. Rainfall can affect a variety of hydrologic factors, including flow, transparency, electrical conductivity and fluviometric level, which are directly related to spawning (Baumgartner et al, 2008;Vazzoler, 1996) and to the transport and survival of ichthyoplankton and recruitment (Baumgartner Despite the damming limiting the influences of flow velocity and fluviometric level, rainfall apparently influences the onset of migration to free stretches of the tributaries, where the species spawn (Marques et al, 2018).…”

Fish reproductive activity reveals temporal variations predominating spatial heterogeneity in maintaining high functional diversity of a Neotropical reservoir

“…According to the RLQ results, elevated values of electrical conductivity, turbidity and rainfall were associated with the highest occurrence of the larvae of migratory and native species, including Salminus spp., Prochilodus lineatus , Brycon orbignianus , Rhaphiodon vulpinus , Pinirampus pirinampu and Pseudoplatystoma spp. The reproduction of migratory fish is directly linked to the hydrological cycle (Agostinho et al., 2004; Harvey & Carolsfeld, 2003; Lozano et al., 2019; Rosa et al., 2018), and the rainfall regime can be a trigger for tropical fish reproduction (Lopes et al., 2018).…”

Recruitment of migratory fish in free‐flowing rivers with limited floodplain development

“…the Paraná and Paraguay rivers) in their geomorphological and hydrological aspects, as it is more channelized and has steeper slopes, which create a lotic system with limited lateral connectivity. The limited development of floodplains and wetlands isexpected to restrict the recruitment of migratory fish, whose young depend on specific environmentsmainly floodplain lagoons that provide greater habitat diversity, food supply and shelter against predators (Araujo-Lima et al, 2001;Leite, 2004;Lozano et al, 2019).In these river systems, recruitment must take place in other environments, such as the river channel(Silva et al, 2020), which seems less suitable for the development of early stages. In the present study, juveniles were captured in the main channel and tributaries of the Uruguay River, but greater abundances occurred near the mouth of the Ibicuí River (site SS4), where a small floodplain develops during the wet season.…”