Recruitment dynamics of a migratory fish in a semiarid river system

Silva, Fernanda de Oliveira; Neto, Francisco Ricardo de Andrade; Silva, Samara Hermes; Silva, Jade De Oliveira Da; Zaniboni‐Filho, Evoy; Prado, Ivo Gavião; Peressin, Alexandre; Pelicice, Fernando Mayer

doi:10.1080/20442041.2020.1805977

Cited by 10 publications

(10 citation statements)

References 81 publications

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“…In these systems, recruitment dynamics differ to some degree, especially because the absence of wetlands affects the availability of nursery areas. For example, a recent study carried out in the upper Jequitinhonha River, where floodplain areas are limited, showed that spawning takes place at multiple sites along the main channel and in tributaries, while the confluence of small streams acts as nursery grounds (Silva et al, 2020). Few studies have been conducted in these systems, so migration and recruitment dynamics remain poorly understood.…”

Section: Introductionmentioning

confidence: 99%

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

Pachla

Hartmann

Massaro

et al. 2022

Aquatic Conservation

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1. Hydrological connectivity is a basic feature of river ecosystems, responsible for important ecological processes. Human activities, however, have progressively modified natural connectivity, threatening the maintenance of aquatic biodiversity.2. Neotropical potamodromous fish depend heavily on fluvial connectivity to complete their life cycles. However, important ecological aspects remain poorly understood, especially in river systems with limited floodplain development (i.e. channelized rivers and drylands), where the environment poses constraints to fish recruitment. The Uruguay River Basin is such a system, with several migratory fish, small floodplain areas, and limited information about recruitment dynamics and nursery grounds. 3. The lack of information on critical habitats limits conservation and management actions, especially in scenarios of increasing environmental degradation and river regulation. This study investigated recruitment dynamics of migratory fishes in the Middle Uruguay River, a long fluvial segment targeted for hydropower development. The study investigated spatial variations in the abundance, composition and size structure of juvenile fish among different sites along an extensive fluvial gradient (ca. 650 km), comparing the main channel with tributaries.4. Juveniles of migratory fish were widely distributed in the region, totalling nine species, with a predominance of Characiformes. Spatial distribution was variable among species and size classes, with a differential use of tributaries, wetlands and the main channel. Juvenile composition differed between sampling sites and environments, and was correlated with different limnological and spatial variables.Greater abundances occurred in the mouth of a tributary where a small floodplain develops during the wet season.5. The results emphasize the importance of fluvial connectivity for fish migration, dispersal and recruitment, providing valuable information about migratory fishes in river systems with limited wetland development. These findings have significance for the management and conservation of migratory fish under scenarios of hydropower expansion, as comprehensive studies on recruitment are rare in free-flowing rivers.

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Section: Introductionmentioning

confidence: 99%

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

Pachla

Hartmann

Massaro

et al. 2022

Aquatic Conservation

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“…Neotropical migratory fish rely heavily on environmental cues, such as variations in river flow and water conductivity, to complete their migratory and reproductive cycles (Lopes et al, 2018), and these environmental parameters are greatly affected by dam construction and operation. The environmental impacts of damming are numerous and include both downstream and upstream changes in river flow, water quality and ecosystem functioning (Bailly, Agostinho & Suzuki, 2008;Luz-Agostinho et al, 2009;Nestler et al, 2012;Pelicice, Pompeu & Agostinho, 2015;Silva et al, 2020). In this scenario, changes to the behaviour of migratory fish are expected to occur.…”

Section: Introductionmentioning

confidence: 99%

Dazed and confused: Behavioural constraints impose major challenges to fish passage in the neotropics

Lopes

Alves²,

Peressin

2021

Aquatic Conservation

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1. The role of fish translocation upstream of dams, for the conservation of migratory species, is controversial. An important but still unaddressed question is whether migratory patterns are affected, after the translocation events, by a hydropower dam. In existing dams, a useful means to test this might be to compare the behaviour of translocated fish with those in undammed river segments in the same region.2. The objective of this study was to evaluate the effectiveness of fish translocation in promoting access to spawning areas through a behavioural approach using Prochilodus costatus as a study model in the São Francisco River, south-east Brazil.3. The reservoir acted as a barrier to the dispersal of translocated individuals with only a small fraction of the population able to locate lotic stretches in the tributaries. Individuals translocated to undammed stretches of river upstream of the reservoir exhibited movement behaviour that was markedly different from that of individuals native to this region. Translocated individuals mainly displayed an erratic pattern of movement between upstream and downstream stretches of river with no specific route. In contrast, local individuals made long-distance upstream spawning migrations and downstream return migrations to feeding sites during specific periods of the year. The results indicate that translocating individuals upstream of Três Marias damtends to be ineffective for the conservation of P. costatus in the region. The study showed that the behaviour of translocated individuals, a largely neglected factor for the tropical region, may be an additional barrier to the success of conservation programmes based on fish passage systems. For the population studied, the maintenance of a free-flowing stretch where fish are able to complete their life cycle is a more viable and effective alternative for conservation.

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“…The Irapé reservoir is formed by the dam built along the Jequitinhonha Rivers and its tributary Itacambiruçu. It is a large accumulation reservoir with 100 km of extension and 280 days of water residence time (Silva et al, 2020). In operation since 2006, it has a total installed power capacity of 360 MW (Cachapuz, 2006).…”

Section: Study Areamentioning

confidence: 99%

Vertical distribution of fish in the deepest Brazilian reservoir

Porto

Casarim

Prado

2022

Fisheries Management Eco

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Despite the large number of dams in most important rivers of Brazil, little is known about fish vertical distribution in neotropical reservoirs, especially deep ones. This study aims to understand how fish were vertically distributed in the deepest reservoir in Brazil, located in the Jequitinhonha River. Three areas of the reservoir were sampled quarterly using an echosounder. The deepest fish detected was at 115 m, but most were shallower than 25 m. Diel vertical migration of fish was detected, but not in all the sampling areas and campaigns. Fish distribution was determined by several limnological factors of the reservoir, but mainly by thermal variation in water column. These results can provide guidance for environmental and fisheries managers and ecologists to improve sampling techniques in deep reservoirs since vertical distribution and its relation with habitat use are determinant to propose management measures in similar ecosystems.

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Recruitment dynamics of a migratory fish in a semiarid river system

Cited by 10 publications

References 81 publications

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

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

Dazed and confused: Behavioural constraints impose major challenges to fish passage in the neotropics

Vertical distribution of fish in the deepest Brazilian reservoir

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