Importance of a turbulent river section below a giant waterfall for fish spawning: Indications from drift and dispersion patterns of early life stages

Makrakis, Maristela Cavicchioli; Refatti, Alcione; Keckeis, Hubert; Silva, Patrícia S. da; Assumpção, Lucileine de; Kashiwaqui, Elaine Antoniassi Luiz; Gamaro, Paulo Everardo Muniz; Makrakis, Sérgio

doi:10.1002/eco.2356

Cited by 6 publications

(3 citation statements)

References 60 publications

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“…On the contrary, the frequency of fish eggs and larvae sampled in the surface sampling may be attributed to the greater presence of pelagic eggs and the turbidity of the sampled rivers. Recent studies have suggested that precipitation and turbidity are the main triggers for spawning, which provide higher densities of fish eggs and larvae under these conditions (Brambilla et al ., 2022; Lopes et al ., 2019; Makrakis et al ., 2022). Furthermore, it is known that the presence of eggs may be the result of past events ( i.e ., 1–3 days earlier; see Nakatani et al ., 2001); consequently, the density of eggs may be attributed to the time from development to hatching and not only to the spawning time.…”

Section: Discussionmentioning

confidence: 99%

Spatial and seasonal distribution of fish eggs and larvae in one free‐flowing river in the Neotropical savanna

Carnicer

Lima

Taguti

et al. 2023

Journal of Fish Biology

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Reproduction is one of the most important biological aspects for the maintenance of viable populations, and understanding the spatial and seasonal patterns in the reproduction of Neotropical fish is a point that still needs considerable investigation. In this study, the main aim was to reduce knowledge gaps concerning fish eggs and larvae distribution patterns. Therefore, the River Araguaia basin, one of the main hydrographic basins of the Neotropical savanna, was used as the focal point of study. Samplings of fish eggs and larvae were carried across the hydrological regime during flooding and drought events between December 2018 and July 2020 at 15 sites distributed along a 350 km stretch of the River Araguaia basin. Fish eggs and larvae were found in all sampling sites, with the highest number of catches in the flood season. The fish larvae were represented by 5 orders, 22 families and 22 at the genus or species level. Both environments, tributary and main channel of the River Araguaia, are important for fish reproduction, and no difference was found in the use between the main channel and the tributaries. The results showed that spatial factors are important to explain the change in larval composition, which may have a wide or restricted distribution related to specific habitats. The main factors related to the reproductive activity of fish in this region are the physical and chemical changes in the water that occur in the flood season. These results indicate that the River Araguaia basin has environmental integrity and provides favourable conditions for the reproductive activity of fish, including long‐distance migratory species. Considering this, mitigate measures that guarantee the preservation of the natural flow are crucial for the maintenance of fish biodiversity.

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Section: Discussionmentioning

confidence: 99%

Spatial and seasonal distribution of fish eggs and larvae in one free‐flowing river in the Neotropical savanna

Carnicer

Lima

Taguti

et al. 2023

Journal of Fish Biology

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“…Due to the capture of eggs in development having been recorded close and even in these rapids, we confirm that this region should be considered an essential area of gene flow for the ichthyofauna of the Tapajós River. This result was expected since stretches with high water flow are conducive to intense reproductive activity, especially of migratory species (Silva et al, 2012;Ávila-Simas et al, 2014;Makrakis et al, 2022). However, more in-depth studies investigating the embryonic stages are needed to define spawning areas with greater precision.…”

Section: Figurementioning

confidence: 93%

Ichthyoplankton and plastic waste drift in a river in the Amazon Basin, Brazil

Oliveira

Oliveira-Junior²,

Cajado³

et al. 2023

Front. Environ. Sci.

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Egg and larvae drift is a key mechanism for early fish stages to colonize nursery and growth areas and provides insights into ichthyofauna spawning times and spawning locations—crucial information for understanding fish biology. In the Tapajós River, Amazon Basin, no study has investigated the drift of ichthyoplankton along the hydrological phases nor the occurrence and dispersion of plastic waste associated with plankton. Thus, we aimed to present an overview of the spatio-temporal drift of ichthyoplankton and plastic waste in this river. Temporal sampling was carried out along a spatial gradient of approximately 300 km, covering different sectors of the river. Ichthyoplankton and plastic waste were captured through horizontal trawls on the subsurface of the water column for 10 min. Fish larvae belonging to 10 taxonomic orders and with an average size of 4.98 mm ± 3.14 mm were captured. Clupeiformes larvae occurred in all hydrological phases and reproductive peaks for other orders were recorded. Plastic waste was classified into 20 types according to color and shape and an average size of 1.55 mm ± 1.27 mm. Green fragments and blue filaments were the most abundant. We found the highest density of fish eggs and larvae drifting during the drought phase in stretches with greater environmental structure, whereas plastics were more abundant during the receding water phase in more turbulent stretches that have impacts from illegal mining. Simultaneous drift of ichthyoplankton and plastic waste was recorded in all hydrological phases and sampled sectors. This is worrying because, although we did not analyze the ingestion of plastics by fish larvae, plastic waste can enter the nursery areas of the Tapajós River and reduce the function of these areas for fish. Here we discover through the high densities of fish eggs and larvae deriving that the Tapajós River is an important reproduction site for ichthyofauna and that the presence of different landscape configurations prove to be a key factor in the dispersion, retention and development of ichthyoplankton and plastic waste.

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“…The downstream drift of larval fish, from spawning sites to favourable nursery habitats in floodplains, is a fundamental process for the recruitment success of populations for many riverine fish species (Lechner et al, 2016; Nagel et al, 2021; Pavlov, 1994). Inshore zones within the channel generally support greater larvae diversity and abundance than adjacent offshore areas and therefore play an essential role in feeding, growth and survival of larval fish (Lechner, Keckeis, Schludermann, Humphries, et al, 2014; Makrakis et al, 2022; Mills & Mann, 1985). Compared to the deep and fast‐flowing offshore areas, inshore habitats of unmodified rivers often exhibit large shallow areas with slow flow velocities and high structural complexity.…”

Section: Introductionmentioning

confidence: 99%

Shoreline hardening affects species composition and condition of larval fishes in the Yangtze River: Implications for conservation and inshore habitat restoration

et al. 2023

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Inshore habitats play a crucial role in the downstream drift of larval fish in large rivers. Natural inshore habitats of most of the world's large rivers have been heavily degraded by shoreline stabilization measures, but the knowledge about consequences for the condition and distribution of larval fishes is extremely limited. Investigations during the peak season of larval drift into species composition as well as into feeding intensity and body injuries of representative taxa were conducted at different inshore mesohabitats along semi‐natural and stabilized shores in a free‐flowing section in the middle Yangtze River. Species were unambiguously identified by a combination of DNA barcoding and morphological analyses. Overall, 37 taxa from seven families were detected from a total of 9,915 fish larvae caught. Earlier developmental stages greatly outnumbered the later stages in diversity and abundance in each investigated mesohabitat. Abundance and assemblage structure as well as the body injury rate differed significantly between mesohabitats. Generally, overall species richness and abundance tended to be lower, and divergence of the assemblage and body injury rates tended to be higher at heavily hardened shores, which could be contributed to the poor riparian vegetation and restricted suitable hydraulic conditions there. Our results may reflect the underestimated impact of inshore habitat degradation on larval fishes and highlight the demand for creating adequate areas of shallow and slow‐flow habitats with good riparian vegetation conditions along the shores. These measures will foster an appropriate connectivity between spawning areas and high‐quality nurseries for larval fishes.

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Importance of a turbulent river section below a giant waterfall for fish spawning: Indications from drift and dispersion patterns of early life stages

Cited by 6 publications

References 60 publications

Spatial and seasonal distribution of fish eggs and larvae in one free‐flowing river in the Neotropical savanna

Spatial and seasonal distribution of fish eggs and larvae in one free‐flowing river in the Neotropical savanna

Ichthyoplankton and plastic waste drift in a river in the Amazon Basin, Brazil

Shoreline hardening affects species composition and condition of larval fishes in the Yangtze River: Implications for conservation and inshore habitat restoration

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