Trophic relationships in fish assemblages of Neotropical floodplain lakes: selectivity and feeding overlap mediated by food availability

Dias, Rosa Maria; Ortega, Jean C. G.; Gomes, Luiz Carlos; Agostinho, Ângelo Antônio

doi:10.1590/1678-4766e2017035

Cited by 13 publications

(18 citation statements)

References 56 publications

(82 reference statements)

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“…Ichthyofauna in this case largely include small-sized species of high reproductive potential and trophic plasticity. In environments with high levels of food availability, fish species become less selective, resulting in less intraspecific competition (Dias, Ortega, Gomes, & Agostinho, 2017) and affording more chances of success in reservoirs.…”

Section: Discussionmentioning

confidence: 99%

Fish trophic guild responses to damming: Variations in abundance and biomass

Dias

Ortega

Strictar

et al. 2020

River Research & Apps

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Dams and associated reservoirs cause drastic changes in the composition and structure of ichthyofauna. Therefore, functional groups within a fish assemblage may respond distinctly to such human interventions in rivers. The objective of this study was to evaluate how fluctuations in fish abundance and biomass differ among trophic guilds. Fish were sampled before and after damming four reservoirs, in their inner areas (more heavily impacted areas) and upstream (less impacted areas). To evaluate possible changes, we used a before–after and control‐impact experimental design. Fish were classified into trophic guilds through diet analysis and based on information available from the literature. Six trophic guilds were identified. The effect of periods (before and after damming) and sites (more and less impacted) on abundance and biomass differed among the trophic guilds. Highly specialized trophic guilds, such as herbivores and detritivores, were negatively affected by damming. Invertivores were negatively affected in the impacted area and increased in abundance and biomass in the less impacted sites. The findings of this study show that modifications imposed by damming are reflected in the abundance and biomass of fish trophic guilds, but the degree of such impacts vary according to characteristics of the considered trophic guild.

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Section: Discussionmentioning

confidence: 99%

Fish trophic guild responses to damming: Variations in abundance and biomass

Dias

Ortega

Strictar

et al. 2020

River Research & Apps

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“…In the less regulated reach, cyprinid larvae had a generalist diet, while in the heavily channelised reach individuals exhibited a more specialised diet oriented towards several macroinvertebrate taxa or aquatic vegetation. Many authors reported that IS is a way to reduce trophic competition (Araújo et al., ; Dias, Ortega, Gomes, & Agostinho, ). In the channelised reach of the Meuse River, larval specialisation seems to be a way to deal with plankton rarefaction and increased trophic competition for macroinvertebrates with older stages of fish.…”

Section: Discussionmentioning

confidence: 99%

River habitat homogenisation enhances trophic competition and promotes individual specialisation among young of the year fish

et al. 2019

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In large rivers, fish ontogenic development success is mainly influenced by resource availability and by the possibility of species to adapt their diet (i.e. trophic niche). Humans have drastically modified freshwater habitats, notably for navigation purposes. Such modifications may reduce food availability for young of the year (YOY) fish and, consequently, influence their ability to reach the adult age. In the Meuse River, decrease of fish abundance is thought to be linked to a drastic reduction of phytoplankton biomass. In this context of decreasing phytoplankton biomass, we studied trophic niches of three cyprinid species (common bleak Alburnus alburnus, chub Squalius cephalus, and roach Rutilus rutilus) and one percid species (European perch Perca fluviatilis) at various stages of development, using stable isotope analysis in order to compare intra‐ and interspecific competition between sites differing in degree of channelisation. Two reaches of the Meuse River differing by their degree of regulation were investigated. We hypothesised that habitat homogenisation would (1) decrease food resource availability and diversity and (2) increase trophic competition, particularly among earlier ontogenic stages, and promote individual specialisation. Our study provides evidence that in the context of low planktonic biomass, most YOY relied on benthic food sources. Furthermore, the Meuse River flow and depth regulation significantly impacted the abundance and species richness of YOY. In the heavily channelised reach, between‐stages competition and low resource diversity lead to an increase in diet partitioning between cyprinid larvae, as well as consumption of non‐optimal energetic food sources such as aquatic vegetation by some individuals. By contrast, in the less channelised reach, larvae displayed a generalist feeding habit focusing on high energy content prey such as different taxa of macroinvertebrates, suggesting that the diversity of habitat reduces the food competition within and between stages. Intraspecific resource repartition is a key point for YOY fish having to cope with plankton‐depleted conditions. Younger cyprinid stages seem more affected by intra‐ and inter‐specific competition in the more channelised reach. YOY fish communities were also less diversified and abundant in the more altered site, which highlight the importance of limiting channelisation to better conserve fish communities.

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“…Nevertheless, the mechanisms acting to promote this high level of coexistence of species with similar niches have yet to be clearly identified. Dias et al (2017) studied fish assemblages of the Paraná River floodplain and proposed that predator selectivity and feeding overlap are mediated by food availability, but they did not consider morphological aspects of these predators. In this study, we aim to fill these research gaps by addressing the following questions: Is there a correlation between morphology and diet of Amazonian predator fish?…”

Section: Introductionmentioning

confidence: 99%

Diet and ecomorphology of predator fish species of the Amazonian floodplain lakes

et al. 2019

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Amazonian floodplain lakes host a high diversity of predatory fish which coexist and exploit the high diversity of available prey. Morphology could be the characteristic most closely associated with their preferred feeding sources (prey). However, it is unclear whether this association is direct or indirect. If it is indirect, swimming performance or preferential position in the water column could be the most evident characteristic. To examine the degree to which fish morphology of predator fish species is correlated to their dietary inputs, we compared the existence of morphological and feeding dissimilarity among eight predator species with the association between predator morphologies and preferred prey. We collected, measured, and sampled the stomach contents of fish from two lowland floodplain lakes associated with the Solimões River, Brazil, in May, August, and November of 2014. Of 187 collected fish across eight species, five species showed fish to be the most important item in their diets and three preferentially ate shrimp. Principal components analyses of ecomorphological attributes divided the species according to their ability to find the prey, swimming performance of the predator, and prey size. While there was significant distinction between the varying morphologies of predators, we were unable to distinguish between the specific diet of these species and did not find a correlation between morphology and feeding. These results are likely due to the fact that there is great abundance and diversity of available prey in the Amazonian floodplain lakes, so opportunistic feeding may be the primary foraging strategy of predator fish species living in these environments.

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Trophic relationships in fish assemblages of Neotropical floodplain lakes: selectivity and feeding overlap mediated by food availability

Cited by 13 publications

References 56 publications

Fish trophic guild responses to damming: Variations in abundance and biomass

Fish trophic guild responses to damming: Variations in abundance and biomass

River habitat homogenisation enhances trophic competition and promotes individual specialisation among young of the year fish

Diet and ecomorphology of predator fish species of the Amazonian floodplain lakes

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