&lt;b&gt;Trophic structure of fish assemblages associated with macrophytes in lakes of an abandoned meander on the middle river Purus, brazilian Amazon

Monik Da Silveira Suçuarana,Lisandro Juno Soares Vieira,Lucena Rocha Virgílio

doi:10.4025/actascibiolsci.v38i1.28973

<b>Trophic structure of fish assemblages associated with macrophytes in lakes of an abandoned meander on the middle river Purus, brazilian Amazon

Monik Da Silveira Suçuarana, Lisandro Juno Soares Vieira + Show 1 more

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https://doi.org/10.4025/actascibiolsci.v38i1.28973

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Abstract

The trophic structure of fish assemblages associated with banks of aquatic macrophytes in abandoned meander lakes on the river Purus is investigated. Comparisons between lakes and between different periods of the hydrological cycle are undertaken. Fish samples were collected in six lakes during the rainy (February), ebb (May) and dry (September) season in 2012. Fish stomach contents were analyzed by frequency of occurrence and volume methods, combined in the Feeding Index (IAi). Fish species were included in nine trophic categories, based on IAi rates. The richness and abundance of fish species, by trophic category, was influenced by temporal variations, with no significant spatial variation. Some species changed their diets and were included in different trophic categories according to the period and lake under analysis. Specialist species have also been identified, but failed to change their diets. Differences may be due to the characteristics of macrophytes banks and to the flooding regime which change the availability of food resources.

Highlights

There are several factors that influence population dynamics and interactions between species, the most important of which are physical factors and seasonal changes in habitat quality
The great abundance of fish recorded in the rainy season and the low abundance recorded during the dry season are probably associated with the dynamics of the macrophyte banks, in its turn, influenced by fluctuations in water level
As the water levels lowered, there was a decrease in the size of macrophyte banks, which was accompanied by a reduction in the abundance of fish

Summary

Introduction

There are several factors that influence population dynamics and interactions between species, the most important of which are physical factors and seasonal changes in habitat quality. The dominant seasonal change in the Amazon basin comprises the fluctuation in river levels coupled to the flat topography of most of the basin, annually flood and drain large areas of the floodplain (Junk, 1993). The annual sequence of dynamic hydrological changes seasonally impacts. In regions with extensive river-floodplain systems, the trophic structure of fish assemblage is influenced qualitatively and quantitatively by the hydrological regimes (Lowe-McConnell, 1999), since food source organisms experience changes due to water level fluctuations (Algarte, Siqueira, Murakami, & Rodrigues, 2009). The abundance of food resources during flooding is high since great quantities of Maringá, v. The availability of food resources decreases in the low water season (Abelha, Agostinho, & Goulart, 2001)

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