Effects of fishing technique on assessing species composition in aquatic systems in semi-arid Brazil

Esf Medeiros,Rtc Ramos,Brs Figueiredo,Tpa Ramos,Mj Silva

doi:10.1590/s1519-69842010000200004

Esf Medeiros, Rtc Ramos + Show 3 more

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https://doi.org/10.1590/s1519-69842010000200004

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Abstract

In most ecological field research, appropriate sampling is critical for the understanding of processes underlying fish populations and communities, and is even more important in heterogeneous environments such as the aquatic systems of the semi-arid region of Brazil. This study intends to make a contribution to the development of sampling programs and gear selection in aquatic systems of semi-arid Brazil by evaluating the effects of different fishing techniques on the assessment of richness and composition of the fish fauna in selected aquatic environments. Six sites were selected to represent typical artificial (reservoirs) and natural (intermittent streams) environments and four different types of sampling gear were applied to each site during four occasions. The present study shows that when selecting sampling techniques to be used in aquatic systems in semi-arid Brazil, one must consider the objectives of the study, e.g. ecological or taxonomic, in order to decide on inclusion of rare species in the sampling population. Also, the effect of the sampling gear on natural abundances of fish must be considered given that some sampling techniques are highly detrimental to fish population numbers.

Highlights

IntroductionAquatic systems in semi‐arid Brazil include three major groups of environments: intermittent streams and rivers (except for the perennial São Francisco River and artificially regulated rivers) (Maltchik and Medeiros, 2006a), natural shallow lakes (Maltchik et al, 1999), and artificial reservoirs (Medeiros et al, 2006)
Aquatic systems in semi‐arid Brazil include three major groups of environments: intermittent streams and rivers (Maltchik and Medeiros, 2006a), natural shallow lakes (Maltchik et al, 1999), and artificial reservoirs (Medeiros et al, 2006)
The total number of species found in the present study is in accordance with other studies in the semi‐arid region of Brazil (e.g. Medeiros and Maltchik, 2001a; Rosa et al, 2003; Medeiros et al, 2006), indicating that the sampling gear chosen is capable of taking representative samples of the fish fauna in the study habitats

Summary

Introduction

Aquatic systems in semi‐arid Brazil include three major groups of environments: intermittent streams and rivers (except for the perennial São Francisco River and artificially regulated rivers) (Maltchik and Medeiros, 2006a), natural shallow lakes (Maltchik et al, 1999), and artificial reservoirs (Medeiros et al, 2006). These systems are distinctive landscape features, comprising a range of associated sub‐systems and existing as an. Because the physical structure of the aquatic habitat is viewed as a framework for colonization by the aquatic fauna (e.g. Martin‐Smith, 1998), the state of this living space will influence biotic structure and organization within aquatic systems (Mugodo et al, 2006)

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