| Summary: | The aim of this study was to develop effective tools based on fish
assemblages, allowing the development of an effective assessment
approach for the ecological status of running waters. Fish samples
were collected using gill-nets with mesh sizes of 8, 10, 12, 14, 15,
18, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75 and 80 mm. Forty
sites were visited from October 2008 to September 2009 in the Bandama
River. A large part of the data set on fish descriptors associated
with environmental parameters was compiled from regional databases.
For each of the fish assemblage descriptors, stepwise multiple linear
regressions with habitat variables were carried out. The residuals of
the models obtained were used as candidate metrics independent of
natural environmental factors. Student t-tests used to compare each
metric in reference and disturbed samples indicated significant
difference (P < 0.05) for six metrics. The
standard residuals of metrics selected were added to constitute the
final index. This multimetric index of fish assemblage integrity could
serve as a practical technical reference for conducting cost-effective
biological assessments of lotic systems.
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