Selectivity of Water Dams on Glass Eel : Transcriptomics Approach
and dispersion of eels. Dams and obstacles also increase the energy demand of fish, even if there is a
fish friendly device to allow them to swim across the obstacle. Besides, local accumulation of eels
below dams may increase the mortality associated with predation. Obstacle to eel migration may
select on different trait of life history. While quantitative impact of dams is subjected to numerous
studies, little is known about their intra-specific selectivity. Even the fishway efficiency analyses are
scarcely hinting at their potential selective effect (Castro-Santos 2004; Noonan, Grant & Jackson 2012).
The main issue of this study is to pinpoint phenotypic traits that predisposed glass eels to dams successful
passage. The approach we adopted is individual-centred and without any a priori hypothesis on traits
involved by the putative dams selective pressure. We analyzed the expression of 15000 known eel genetic sequences
based on previous studies (Coppe et al. 2010; Pujolar et al. 2012). Transcriptome analysis of three main
tissues (brain, liver and muscle) from individuals sampled on three successive forebays separated by
dams indicate different gene expression profiles in brain between the two upstream forebays.
The functional role of the overall set of regulated genes strongly suggests cytosqueletal and neural changes
as well as synaptic plasticity. Their interpretation at higher phenotypic level and further research perspectives