The biological and biochemical effects of temperature on life‐history strategy of female bullhead Cottus gobio were investigated. Fish from two populations (Bez Basin, south‐east France) experiencing contrasted thermal environments ( i.e . more or less stable) were reared during 4 months at three distinct temperatures (7, 9 or 12° C). Both somatic (soma fresh mass and muscle triglyceride content) and reproductive (gonad fresh...

Fish assemblage indicators developed throughout the world were reviewed and key differences in methodologies depending on ecoregions, basins and contrasting fish fauna summarised. Common elements of existing Indices of Integrity were identified to support the development of a European‐wide fish index. These include, using reference condition, accounting for natural fish assemblage variability, evaluating metric precision and s...

Mediterranean river systems are characterised by more diverse fish assemblages and regional ecological processes compared with the rest of Europe. A data set from Mediterranean France, Iberia and Greece (∼2000 sites) was used to describe the characteristics of fish assemblages, explore their responses to anthropogenic disturbance and analyse the implications for river quality assessment. There was a southwards decline in speci...

A fish‐based index applicable at the pan‐European scale should encompass the relative importance of regional and local factors influencing the distribution of riverine fish. An effective way of using information available from fish assemblages to establish such a multimetric index is through the use of the reference condition approach that involves testing a fish assemblage exposed to a potential stressor against a reference c...

The European Union, Water Framework Directive (WFD) requires monitoring of riverine fish fauna. When the WFD came into force in 2000, most of the EU member states did not have fish‐based assessment methods compliant to WFD requirements. Therefore, the objectives of FAME ( http://fame.boku.ac.at ), a project under the fifth R&D Framework Programme of the European Commission were to develop, evaluate and implement a standardised...

The variability of growth variables and age structure in bullhead Cottus gobio was studied in a single river catchment by comparing populations inhabiting river reaches with different thermal regimes. Age and growth variables were determined by examining 540 sagittal otoliths from specimens ranging between 19 and 146 mm total length. Growth of young bullhead (0+ and 1+ years) was higher in the warmest sites, especially in rela...

A population of bullhead Cottus gobio inhabiting a mountainous river network, was examined for the influence of maternal condition (total length, L T , and age class in years) and environmental factors (water temperature and fish density) on fecundity, egg size and net annual reproductive effort ( E R , defined as the ratio of total egg production mass to body mass) within several stocks. Regardless of location within the drai...

Atherina boyeri , a pelagic species, mainly entered a Mediterranean lagoon in the Rhone River Delta, during the day, whatever the flow direction. Flow velocity did not appear to be a significant factor and its swimming abilities seemed to be sufficient to cope with the observed velocity. The combined responses of Pomatoschistus spp., benthic species, to the different environmental factors clearly demonstrated a change in behav...

Mean juvenile fish abundance and fish frequency in a large lowland river during low discharge largely differed among the unvegetated and three morphologically contrasted macrophyte habitats. Single separate models revealed that juvenile fish distribution was largely influenced by trophic variables. With the exception of Leuciscus cephalus , which responded mainly to physical variables (depth and substratum), multiple regressio...