Most of the diadromous fish of the world have decreased in distribution and abundance since the beginning of the twentieth century. They are now threatened, and important conservation issues arise. The causes of these trends vary among species and basins but regional human impact (damming, pollution, fisheries) and global change (climate) are suspected to be responsible for these difficulties. This book contains selected papers from an international symposium organised by the Diadfish network held in Bordeaux (France) in 2005. Readers will find up-to-date information on the ecology, ecotoxicology and physiology of several diadromous species (Atlantic salmon, shads, lampreys, eels) and this whole group in Europe. Main impacts are also documented and analysed in case studies, and solutions or remediation actions are presented.

Diadromy, history and ecology: a question of scale.- Life history correlates and extinction risk of capital-breeding fishes.- Dopaminergic systems in the European eel: characterization, brain distribution, and potential role in migration and reproduction.- Morphological analysis of geographic variation of sea lamprey ammocoetes in Portuguese river basins.- Life history changes in Atlantic salmon from the River Dee, Wales.- Glass eel recruitment, Anguilla anguilla (L.), in a Mediterranean lagoon assessed by a glass eel trap: factors explaining the catches.- Impact of glass eel fishery on by-catch fish species: a quantitative assessment.- Mercury contamination and life history traits of Allis shad Alosa alosa (Linnaeus, 1758) and Twaite shad Alosa fallax (Lacépède, 1803) in the gironde estuary (South West France).- Upstream passage problems for wild Atlantic salmon (Salmo salar L.) in a regulated river and its effect on the population.- Poor water quality constrains the distribution and movements of twaite shad Alosa fallax fallax (Lacépède, 1803) in the watershed of river Scheldt.- Aspects of anadromous Allis shad (Alosa alosa Linnaeus) and Twaite shad (Alosa fallax Lacépède) biology in four Irish Special Areas of Conservation (SACs): status, spawning indications and implications for conservation designation.- Potential re-establishment of diadromous fish species in the River Scheldt (Belgium).- Return of twaite shad Alosa fallax (Lacépçde, 1803) to the Southern Baltic Sea and the transitional area between the Baltic and North Seas.- Does global warming impact on migration patterns and recruitment of Allis shad (Alosa alosa L.) young of the year in the Loire River, France?.