Human Impacts and Fisheries -- Efforts to aid downstream migrating brown trout (Salmo trutta L.) kelts and smolts passing a hydroelectric dam and a spillway -- Walking speed and area utilization of red king crab (Paralithodes camtschaticus) introduced to the Barents Sea coastal ecosystem -- Movements of undersized spotted grunter (Pomadasys commersonnii) in the Great Fish Estuary, South Africa: implications for fisheries management -- Effects of salmon lice infection and salmon lice protection on fjord migrating Atlantic salmon and brown trout post-smolts -- Migration and Behaviour -- Upstream migration of adult chum and pink salmon in the Shibetsu River -- Riverine and early ocean migration and mortality patterns of juvenile steelhead trout (Oncorhynchus mykiss) from the Cheakamus River, British Columbia -- Conventional and EMG telemetry studies of upstream migration and tailrace attraction of adult Atlantic salmon at a hydroelectric installation on the Exploits River, Newfoundland, Canada -- Mid-winter activity and movement of Atlantic salmon parr during ice formation events in a Norwegian regulated river -- Results of satellite tagging of Atlantic bluefin tuna, Thunnus thynnus, off the coast of Ireland -- Fjord migration and survival of wild and hatchery-reared Atlantic salmon and wild brown trout post-smolts -- Hatchery-reared fish have less consistent behavioral pattern compared to wild individuals, exemplified by red tilefish studied using video observation and acoustic telemetry tracking -- Species Conservation and Habitat Rehabilitation -- Sea lamprey (Petromyzon marinus L.) spawning migration in the Vouga river basin (Portugal): poaching impact, preferential resting sites and spawning grounds -- Habitat use and fish activity of landlocked Atlantic salmon and brook charr in a newly developed habitat compensation facility -- Mobility of individual roach Rutilus rutilus (L.) in three weir-fragmented Belgian rivers -- Assessment of a retrofitted downstream fish bypass system for wild Atlantic salmon (Salmo salar) smolts and kelts at a hydroelectric facility on the Exploits River, Newfoundland, Canada -- PIT telemetry as a method to study the habitat requirements of fish populations: application to native and stocked trout movements -- Methodology and New Technology -- Introducing a method for extracting horizontal migration patterns from data storage tags -- Feeding activity and opercular pressure transients in Atlantic salmon (Salmo salar L.): application to feeding management in fish farming -- Laboratory protocol to calibrate sea lamprey (Petromyzon marinus L.) EMG signal output with swimming -- Effects of antenna length and material on output power and detection of miniature radio transmitters -- Comparison between PIT and radio telemetry to evaluate winter habitat use and activity patterns of juvenile Atlantic salmon and brown trout -- Assessment of largemouth bass (Micropterus salmoides) behaviour and activity at multiple spatial and temporal scales utilizing a whole-lake telemetry array -- Techniques for evaluating the spatial behaviour of river fish -- Use of muscle activity indices as a relative measure of well-being in cultured sea bass Dicentrarchus labrax (Linnaeus, 1758) -- Efficacy and accuracy of portable PIT-antennae when locating fish in ice-covered streams -- Growth, survival, and tag retention of steelhead trout (O. mykiss) surgically implanted with dummy acoustic tags. This volume includes 33 peer-reviewed papers presented at the Sixth Conference on Fish Telemetry held in Europe (Sesimbra, Portugal, 5-11 June 2005). The papers focus on the application of aquatic telemetry techniques by scientists to investigate fundamental aspects of animal biology in order to conserve and manage natural resources. The topics addressed in this issue are human impacts and fisheries, migration and behaviour, species conservation and habitat rehabilitation, and methodology and new technology. This book is aimed at scientists and engineers actively involved in aquatic telemetry projects, aquatic biologists (marine and freshwater), fisheries biologist and managers.