Mortality rates of wild Atlantic salmon Salmo salar smolts implanted with acoustic transmitters were assessed to determine if mortality was size dependent. The routinely accepted, but widely debated, ‘2% transmitter mass: body mass’ rule in biotelemetry was tested by extending the transmitter burden up to 12·7% of body mass in small [mean fork length ( L F ) 138·3 mm, range 115–168 mm] downstream migrating S. salar smolts. Ove...

The unimpeded downstream movement patterns and migration success of small female and male Anguilla anguilla through a catchment in north‐west Europe were studied using an acoustic hydrophone array along the River Finn and into the Foyle Estuary in Ireland. Twenty silver‐stage A. anguilla (total length, L T , range: 332–520 mm) were trapped 152 km upstream from a coastal marine sea‐lough outlet and internally tagged with acoust...

A genetic stock identification ( GSI ) study was undertaken in a fishery for Atlantic salmon Salmo salar to determine the effects of restrictive fishery management measures on the stock composition of the fishery, and if accurate and precise stock composition estimates could be achieved on the small geographical scale where this fishery operates, using a suite of only seven microsatellite loci. The stock composition of the Foy...

Removal sampling by electric fishing is widely used for assessing fish population size. As it is manpower consuming, less‐demanding techniques have been proposed to increase the number of sites covered with the same human resources. These techniques essentially provide relative abundance measures. To be used for absolute abundance estimation, they need to be inter‐calibrated with another method such as removal sampling. Here,...

The effect of marine climatic conditions in the North Atlantic on the abundance of returning migrant Atlantic salmon Salmo salar in the River Foyle, Ireland was examined. Catches of Atlantic salmon from commercial netting stations significantly predicted a measure of population size independent of catches over a 48 year period, thus commercial net catches were used as a measure of relative population size over a longer period...