Atlantic salmon, Salmo salar L., smolts were exposed to environmental levels of the pesticide atrazine in a hatchery, tagged with acoustic transmitters and released into fresh water at the peak of the smolt run. The subsequent movements of the smolts were monitored within the freshwater and immediate coastal zones using an array of acoustic receivers. In laboratory‐based studies, exposure to a 0.1 μg L −1 concentration of atra...

The present study investigated, for the first time, a non‐invasive technique for monitoring cortisol levels in fishes that had been implanted with electronic transmitters. This technique involved the measurement of cortisol released into the water by individual fish. Carp Cyprinus carpio and roach Rutilus rutilus that had been tagged with miniature dummy acoustic transmitters responded to the surgical implantation of the tags...

Electro‐olfactogram (EOG) recordings of the olfactory epithelium of both male and female roach Rutilus rutilus demonstrated that both sexes were able to detect free and glucuronidated 17,20β‐dihydroxy‐4‐pregnen‐3‐one (17,20β‐P) with high sensitivity. Male, but not female, roach were also sensitive to androstenedione. Sexually mature female roach were shown to release free 17,20β‐P, glucuronidated 17,20β‐P and androstenedione i...

Electrophysiological studies demonstrated that the olfactory epithelium of mature male brown trout Salmo trutta parr was acutely sensitive to F‐series prostaglandins (PGFs) PGF 1α and PGF 2α , with detection threshold concentrations of 10 −11 M. The olfactory epithelium was also sensitive to the PGF metabolite 15‐ketoPGF 2α (threshold 10 −8 m), but did not detect a further metabolite, 13,14,‐dihydro‐15‐ketoPGF 2α Immature brow...

The feeding rate of a group (DS) of two small, two medium and two large 1+ Arctic charr Salvelinus alpinus was higher than in a group of six fish of the same size (SS), suggesting that size distribution had an effect on feeding behaviour, with a correlation between the size of the fish and the amount of food eaten–the largest fish eating the most. Against predictions, rate of aggression was not higher in the SS groups; rather...