25 research outputs found
Not just for adults! Evaluating the performance of multiple fish passage designs at low-head barriers for the upstream movement of juvenile and adult trout Salmo trutta
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Wild and hatchery-reared brown trout, Salmo trutta, differ in smolt related characteristics during parr-smolt transformation
A test of how predator conditioning influences survival of hatchery-reared Atlantic salmon, Salmo salar, in restocking programmes
Fluctuating recruitment and variable life history of migratory brown trout, Salmo trutta L., in a small, unstable stream
Association between growth, body condition and anti-predator behaviour in maturing and immature brown trout parr
Does dispersal from landlocked trout explain the coexistence of resident and migratory trout females in a small stream?
Predator-induced hyperventilation in wild and hatchery Atlantic salmon fry
Following exposure to a predator stimulus (a brown trout Salmo trutta), the opercular rate of Atlantic salmon Salmo salar fry increased by 35.3 +/- 11.0% (mean +/- 95% CI). The time taken for opercular rate to decline to baseline levels depended upon the occurrence of any associated locomotory activity. Opercular rates of fish that dashed when exposed remained elevated for 38.2 +/- 20.6 min, whereas those of individuals that did not move ('freezers') recovered within 7.2 +/- 2.9 min. The duration that opercular rate remained elevated was positively correlated with the magnitude of the elevation, which was higher in 'dashers' than freezers. The maximum opercular rate in 'freezers' was similar between wild fry and hatchery-reared fry (from wild parents). There was a significant delay, however, in hatchery compared with wild fry in the time until peak ventilatory response and onset in the decline phase. This difference in opercular response suggests that hatchery fish were slower to realize fully the potential danger from the predator. Any delay in response could be directly attributed to the effect of hatchery-rearing environment, rather than domestication or hatchery selection effects. (C) 2004 Crown copyright.</p