Abstract

Atlantic salmon (Salmo salar) exhibit maladaptive behaviour when stocked into natural streams
following one generation in a hatchery setting, reducing post-stocking survival. These behavioural
patterns are commonly attributed to ‘hatchery selection’, where maladaptive phenotypes arise from the
inadvertent selection of behavioural traits, lack of experience caused by captivity, or a combination of
both. ‘Life skills training’, in which hatchery-reared fish are conditioned to exhibit appropriate
behaviour responses, may increase post-stocking survival.
A semi-natural field experiment, using in-situ mesh enclosures, compared wild-caught juvenile salmon to
hatchery-reared counterparts from the same population. Fish were observed for antipredator, foraging,
and territorial defense responses. Results showed no significant differences between wild and hatchery
raised fish, although behaviour was significantly different between years. Overall, week long trials were
insufficient in separating significant differences between strains, indicating one generation in captivity
may not create major behavioural separation between wild and hatchery fish from the same population,
or that more than one week is required for differences to become apparent. Behavioural response
training protocols are suggested for hatchery raised experientially deprived fish destined for stocking.