Does life-skills training enhance post-release survival?

Fish have been bred and reared in captivity for hundreds of years. Much of the methodology associated with hatchery production is geared towards producing fish destined for our tables. More recently, however, hatcheries have also been recruited to enhance natural populations for conservation or fisheries objectives. There is now ample evidence that rearing fish in artificial conditions has a dramatic impact on a wide range of morphological, physiological and behavioural parameters which makes them unsuited to life in the wild. Essentially there is a huge mismatch between the rearing environment and the release environment and this is reflected in the selective pressures fish respond to both over multiple generations (artificial selection) and during early ontogeny (plasticity). To redress some of these deficiencies, hatcheries have begun to implement a range of measures including habitat enrichment and life-skills training. This paper reviews these practices and will attempt to determine if these mitigation measures have generally worked (ie enhanced post-release survival) and if so, identify if a consensus approach to enhancing post-release survival of hatchery-reared fish has emerged.