from that of wild fish. These changes are partly phenotypic and partly

• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2005
• Subjects: captive; competition; cultured; density-dependence; farmed Atlantic salmon; hatchery rearing; spawning; Atlantic salmon
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.484.9365; http://icesjms.oxfordjournals.org/content/63/7/1162.full.pdf

ow nloaded from veniles ’ faster growth rate influences age and size at smolting and maturity, reproductive output, and longevity. Fast-growing parr tend to smolt younger, produce more but smaller eggs, attain maturity earlier, and die younger. Juvenile learning influences a number of be-havioural traits, and differences in early experience appear to affect feeding and spawning success, migratory behaviour, and homing ability. Genetic change in hatcheries is chiefly the result of natural selection, with differential mortality among genotypes and broodstock selection based on production traits such as high adult body mass and fast growth rate. Ex-perimental evidence has revealed that cultured parr’s greater aggression often allows them to dominate wild parr, although smaller cultured parr can be subordinated if they co-occur in fast-flowing water and if wild smolts have established prior residence. During spawning, the fitness of wild salmon is superior to that of cultured conspecifics. Cultured males are inferior to wild males in intra-sexual competition, courting, and spawning; cultured females have greater egg retention, construct fewer nests, and are less efficient at covering their eggs