ABSTRACT
Natural spawning occurs annually during autumn/winter, with maturation occurring in response to temperature and photoperiod cues, but environmental manipulation under farm conditions allows breeding all year-round, with apparently minimal effects on milt quality. Trout breeding involves the hand-stripping and dry fertilisation of ripe eggs and sperm from 2-4 year old mature fish held on site. Fertilised eggs are incubated in flow-through containers and hatch after approximately 6 to 9 weeks at temperatures of 5 to 10ºC. Survival to hatching is usually up to 80%. Fertilization out of season usually reduces this percentage.
