A Trout's Life

Egg

Once an egg is fertilized, it begins to develop and various organs such as eyes become visible. Depending on temperature, it takes 6 to 8 weeks from fertilization to hatch.

Fry

Once the egg yolk has been absorbed, a young fish emerges as a free swimming fry, reliant on external sources for nutrition. Young fish are generally considered fry during their first year of life.

Parr

This term refers to young fish during the freshwater period, from the time they enter their second growth season to the time they transform to smolt. Parr are characterized by "parr bars", or a series of parallel vertical markings along their sides.

Smolt

Immediately prior to emigration from the natal stream, juvenile fish undergo a physiological, behavioural and physical transformation, enabling them to adapt to the new environment in which they will rear to adulthood. In the case of anadromous species, this transition occurs from coastal streams and lakes to saltwater. For purely freshwater forms and species, this transition occurs from small natal streams to larger rivers or lakes. Smolts lose their parr markings and take on a very silvery colouration.

Adult

Salmonids generally spend one or more years feeding and growing either in saltwater or in larger river/lake systems prior to returning to their natal stream to spawn. The exception is resident fish (including some rainbow trout, cutthroat trout and other salmonids) which do not leave their natal system prior to spawning. Fish that undergo migration to larger systems can generally access greater food resources and will grow larger than resident populations.

Spawning Adult

Upon maturation, fish undergo a series of physiological, behavioural and physical changes to ready them for spawning. The most obvious physical changes are colour—from silver to distinct spawning colours (usually brightly coloured)—and morphology (particularly males) associated with competition for mates and nest-building.