Trout Life Trout Life CycleCycle

EggEgg

The egg is the first step in the life The egg is the first step in the life cycle of the trout.cycle of the trout.

Just after fertilization eggs are very soft and Just after fertilization eggs are very soft and sticky.sticky.

They are called ‘green’ eggs.They are called ‘green’ eggs.

The source of energy for the embryo comes The source of energy for the embryo comes from the yolk.from the yolk.

The developing embryo uses the yolk as The developing embryo uses the yolk as its food.its food.

Eyed-EggEyed-Egg

When the egg is in this When the egg is in this stage it is more stage it is more stable. The outer stable. The outer surface is harder surface is harder than when the egg than when the egg was first laid.was first laid.

The egg is called an The egg is called an eyed -egg because eyed -egg because the black dots you the black dots you see are the eyes of see are the eyes of the embryo inside.the embryo inside.

HatchingHatching

Alevin or Sac FryAlevin or Sac FryWhen the trout hatches from the egg, it retains its yolk sac.When the trout hatches from the egg, it retains its yolk sac.

It is called an alevin or sac-fryIt is called an alevin or sac-fry

The alevin also use the egg yolk as its food The alevin also use the egg yolk as its food source.source.

The alevin remain in the gravel The alevin remain in the gravel until they reach the fry stage. until they reach the fry stage.

These alevin are almost to the ‘button-These alevin are almost to the ‘button-up’ stage.up’ stage.

FryFry Once the egg Once the egg

sac has been sac has been

absorbed, the absorbed, the

fry leave the fry leave the gravel and gravel and become free- become free- swimming.swimming.

The fry now has to forage The fry now has to forage for food. for food.

ParrParr-Parr are older fry that -Parr are older fry that

show special show special markings called ‘parr markings called ‘parr

marks’.marks’.

-Parr marks can be -Parr marks can be used as camouflageused as camouflage

Parr marks can help identify small trout Parr marks can help identify small trout and salmon.and salmon.

ChinookChinook

SteelheadSteelhead

SockeyeSockeye

JuvenilesJuveniles

Juveniles are small adults. Juveniles are small adults.

Most eventually lose their parr marks.Most eventually lose their parr marks.

Adult rainbowAdult rainbow

Adults spawningAdults spawning

Females dig the depression (‘redd’) and lay Females dig the depression (‘redd’) and lay their eggs. Males deposit the ‘milt’ with their eggs. Males deposit the ‘milt’ with sperm to fertilize the eggs. sperm to fertilize the eggs.

ReddRedd

ReddRedd

The female buries the fertilized eggs as she digs more of the The female buries the fertilized eggs as she digs more of the redd.redd.

How redds are builtHow redds are built

……and it starts again….and it starts again….