Living the Life of a Trout!

Tracking a Trout’s Life Cycle

What is a life cycle?

• Biological (& continuous) process that all organisms undergo

• Period of time where an organism is produced, grows, and becomes sexually mature and reproduces

• Consists of various defined stages in the growth and development of an organism

Every organism has a life cycle!

•  Term used to describe a variety of freshwater fish

• Play an important role in the ecosystem – Source of food and nutrition

• Trout common to NJ:– Rainbow, Brook, & Brown

Brown Bear w/ Salmon

Trout

Brook TroutSalvelinus fontinalis

Trout Life Cycle

Eggs

Alevin

Fry

Fingerling

Juvenile

Mature Adult

Spawning• Biological process used by a majority of

fish and aquatic creatures to reproduce• Requires sexually mature trout (~3 yrs

old) to release eggs and sperm– Egg and sperm are reproductive cells• Also known as gametes

• A female ready to mate will build a nest called a redd

• Uses fins to remove gravel & debris from the bottom of a lake or stream–Usually a shady location

• Location where the eggs will begin to grow and development.

The REDD

Stage 1: Eggs• Female releases her eggs into the redd’• Male releases milt (sperm) to fertilize the

eggs• Afterwards, the female covers the eggs

with gravel – Female will move to a different location to

create another redd and mate with another male

In a hatchery, eggs are removed from the female to be fertilized

Egg Development• Undergo process of ‘hardening’– Occurs within 1 hour after fertilization– All pores on the egg are closed and sealed• Makes eggs sticky

• After ~20 days, eye spots develop in the embryo

Eye Spot

DevelopingBody

Fertilized Egg

Alevins• After the eggs hatch (approximately 2-3

weeks), trout are classified as alevins • Remain attached to the yolk sac at their

belly– Yolk sac provides nutrition

• Continue living in the redd

November 1, 2013

Recently hatched trout!

NOVEMBER 25, 2013

Eventually, the alevins deplete their yolk sacs. At this point, they begin swimming to the surface of the tank to look for food. Once the yolk sacs are

completely depleted, the fish are independent and move into the next stage of life.

Fry•  Trout are independent of the yolk

sac and begin looking for food• No more yolk sac: Actually look like

fish!

Yolk sac

November 27, 2013

The trout are released from the net and the Styrofoam is removed from the front.

Only the trout independent of their yolk sacs swim throughout the tank (all others line the bottom).

December 9, 2013

Digital Thermometer

All the fish congregated at the top of the tank are looking for food since they no longer have a yolk sac

Lookin’ like Brook trout!

April 28, 2014: Release day

Trout released into the stream bed

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Mature Trout•  Trout will move to the main current

of the stream• Feed primarily on insects• For the next three years, the trout

will continue to grow and develop until reaching sexual maturity

• Then the life cycle continues…