Early Spawning Fish
|Click for full size image:.
Photo 1: A typical
redd on the Goulburn River
Photo 2: A hen
Photo 3: A
closer view of the same activity
Photo 4: Two
fish paired up and ready to spawn (June
Photo 5: A
large 5lb buck fish defends the redd and
hen from an annoying, smaller male
early run fish are now spawning with the majority of trout
still a way off yet. Read on for what to look for and
avoid, on this the last weekend of season 2000.
This weekend marks the
end of the Trout Season on the rivers of Victoria. As
expected the early fish have started to spawn in the
past 10 days with the vast majority not yet on the job.
Despite the politics going on at the moment between
those who want the closed season extended and those
who do not, there is an underlying common desire shared
by most of us. That is the protection of any trout already
Spawning is the name for
trout reproduction. The process of female trout laying
eggs and male trout fertilizing the eggs is spawning.
Many factors influence the place where a trout may spawn.
- Stream bottom (usually
- Water depth (between
- Water velocity
- Stream cover (trees,
bushes, logs, etc.)
Brown trout in our district
spawn during late May, June and early July, depositing
their eggs in saucer-shaped nests called redds, which
are dug by the female in the clean gravel lining the
bottom of streams. The redd is created by the female
fish while lying on its side and rapidly beating its
tail in an up-and-down motion, allowing the current
to move the gravel slightly downstream See Photos 2
and 3. When she is finished building the redd, she then
lays her eggs and the male fertilizes them. Usually
one but up to two males can sometimes fertilise the
The female travels upstream
and begins to dig another pit. She does this so that
the gravel from the new pit will be carried downstream
and thus cover the eggs she laid in the redd. The female
moves to the upstream edge of the redd, again beating
its tail on the stream bottom, burying the eggs in gravel.
After spawning is completed, the eggs are abandoned.
The eggs incubate through the winter, hatch during late
winter, and the tiny fry emerge from the gravel some
six weeks later on average. This whole process is, of
course, temperature dependent. With a constant water
temperature of 10 degrees Celsius hatching occurs in
41 days. The number of eggs produced depends on fish
size. An 8-inch mature brown trout may spawn 200 eggs,
while a 10-pound female might spawn over 8,000 eggs.
Males usually become sexually mature at two years of
age and females at three.
After the eggs are fertilised
they begin developing. The first stage of development
is the eye. A yolk sac, that provides nutrients to the
small fish, then develops. These small fish are called
'sac fry'. When the yolk sac is absorbed the small fish
make their way out of the riverbed gravel. The incubation
time as mentioned earlier depends on water temperature
with the warmer the water the faster the development.
It is very important that
water flows through the gravel to allow oxygen to make
its way to the eggs. Sediment can interfere with this
process. Some of the natural causes of sediment are
fires (Gippsland several years ago) and mudslides. Man-made
causes include overgrazing, poorly designed roads and
digging near stream beds.
When you factor in all
of the possible limiting factors on trout spawning successfully
you soon see that the odds are really stacked against
them. So what can we do? Well we can firstly not target
these fish during this vulnerable time. We fish for
sport and their is little sporting value in catching
a fish that is too concerned with sex to worry about
self preservation. Secondly we can avoid walking on
these redds and adding to the mortality rate. These
early spawning fish should be allowed to go about it
Watching trout spawn can
be one of the most interesting experiences a fly fisher
can ever have. Getting close to a large fish on the
gravel is exciting even to the most experienced of anglers
and it really is a privilege to be able to watch it
. We would recommend that next time you are out on the
river that you take a look. Leave the rod in the car,
take a sandwich and a camera and enjoy the show. It
is something special that we should all protect for
when all is said and done it is the future of our fishery.
More info on Spawning Fish
- Click on the link below
Spawning in the Goulburn! The Facts!