In late spring, once the
yolk sac is absorbed, the little salmon, now known
as fry, wriggle upwards out of the gravel and commence
feeding
for themselves. They instinctively face into the current,
using the stones as shelter, and intercept items drifting
past in the flow. The fry principally live on the larval
stages of many species of fly which live in water.
From the start the fry
are territorial and compete with each other, and their
older brethren, for a good feeding spot. Bigger fish,
known as parr, force the fry to remain in the shallowest
water, often only an inch or two deep, where the bigger
fish cannot go. The sites where most fry are found tend
to be shallow, stony but with a good current. Slack
areas and back eddies are avoided. The bigger the stones
the stronger the current which can be resisted.
Competition forces some dispersal of the fry away from the redd and those which do not find a suitable territory die. The most successful get the best feeding spots, grow fastest and gain even more advantage. It is a cruel world they inhabit!
Parr
As they grow the fry utilise ever deeper water and become known as parr. The typical habitat favoured by parr again tends to be shallow stony or even bouldery rivers with a strong current. From about 3 inches to about 12 inches seems to be a pretty ideal depth. Over time the parr might move significant distances moving between habitats as they grow. Some move upstream as well as downstream.
The speed at which the parr grow depends on the amount of food in the river, the temperature of the water, the amount of competition etc. After they have reached a sufficient size, in the spring time the parr undergo a physiological transformation and become known as smolts and head towards the sea.
Play this short video clip
to see juvenile salmon being electrofished on
the River Ericht. From the numbers caught in
such a small area it can easily be seen that
there are in fact very great numbers of juvenile
salmon in the river as a whole. (All these fish
were returned safely after being counted and
measure)
Immediately they emerge from
the redd the fry lead a secretive life among the
stones on the streambed. They instinctively face
into the current to intercept drifting insect
larvae and can use their fins to help the current
pin them onto stones without having to swim.
When the fry grow a little bigger
they become known as "parr" which still
bear the characteristic vertical bands known as
"parr marks".
In the Tay district juvenile
salmon mostly spend two years in the river before
going to sea. Therefore, samples of juveniles
usually are comprised of two size groups - fry
and one year old parr.
Fry tend to inhabit relatively
shallow stony water such as in this stream or
in areas of similar depth along the margins of
bigger tributaries or the River Tay itself.
Parr tend to inhabit deeper
water than fry and typically use fast bouldery
tributaries like this.
Juvenile salmon are very secretive
and are seldom seen by anglers. Yet the can occur
in surprising abundance. Electrofishing is a technique
which draws them out of crevices and allows populations
to be monitored.
Tay District Salmon Fisheries Board, Site
6, Cromwellpark, Almondbank, Perth, Perthshire, PH13LW.
Telephone (01738) 583733 .
(Mobile) 07974 360 787 .
Fax (01738) 583753 (Please call beforehand as the Fax is usually turned
off to avoid spam)
