Marble or marbled trout (Salmo trutta marmoratus, Cuvier 1817)
is a special form of brown trout that is estimated to be only native
to rivers of the Adriatic river system. Although it can be found in
waters from Italy down to the end of Albania, many Slovenians still
cherish this beautiful creature as THEIR trout! This is more than
unfair to our brown trout (Salmo trutta f. fario) that is also native
in majority of our rivers, but the uniqueness and mystery that
surrounds this beautiful marbled "subspecies" is constantly echoing
in heads of our ichtyiologists and flyfishermen.
Northwest part of Slovenia with it's famous rivers. On the west side is
Italy and on the north side is Austria. Missing on the south lies Croatia.
The most known rivers that inhabit this "kind" of trout are Soca
(pr. Sotcha, or in Italy Isonzo!) and Idrijca (pr. Ydrytsa) with their
tributaries. Soca is the river after which Slovenians named this
trout "SOSKA POSTRV". In direct translation it means "trout
from river Soca". After successful breeding in the recent past we
can hope that this subspecies, form or whatever taxonomic category
will finally prevail among disunioned scientists, will survive.
Marble trout in it's natural environment-crystal clear
and in deeper parts "emerald green" Soca.
Personally I do not agree with few scientists in the past that
classified marble trout as a "species" because it is a fact that
it can be crossed with brown trout and the descendants ARE
fertile! This is still is the rule #1of the biology and at least for
now I think we should live it that way. So these two forms of
trout must be the same species if we follow the biological
definition of the "species". No matter if it is a form, subspecies
or whatever, I think we all agree that it should and must be
preserved. Let's rather say a word or two about marble trout's
The most recent genetic studies revealed that in fact we could
have several different types of marble trout in Slovenia. The
best part is that all of them can grow to very decent size for
every flyfisherman! Because on a "right" day, specimens around
35'' can be seen in those rivers. But like I said, they can be easily
seen - not caught! Carying genetic heritage of (most probably)
the same ancestor as our brown trout, it is one of the wariest fish
among salmonids. Although most of the fishermen still acknowledge
only one type of marble trout as "genuine one" and that is now called
It is named after Soca's famous tributary where natural barriers
seemed to keep our brown trout (Salmo trutta f. fario) away,
providing a habitat for detached population. This type is olive-brown
or olive-green with that special marbled pattern which sometimes
goes way down to the belly. The color of the belly is usually
yellowish-white or olive. Variability of shadings is incredible!
They can be so pale that marbled pattern is hardly seen and on
the other hand very dark too. This type has no red spots on the
body! Some years ago all the fish with marbled pattern with at
least one red spot were estimated to be "crossings with brown
trout". Now they seem to be a type of marble trout as well. "Real
crossings" just add their share to the confusion.
For majority of people this is still the only "pure"
marble trout (Type Zadlascica.) This one has marbled pattern
even on it's dorsal and adipose fin.
Usually the biggest specimens live in deeper water or
canyons, well hidden from the fishermen. Especially in river Soca.
They are territorial and as they grow they start feeding on fish. As
every decent predator this fish has also very sharp teeth. All that
makes flyfishing for big marbles very difficult considering use of
barbless hooks and flies that can reach them. Getting deep enough
in fast water is not very easy as we all know and tackle must be
strong enough too. Unfortunately "catch &release" is not a very
common regulation in our country. Now we are able to keep one
marble per day with a size limit over 40cm (somewhere 50cm
depending on what river we are fishing). So at least fish under
the size limit must be released.
Sharp teeth make the prey travel only "one way."
Marble trout has recently become interesting trademark of
Slovenian flyfishing. Due to the work of devoted domestic
and some foreign scientists from different parts of Europe,
especially from France, it seems it will remain in our streams
and keep bringing flyfishermen from all over the world to
our small and beautiful country. ~ Tomaz Modic, Ljublijana Slovenia