FLESH COLORS IN FISHES
by Ranger Naturalist Harry Woodward
Common names have been applied to many types of our flora and fauna
in such manner as to cause park visitors to become confused,
particularly is this true of fishes and flowers. Speckled trout,
mountain trout and salmon trout are the most frequently heard when
reference is made to our most widespread species here in Yellowstone,
the cutthroat (Saline lewisii). All of our trout are more or less
speckled and those inhabiting mountain streams may be commonly termed
mountain trout.
The pink flesh of the cutthroat caught at Fishing Bridge gives rise
to many inquiries and no doubt leaves the impression with many that they
may be properly termed "salmon trout."
It is true that salmon and trout belong to the same family, the
Salmonoidea. Their common ancestor may have been a trout or a salmon or
an ancestral type somewhat common to both, the Rhabdo fario facustris,
such as has been brought from the Pliocene beds of Idaho, or the fossil
salmonoid fish found in the Miocene of Bohemia.
The flesh color of most fishes, regardless of family, is white,
flaky, and readily digestible and with a palatable flavor. Some fishes
as the salmons and trouts, may have an orange hue because the flesh is
charged with oil. This heavy oil bears the color. Others have a
colorless oil which may be of a different constituency. It has been
stated that some fishes with a dark red flesh contain an unusually heavy
oil which becomes acrid and rancid when stale.1
The presence of this oil in the salmonoids is inherent. The body
secretions in action upon the type of food eaten colors the natural
oils. These pigments color the eggs at the expense of the muscles, and
spawning fish will have a paler hue. This is especially true of the
quinnat or king salmon whose rich salmon-red flesh becomes suddenly pale
as the spawning season approaches.
The presence of oils with salmon-colored pigment, so noticeable in
the salmon and the trouts, is noted in the charrs as well, and many
times the Eastern Brook trout, which is a true charr, may bear
salmon-colored flesh. This may depend upon the inheritance of the
individual and the food. The Mackinaw or Lake trout (Cristovomer
namaycush) is also allied to the charrs and a near relative to the
Eastern Brook (Salvelinus fontinalis) but it bears a light oil and the
flesh is white.
1. FISHES, David Starr Jordan, D. Appleton & Co., 1925, p.
129.
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BLOBS AS TROUT FOOD
by James Simon
While collecting fishes on Falls River on September 9 and 10, we
experienced great difficulty in taking Blobs (Cottus). Our problem was
solved when we found that the Rainbow trout (Salmo shasta) there were
feeding on them. By catching trout and taking blobs from their stomachs
we made our collection complete. One ten-inch Rainbow trout from Falls
River, when opened in the presence of District Ranger Tom Garry, yielded
a blob (probably Cottus semiscaber) of five inches in length.
Other Rainbow trout caught yielded blobs from one to two inches in
length.
