7064

• UCREFRP Catalog Number: 7064
• Author: Berry, C. R., Jr.
• Title: Humpbacks and Bony Tails
• USFW Year: 1979
• USFW - Doc Type: Utah's Rare Fish
• Copyright Material: YES

Charles R. Berry I Jr.

year-old fish are about 100
mm (4 in) in length, 6-year-
olds about 400 mm (16 in), and
ll-year-olds about 600 mm (2
ft) .
The 45 kg squawfish aren't
found today. The largest fish
taken recently weighed about 9
kg (20 Ib). We know that they
do migrate upstream and into
tributaries during the spring
and summer. We also know
that the squaw fish population
has suffered a drastic decline in
numbers and range since the
early 1900s. It was common
throughout the Colorado
River system from Wyoming
to California. Now it is only
found in parts of the upper
Colorado basin where only
small numbers can be found.
The squawfish is now an en-
dangered species.

As the Stream is Bent. . .

The Colorado River and its
tributaries are a special river
system. The Colorado itself
historically contained less than
ten fish species, a very small

species diversity for such a
large rivl~r. This lack of diver-
sity, however, may be due to
the extreme conditions which
have made the Colorado
famous. The river drops in
elevation nearly 3.2 km (2 mn
in its 2,700 km (1,700 mi)
journey Ifrom Wyoming to the
Gulf of California. This
relatively rapid elevation drop
makes for some of the most
turbulent river water on earth.
Seasonal flow patterns are also
extreme. Spring flows may be
a thousand times greater than
dry weather flows. The erosive
nature of the basin's soils
results in very high mineral
and silt loads in the rivers of
the basin. In one year, the Col-
orado carries to the Gulf the
equivalent of 0.3 (1 ft) of top-
soil from a 405 km2 (156 mF)
area.
. . . So the Fish Will Grow

It was under these condi-
tions that the squawfish and
other naltive fish evolved with
very str,ange adaptations. The
humped backs, streamlined

Grad stude"ts pulli"g a sei"e . . .

and looking O1'er a "aul. Notice
u"lucky catfis" amo"g t"e small fry

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Spinedace or "Shiner"

23
April 1979