VII. DESERT FISHES
399
land seas which, in place of alkali flats, once floored the many basins in the
area of interior drainage. Across the larger of the bare and level lake beds
we may drive in any direction, foot down on the pedal and hands off the
wheel if we wish, ever chasing the mirage of water which the heat waves cause
to rise before us. Glancing back the mirage is seen to follow us, as though the
ghost of the waters that once filled the basin were rushing to engulf us. As
the coolness of the evening dispels these unreal waters, the mountains come
forth in the ruggedness of their naked rock, in clearness that belies their distance. Across their bases, yet to a height of many hundreds of feet are seen
clear-cut terraces and great sea cliffs . . . which were cut by the very obviously real waters of former times. By reason of the dry climate, the terraces
have been preserved through centuries with such fidelity that geological skill
is not needed to interpret their significance. Great bars of wave-washed
gravel, now bone-dry, also tell convincingly of former shore lines and strong
currents . . . . The great Quaternary seas of the west—some comparable in
area and depth with the Great Lakes—may have persisted long enough to
have been gazed upon by desert Indians, who had legends of great waters.
These seas, however, had evaporated into the dry desert air long before
civilized man arrived to paint their glory in colors and words, to cover their
surfaces with great ships of commerce, and to pollute their waters with the
waste products of the great cities which would surely have arisen along their
now dry and unpeopled shores.
Few natural lakes presently exist in deserts, and many of those that do
are too saline or astatic to support fishes. Many remnant lakes have only
recently become extinct or uninhabitable by fishes because of salinity, as
a result of beheading of tributary streams by dams (Minckley and Cole,
1968), actual drainage (Williams, 1967b), pumpage from their basins,
or other man-induced catastrophes. It is notable that the reverse situation
also has rarely occurred, such as the inadvertent formation of the Salton
Sea in the basin of pluvial Lake LeConte (Hubbs and Miller, 1948a) beginning when the Colorado River broke through irrigation works in the
flood of 1905 and produced a lake 25 meters deep and 1334 km
2
in surface
area (MacDougal, 1914; Walker, 1961).
With few exceptions, environments of closed-basin lakes include shallow
waters subject to severe wind action and thermal variations, at least local
conditions of high turbidity and salinity, and a pronounced monotony of
bottoms, shorelines, and other features. On occasion, diverse deposits of
travertines are formed (Dunn, 1953). Dome-shaped formations, the
algal biostromes of Carozzi (1962), grow through accretion of salts and
debris, physicochemically and by algae, in places generally protected from
violent waves. As with marshes, some desert lacustrine habitats resemble
in many respects lagoons along desert sea coasts.
Only a few deep, relatively ancient lakes persist in arid lands, such as
Pyramid Lake, Nevada (Fig. 3). Lakes associated with riverine environments, and large limnocrenes, are discussed relative to their origins.
399
land seas which, in place of alkali flats, once floored the many basins in the
area of interior drainage. Across the larger of the bare and level lake beds
we may drive in any direction, foot down on the pedal and hands off the
wheel if we wish, ever chasing the mirage of water which the heat waves cause
to rise before us. Glancing back the mirage is seen to follow us, as though the
ghost of the waters that once filled the basin were rushing to engulf us. As
the coolness of the evening dispels these unreal waters, the mountains come
forth in the ruggedness of their naked rock, in clearness that belies their distance. Across their bases, yet to a height of many hundreds of feet are seen
clear-cut terraces and great sea cliffs . . . which were cut by the very obviously real waters of former times. By reason of the dry climate, the terraces
have been preserved through centuries with such fidelity that geological skill
is not needed to interpret their significance. Great bars of wave-washed
gravel, now bone-dry, also tell convincingly of former shore lines and strong
currents . . . . The great Quaternary seas of the west—some comparable in
area and depth with the Great Lakes—may have persisted long enough to
have been gazed upon by desert Indians, who had legends of great waters.
These seas, however, had evaporated into the dry desert air long before
civilized man arrived to paint their glory in colors and words, to cover their
surfaces with great ships of commerce, and to pollute their waters with the
waste products of the great cities which would surely have arisen along their
now dry and unpeopled shores.
Few natural lakes presently exist in deserts, and many of those that do
are too saline or astatic to support fishes. Many remnant lakes have only
recently become extinct or uninhabitable by fishes because of salinity, as
a result of beheading of tributary streams by dams (Minckley and Cole,
1968), actual drainage (Williams, 1967b), pumpage from their basins,
or other man-induced catastrophes. It is notable that the reverse situation
also has rarely occurred, such as the inadvertent formation of the Salton
Sea in the basin of pluvial Lake LeConte (Hubbs and Miller, 1948a) beginning when the Colorado River broke through irrigation works in the
flood of 1905 and produced a lake 25 meters deep and 1334 km
2
in surface
area (MacDougal, 1914; Walker, 1961).
With few exceptions, environments of closed-basin lakes include shallow
waters subject to severe wind action and thermal variations, at least local
conditions of high turbidity and salinity, and a pronounced monotony of
bottoms, shorelines, and other features. On occasion, diverse deposits of
travertines are formed (Dunn, 1953). Dome-shaped formations, the
algal biostromes of Carozzi (1962), grow through accretion of salts and
debris, physicochemically and by algae, in places generally protected from
violent waves. As with marshes, some desert lacustrine habitats resemble
in many respects lagoons along desert sea coasts.
Only a few deep, relatively ancient lakes persist in arid lands, such as
Pyramid Lake, Nevada (Fig. 3). Lakes associated with riverine environments, and large limnocrenes, are discussed relative to their origins.