400
JAMES E. DEACON AND W. L. MINCKLEY
III. General Ecology
A. PHYSICAL FACTORS
7. Current and Turbulence
Flashflooding, one of the more frequently dicussed features of deserts,
seldom annihilates fishes from a habitat despite its impressive violence.
As is typical in nature, desert fishes avoid the problem if possible, moving
behind boulders, or along the banks at the onset of flooding, then into
backwaters as water overrides the banks. In narrow, high-gradient streams,
no refuge may be available. John (1964) recorded possible extirpation
of a population of speckled dace (Rhinichthys osculus) from a small
mountain creek in the Chiricahua Mountains, Arizona. Hubbs and Miller
( 1943 ) wrote of depletion and changes in population structure of the minnows Siphateles (= Gild) mohavensis, Gila orcutti, and their hybrids,
after severe flooding in the Mohave River, southern California, and in a
later paper (Hubbs and Miller, 1948a) they hypothesized that a number
of tributaries to pluvial Lake LeConte (Salton Sink) were fishless as a
result of past flooding. One population of the Gila chub {Gila intermedia)
was severely decimated, if not destroyed, in the narrow gorge of Fish
Creek, Maricopa County, Arizona, by flooding in winter of 1965-1966.
That canyon ranges from 6 to 20 meters wide, and Fish Creek typically
consists of a series of deep pools connected by trickles of water. Marks
on the walls were 12 meters above normal water levels in narrower places.
A tremendous flood in September, 1970 in Sycamore Creek, Maricopa
County, Arizona, completely scoured the stream channel, destroyed all
gauging devices, caused unestimated damage to property and streamside
habitat, and took a number of human lives. Only a few longfin dace
(Agosia chrysogaster) lived through the catastrophe, but within 1 week
young of that species were hatching, and by 1 month, young fish virtually
filled the creek. Adults were exceedingly rare, occurring in only the largest,
most permanent and protected pools, but their populations seemed to
increase in those places through the days following flooding, perhaps
through migration of fish back into their home areas after displacement
downstream.
A similar, but somewhat less severe flood was observed in 1960 in Rio
Canon, north of Cuatro Ciénegas, Coahuila, Mexico. Rain exceeded 5 cm
overnight, and the creek that normally flowed about 12m
3
/minute rose
3 meters, filling its canyon wall to wall as it concentrated in narrow places.
Severe flooding occurred in the village which lies near the canyon mouth,
and numerous cichlid fishes (Cichlasoma spp.) were stranded in the streets
when water receded. These presumably washed from the pond at a winery,
JAMES E. DEACON AND W. L. MINCKLEY
III. General Ecology
A. PHYSICAL FACTORS
7. Current and Turbulence
Flashflooding, one of the more frequently dicussed features of deserts,
seldom annihilates fishes from a habitat despite its impressive violence.
As is typical in nature, desert fishes avoid the problem if possible, moving
behind boulders, or along the banks at the onset of flooding, then into
backwaters as water overrides the banks. In narrow, high-gradient streams,
no refuge may be available. John (1964) recorded possible extirpation
of a population of speckled dace (Rhinichthys osculus) from a small
mountain creek in the Chiricahua Mountains, Arizona. Hubbs and Miller
( 1943 ) wrote of depletion and changes in population structure of the minnows Siphateles (= Gild) mohavensis, Gila orcutti, and their hybrids,
after severe flooding in the Mohave River, southern California, and in a
later paper (Hubbs and Miller, 1948a) they hypothesized that a number
of tributaries to pluvial Lake LeConte (Salton Sink) were fishless as a
result of past flooding. One population of the Gila chub {Gila intermedia)
was severely decimated, if not destroyed, in the narrow gorge of Fish
Creek, Maricopa County, Arizona, by flooding in winter of 1965-1966.
That canyon ranges from 6 to 20 meters wide, and Fish Creek typically
consists of a series of deep pools connected by trickles of water. Marks
on the walls were 12 meters above normal water levels in narrower places.
A tremendous flood in September, 1970 in Sycamore Creek, Maricopa
County, Arizona, completely scoured the stream channel, destroyed all
gauging devices, caused unestimated damage to property and streamside
habitat, and took a number of human lives. Only a few longfin dace
(Agosia chrysogaster) lived through the catastrophe, but within 1 week
young of that species were hatching, and by 1 month, young fish virtually
filled the creek. Adults were exceedingly rare, occurring in only the largest,
most permanent and protected pools, but their populations seemed to
increase in those places through the days following flooding, perhaps
through migration of fish back into their home areas after displacement
downstream.
A similar, but somewhat less severe flood was observed in 1960 in Rio
Canon, north of Cuatro Ciénegas, Coahuila, Mexico. Rain exceeded 5 cm
overnight, and the creek that normally flowed about 12m
3
/minute rose
3 meters, filling its canyon wall to wall as it concentrated in narrow places.
Severe flooding occurred in the village which lies near the canyon mouth,
and numerous cichlid fishes (Cichlasoma spp.) were stranded in the streets
when water receded. These presumably washed from the pond at a winery,