"The Devils Hole pupfish is probably the most restricted vertebrate species
in the world, with both the entire population and the entire species
naturally existing only in Devils Hole. Because of its endangered status and
unique habitat, much information about population size has been gathered in
recent years. Most individuals live in the vicinity of a small rocky shelf
or in open water near the surface, but observations by SCUBA divers have
shown that some often venture as deep as 26 m into the limestone cavern. At
present, the population size fluctuates from a low of about 150—200 fish in
winter to 300—400 in summer and early autumn. In the past as many as 800
fish were present during summer, but reduced water levels have decreased the
maximum summer population by reducing the critical food supply. Annual
changes in population size are known to be related to seasonal food
production of algae."
"Fish populations in marshes and streams strikingly contrast with those in
spring habitats, in that populations annually oscillate 10 to 20 fold. These
estimates are complicated because low winter temperatures cause fish to
become inactive and bury in sediments, so that accurate estimates of
population size are impossible. Observations strongly suggest stream and
marsh populations are seasonally much larger and denser than those in
springs. A good example is the Salt Creek pupfish population. During winter,
when the evaporation rate is low, Salt Creek flows for 3 to 6 km along the
floor of Death Valley. During spring months, large numbers of Salt Creek
pupfish move into this newly available habitat. A conservative estimate
places the population at one million fish during its peak. When summer
approaches, the stream begins to dry up at its lower end, isolating large
numbers of fish in the remaining pools. By late summer the stream flows for
only about 1.0 km below the spring sources and the number of Salt Creek
pupfish is reduced to only a few thousand individuals, densely packed in the
remaining habitat. Winter floods may further decimate the population."
Jay
-----Original Message-----
From: owner-nanfa_at_aquaria.net On Behalf Of
rjs_at_silcom.com
Sent: Sunday, October 17, 1999 6:01 PM
To: nanfa_at_aquaria.net
Subject: Re: NANFA-- RE: Desert Pupfishes
Thanks for the corrections, Jay. I neglected to mention
that he specifically referred to the Salt Creek pupfish when
saying there were "millions" of them during the wet season.
He did say that all pupfish in the area had been listed as
endangered, though. I apprecite the correction.
Do you happen to know if the Salt Creek pupfish, C. salinus
make good aquarium fishes? Having viewed a "pupfish pond"
at the Anza-Borrego desert visitors center, I was fascinated
by their general behavior - as well as the coloration, of course.
Bob Sinclair
Santa Barbara CA
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