Hola.
Sí que les han sucedido esos cambios al sacarlos de su hábitat, por eso ya no lo hacen.
Con su permiso, copio aquí un mensaje que me envió David Koran de la AKA sobre estos temas y los problemas de la conservación de esta especie:
Devil's Hole is a cavern (I can send pictures of Devil's Hole and some of the
refuges previously constructed if you want at a later time) and sunlight only
penetrates the cavern for up to four hours a day except in late fall to early
spring when the sun angle is too low. So you problem number one - energy
influx is limited. Problem number two (the owl example), nutrient influx is
also limited. Problem number three - there is a submerged rock ledge or
shelf just below the water surface where the fish feed and spawn on algae -
prior to a court ruling to regulate the amount of groundwater pumping in the
area there were fears that the shelf (either portions of it or all of it)
would be exposed as water levels dropped.
The water level can be influenced by earthquakes hundreds of miles away! The
water from the cave system usually maintains a year round temperature of
about 32-33oC, however, during the period the sunlight impinges on the shelf
the water temperature will jump up to 4Co (something I thiink trigger
spawning in all pupfish). What you see is a fish that is thermally
challanged which is smaller than "refuge" fish and lacks pelvic fins. Fish
probably burn out quickly at this elevated energy level of existance.
They created three refuges for diabolis to date. The School Springs refuge
was created first but the water to feed the artifical refuge (more or less a
large flat tank partly dug into the ground) comes from a different spring at
a much higher temperature and needs to be cooled before flowing into the
refuge. Unfortunately the cooling tank is oriented with a large flat steel
surface almost perpendiculr to the daily path of the sun. Hence on the
hottest days when you need cooling of the water, the sun heats the tank
reservoir and defeats the purpose of cooling. All controls are manual and
there is no flow regulation on the valve to control water flow - it is all
guesswork. About 2-3 years ago this refuge failed and the last fish died due
mainly to a takeover by blue-green algae in the "tank".
They created another refuge at the Hoover Dam south of Las Vegas, at least
200 Km from Devil's Hole. The refuge concrete tank had a deep section to
mimic slightly the cavern at Devil's Hole. I don't think the water chemistry
was quite the same as at Devil's Hole. It never maintained more than a small
population of diabolis but the fish got larger than the fish in Devil's Hole
and developed pelvic fins. Some felt this was a hybridization and produced
different fish (since then studies have shown a hormone is lacking in the
Devil's Hole fish brought on by the severe conditions which causes the
"natural" deformities). After the disaster a few years ago these fish were
brought in and placed at the Willow Bay National (Federal) Fish Hatchery.
The most successful refuge was the Point of Rocks Springs refuge constructed
in the early '90's. The water source for the refuge was a short distance
from Devil's Hole (probably a different aquifer source) but was cooler. I
had advised utilizing a cover to hold in heat that escaped during the winter
period which delayed the pool warming to more than 27oC until late in the
spring. Productivity was limited to only a few months and most of the fish
produced were males. By adding the translucent layer onto the heavy guage
wire cover that rolled over the pool to to prevent preditation or vandalism
they extented the breeding season and got a much better sex ratio.
As I previously said a court order limited groundwater pumping and prevents
what might be agriculutral development in the area. Many residents don't
think that should be sacrificed for the pupfish and threats have been made
about how some well placed poison can eliminate the "problem". Devil's Hole
has had its security significantly upgraded in the last ten years, with
concertina razor wire (like a prison) placed on top of the chain-link fence
which surrounds it and does severely limit any access to Devil's Hole.
However, that is not the case at the PORS refuge where standing outside of
the chain-link fence around the refuge can leave you as close as 3 m from the
pool. In the summer breeding season the translucent plastic is removed and
only the large grating of the chain-link fence like cover protects the fish.
Nearby (less than a kilometer) is the PORS habitat for Cyp. nevadensis
mionectes where invasive fish have been removed in recent years and this
endangered fish is thriving. Somehow maybe 6 years ago a mionectes got into
the PORS refuge and has hybridized this backup population. While the amount
of mionectes material is less than 5%, the fish can no longer be used to back
up the diabolis at Devil's Hole. Some think that mionectes swam up to the
water source (a trickle of water eaven a migrating salmon would have trouble
negotiating), took a right hand turn and proceeded down the buried 1.5 cm
pipe that feeds the refuge. For me I think an person immitated a Pau Gasol
from outside the fence and tossed in a few 15 foot jump shots of minoctes
through the the coarse screen protecting the refuge fish which survived and
produced the desired hybrids.
At last years Ecosystem Restoration Conference I chaired a session where the
consultant who was hired to plan a new refuge to replace the failed School
Springs refuge showed slides of their design. It was disheartening to see
that our officials steered them into designing a refuge that would produce
deformed or challanged diabolis like Devil's Hole instead of realizing that
they should look for quantity in order to maintain the gene pool and
diversity.
