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[Killietalk] Fwd: [dfc-l] Devils Hole Pupfish Update

For those interested, here is the latest on the C. diabolis recovery efforts,
courtesy of the Desert Fishes Council.   I think there may be grounds for some
very very cautious optimism, but only time will tell...  And it remains a
mystery as to why C. diabolis is so very hard to breed in captivity.


----- Forwarded message from Paul_Barrett at fws_gov -----
    Date: Wed, 28 May 2008 16:09:39 -0700
    From: Paul_Barrett at fws_gov
Reply-To: Paul_Barrett at fws_gov
 Subject: [dfc-l] Devils Hole Pupfish Update
      To: dfc-l at utlists_utexas.edu

Dear DFC Members:

Recently Phil Pister asked that I update the membership on the current
status of Devil Hole pupfish and our recovery efforts.

As most of you know, the pupfish population fluctuates annually with low
counts in the spring (sp) and higher counts in the autumn (au).  It has
been in a severe decline since the mid to late 1990s.  It dropped from an
historical high of approximately 200 sp/500 au to a low of 38 sp in 2006
and 2007 and 86 au in 2006.  There has been a lot of speculation and some
compelling theories a change in the ecosystem dynamics to a genetic
collapse resulting from past bottlenecks but no definitive reason for the
population decline has been identified.

Beginning in the winter of 2007 under the joint auspicious of the Nevada
Department of Wildlife, National Park Service including Death Valley
National Park, and the Fish and Wildlife Service supplemental food was
begun to be added to Devils Hole to increase the robustness of the fish,
particularly as they pass thorough the lean winter months.

The autumn 2007 survey was 95 individuals and the most recent survey on 5
April 2008 resulted in a count of 45 fishes.  Although the population
remains precariously low, this is one of the first increases in seasonally
adjusted numbers since the mid 1990s.  Furthermore, divers reported, and
our biweekly larval surveys confirm, the fish are indeed much more robust
than in past years.

We are now examining ways to increase egg and larval production in Devils
Hole.  To this end, with the assistance of Gary Scoppettone of USGS, a
floating exclosure has been constructed and deployed in Devils Hole.  The
enclosure consists of a PVC frame and 50 micron mesh.  Gravel substrate
was placed in the bottom on the enclosure and it was inoculated with algae
and microfauna from Devils Hole.  Our thoughts are that if we can produce
larvae and place them in the enclosure we may be able to determine if
predation is a major factor in larval production and survival as has been
speculated.   We are about to deploy a similar, but smaller enclosure that
will contain a bowl with gravel substrate.  Adults from Devils Hole will
be placed in this second enclosure and hopefully deposit fertile eggs on
the gravel.  The bowl will then be moved to the first enclosure where they
will mature and larvae developed.  By using the second enclosure we can
conduct multiple trials by moving only bowls of gravel that will only
temporarily be placed in the grow out enclosure.

Despite strong efforts we have not had success propagating pure Devils
Hole pupfish in captivity, although we have little trouble producing
Devils Hole x Ash Meadows Amargosa pupfish hybrids.  Currently there are
no pure Devils Hole pupfish in captivity and until we build up the
population in Devils Hole we will not be taking individuals into
captivity.  However we continue to work with the hybrids as surrogates to
develop and refine possible propagation techniques.  Scott Bonar at the
University of Arizona will be helping with that research.

We are also working with several universities to develop a temperature
model of Devils Hole, refine our population estimates, and other issues.

Many entities have contributed to the effort to stabilize and increase the
population including Shark Reef at Mandalay Bay, UNLV, and of course the
Recovery Team.  There are certainly others Iâ??ve missed in this brief
communication but it has been a true multi-agency, multi-entity effort and
Iâ??d like to thank all involved, including the Council for your interest.
If anyone wishes for more information on the current status and
activities, please donâ??t hesitate to contact me.

Paul Barrett
paul_barrett at fws_gov

Paul J. Barrett Ph.D
USFWS Devils Hole Pupfish Recovery Coordinator
702.515.5225 (Las Vegas)
702.606.5044 (Mobile)
paul_barrett at fws_gov

----- End forwarded message -----


Bruce J. Turner
Dept. Biol. Sci.
VIRGINIA TECH
Blacksburg, VA 24061 USA



                          "Truth, she lives in a distant land
                           of snow, and ice... And burning sand."

                          "Daily beatings will continue
                           until morale improves..."
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