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NFC: endangered stuff

Beyond Captive Propagation
Excerpt from Endangered Species Bulletin May/June 1999
Mike Demlong

For native species like the black-footed ferret (Mustela nigripes),
California condor (Gymnogyps californianus), and Mexican wolf (Canis
lupus baileyi), the role of zoos and aquariums in partnership recovery
efforts seems fairly straightforward. Our roles include propagating
animals for reintroduction to native habitats and interpreting the plight
of these species and their ecosystems for our millions of visitors. But
our efforts extend well beyond captive propagation and visitor awareness.
Zoo and aquaria staff throughout North America also contribute to the
recovery of native species by participating in habitat renovation,
population surveys, basic research, control of non-native species,
interpretive materials design, and maintaining genetic refugia. The
Phoenix Zoo has been active in many of these areas, some examples of
which follow:

Native Fish

The introduction of exotic sport fish and the diversion or impoundment of
southwestern rivers has contributed to the extirpation, or some cases
extinction, of many native fish species. The Phoenix Zoo grounds contain
a series of artificial lakes, ironically filled decades ago with water
diverted from a now dry river that once flourished with native fish
species. In partnership with biologists from Arizona State University,
the American Zoo and Aquarium Association's Freshwater Fish Taxon
Advisory Group, the Fish and Wildlife Service (FWS), and the Arizona Game
and Fish Department, zoo staff created a plan to use one of the lakes as
a refugium for endangered native fish.

The zoo's main lake was chosen due to its central location (a natural
focal point for our visitors) and size (approximately 15 acre-feet). FWS
fishery biologists assessed the lake and found it suitable as long-term
habitat for a population of endangered bonytail chubs (Gila elegans) and
razorback suckers (Xyrauchen texanus). Our objectives were to create a
genetic or broodstock refugium and to "head start" juvenile fish in a
semi-natural environment. The plight of native fish in the wild and the
zoo's role in their recovery are explained on large interpretive panels
around the lake. Each of the panels displays life-size sculptures of the
fish that inhabit the lake. Before juvenile native fish were released,
the exotic sportfish in the main lake were removed to other urban lakes.
The lake was then drained and refilled with water filtered through a
passive gravel bed to impede the reinfestation of sportfish.
Approximately 200 bonytail chub and 5,000 razorback suckers reared at
Dexter National Fish Hatchery and Willow Beach National Fish Hatchery
were released into the lake in the summer of 1996. By the fall of 1998,
some of the fish had reached a predator safe, sexually mature size and
over 100 razorbacks were returned to their historic range in the Colorado
River. Another release of fish head-started at the zoo is planned for
this year.

In addition to bonytail chubs and razorback suckers, the zoo also
maintains three other ponds for desert pupfish (Cyprinodon macularius)
and Gila topminnows (Poeciliopsis occidentalis). Although these species
were originally established at the zoo as refugia or research
populations, the pupfish and topminnow also provide the unexpected
benefit of natural mosquito control for the zoo. Also, a small group of
adult and juvenile pupfish will be moved to Cibola National Wildlife
Refuge to establish another refugium population.

Whether it's a snail, fish, or frog, our nation's zoos and aquaria often
do much more for wildlife than captive propagation. Just ask us!

Mike Demlong, formerly the Ectotherm Curator at the Phoenix Zoo, is now
the Amphibians and Reptiles Program Manager for the Arizona Game and Fish

Robert Rice
Join the NFC and help save our fishes.   http://www.nativefish.org/  

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