Beyond Captive Propagation




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:


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 Department.