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3 animals you’d never notice unless they were gone

Posted by: Gigi Allianic, Communications

They may not be as well-known by the 180 million people who visit Association of Zoos and Aquariums (AZA)-accredited zoos and aquariums each year, but desert pupfish, freshwater mussels, and Polynesian tree snails play important roles in their respective ecosystems. If not for the hard work of AZA-accredited institutions and their conservation partners, some of these and many other animals would already have vanished from the planet.

With a growing number of human-influenced threats threatening animals around the world, including poaching, deforestation, and an expanding population that already exceeds 7 billion people, we are facing what some scientists call the “Sixth Extinction.”

The 228 accredited members of AZA continue to build upon their history and expertise of saving endangered species such as breeding programs that coordinate across many institutions to ensure healthy genetic and demographic diversity and partnerships with local, national, and international conservation organizations working on the recovery of these species.

Partula snail close up. Photo by Ryan Hawk/Woodland Park Zoo.

“The Polynesian tree snail, Partula nodosa, is extinct in the wild, but thanks to the collaborative efforts of Woodland Park Zoo and other AZA zoos, plans are underway to reintroduce the species back to Tahiti in the next couple of years,” said Erin Sullivan, a collection manager at Woodland Park Zoo. “The wildlife preserve, an approximately 20-meter square protected site, might just be the smallest wildlife preserve in the world.”

Partula snails are tiny! Photo by Ryan Hawk/Woodland Park Zoo.

Woodland Park Zoo has a lab exclusively for the snails, which provides a special and secure space and optimal breeding conditions. According to Sullivan, the population hovers at a little more than 900 snails at any given time. The lab is on view to zoo-goers.

The Tree Snail Laboratory at Woodland Park Zoo. Photo by Kirsten Pisto/Woodland Park Zoo.

Woodland Park Zoo currently partners with more than 35 field conservation projects taking place in the Pacific Northwest and around the world. Woodland Park Zoo supports the Partula Recovery and Reintroduction Project, whose goal is to preserve and enhance the survival of all surviving endemic tree snail species of the family partulidae within their natural range in French Polynesia, and to re-establish, where feasible, the 11 species that currently exist only in the international conservation breeding programs.

Fish and mollusks are among some of the oldest groups of animals still alive today, pre-dating even the earliest insects. Despite hundreds of millions of years of evolutionary success, many of these species are vulnerable to a variety of threats, and their future is uncertain. AZA-accredited zoos and aquariums are doing everything they can to protect the most imperiled fish and mollusks from extinction.

Over the next several months, AZA-accredited zoos and aquariums will be celebrating these initiatives and inviting the public to support efforts to save even more species. Through December, fish and mollusk species are spotlighted, including:

Northern riffleshell mussels. Photo courtesy of U.S. Fish and Wildlife Service.

Freshwater mussels

Found in the rivers and streams that traverse the North American continent, these bivalves are essentially living water filters, with some individuals capable of moving eight gallons of freshwater through their systems every single day. Freshwater mussels prevent buildups of algae and bacteria and are in turn preyed upon by animals such as fish and birds. Nearly 300 species live in the United States alone, many of which are threatened by pollution, damming, and competition from the invasive zebra mussel. Scientists at the Columbus Zoo and Aquarium have collaborated with local wildlife agencies to establish the Freshwater Mussel Conservation and Research Center (FMCRC), one of only 10 freshwater mussel conservation facilities in North America, to assist in the propagation and conservation of highly endangered freshwater mussel species. Over a five-year period alone, the Center reintroduced 6,200 endangered northern riffleshell mussels to Ohio waterways, the largest reintroduction ever to occur in Ohio. The riffleshell mussels are tagged with microchips so that they can be identified during annual surveys, and thus far the survival rate of reintroduced mussels has been extremely high.

Desert pupfish. Photo by Andrew Borcher via Wikimedia.

Desert pupfish

You wouldn’t think to look for fish in the desert, but this hardy species thrives in super-salty ponds and streams scattered throughout the American southwest. In fact, closely-related pupfish species found in isolated bodies of water offer evidence that a series of prehistoric desert lakes were once connected. These days, the desert pupfish is threatened by human developments and invasive species that compete for the precious little aquatic habitat that remains. Under the leadership of Phoenix Zoo and The Living Desert, the desert pupfish is being bred in captivity and released into protected areas so that it can carry on the story of the desert’s history. With their abilities to live in some of the most extreme desert environments, these fish demonstrate the incredible range of adaptations found in healthy ecosystems.

Up close detail of Partula tree snail. Photo by Ryan Hawk/Woodland Park Zoo.

Polynesian tree snail (Partula nodosa)

Considered among the smallest of all endangered species, this species of partula snail is already extinct in the wild and would be gone completely were it not for the work of AZA-accredited zoos (Akron Zoo, Detroit Zoo, Disney's Animal Kingdom, Saint Louis Zoo, and Woodland Park Zoo) and international partners that are breeding these snails for reintroduction in their native range in the South Pacific. Like so many other mollusks, the Polynesian tree snail declined from the introduction of an invasive species—in this case, a predatory snail that was introduced to control the population of yet another introduced snail. These snails were first described from specimens collected by the British explorer Captain James Cook, have been the subject of extensive field and laboratory research, are prominent in Polynesia’s cultural history, and play important roles in nutrient recycling and in the food chain of their native ecosystem.

For a list of AZA-accredited zoos and aquariums where you can see some of these incredible animals in person, visit