Whipsnade Zoo and Bristol Zoo Project launch ambitious plan to save a rare fish from extinction

Two zoos are spearheading a dramatic conservation effort to save a rare fish species from extinction.  

Last week, Whipsande Zoo transported precious Boxer pupfish eggs to Bristol Zoo Project, following the revelation that the last remaining wild population is feared to have been wiped out.   

Found only in Lake Chichancanab in Mexico, Boxer pupfish (Cyprinodon simus) are one of seven pupfish species endemic to this specific habitat. While their official IUCN status classifies the fish as Near Threatened, a recent survey by ZSL – the conservation charity which runs Whipsnade Zoo – conservation partners in Mexico suggests that the wild population has been completely decimated, likely caused by the introduction of invasive fish species such as the Mayan cichlid.   

Aquarists at Whipsnade Zoo were told by conservation partners that the world’s last remaining Boxer pupfish resides in their care, initiating an urgent plan to safeguard the species.  

Alex Cliffe, ZSL’s Assistant Curator of Fish, and the European programme coordinator for pupfish, said: “Finding out that the last remaining wild Boxer pupfish could be extinct was a really sobering moment, but we knew we didn’t have time to dwell and had to act quickly to safeguard the future of this species.  

“As a world leader in managing and reintroducing extinct-in-the-wild species, and the founders of the Extinct-in-the-wild Alliance, ZSL has a responsibility to drive forward the recovery of the worlds most threatened species.” 

In a bid to ensure that not every Boxer pupfish egg was in one basket, Whipsnade’s team began the delicate process of moving 50 Boxer pupfish eggs to Bristol Zoo Project, which is run by conservation and education charity Bristol Zoological Society, to start a new population in the conservation breeding programme. This will ensure both zoos preserve a healthy and genetically viable back-up population which can one day be used to restore the fish to the wild.

“Thanks to the fast response of the keepers at Bristol Zoological Society, and the skillful care of our aquarists at Whipsnade, within just four days we had collected and transported the precious eggs to be hatched, reared and cared for by our fellow conservationists,” said Alex.   

The tiny, translucent pupfish eggs were carefully collected by keepers from bundles of wool, which replicate the plants and algae where the fish would usually lay their eggs, placed in the pupfish tanks. The eggs were extracted and transferred to pots filled with water, ready to be transported to new homes where they will hatch.  

Brian Zimmerman, Director of Conservation and Science at Bristol Zoological Society, said “Freshwater fish are one of the most imperiled groups of animals on earth, with more than 3,000 species at risk of extinction. Conservation zoos and aquariums have a key role on the front line of saving species from that fate, and our collaboration with ZSL further demonstrates the role that conservation zoos can play to fight extinction. By strengthening the numbers of the Boxer pupfish across more than one institution, we will ensure that the species survives, even if it is lost in the wild.”  

Boxer pupfish are vital to the ecosystem of Lake Chichancanab, and their extinction puts other animals in that ecosystem, such as species of bird and reptiles that feed on them, at risk.  

“When a species no longer exists in the wild, its future relies completely on conservation zoos. At Whipsnade, we now have the incredibly important responsibility of preventing this tiny fish from slipping into extinction – a responsibility we take very seriously,” explained Alex.   

“Thanks to human-caused threats including climate change, habitat destruction, or the introduction of invasive species, sadly, Boxer pupfish are not the only fish species facing a perilous future.

“The drastic decline in Boxer pupfish numbers over the last six years highlights the fragility of wildlife, but thanks to the unique conservation expertise and agility of zoos and aquariums, we can reverse the damage caused and restore the species in our care” Alex concluded.

Whipsnade Zoo will work with partners in Mexico and the IUCN to confirm the status of the Boxer pupfish, but in the meantime as part of ZSL’s work to halt human induced species extinction, they will co-ordinate breeding efforts to ensure the protection and continuation of the species.