Helping to save Mexican pupfish from extinction

Precious eggs from a rare Mexican fish species have successfully hatched thanks to the work of Bristol Zoological Society!

Our ectotherm experts took delivery of more than 50 boxer pupfish eggs before Christmas, from ZSL’s Whipsnade Zoo, as part of efforts to safeguard the species, which is believed to be Extinct-in-the-Wild.

The small eggs were collected from the aquarium at Whipsnade after the fish laid them on bundles of wool, which replicate the sorts of plants they would normally lay their eggs in. Once they arrived at their new home in Bristol, they were carefully transferred into pots filled with water.

Now, thanks to the efforts of our ectotherm keepers, the fry have hatched successfully and are thriving.

Tamara Canalejas, Curator of Ectotherms at Bristol Zoological Society, said: “Over 29 of the eggs received have hatched and are thriving, which is fantastic news considering the precariousness of transporting and rearing a species we have never worked with before.

“The insights we have gained from these recent egg transfers have been incredibly valuable for planning future shipments to establish new viable populations. This really is a triumphant milestone in freshwater fish conservation!”

Boxer pupfish, Cyprinodon simus, is one of seven pupfish species native to Lake Chichancanab in Mexico. However, concerns about their existence are growing as surveys have not recorded a population there for over two years. Researchers believe this population destruction is down to the introduction of invasive fish species, such as the Mayan cichlid

Working closely with Whipsnade Zoo in Bedfordshire, where the only other known population of Cyprinodon simus previously existed, this new breeding programme is crucial for the conservation of this extremely rare species.

Brian Zimmerman, Director of Conservation and Science at Bristol Zoological Society, added: "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. The next step in the programme will be to introduce juveniles from Whipsnade and begin breeding between the two collections. We aim to increase our numbers to at least 100 and maintain a stable population.”

Our team is also planning a trip to Laguna Chichancanab this year to assess the lake, search for this rare species of pupfish, as well as engage with the local community.

Last year, alongside working in nine countries, across four continents, and directing 14 field conservation projects with 31 local partner organisations, we collaborated with other conservation leaders to breed species for population boosts and re-introduction into the wild. This included Extinct-in-the-Wild species of Partula snails and Critically Endangered Desertas Island land snails, in partnership with a number of other UK zoos.