Extinct tequila fish makes comeback in Mexico

Conservationists from Michoacana University of Mexico return fish to the Teuchitlán River

A tiny fish that has not been seen for more than 15 years has made a comeback in Mexico.

The tequila fish, a small species which grow no bigger than 70mm long, disappeared from the wild completely in 2003 due to the introduction of invasive, exotic fish species and water pollution. Thanks to efforts from conservationists at Chester Zoo, UK, and the Michoacana University of Mexico, more than 1500 fish have been returned to a series of springs in the Teuchitlán River, in the state of Jalisco, south west Mexico.

In 1998, at the outset of the project, scientists at university received five pairs of fish from Chester Zoo. These 10 fish founded a new colony in the university’s laboratory, which experts there then maintained and expanded over the next 15 years.

In preparation for the reintroduction, 40 males and 40 females from the colony were released into large, artificial ponds at the university. After four years, this population was estimated to have increased to 10,000 individuals and became the source for the reintroduction to the wild.

"With the skill and expertise of conservationists, and with local communities fully invested, species can make a comeback from environments where they were once lost."

Dr Gerardo Garcia, Chester Zoo

Dr Gerardo Garcia, curator of lower vertebrates and invertebrates at Chester Zoo said: “This is an important moment in the battle for species conservation. "It is a real privilege to have helped save this charismatic little fish and it just goes to show that with the skill and expertise of conservationists, and with local communities fully invested in a reintroduction project, species can make a comeback from environments where they were once lost.

“This is also a great example of how good zoos can play a pivotal role in species conservation. Not only have we been involved technically and financially, the breeders, which became the founding population for the reintroduction of the tequila spitfin, originated at Chester Zoo. Without the zoo population keeping the species alive for many years, this fish would have been lost forever.

“Following years of hard work by our partners at the Michoacana University of Mexico, the wild population is, thankfully, now thriving – they’re breeding naturally at a tremendous rate. It very much goes to show that animals can re-adapt to the wild when reintroduced at the right time and in the right environments.

"Our mission is to prevent extinction and that’s exactly what we’ve done here.”

The project has been cited as an International Union for the Conservation of Nature (IUCN) case study for successful global reintroductions – with recent scientific studies confirming the fish are thriving and already breeding in the river.

Experts say it has created a blueprint for future reintroductions of other highly endangered fish species, with a rescue mission for another, the golden skiffia, now well underway.

Image: Chester Zoo
Some 1,500 fish have been returned to the Teuchitlán River. Image: Michoacana University of Mexico