Skiffia francesae: Back from the Dead on Day of the Dead

Golden skiffia Day of the Dead artwork by Adriana Arellano Tinoco

Back from the Dead on Day of the Dead: Extinct-in-the-wild fish will return to its natural habitat in Mexico

In a boost for freshwater species and ecosystems, conservationists will release the golden skiffia back into the Teuchitlán River after it vanished from the wild 28 years ago.

More than two dozen years since the golden skiffia (Skiffia francesae) disappeared from its only natural habitat in Mexico, a team of conservationists will release the species back into the wild. The release date set for Nov. 4—in the midst of the country’s cultural Day of the Dead celebrations—is fitting as families honour their departed ancestors and welcome them back from the dead for a night. Day of the Dead is Nov. 2, but celebrations continue locally.

Golden skiffia, Skiffia francesae, a small livebearing goodeid that has been extinct in the wild for almost three decades, persisting only in private hobbyist and institutional aquarium collections.

“The Day of the Dead is a traditional Mexican celebration, when it is believed that people’s deceased ancestors return to the land of the living for one night, to talk and spend time with their families,” said Omar Domínguez-Domínguez, a professor and researcher from the Michoacan University of Mexico, who is leading the golden skiffia reintroduction. “Releasing the golden skiffia around this time is a metaphor for how the species has come back from the dead to return to its home, not for one night, but forever.”

Bringing the species back from the ‘dead’ is the result of collaborative conservation work between Michoacan University of Mexico, Chester Zoo, Goodeid Working Group, Re:wild and SHOAL. On November 4th, 2022, the team will release approximately 1,200 golden skiffia into the species’ native range in the Teuchitlán River, Jalisco, Mexico. The fish all come from a conservation breeding program.

The Teuchitlán River hasn't been home to Skiffia francesae for nearly three decades. — The Teuchitlán River hasn’t been home to Skiffia francesae for nearly three decades.

The golden skiffia has not been seen in the wild since the 1990s. Human impacts such as dam construction, water extraction, pollution, and the introduction of invasive species have caused major changes to the skiffia’s habitat, pushing it to extinction in its only home. Conservationists hope that the fish released on Nov. 4 will ultimately result in a healthy, self-sustaining population taking hold so the species can fulfill its important natural role in the ecosystem of eating algae and mosquito larvae, which helps keep populations of those species in check.

“With thousands of freshwater species threatened with extinction, the story of the golden skiffia returning to the wild is inspiring evidence of the many opportunities for conservation impact that together can reverse the freshwater biodiversity crisis,” said Harmony Patricio, SHOAL conservation program manager and Re:wild’s freshwater fish conservation program manager. “The SHOAL partnership is expanding freshwater species conservation awareness, funding, capacity, and action to meet the level of the challenge, and positive stories such as the golden skiffia reintroduction can help draw attention to the challenges facing freshwater ecosystems, which have historically been overlooked and underfunded.”

The release of the golden skiffia has been many years in planning: in 2014, scientists from the Michoacan University of Mexico and passionate fishkeepers from the Goodeid Working Group helped restore the species’ degraded habitat and remove non-native species from the Teuchitlán ecosystem, removing the threats that caused the species to become extinct in the wild and laying the foundations for a successful reintroduction.

This project is part of Fish Ark Mexico, a conservation project in central Mexico that focuses on 41 highly threatened species of freshwater fish. Fish Ark Mexico has more than 20 years of experience in Mexican fish conservation and has succeeded in keeping 39 species of endangered and extinct-in-the-wild goodeid species in captivity. The Fish Ark facility at the Michoacan University of Mexico in Morelia has been supported by several national and international conservation organizations, including Chester Zoo, Re:wild, and SHOAL.

The golden skiffia release comes six years after the successful reintroduction of the tequila splitfin (Zoogonetcus tequila), which faced very similar threats to the golden skiffia and which was also bred in a conservation breeding program and released into the Teuchitlán River. Domínguez-Domínguez also led that work. The population of tequila splitfin there is now thriving, and the project has been cited as an International Union for the Conservation of Nature [IUCN] case study for successful global reintroductions.

“Releasing this species back into the wild is a light of hope for this wonderful family of fishes—the goodeids—and for the conservation of freshwater fish more generally,” Domínguez-Domínguez said. “Knowing that universities, zoos and aquarists can come together to fix some of what has been destroyed and return to nature some of what has been lost is an amazing thing. The reintroduction will benefit not only the natural ecosystem but, because of the habitat restoration work that has already occurred, the communities that live near the river as well.”

In preparation for the species’ return to the wild, individuals due for release have first been placed in ponds, where they are expected to adapt to semi-captive conditions. Individuals due for release are dewormed and marked, then taken to floating cages in the river known as mesocosms where they are kept for at least a month, so that they can adapt to natural conditions before release.

Mesocosms in the Teuchitlán River. Image credit: Manfred Meiners

Aerial view of the mesocosms that housed Skiffia francesae prior to release.

Individuals released into the wild are tagged with a non-toxic elastomer before release and will be monitored for the next five years to assess whether the population is increasing and whether the fish are reproducing and growing successfully in their natural habitat.

With one in three freshwater fish threatened with extinction, they are the most threatened group of vertebrates on the planet. Conservation work such as the release of golden skiffia back into the wild will be vital to ensuring extinctions are halted and populations are given the best possible chances of bouncing back from the brink. The Michoacan University of Mexico, Chester Zoo, the Goodeid Working Group, and SHOAL are currently developing a plan to save Mexican goodeid species—one of the world’s most threatened group of fish—which includes the golden skiffia and tequila splitfin.

“This project is a great example of how zoos can contribute to conservation in the field through captive breeding and research, using animals born in captivity, and the skills and experience that have been developed through their captive management, to establish new wild populations, or to strengthen existing populations,” said Paul Bamford, regional program manager for Latin America at Chester Zoo. “By holding goodeid species up as flagships for freshwater conservation in Mexico and building projects and strategies to protect them and the ecosystems where they live, we are not only protecting biodiversity and the wellbeing of freshwater environments, but also the people and communities that live alongside them.”

This project has been made possible by generous funding and support from ZooParc de Beauval, Wilhelma Zoo, Haus des Meers Aquarium, Zoo Ostrava, Poecilia Scandinavia, American Livebearer Association, Mohamed Bin Zayed Species Conservation Fund, Zoological Society for the Conservation of Species and Populations (Zoologische Gesellschaft für Arten- und Populationsschutz – ZGAP), European Union of Aquarium Curators and The Fishmongers’ Company.

Continue to see photos from the release.

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