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Amphibian set to appear on Mexican currency nearing extinction in the wild

The number of axolotls, which despite their colloquial name are not fish but rather amphibians, plunged dramatically over a 16-year span

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An image of the axolotl, or Mexican walking fish, will grace that country''s 50-peso bill (worth around $2.60) starting in 2022, yet the government has taken no urgent measures to protect this critically endangered species from possible extinction, experts said in an interview Tuesday with Efe.

The number of axolotls, which despite their colloquial name are not fish but rather amphibians, plunged dramatically over a 16-year span, falling from 6,000 per square kilometer in 1998 to just 36 per sq. km in 2014, Luis Zambrano, a researcher at this capital''s National Autonomous University of Mexico (UNAM) told Efe.

A species of salamander endemic to Mexico City, the axolotl is projected to survive for only between 10 and 15 more years in the canals of the capital''s southern district of Xochimilco, known as the "Venice of Mexico" and a UNESCO World Heritage site, according to a population viability study carried out by experts.

Zambrano, head of the Ecological Restoration Laboratory at UNAM''s Institute of Biology, said a new census will be released in the coming months despite the difficulties in obtaining government funding.

"One of the tactics used by federal and local governments of the past 20, 30 years is that they think if they don''t look at or talk about the issue that it will solve itself, and that''s not the case. The axolotl is still in danger of extinction", he said.

In its "The Global Risks Report 2020," the Switzerland-based World Economic Forum said the plight of the axolotl exemplifies the "dangers of accelerated biodiversity loss".

"It''s strange because (an awareness of the problem) has reached the World Economic Forum, but Mexican authorities still don''t see it (even though) we now have a lot of information about what we should do," Zambrano said, adding that "to save the axolotl you have to recover its habitat".

The main threats to this amphibian are urbanization, contamination of its ecosystem with fertilizers and pesticides and the introduction of two predatory fish - carp and tilapia - into its habitat in the 1970s.

"These three big problems have led to a worsening of the quality of the water and a reduction of the amount of axolotls in the ecosystem", the expert said.

To improve the species'' habitat, UNAM''s Institute of Biology is carrying out restoration programs that use filters to control predators and contaminants.

"When we do this, the whole canal returns to how it was before. It's more transparent and we have a system very similar to what it was before in very little time, two or three months", Zambrano said.

"If Xochimilco had the necessary financing, the entire habitat could be restored in relatively little time", he added.

The ecosystem could be quickly recovered at a cost of 20 million pesos ($1.05 million) annually and traditional chinampa farming (raised field agriculture used in wetlands, sometimes called floating gardens) could be revived and be used to supply food to 20 percent of Mexico City''s population, the expert said.

The Xochimilco canals are one of Mexico''s most biologically diverse areas and a place where the axolotl is losing its battle for survival, Hesiquio Benitez, director general of International Cooperation and Implementation at the National Commission for the Knowledge and Use of Biodiversity (Conabio), told Efe.

The axolotl (Ambystoma mexicanum) has unique limb regeneration capabilities that have made this species the subject of DNA studies worldwide, he said.

"To the point where unfortunately there are now more Mexican axolotls in Europe than in Mexico," Benitez added. "It''s ridiculous that there are thousands and thousands of axolotls in laboratories, and we as a population don''t conserve them in their habitat".

The biologist said programs have been carried out for years with local governments to halt the granting of new building permits and regulate water pollution sources.

"There''s a lot of illegal construction and sewers that are illegal and have been polluting for a long time ... besides, this is a very important area for vegetables that are sold as organic and that we''re consuming (despite the water quality)", Benitez said.

Wetlands that sink roughly 30 centimeters (11.8 inches) each year due to urban settlements could be recovered through better coordination between authorities and citizens, but the will to achieve this has been lacking thus far, the experts agreed.

The Aztecs used the axolotl as a food source and for its curative properties but also recognized its importance in nature.

In Nahuatl mythology, the axolotl symbolized one incarnation of Xolotl, god of lightning, death and sunset and the twin brother of the god Queztalcoatl (feathered serpent).

But in the absence of urgent government measures, an iconic species with the cultural significance to be featured on a Mexican banknote may soon become extinct in the wild.

(María José Pardo)