Axolotls battle for survival

Aztec legend has it that the first axolotl, the feathery-gilled salamander that once swarmed through the ancient lakes of Mexico, was a god who changed form to elude sacrifice.

But what remains of its habitat today is a polluted network of canals choked with hungry fish imported from another continent.

“They are about to go extinct,” said Sandra Balderas Arias, a biologist at the National Autonomous University of Mexico working to conserve axolotls in the wild.
Its extinction in the wild could also erase clues for scientists studying its mystifying traits.

They have been raised as exotic pets or as laboratory specimens for scientists investigating their extraordinary ability to regrow a severed limb or tail.
It is an odd-looking salamander with a flat head and spiked feet and it often spends its entire life in the larval stage.

Many challenges

 The Aztecs and their descendants consumed axolotls as part of their diet. Biologist Armando Tovar Garza says, “The axolotl is suffering on two fronts. One is the water quality. It’s not improving. The axolotl’s second challenge is the increasing population of tilapias.

“The tilapias reproduce faster than they can be caught, and they feed voraciously on the plants where the axolotls lay their eggs.

Signs of hope

Roberto Altamirano, president of the fishermen’s association, is working to save them. Some are adamant that the axolotl should be preserved only in its environment, but others are convinced it can survive only if new populations are introduced elsewhere.

They were once at the top of the food chain and their continued survival in the canals is a sign that the ecosystem of Xochimilco can endure as well. Finding them a new home would be tantamount to giving up, Zambrano argued.

“His solution is two-pronged. First, he is promoting traditional methods of agriculture because he believes that Aztec practices provide an alternative to the polluting pesticides and fertilisers that many farmers in Xochimilco have adopted.

He has found a few farmers willing to help his work, and in a twist, his team is grinding up tilapia to make organic fertiliser. He is also creating a series of small tilapia-free sanctuaries by blocking off the entrances to certain canals.

After placing trackers on test axolotls, the team was surprised to see how lively they were in the wild. Another team of researchers has begun testing for a new home far from the multiplying troubles of Xochimilco, in an artificial lake in Tecamac.

Balderas and her student assistant, Marlen Montes Ruiz, are monitoring laboratory-bred axolotls to see if they are capable of hunting water bugs and other prey and coping in the wild after being pandered to for so long.

So far, they say, axolotls have adapted well and have even become adept at hiding from the researchers, just as the ancient god eluded his captors.