Mexico captured a rare vaquita marina porpoise as part of a bold program to save the critically endangered species, but released it because it was too young to be separated from its mother, officials said.

The vaquita, the world's smallest porpoise, has been pushed to the brink of extinction by illegal fishing. But the Mexican government and conservation groups have launched an unprecedented plan to save the species by transporting as many as possible to a protected marine reserve.

The six-month-old calf caught Wednesday is the first vaquita ever to be captured, officials said, calling it a sign that the program could work.

"The successful rescue made conservation history," Mexican Environment Minister Rafael Pacchiano said in a statement.

"No one has ever captured and cared for a vaquita porpoise, even for a brief period of time. This is an exciting moment and as a result, I am confident we can indeed save the vaquita marina from extinction."

The program, which began field operations a week ago, is trying to locate the remaining vaquitas -- estimated to number less than 30 -- using acoustic monitoring, visual searches and dolphins trained by the US navy.

Captured vaquitas will be transported to a marine sanctuary, where it is hoped they will breed before being released back into the wild.

Veterinarians determined the captured vaquita calf was showing signs of stress and released it "in an abundance of caution," said the statement.

It was released in the same spot it was captured in the Gulf of California -- the only place in the world vaquitas are found.

Researchers first took tissue samples that will be used to sequence the vaquita's DNA and possibly clone it someday.

The vaquita has been nearly wiped out by gillnets used to fish for another species, the also endangered totoaba fish, whose swim bladder is considered a delicacy in China and can fetch $20,000 per kilogram.

In June, Mexico announced a series of measures to protect the vaquita, including a permanent ban on gillnets in its habitat.

In all, the government has committed more than $100 million to protecting the vaquita while supporting the local fishing community.

Source: AFP