Updated

Activists and artists in Mexico held a mournful, dirge-like procession for the critically endangered vaquita porpoise Saturday, as the species' numbers fell below 30.

With drums, chimes and a carved vaquita skull, hundreds of people made their way through a downtown Mexico City park.

Organizers said the procession wasn't a funeral for the vaquita, but experts suggest that perhaps as few as 18 remain in the upper Gulf of California, also known as the Sea of Cortes.

The vaquita's numbers have been decimated by nets set for the totoaba fish, a delicacy in China.

About 30 of the mammals remained one year ago, and experts say a 40 percent annual decline continues unabated.