Fishermen fight to save Aztec floating gardens

MEXICO CITY - Roberto Altamirano has the lake to himself as he casts his glistening net onto the still water in a perfect circle, lets it sink, then slowly pulls it in.

It comes back bearing a large haul of tilapia and carp - and that is exactly the problem.

Altamirano is one of just 20 or so fishermen who remain in the floating gardens of Xochimilco, an idyllic network of lakes, canals and artificial islands improbably tucked into the urban sprawl of Mexico City.