MEXICO CITY — Mexico’s agriculture and fisheries department says it is extending a ban on gillnets in much of the upper Gulf of California as part of an effort to save the endangered vaquita porpoise.

A Wednesday statement from the department says it will continue to provide monetary and other support for fishermen affected by the measure.

Despite Mexico’s campaign to help the porpoise species, estimates of remaining vaquitas have dropped below 30.

Vaquitas are often caught in nets illegally set to catch totoaba fish, whose swim bladder is prized in China.

The World Wildlife Fund says the measure won’t be enough to save the vaquita. It says a permanent ban and recovery efforts are needed.

Authorities say they will start later this year to capture and enclose the few remaining vaquita porpoises.