MEXICO CITY, April 20 (Xinhua) -- Mexico's government on Friday expanded the size of a sanctuary designed to protect the endangered vaquita porpoise from extinction.

The refuge in north Mexico's Gulf of California, also known as the Sea of Cortez, was extended to cover 1,841 square kilometers, the Environment Ministry said.

The plight of the vaquitas gained worldwide attention when Hollywood actor Leonardo DiCaprio traveled to Mexico in June 2017 to urge the president to take stronger action to save the species.

Experts believe only around 30 vaquitas are left in the Gulf of California, where they are accidentally caught in fishing nets designed to capture totoaba, a fish whose bladder is believed to have aphrodisiac properties and sells for up to 60,000 U.S. dollars per kilogram on the black market.

The decision to expand the sanctuary follows a study that showed the only marine mammal native to Mexico inhabits an area much larger than the original parameters set in 2015.

"It is necessary to expand the ... refuge area for the protection of this aquatic species," the ministry said in a statement.

The sanctuary aims to protect the porpoise from fishing and sailing activity.