Kendal Blust/KJZZ

Sea Shepherd patrols the Sea of Cortez for illegal gillnets used to catch a large fished called the totoaba. The nets are a threat to the world's most endangered marine mammal, the vaquita marina.

An activist ship that patrol’s Mexico’s Sea of Cortez to protect an endangered porpoise was attacked by alleged poachers Wednesday as tensions between poachers and activists escalate just south of the U.S.–Mexico border.

In a video filmed by activist crew members aboard about 35 small fishing boats surrounded and attacked Sea Shepherd Conservation Society’s patrol ship.

The suspected poaching vessels circled the activist ship as it patrolled for illegal fishing nets used to catch a huge, endangered fish called the totoaba. The nets also ensnare and drown the world’s most endangered marine mammal, a small porpoise called the vaquita marina.

“They’ve been aggressive with us before, but not to this point,” said J.P. Geoffroy, campaign leader for the conservation group Sea Shepherd in the northern Sea of Cortez. “They never tried to get on board the boat and they managed to do that this time.It was kind of shocking at the beginning.”

He said the poachers threw things at the crew and put a net in front of the ship to make them stop. Then five men boarded and began stealing things off the deck, though they were not able to get inside.

A Mexican Navy helicopter responded quickly to the attack and the poachers fled the scene, Geoffroy said.

He added that the attack won’t deter Sea Shepherd from protecting the vaquita marina.

“We’re not going to move back, we’re not going to step back,” he said