By MARK STEVENSON Associated Press

Three ships manned by the Sea Shepherd organization cruise the waters of the Gulf of California on March 5, 2018. (Sea Shepherd via AP)

MEXICO CITY (AP) — Experts said Wednesday that at most only 22 vaquitas remain in the Gulf of California, where a grim, increasingly violent battle is playing out between emboldened fishermen and the last line of defense for the smallest and most endangered porpoise in the world.

Jorge Urban, a biology professor at the Baja California Sur University, said the 22 vaquitas were heard over a network of acoustic monitors at the end of summer. That was in fact higher than many had expected; some had estimated as little as 15 would remain in the Gulf, also known as the Sea of Cortez, the only place in the world where the vaquita marina is found.

It may be a sign the vaquita is holding on, and what is keeping it alive is a thin line of defenders: Every night 22 volunteer crew members from ships operated by the environmentalist group Sea Shepherd go out to search the upper Gulf for hidden gill nets that catch prized – but protected – totoaba fish and drown vaquitas.

It is increasingly dangerous work. Over the last month, the Sea Shepherd ship Farley Mowat has suffered two attacks in which dozens of fast fishing boats pounded the ship with rocks and firebombs.

“If we stop operations, the vaquita will go extinct,” said Sea Shepherd first mate Jack Hutton. “It’s just out here removing nets, if we stop removing them then there’s no hope for the vaquita.”

The prime season to catch totoaba, which peaks in May, is causing a frenzy. The big fish’s swim bladders are considered a delicacy in China and can bring thousands of dollars apiece at retail. With so few vaquitas left, a mass totoaba fishing effort this spring could wipe out the species.

“We know we are going to keep getting attacked,” said Hutton, who was operating a drone that fishermen shot out of the sky last year. “We know we are risking our lives, but if we don’t the vaquita has no chance.”

The activists are not alone. Mexican marines and federal police aboard the Farley Mowat fired rubber bullets during the most recent attacks. But officials are clearly not capable of handling the attacks, or preventing fishermen from setting the submerged, hidden nets, which are banned by law from the area. The Mexican Navy and Environment Ministry did not reply to request for comments.

But marines have been intimidated by the fishermen, said documentary filmmaker Richard Ladkani, who filmed as they stood by while fishermen set out in their boats or as they battled authorities to free detained fishermen. Ladkani directed “Sea of Shadows,” which won the audience award at the Sundance film festival this year for world documentaries.

Ladkani said he accompanied the Navy on wild, dangerous nighttime chases at top speed in which fishermen tried – and sometimes succeeded – in ramming naval patrol boats to disable their engines. “Why is the navy not using force?” Ladkani wondered. “We were on 10 chases, and every time the pangas (boats) got away.”

Ladkani also has a theory about why the fishermen are getting so violent and desperate: Sea Shepherd is successful enough at pulling out nets – which cost about $3,000 apiece – that the fishermen are going into debt, borrowing money from the cartel of Chinese and Mexican totoaba traffickers to buy new nets.

“This is a vicious circle where people get more indebted,” said Ladkani. “This one fisherman wound up owing the cartels $54,000 for 18 nets. He tried to get out, he finally came out and said there is no way I can repay the cartel. He was murdered.”

Sunshine Rodriguez, a leader of the fishermen in the Baja California town of San Felipe, agreed that the illegal totoaba trade has not brought riches to the town: A total ban on gillnets has paralyzed the fishing fleet, and government payments meant to compensate for lost fishing income haven’t been paid in at least three months.

“I know people who are dedicated 100 percent to that (totoaba) business, and don’t even have $10 to put gas in the tank of their panga,” said Rodriguez. “The Chinese are making the profit, that I can tell you.”

“What did they expect the people to do, starve?” Rodriguez asked, saying the idea that fishermen make thousands of dollars for each totoaba bladder is a myth. He said a half-kilogram bladder from an average-sized fish commands only about $400, and prices are dropping.

Rodriguez said the Chinese-Mexican illegal dealers keep cutting the price because the fishermen “are starving. … They say ‘we’ll keep on dropping it, we’ll keep on making more profit, and these people are going to keep fishing because they have nothing else to do.”

Investigator Andrea Crosta of the group Elephant Action League agreed that prices appear to be falling, calling that “the first good news for the vaquita in a long, long time.” He attributed that to his group’s work in identifying illegal traders in Baja California’s Chinese community, noting that the Chinese government recently arrested 16 traders.

Crosta, who spent a year and a half working undercover to expose the totoaba trade, agreed with Rodriguez on another point: The Mexican government’s strategy of focusing almost exclusively on cracking down on the fishermen is never going to work unless it also cracks down on the middlemen and the traders.

“As long as you hammer, put all your efforts only on the fishermen, only on removing the nets, you will fail,” Crosta said. “You don’t address the problem, and the problem is a very sophisticated supply chain

As long as you don’t hit these people and you do that … you’ll bleed out, not only the vaquita but the whole marine life in the Sea of Cortez.”

Rodriguez, the fishermen’s leader, puts it this way: “Everybody is illegal out there. Regardless if it’s a shrimp net or a totoaba net, there is a ban on nets.

“So if you’re going to catch me and take my boat away for using a shrimp net, what do you think I’m going to do instead? I’m going to do the most profitable illegal thing because I’m still illegal.”

But in the meantime, the Sea Shepherd goes each night and hauls in nets, sometimes as many as 15 per night. The fishermen go out each night and lay nets because many of them can’t stop; they’re too in debt to the traders.

The Sea of Cortez, which Jacques Cousteau once called “the aquarium of the world,” is suffering long-term damage from the nets, which are carefully weighted to float below the surface to avoid detection.

“The fact that they hide their nets does mean that we find active nets months later that have not been checked or forgotten about or lost by the poachers,” said Hutton. “It means that there’s walls of death that are just going to sit out there forever if no one picks them up

Ladkani said, “When it’s totoaba season at the end of May, they may have killed everything by then.”