- Over the past two years, the Mexican Navy has installed hundreds of anti-trawling hooks to prevent vaquitas being caught in illegal gill nets in the Upper Gulf of California.
- The long hooks, attached to concrete blocks, are designed to snag the gill nets that target totoaba fish, but which have become notorious for driving the vaquita porpoise to the brink of extinction.
- The project was initially credited with an immediate drop in illegal fishing boats in the vaquita’s core habitat, but fishers from the community of San Felipe say new blocks were installed without warning outside the core habitat, snagging more of their equipment and creating ghost nets that could harm vaquitas.
- Results from the latest vaquita population survey are expected in June; last year, scientists said as few as 10 of the critically endangered porpoises may still be alive.
The latest attempt to save the critically endangered vaquita porpoise from being snagged in nets meant for the coveted totoaba fish may prove to be the most effective yet. But the way it’s being administered by the Mexican Navy is opaque and underhanded, local fishers say, and may even prove a threat to the species it purports to conserve.
Over the past two years, the Navy has placed hundreds of long metal hooks attached in pairs to concrete blocks in the Upper Gulf of California, off the coast of San Felipe, a fishing town in the Mexican state of Baja California. At first, all of the blocks were sunk in the vaquita’s core habitat, where fishing is banned entirely, called the zero tolerance area (ZTA).
The vaquita (Phocoena sinus) has been driven to the brink of extinction by gillnet fishing, a type of stationary trawling where a net is left hanging vertically in the water like a wall for fish to swim into. The holes in a gillnet are sized to capture specific animals, from shrimp to corvina, but are notorious for ensnaring marine megafauna such as sharks, turtles and cetaceans as bycatch.
There are between 10 and 13 vaquitas left in the world, according to the most recent survey last summer.
Gillnet fishing has been banned from the Upper Gulf of California for the past seven years. But amid widespread breaches of the ban, in the mid-2022 the Navy began placing the concrete blocks, each with two rebar hooks attached, within the ZTA. In November 2023, more blocks were sunk outside the protected area, leading to complaints from fishers that they weren’t adequately warned of this new move.
“Little by little they are throwing blocks in and taking us out,” said Javier Valverde, a veteran local fisherman who says a hook recently destroyed one of his nets outside the ZTA. “We are no longer going to be able to work in the Upper Gulf in the future because they are armoring the sea.”
The hooks are a type of antitrawling device, which have been used to protect against illegal fishing in other waters. Conservationists used bags of concrete filled with rebar spikes to destroy shallow gill nets in Cambodia, but the Mexican Navy is first to use antitrawling hooks against gill nets in deeper water, according to the IUCN, the global wildlife conservation authority.
In an August 2023 press release, the Navy said the project was expanded in response to increased echolocations of vaquitas outside the core area. But fishers say the unexpected blocks could pose an even greater threat to the vaquitas themselves if more nets are snagged and left underwater to ensnare wildlife, becoming so-called ghost nets.
With the last of the new blocks due to be placed by the end of June, their effect on the vaquita — positive or negative — is expected to be near-instant, conservationists say, as the results of an ongoing population survey are set to be announced the same month.
The effect from the initial placement in 2022 was almost immediate, said Kristin Nowell, executive director of vaquita conservation charity the Cetacean Action Treasury. “They were such a miracle,” she said. “What the blocks did is it bought a passive enforcement response. It’s like a deterrent.”
In the past, in-person enforcement of the ZTA, created in 2020, has often appeared lax or spiraled into violence. In one infamous confrontation in 2020, a fisherman died when his boat was crushed by a patrol vessel run by the international environmental charity Sea Shepherd.
The blocks, however, appear to have quickly discouraged fishing in the ZTA. After the first batch was sunk, there was an almost 80% drop in the peak number of fishing boats, known locally as pangas, spotted in the ZTA during fishing tides, according to data compiled by Sea Shepherd. Gill nets targeting totoaba (Totoaba macdonaldi) can stretch more than 1 kilometer (0.6 miles) and cost the equivalent of tens of thousands of dollars, making them unaffordable to replace for most fishers in the small community of San Felipe.
The number of vaquita acoustic encounters in the ZTA also more than doubled after the blocks were installed.
“We call them sleeping policemen, because they’re not active,” Nowell said. “They’re sleeping on the bottom of the ocean. It has made enforcement that much easier because there’s only five pangas in the ZTA to chase around instead of 100. The Navy can actually do that.”
Buoyed by this success, the Navy began placing a second round of blocks in August 2023: 12 more inside the ZTA, 52 on its boundaries, and 152 in an expanded area 4 km (2.5 mi) south and west of the most protected zone.
According to Felipe Rocha, field coordinator with San Felipe-based sustainable fishing charity Pesca ABC, this was when the project went too far, too quickly. “It was very extreme,” Rocha said. “It is one of the most effective measures ever … but I also think the blocks that were placed afterwards to expand were a very underhand move.
“It’s a problem of transparency,” he added.
Rocha said he understands why the new blocks were added — a recent map of vaquita echolocations shows broad streaks of activity west and south of the ZTA, with a large orb of sightings just outside its southwest corner — but said that without knowing where the new blocks are, more ghost nets will be left underwater attached to the hooks. “What’s to say that maybe one of those nets doesn’t catch a vaquita?”
The risks posed by new hooks outside the ZTA were known to the Navy before the expansion began, according to internal government documents. “If a systematic review of the sites is not followed, there could be a risk that specimens of Vaquita Marina and other organisms are trapped in nets captured by the hooks of the blocks,” reads an environmental impact statement sent to Navy officials in August last year. It adds that trapped nets could also introduce more microplastics to the water.
Navy officials declined Mongabay’s interview request, but in response to written questions about the potential for new ghost nets said, “Because illegal fishermen know the areas where the blocks are placed, they avoid setting their blocks there. Some astute ones that have tried to fish with illegal nets in the Vaquita refuge area have had to leave their nets abandoned.”
While anecdotes of destroyed nets are becoming more common in San Felipe, it’s hard to know how many nets may have been caught underwater. Pesca ABC runs a diving program to recover ghost nets, but the Navy doesn’t allow diving near the hooks, citing safety concerns.
Asked about the blocks in an April 16 press conference, Navy officer Juan Miraflores said the Navy had recovered three ghost nets from blocks since the beginning of the project. That appears to only count blocks inside the ZTA, however, as Sea Shepherd records freeing at least four nets from blocks, one outside the ZTA this March.
In response to written questions, Sea Shepherd, which helps the Navy monitor the ZTA, said it checks the blocks inside and outside of the ZTA for nets using sonar as “part of our everyday operations,” but wouldn’t say how many ghost nets it had reported.
For fisherman Valverde, his recent experience wasn’t the first time his net was caught. “We were fishing outside the zero-tolerance zone,” he said, adding that Sea Shepherd comes to cut free nets caught inside the ZTA but outside ensnared nets are more likely to be left. “There are no authorities, no nothing.”
Valverde said at the time he was fishing for corvina (Cynoscion othonopterus) with a gill net. While gill nets are banned in the area, fishers frequently and openly use them.
The environmental impact statement for the first batch of blocks, obtained by the Center for Biological Diversity using freedom-of-information requests, goes on to note that Navy officials can only safely remove nets during calm conditions a few days a month, and to suggest that new buoys be placed around the expanded perimeter to deter fishers.
That might have helped, said Lorenzo García Carrillo, head of one of San Felipe’s two main fishing federations. “More than anything it’s to say ‘Ok, here is the cop, this is you and here is the block,’” he said, pointing at a map of the Upper Gulf. “Then I can move so as not to catch on other blocks.”
In November 2023, Carrillo said, one of his fishing teams found three damaged nets entangled outside the ZTA. “Why’d they get entangled?” Rocha said. “Because they didn’t notify people. People already know how the nets get entangled — if you notified them you could have avoided that.”
But the Navy said fishing leaders had been “informed on several occasions” about the new blocks. In October 2023, the Navy’s regional commander, Marco Peyrot Solís, told the Associated Press that blocks would be placed only “once a consensus with the fishing community has been reached.”
Instead, Rocha and Carrillo said, the Navy began placing blocks before any agreement was reached on how large the expanded area would be and how many blocks would be placed. While Rocha said the threat to the vaquita is hypothetical for now, the move risks alienating a community that has clashed with environmentalists and authorities in the past.
“We can’t just protect the vaquita and harm ourselves,” said Carrillo, the fishing leader. “We both live here so we have to find a way for both of us to survive.”
Banner image: Image by NOAA via Wikimedia Commons.
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