Mexico’s Navy said Wednesday it is planning to expand the area where it sinks concrete blocks topped with metal hooks to snag gill nets that are killing vaquita marina porpoises.

The Navy began dropping the blocks into the Gulf of California last year, in hopes it may help save the world’s most endangered marine mammal.

The vaquita lives only in the Gulf, also known as the Sea of Cortez, where as few as ten vaquitas remain. They cannot be held or bred in captivity.

EXPERTS DOUBT MEXICO'S PLEDGE TO PROTECT ENDANGERED PORPOISE

The vaquitas are caught and drown in illegal gill nets set for totoaba, a Gulf fish whose swim bladder is considered a prized delicacy in China, worth thousands of dollars per pound. That is where the concrete blocks come in; the hooks catch on the expensive totoaba nets, ruining them.

That should supposedly discourage illicit fishermen from risking their expensive gear in the "zero tolerance area," a rough quadrangle considered the last holdout for the vaquitas. It’s called that because that’s where the blocks are sunk, and where patrols are heaviest, and there is supposed to be no fishing at all, though it still sometimes occurs.

vaquita porpoise swims

A vaquita porpoise is seen swimming. Mexico’s Navy said Wednesday that it plans to expand the area where it sets up traps to snag nets killing vaquita marina porpoises. (Paula Olson/NOAA via AP, File)

But a strange thing happened when scientists and researchers set out on the most recent sighting expedition to look for vaquitas in May.

They found that most of the 16 sightings (some may be repeat sightings of the same animal) occurred on the very edges, and in a few cases just outside, of the "zero tolerance" area that was supposed to be the most welcoming place for the animals.

MEXICO SETS OUT SEARCH TO FIND VAQUITA MARINA, THE WORLD’S MOST ENDANGERED MARINE MAMMAL

That lead to the Navy announcement Wednesday that it will negotiate with the fishing community of San Felipe, in Baja California state to start sinking blocks outside the zero tolerance zone.

"Once a consensus with the https://www.foxnews.com/category/science/wild-nature/fishmex has been reached, 152 more blocks will be placed in the freezone alongside the zero tolerance area, where there have been visual or echolocation sightings" of vaquitas, said Real Admiral Marco Peyrot Solís, the Navy commander of the region.

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The fishermen of San Felipe say the government has not lived up to previous promises of compensatory payments for lost income due to net bans in the area. They also say the government has done little to provide better, more environmentally sensitive fishing gear.

Experts estimate the most recent sightings suggest 10 to 13 vaquitas remain, a similar number to those seen in the last such expedition in 2021.