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Latest population survey yields good news for vaquita marina

While researchers did not find evidence of a large resurgence in the porpoise’s population, experts view the fact that its numbers have remained steady in recent years as a positive sign.

MEXICO CITY (CN) — The resilient little vaquita marina appears determined to survive the illegal fishing that has brought it dangerously close to extinction, according to the latest population survey. 

Despite an estimated annual decline of 45% in 2018, the endangered porpoise appears to be holding steady over the last five years, according to a report published Wednesday by the International Union for Conservation of Nature, or IUCN. 

Its numbers have dwindled to nearly zero in recent decades thanks to gill net fishing for totoaba, a large member of the drum family whose swim bladder is prized in Chinese medicine for its alleged healing properties. The vaquita marina is bycatch of this illegal activity.

Scientists with the IUCN’s Cetacean Specialist Group reported seeing in May around the same numbers of vaquitas they saw in surveys conducted in 2019 and 2021, leading the researchers to hail the “tenacity” of the world’s smallest porpoise. 

They saw about 10 individual vaquitas, including at least one calf. The previously published estimate for the porpoise’s numbers was as low as eight. The researchers raised that calculation to as many as 13.

“All the animals looked healthy and they were feeding,” the IUCN said in a press release announcing the report. 

The survey and its promising results were made possible by a significant decrease of gill net fishing in the Upper Gulf of California. Gillnetting has abated by 90% in the area in recent months, according to the Sea Shepherd Conservation Society, which monitors such activity in what is designated as the zero-tolerance area of the gulf. 

The IUCN press release called this reduction “probably the most significant step taken to date toward saving the species.”

A bump-up to an estimated 13 individuals from eight may not seem like a big step forward, but the point is that “the vaquitas are hanging in there,” said Lorenzo Rojas-Bracho, the world’s leading vaquita specialist.

“If we stop killing them, they will come back,” he said, adding that the decline in gill net fishing is primarily thanks to 3-meter-tall hooks sunk to the seafloor on concrete blocks that tear up gill nets, rather than significant enforcement efforts by the Mexican government.

Heartening as the report is, it should not be taken to mean that all is well.

“We have to be optimistic, but not overly optimistic,” said Rojas-Bracho.

Conservation groups echoed his cautious hopefulness, emphasizing that there is still much work to be done. 

“This is encouraging news and it shows that vaquita are survivors,” said Alex Olivera, senior Mexico representative at the Center for Biological Diversity. “But we still need urgent conservation efforts to save these tiny porpoises from extinction.” 

One hurdle to the vaquita’s survival is its slow growth rate, Olivera said. This makes their recovery even more difficult and shines a light on how human activity affects the species.

“Even in a gill net-free habitat, it will take about 50 years for the population to return to where it was 15 years ago,” he said, calling on the Mexican government to do more to crack down on illegal fishing in its habitat.

A sanction by the Convention on International Trade in Endangered Species of Wild Fauna and Flora in March restricted Mexican exports of wildlife products whose commerce is controlled by the treaty. These included mahogany timber, crocodile leather, tarantulas, pet reptile, cactuses and other plants. 

CITES did not respond to a question about if or how the IUCN report might affect that sanction by the time of publication. 

The U.S. Fish and Wildlife Service certified Mexico’s failure to protect the vaquita in late May, giving the Biden administration 60 days to decide whether or not to place U.S. sanctions on the country.

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Categories / Environment, International

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