Many scientists once believed the vaquita dolphin, the world’s most endangered marine mammal, had vanished. Yet a small, stubborn group persists. New research shows that a few survivors are breeding and that some have learned ways to avoid gill nets. The biggest danger remains the fishing gear that has driven them toward extinction in recent times.
Earlier projections suggested the vaquita would be extinct by now. A study led by the University of Saint Andrews in Scotland, with partners in Mexico, the United States, and the United Kingdom, and published in Endangered Species Survey, offers a glimmer of hope.
Despite evidence of ongoing illegal fishing in the last remaining stretch of Mexico’s vaquita marina habitat, the new findings imply that the surviving animals may have found better chances to survive without falling prey to gill nets, especially in areas known to be critical for their existence.
“Given the rapid declines recorded in prior censuses, it is remarkable to see any persistence in the field,” remarked Lorenzo Rojas-Bracho, the study’s lead author. He stressed that these survivors, confined to a region endemic to Mexico, deserve protection as the species’ future hinges on them.
Scientists estimate that between 7 and 15 vaquitas were observed in 2019 and between five and 13 in 2021, with calves noted in both years. Previous work had estimated fewer than 20 individuals remained in 2018, with populations shrinking by about half each year.
The goal is to avoid the gill nets
With the collected data, experts believed extinction was imminent, yet there is cautious optimism. “It seems miraculous to witness these survivors,” the researchers wrote, given the apparent rise in gill nets as the primary threat to the species.
The gill nets have historically driven the vaquita to the brink. Shrimp and fish are targeted by artisanal fishermen who use these nets, but vaquitas can become entangled and suffocate in them.
Scientists emphasize that the only viable path to saving the vaquita is to ban gill nets within the small area where the porpoises are found, in the upper Gulf of California. This restriction is essential until communities can transition to alternative fishing gear without compromising livelihoods.
The report is clear: extinction is still a real possibility if nets remain in use and if other protective measures fail to take hold. While there are alternative gears, their adoption requires investment, effort, and compliance. Studies over recent years have not found a fully ready alternative fishing tool that can be widely implemented yet.
“Despite everything, there is one last chance to save the vaquita,”said a co-author of the paper. “Giving these animals a real chance could keep them from vanishing.”
The research used an established method called expert inference to estimate the number of vaquitas observed across multiple censuses in 2019 and 2021, concentrating in a 12 by 24 kilometer area where nearly all sightings occurred in recent years.
A “very ingenious” animal
The count of individuals is treated as a minimum population estimate. There is not enough information to determine a more precise total population, the scientists conclude.
Len Thomas of the University of Saint Andrews, who co-led the expert analysis with Cormac Booth, notes that in the absence of direct data, expert opinion acts as a practical guide for decision making and helps define uncertainty ranges used in planning.
Examples from field observations suggest some vaquitas may have learned to avoid gill nets. During a 2017 effort to protect other animals in captivity, they appeared to steer clear of nets. Some individuals also bore marks from previous encounters with nets, yet survived.
“If one species can be saved, it would be through understanding how a single survivor persists. Models may not fully capture intelligence and adaptive behavior that helps vaquitas escape nets,” said a researcher involved in the study.
“Saving this species may take longer, but extinction is not yet a given. The main obstacle remains the continued livelihood reliance on gill nets in nearby towns, and even protecting the small habitat where the vaquitas stay is a challenge,” the researchers noted in their analysis.
They concluded: until fishermen have access to and training in alternatives to gill nets, vaquita extinction remains a real risk. The team believes Mexico has the capabilities and the political will to implement management actions that could secure a long-term recovery for this iconic species.
Citation: International Journal of Ecology and Species Research, volume 48, pages 225-234.