Co-authored by Erica Cirino
When most people think of cetaceans, they think of the most iconic species: dolphins and whales. The vaquita—a small gray porpoise with an elusive lifestyle that’s native to Mexico’s Gulf of California—isn’t well known to most people, despite its “Critical” status on the Endangered Species List. But thanks to the efforts of scientists, this vulnerable cetacean is beginning to move into the spotlight, for a serious reason: Without immediate action to protect its population, the vaquita will surely go extinct.
Last spring, a group of researchers belonging to the International Committee for the Recovery of the Vaquita (CIRVA) estimated just 60 vaquitas remained in the wild, representing a more than 92 percent population decline since 1997. In November 2016 CIRVA updated its population estimate to 30 vaquitas, an even more dire number.
Mostly, vaquitas are dying as unintentionally captured animals, or “bycatch,” trapped in illegal gillnets fishers use to catch another endangered marine species called the totoaba. The totoaba is an enormous, 300-pound fish. It contains a swim bladder used in Chinese medicine to make a soup called fish maw, which is believed to boost fertility.
In May 2015, Mexican President Enrique Peña Nieto called for an emergency two-year ban on gillnets throughout the range of the vaquita. But illegal totoaba fishing is causing the vaquita population to continue to plummet. Scientists agree time to save the endangered porpoise is running out—fast.
“CIRVA has been recommending for many, many years that all gillnets should be banned in the Upper Gulf if vaquitas are to survive as a species,” something that would require the development of new, vaquita-safe fishing gear, says CIRVA scientists Lorenzo Rojas-Bracho of Mexico’s National Institute of Ecology and Climate Change and Barbara Taylor of NOAA’s Southwest Fisheries Science Center. “Sadly, the lack of interest in vaquita conservation by fishing authorities has made progress on developing alternative fishing gear much too slow.”
Rojas-Bracho and Taylor say CIRVA has worked to introduce people living off the Gulf of California to economic activities other than fishing, such as tourism and crafts. While CIRVA saw some progress in getting people out of the totoaba fishing business, they say the total number of totoaba fishers—including non-locals living outside the Gulf—has increased, probably because the fish is valuable when sold on the black market.
Another major effort to protect the vaquita includes the establishment of a vaquita refuge in the Gulf of California in 2005. Despite the creation of this intended vaquita safe zone, illegal fishing there is rampant. Experts report that on one day in September 2014, 90 fishing boats were photographed inside the vaquita refuge.Dead vaquita caught in a gillnet set for totoaba. Photo by NOAA Fisheries West Coast (Flickr).
Vaquitas often are hard to spot, swimming in shallow water echolocating continuously to find their prey. Together these factors mean it’s more helpful for scientists monitoring vaquita populations to listen for the porpoises as opposed to looking for them. Besides being a more efficient way to collect data on vaquitas, acoustic studies are less expensive than visual monitoring from boats. One 1997 estimate found that the cost of one vaquita sighting was about $4,400 while one acoustic detection cost just $250, according to Armando Jaramillo-Legorreta, of CIRWA and Mexico’s National Institute of Ecology and Climate Change.
Between 1997 and 2007 CIRWA scientists randomly deployed 15 acoustic detectors throughout the Gulf of California. In one study CIRWA scientists deployed several dozen more detectors between 2011 and 2013 in and around the vaquita refuge. The detectors recorded vaquitas’ vocalizations continuously for three months at a time over five years. Once recorded, the vocalizations are processed by pattern-recognition software and that data is later analyzed by a human expert to help quantify the number of individual vaquitas that are vocalizing.
Besides discovering a major decline in the vaquita population, CIRWA scientists were surprised to discover just how significantly fishing gear can impact a species in such a short period of time. It proves “that saving a species is an international effort even if distributed in only one country’s waters,” say Rojas-Bracho and Taylor. What’s more, CIRWA’s latest acoustic data demonstrates the importance of robust population monitoring for endangered species.
“Being able to monitor status every year is key for many other species in the world,” say Rojas-Bracho and Taylor. “One of the challenges to conservation biologist is to estimate population size and trends of small populations. We have showed how critical acoustic methods were for vaquitas to solve this and think similar approaches could be used for many other species.”
As conservationists push for greater political protection for vaquitas, CIRWA scientists are continuing their Gulf of California acoustic monitoring research. They hope that more data will spark stronger vaquita recovery efforts that could save the species from extinction.