Only ten vaquitas remain in the Gulf of California (Mexico). Ten specimens of the endangered cetacean 'Phocoena Sinus' have been found. According to a study published by Science, they are rare, but have enough genetic diversity to allow the species to recover. Jacqueline Robinson (a researcher at the University of California San Francisco, and one of the researchers of the research) says that genetically they still have the diversity which allowed them to thrive for hundreds of thousand of years before gillnets were invented.
This conclusion was reached by the authors of the new study after they analyzed the genomes 20 of the specimens derived from tissue samples collected since 1985. Vaquita porpoise is a large, solitary animal that can reach a length of 1.5m and weighing 50 kilos. The vaquita porpoise is a single-eyed animal that eats fish and squid. It is rarely seen in large groups of more than three to five individuals. It lives in the shallow waters of northern Gulf of California, or Sea of Cortez. The area is bordered on the west and east by the Baja California peninsula and the Sinaloa and Sonora states. Genetic studies have shown that the species was born 2.5 million years ago. It has never been more than 5,000 individuals in the last 250,000 years.
"At such small populations, inbreeding among distant relatives is very beneficial to the removal or purging harmful recessive mutants. Although it may seem counterintuitive that the vaquita is a good choice for recovery from a drastic population decline, due to its small historical population, Lorenzo Rojas Bracho from the Commission explains the situation to this newspaper. National Protected Natural Areas of Mexico, co-author of this study.
The Mexican biologist who has dedicated his life to the conservation of the vaquita over the past two decades, says that "we have to break the paradigm that small population are doomed for extinction." He mentions as examples the California channel islands foxes and California condors. It is believed that the population of this animal was about 20-30 individuals in the last case. It recovered to approximately 150,000 thanks to very low genetic variability," Rojas Bracho says.
It was well known by the 1990s that vaquitas' accidental mortality (as a result fishing) was not sustainable. It was estimated that 600 people lived in 1997. In 2015, 97 people were surveyed and 67% disappeared. Rojas Bracho said that scientists found evidence of "nearly seven to eight" individuals in the "supposedly no catch" area of the Gulf of California.
Gillnets are a vertical gear that is attached to the bottom and rises up like walls to trap fish and other animals. They pose a great threat to the vaquita porcoise. They have been banned in the northern Gulf of California since 2017. However, illegal fishermen still use them to catch white croaker or totoaba. The swim bladder of this fish is highly sought after in China and Hong Kong due to its healing properties, which have never been proven. The illegal totoaba fishermen can make thousands of dollars a day by trapping whales, vaquitas, and dolphins in their gear.
Because conservation of the vaquita has been neglected since recent years, the current situation is unfortunate. Rojas Bracho lamented that "we were never able to depend on the support from the fishing authorities", as he lacked the institutional commitment to create, with fishermen, alternative gear for gillnets. The biologist acknowledges that the situation is complicated without alternative fishing gear to allow fishermen to bring food to the table, and with organized crime in the totoaba swimming bladder, but he still believes in the recovery of the species in the event of accidental deaths. You must have faith when you work in conservation. It is better to look for another job if you don't have faith.
We have the power to ensure that individuals and species survive. Phillip Morin, a geneticist with the National Oceanic and Atmospheric Administration of the United States, says that there is a high chance that they will recover genetically. Co-author of this research.