Vaquita: Only 10 porpoises left in the California harbor

porpoises in california
Only ten animals left worldwide: does the vaquita still have a chance?

The world’s smallest porpoise is threatened with global extinction

© picture alliance / Cristian Faesi / WWF / dpa | Christian Fassi

For years, experts have maintained that there must be more protection for the vaquita or the non-captive species will disappear from the face of the earth. But nothing happened. There are only ten animals left now. Is the end of species inevitable?

It is said that there are only ten porpoises left in the California harbor, which seems to decide the fate of this species. But the research team gives hope in the journal Science: based on genetic analyzes, they come to the conclusion that the small group of animals, also known as the vaquita, has a high chance of recovery despite inbreeding and a small gene pool — but only if hunting is stopped. Illegal with so-called gill nets in its environment immediately.

california porpoise (fukuina sinus) The vaquita (“little cow”) is the smallest member of the porpoise family. The animals, whose length reaches one and a half meters, live in the Gulf of California on the west coast of Mexico and are considered among the most endangered marine mammals in the world: according to the authors of the study, only ten specimens remain .

The IUCN reported 18 adults on the Red List of Threatened Species as of 2017. Attempts to capture some of the animals and ensure the species’ survival through breeding have failed.

Vaquita suffers from illegal gill hunting

The population suffers primarily from the illegal hunting of tuabas that live in the same area (Totuaba McDonald’s), which is valued in some countries for its purported medicinal properties. The fish species, also threatened, is caught with gillnets, as the vaquita is also caught and dies in agony because they can no longer breathe.

In light of the few remaining animals, some experts believe the end of the vaquita is inevitable even if illegal gill hunting is stopped. Genetic diversity is now very low. In small, limited populations, for example, it can lead to increased susceptibility to diseases or certain genetic disorders.

However, the genetic risk in California porpoises appears to be low, as the analysis has now shown. “Interestingly, we found that the vaquita is not judged by genetic factors such as harmful mutations that affect many other species whose gene pools have similarly shrunk,” said biologist and study author Christopher Kyriazis.

The researchers analyzed tissue samples from 20 vaquitas who lived between 1985 and 2017. “Genomics gives us insight into the species’ past, but also allows us to look into the future,” said co-author Lorenzo Rojas-Bracho. According to him, over the past 250,000 years, the abundance of species has varied from a few thousand to about 5,000 animals, which makes Vaquitas already a rare species compared to many other marine mammals.

Genetic diversity of vaquitas

“It’s basically the marine equivalent of an island species,” co-author Jacqueline Robinson explained. Of the 12 species of marine mammals the researchers analyzed, the vaquita had the fewest potentially harmful mutations. “The genetic diversity of vaquita is not so low as to pose a threat to their health and survival. It only reflects their natural rarity.”

In computer simulations, researchers modeled population evolution under different protection scenarios. Thus, immediate and complete elimination of gill reticulum mortalities will likely result in a recovery of the species. However, even the persistent low mortality rate from gillnets would rapidly reduce the species’ chances of survival.

As the scientists explained, the few remaining samples appeared to be healthy in the last survey. Some had calves, indicating a recent breeding. “If we can get these animals to survive, they can outpace the rest,” said Jacqueline Robinson.

Christopher Kyriasis added that the vaquitas would have very little time for this: “If we lose them, it will be the result of our human decisions and not genetic factors.”

Alice Lanzky, dpa

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