Endangered marine mammals: the last ten vaquita – Wikipedia

The vaquita was last seen with young animals in the fall of 2021 off the Mexican coast near San Felipe. Note is rare. Species inventory Phocoena sinus or “California porpoises” estimated at 10 animals or less.

Above all, it is gillnetting that wiped out more than 500 animals 25 years ago, according to the Nature Conservancy WWF, to the small percentage that remains. Animals die from unwanted by-catch in nylon nets, which you can hardly see.

However, the results of a new genetic analysis now published in Science suggest that the population may be recovering. The international research team reports that the negative effects of inbreeding among the remaining animals may not lead to the extinction of the species.

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Indigenous peoples of the Gulf of Mexico

“If we allow these animals to survive, they can do the rest,” study author Jacqueline Robinson of the University of California, San Francisco, said in a statement from the US Environmental Protection Agency (NOAA). “The genetic diversity of vaquita is not low enough to threaten their health or the survival of the species, it’s just a sign of their natural rarity,” Robinson says.

The researchers examined the genomes in tissue samples taken from 20 animals since the 1980s. The distribution of different genetic features in them leads to the conclusion that the species most likely evolved 2.5 million years ago in adapting to the living conditions in the nutrient-rich, flat northern part of the Gulf of Mexico.

To this day, the waters are the only distribution area for vaquita whales, which are among the smallest whales with a maximum body length of 1.5 meters. The name means something like “calf” – which also indicates that hunters certainly valued the meat of animals they caught by chance. It is similar to “porpoise” (Phocoena phocoena).

During the captivity campaign in 2017, tissue samples were taken from the animals, here from a young female.Photo: VaquitaCPR

In the past 250,000 years, the vaquita population – at least the breeding animals – may not have exceeded 5,000. This is not much compared to other marine mammals. However, for the survival of the species, this could now be an advantage. The set of genes of a species, the sum of all genetic variations in a population, is relatively small.

However, this also means that harmful genetic variants are rare. If carriers of such genetic information interbred, the offspring may not be able to reproduce and no longer feed the genetic trait into the gene pool. If the vacitas are closely related and genetically similar in the future, it is likely that their offspring will be healthy. This is also confirmed by the latest observations on animals. When the vaquita was seen, the animals appeared to be healthy and some of them also had calves.

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Survive the simulation

Using genetic diversity in the tissue samples collected, the research team ran a computer simulation of how a population could evolve with different protective measures. They also reported, if gillnet fishing was completely stopped in their area of ​​distribution, there would be a high probability that the stock would rise again. But even with low mortality from gillnets, the species’ chances of survival are rapidly dropping.

Gillnet fishing is prohibited in the area. However, the hunters encounter Tutuaba (Tutuaba McDonald’s) distance. Swimming bladders of this fish are traded at high prices in some countries due to their purported medicinal properties. The fish, which is also only found in the Gulf of Mexico, is also endangered because the ban on fishing is not sufficiently enforced.

“Although we now know that vaquitas’ ability to recover is not limited to their genes, they have very little time left,” says Christopher Kyriazis, a study co-author from UCLA. “If we lose them, it will be the result of our human choices and not genetic factors.”

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