How to restore the dolphin population in the Black Sea shutterstock

How to restore the dolphin population in the Black Sea

Katerina Belousova

Dolphins give birth once a year or two, and only one cub is born

Scientists believe that in Ukraine it will take up to 50 years to restore the dolphin population after the war, provided that protected areas are created and there are no poachers.

After all, the number of dolphins in the Black Sea is low, and the mortality from the influence of war is very high, reports Rubryka.

Ivan Rusev, director of the National Natural Park (NNP) Tuzlovsky Limany in the Odessa region, called the problem of dead dolphins the most significant, because it will be very difficult to restore their population.

Scientists cannot establish the number of dolphins that became victims of the war, because new cases are constantly appearing. Also, the sea brings ashore only a part of the dead animals.

The BioEcoLinks environmental research and protection organization, which has the Dolphins of the Sea of ​​Azov and the Black Sea blog, states that since February, there have been an unusually high number of detected cases, and the death peak occurred in March, May, and June. They still don't stop.

Several hundred deaths of dolphins have been confirmed, of which more than 100 are predominantly in the Crimea and in the south of the Odessa region. This problem has already become international, with scientists in Romania, Bulgaria and Turkey reporting on the beached mammals.

"Military operations in the Black Sea harm the Ukrainian environment and the entire planet," the article noted.

The fighting takes place with the use of surface and submarines, where sonar is used that emit powerful signals. These signals are detrimental to dolphins, because they disable their navigation and echolocation organs, which makes it impossible to navigate in space and hunt.

"Blind" dolphins are in stress and panic, they cannot navigate in space.

Dolphins also fall into deadly traps - fishing nets.

Zoologist Pavel Goldin explained that the number of porpoises, one of the Black Sea dolphin species, is strongly affected by death in fishing nets. Up to 20,000 porpoises perished in the Black Sea every year.

Before the war, there were approximately 3,000 kilometers of poaching nets and fishing nets in the northwestern part of the Black Sea. Although there are none, the number of dead dolphins has increased significantly.

It can be argued that the dolphin got tangled in the net and suffocated under water, since determining the cause of the dolphin's death is very simple: fishermen, afraid of getting a fine for killing a Red Book animal, try to unravel the net as quickly as possible, pull the dolphin out and throw it into the sea. To do this, they cut off their fins, often traces of nets remain on the bodies of animals. Such cases occur in the Turkish part of the sea.

Poacher nets differ from the nets of legal fishermen in that legal nets can be equipped with pingers – a special acoustic repellent device. In the last two years they have been used in Bulgaria and Turkey. However, a dolphin blinded by sonar does not respond to pinger signals.

Russian scientists attribute the numerous deaths of dolphins in the Black Sea during hostilities to infectious diseases and getting caught in nets, but infections are a secondary phenomenon during hostilities.

"Infectious diseases are the real killer of dolphins, and it has been happening yearly, especially in recent years. Some of these diseases are caused by microorganisms entering the sea from livestock complexes. For several years in a row, infection episodes have originated in russian waters. In the North Caucasus, vast livestock complexes are concentrated there, and it may happen that they were the source of these infections, which then spread to dolphins throughout the Black Sea," said Goldin.

Rusev added that everything in nature is interconnected, and in stressed dolphins weakened by sonar, immunity is sharply reduced. So animals become objects of infection with infectious agents, the viruses of which live in them constantly. Healthy dolphins have strong immune systems and rarely die from infections. Therefore, the main reason for the death of dolphins is military operations.

"One way or another, we will know the answer to the question of what caused this year's deaths of the Black Sea dolphins after all laboratory tests are carried out in the world's best laboratories," the article noted.

In addition, dolphins are harmed by microplastic toxins and chemicals in the Black Sea.

"We've begun a wide screening of various toxic substances and seen that the Black Sea has substances that we didn't even suspected before, and new ones appear every year," Goldin said.

According to him, this is due to technological progress, annually inventing new substances for its activities. In the end, they all fall into the sea and lead to negative consequences.

"For example, 40 years ago, humanity was very concerned about organochlorine substances getting into the water; they led to chronic poisoning and infertility of animals. Now we can say that organochlorine compounds are becoming less frequent. However, waste pollution brings particles of microplastics with complex substances forming around them, like antibiotics. This is also dangerous because when they enter the water, the bacteria living in the marine environment develop immunity and evolve. That is, there are a lot of harmful substances, and we do not know enough about how dangerous they are. The environment is changing every day. It affects both dolphins and other marine animals," the zoologist explained.

A study by Recep Tayyip Erdogan University in 2021 showed that microplastic pollution of the Black Sea, in particular off the coast of Turkey, is more than 1 million particles per square meter of sea surface. It has even been found in zooplankton.

To draw conclusions about the number of dolphins in the Black Sea, it is necessary to conduct an aviation survey.

Goldin also called for the installation of pingers on fishing nets. After all, if you remove or reduce other factors of death, the population will be much easier to recover from hostilities.

However, reproduction in dolphins is a long process, because they give birth once a year or two, and only one dolphin is born.

Therefore, after the war, poachers and fishers should not be allowed into the sea in those places where dolphins breed and where they live; it is essential to create large areas of national parks and reserves. There should be a national park with an area of 2–3 thousand square kilometers, where dolphins will be protected. Tourists will not go to the dolphinarium and look at the unfortunate dolphin in a cage but will come on boats and watch dolphins in the wild. In this way, we can avoid the death of dolphins in nets and cages. We will have to wait 10–15–20–50 years, but this will be a chance for the dolphins," Rusev said.

As EcoPolitic reported earlier, victims of the russian invasion of Ukraine were at least three thousand dolphins in the Black Sea.

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