Scientist Ivan Roussev examines a dead dolphin at the Limans Tuzly Lagoons National Nature Park, near the village of Prymorske on August 28, 2022, amid the Russian invasion of Ukraine. - Ivan Roussev has been keeping a logbook of the effects of the war on nature, but has made a worrying count: the number of dolphin corpses he finds has exploded. (Photo by Dimitar DILKOFF / AFP)

63-year-old Ukrainian scientist Ivan Rusev walks up and down a fine white-sand beach on the Black Sea coast. He breathes a sigh of relief: he didn’t find any dead dolphins today. A few moments earlier he had rushed towards what was only supposed to be a stranded dolphin. It turned out to be just tangled gear.

Rusev spoke to AFP from the Tuzly Estuaries National Nature Park, a 280-square-kilometer protected area in the Bessarabia region of south-west Ukraine. Rusev is the scientific director of the park.

Now his job is to search the anti-tank mine-lined beaches every morning for dolphins that have washed up here since the beginning of the war. “Last year we only found three dolphins on our entire 44-kilometer coastline,” he tells AFP.

“This year we have already found 35 of them in the five kilometers that we still have access to.”

Much of the shoreline has been closed to park employees since Ukrainian troops deployed there to thwart a possible Russian attack on the sea. So Rusev and his team can’t say exactly how many dolphins are stranded in the park and how bad the damage is.

In any case, the number of dead animals is “frightening,” says Rusev, who kept an online diary about the war’s impact on wildlife, which is widely read on Facebook.

When dolphins washed up on shore in March, Rusev and his team had to act quickly to locate the dead animals before the many jackals that roam the area got their hands on them.

“Then we turned to our colleagues in Turkey, Bulgaria and Romania. Everyone noted the same thing: a large number of dolphins have died since the war began,” Rusev said. The Turkish Foundation for Marine Research (TUDAV) warned in March of an “unusual increase” in dead dolphins washing up on the Black Sea coast.

Rusev estimates that 5,000 dolphins were killed – about 2 percent of the Black Sea’s total dolphin population. An estimated two million dolphins lived in the Black Sea in the 20th century, but fishing and pollution have contributed to their decline. A survey found that there were about 250,000 dolphins left in 2020.

For Rusev there is no doubt: the military sonars used by Russian warships are to blame for the current bloodbath. The powerful sonars of warships and submarines “interfere with the dolphins’ hearing systems,” he explains.

“As a result, their inner ear is destroyed, they become blind and cannot navigate or hunt.” They are also more susceptible to deadly diseases due to their weakened immune systems, Rusev said.

The remains of the dolphins show no traces of fishing nets or wounds, which Rusev says is further proof that the animals couldn’t have died in any other way.

But Russia and Ukraine also blame each other for the environmental impact of the war. Rusev’s theory is controversial.

Russian scientists studying the increase in dolphin mortality have blamed it on morbillivirus, a disease that is often fatal to the species. Rusev and his team took samples from recently found dolphins and sent them to Germany and Italy to investigate the cause of death.

Rusev usually sleeps in a hut near the entrance to the park. Today the carcass of a dead dolphin lies next to its hut, in the water of the lagoon.

Rusev covered him with a fishing net. That way, he explains, the fish will eat the flesh, and he can donate the remaining skeleton to a museum.

The scientist, who sometimes interrupts his conversation to admire a white-tailed eagle or a flock of pelicans, is clearly concerned. Military attacks have already hit the national park, burning 100 hectares of protected land.