Suddenly, he rushes: perhaps a dolphin carcass, as he has found dozens since the beginning of the Russian invasion of Ukraine.
False alarm. “It was a tangle of nets rejected by the sea”, he announces in a joyful tone. Today, the quest is in vain and the scientist does not hide his relief.
Weathered face, hat brought back from past adventures in Central Asia, Mr. Roussev, 63, is the scientific director of the Touzly Lagoons National Park, 280 km2 of protected coasts in Bessarabia, an isolated historic area in the Odessa region, in southwestern Ukraine.
The place could seem heavenly with its fine sandy beaches and transparent water. But every day, when he leaves to make his morning inspection in this territory squared by the army, along anti-tank mines deposited at the edge of the road, Ivan Roussev wonders if he will find a new dolphin.
“Last year, on our 44 kilometers of coast, we found in all and for all three dolphins”, he told AFP: “This year, on the only five kilometers where we have the right to operate , we have already recovered 35.”
Indeed, it is impossible to know precisely how many have been stranded elsewhere in the park. For fear of a Russian landing after the outbreak of war in February, the Ukrainian army took up position there, barring most park employees.
But the results are “terrifying”, insists Mr. Roussev, a native of the region and who began from the first day of the Russian invasion to identify the effects of the war on the fauna and flora, in a logbook very followed on Facebook.
The first mammals were stranded as early as March. It was necessary to act quickly to document these deaths: the jackals are numerous and a dolphin carcass never passed the night.
Then, he explains, “we began to communicate with our Turkish, Bulgarian and Romanian colleagues, and they all made the same observation: there has been a huge number of dead dolphins since the start of the war”.
The Turkish Marine Research Foundation (Tudav) already expressed concern in March about an “unusual increase” in the deaths of dolphins found on the Turkish Black Sea coast.
Mr. Roussev puts forward a figure, “5,000 dolphins killed according to the data collected”, or nearly 2% of the total population of this cetacean in the Black Sea.
Estimated at two million in the middle of the 20th century, the three species of dolphins that inhabit this almost closed sea have suffered for decades from fishing and pollution. The last census, in 2020, established their number at 250,000, notes Mr. Roussev.
For him, there is no doubt: the culprits of the current slaughter are the overpowered sonars used by Russian warships and submarines surveying the Black Sea, which disturb “the acoustic system of the dolphins”.
“It destroys their inner ear, they become blind, can no longer orient themselves or fish,” explains Ivan Roussev. Weakened, the dolphins fall ill and die of infections.
He points to the fact that none of the dolphins found this year had any visible injuries or typical wounds indicating that they had gotten caught in a fishing net.
– Balance destroyed –
It remains to confirm this hypothesis, while the war between Moscow and kyiv moves into the ecological field.
Russian scientists, who also note an excess mortality of dolphins, evacuate the thesis of the sonars and ensure that they are victims of a morbillivirus, a cause of frequent fatal epidemics in marine mammals.
To remove the doubt, samples which will be analyzed in Germany and Italy were taken from the last specimens found in the park.
Near the wooden hut in which he sleeps, at the entrance to the park, Ivan Roussev left the carcass of the last dolphin in the stagnant water of the lagoon. He surrounded it with a fishing net: the fish will eat it, then he will recover the skeleton to give it to a museum.
This ornithology enthusiast, who can give up everything to observe a flight of pelicans or admire a white-tailed eagle, does not hide his concern.
The national park was hit by strikes that burned 100 hectares of protected areas.
“War is a scary thing. It impacts the ecosystem as a whole, species that will struggle to recover and restore the balance of nature.”
