Dead dolphins, naval mines: the war that is killing the Black Sea

The body count no one can hide

KYIV, Ivan Rusev, head researcher at the Tuzly Lagoons National Nature Park in southern Ukraine, told Al Jazeera on Saturday that Black Sea hostilities have killed more than 120,000 cetaceans since Russia's full-scale invasion began in February 2022, roughly one in four of the sea's dolphins and porpoises, some 50,000 in 2022 alone.

For four years, Rusev's researchers have walked 59 kilometres of Odesa shoreline, logging what the war washes up. In August, a mother strolling the Odesa seaside with her eight-year-old son watched the boy find an emaciated, decaying dolphin; now a routine sight on a coast where death from the sky arrives almost daily, and death from the sea keeps pace.

What the shoreline ledger actually records

The mechanism is cumulative. Explosions, missile launches from warships, and military sonar deafen echolocation, the animals' primary survival tool, so they can no longer navigate, communicate, or hunt. "If a dolphin can't fish, it loses weight fast," Rusev said. Starving, they burn pollutant-loaded blubber; the self-poisoning collapses their immune system, and they succumb to lethal morbillivirus respiratory infections.

The ledger is partial by design: only about five percent of dead cetaceans wash ashore. Along the monitored 59 kilometres, workers found 200 dead in four years, 95 this summer alone, pointing at roughly 20,000 dead in the first half of 2026.

Independent records corroborate the direction. A 2023 Biology Letters study coauthored by Rusev estimated 37,500 to 48,000 deaths between late April and end of July 2022, with carcass-recovery rates of 6.2 to 8 percent. ACCOBAMS recorded more than 600 observed deaths in 2022 along the coasts of Bulgaria, Romania, Türkiye, and Ukraine, cause still under investigation. Compounding it: munitions chemicals, oil spills from dozens of damaged vessels, the 2023 Kakhovka dam destruction that released 18 cubic kilometres of contaminated water, and mines spotted as far as Istanbul. Dimitar Popov of Green Balkans told Al Jazeera that "sonar systems of warships and submarines definitely affect cetaceans." Russian monitors blame "parasites" and "virus infections," without further detail.

The arithmetic no one can finish

The 120,000 figure rests on an extrapolation: a five-percent carcass-recovery rate per Rusev, 6.2 to 8 percent per the peer-reviewed 2023 study. The honest range spans tens of thousands to more than a hundred thousand, and no registry will resolve it while the fighting continues.

Individual causes are almost never provable; carcasses arrive in advanced decomposition. Nor is the baseline clean: the Black Sea was already one of the planet's most polluted enclosed seas before 2022. Separating the war's assault from the Kakhovka shock and decades of accumulated pollution is work for a peacetime science that does not yet exist.

An apex predator is a measuring instrument

Dolphins sit at the top of the Black Sea food web; a proxy for everything beneath them. "With dolphins at the top of the food chain, everything from zooplankton to fish reaches them," Rusev said. Mullet and bluefish are already becoming scarce in a basin where pollution accumulates rather than flushing away.

The sea is uniquely unforgiving: one of the world's youngest, it holds no oxygen and supports no life below 50 to 100 metres; an anoxic zone compressing all life into a thin surface layer. Ukraine has also opened an ecocide investigation under Article 441 of its Criminal Code, with carcasses preserved as forensic evidence. Rusev's 30-to-50-year recovery horizon means the ecological bill will be collected long after the guns fall silent.

Why does the toll keep rising?

The toll rises because the sea is now a battlespace. The Ukraine War Environmental Consequences Work Group catalogues the unfamiliar lethal factor: warships and submarines emit signals cetaceans can hear, but louder than the animals themselves; inner-ear damage and acoustic trauma no human ear registers. Add mines, missiles, and naval drones, and the Black Sea has become an environment "simply not suitable for cetaceans."

The mined sea lanes that once carried Ukraine's grain to world markets remain a contested military zone, and even the faltering energy ceasefire covers infrastructure on land, not sonar at sea. Read through the 5D lens, this is a stress test of how wars are accounted for: geopolitics decides where the fleet goes, economics prices the fish that never reach market, history records ecocide as a prosecutable crime, and technology supplies the sonar the law has not yet learned to measure. Russia's counter-claim answers a different question than the one the carcasses ask: not what finished them, but what broke them first.

The war's second ledger

The mines do not only kill dolphins. Mines spotted near Istanbul put the Bosporus itself inside the risk perimeter, with war-risk insurance for the whole basin recalibrated around drifting ordnance. A mine that exploded during the Sea Breeze exercise off Burgas in 2022 was a drill; the ones that detonated on Ukrainian beaches in 2023 killed civilians.

Commercial fishing has been strangled by the same geography: with Ukraine's economic zone mined, many Odesa restaurants rely on imported fish. Bulgaria, a fellow littoral state, has learned the same lesson from the other side of the sea. The grim paradox: with hunting nearly stopped, wild boars, foxes, and jackals have multiplied on the surrounding land; the war spares what it does not need to bomb, and drowns what it cannot see. The December 2024 Kerch Strait spill killed 30,000 birds before the oil ever reached a dolphin.

Can the Black Sea recover while the war continues?

Rusev's answer is unsparing: only stopping the hostilities at sea and on land reduces cetacean deaths. Researchers are preserving 95 dolphin skeletons from this summer's strandings for a future war memorial, while carcasses keep flowing to ecocide prosecutors.

Demining will be a decade-scale operation against drifting mines and uncharted fields. ACCOBAMS's investigation into the 2022 deaths remains open; its verdict on causation will shape whether the strandings become courtroom evidence. The emerging global push to protect marine life beyond national borders offers a legal vocabulary that did not exist when the first carcasses washed up in 2022; but treaties do not sweep mines. Thirty to fifty years to rebuild a population is longer than most of today's diplomats have left in office.