ウクライナ侵攻で黒海のイルカが大量死、ロシア軍のソナーが影響か

【プリモルシケＡＦＰ＝時事】ウクライナ人科学者のイワン・ルセフ氏（６３）は、黒海に面した白い砂浜を行きつ戻りつして、安堵（あんど）のため息をついた。きょうは、イルカの死骸が見つからなかったからだ。（写真はイワン・ルセフ氏）
　ルセフ氏は、南西部ベッサラビア地方にあるトゥズリウ川河口国立自然公園の研究責任者を務めている。
　ロシアによるウクライナ侵攻開始後、付近にイルカが漂着し始めた。今では、近くに対戦車地雷が埋設された浜辺を毎朝歩き、打ち上げられたイルカがいないかどうか確認するのが日課の一つとなっている。
　「トルコやブルガリア、ルーマニアの研究者仲間に連絡したところ、皆が同じ状況を目にしていた。戦争開始以来、非常に多くのイルカが死んでいる」とルセフ氏は話す。
　同氏の推定では、死んだイルカの数は５０００頭に上り、これは黒海の生息数の約２％に相当する。ルセフ氏は、イルカの大量漂着の原因はロシア軍艦艇の軍用ソナーであることに疑いの余地はないと考えている。
　軍艦や潜水艦が搭載する強力なソナーは「イルカの聴覚機能を妨害する」とルセフ氏は説明する。「イルカは内耳を破壊されて感覚を失い、方向を認識したり、狩りをしたりすることができなくなる」ほか、免疫機能の低下により致死性の病気にかかりやすくなるという。
　ロシアとウクライナは、戦争による環境への悪影響についても互いを非難しており、ルセフ氏の仮説も、双方から受け入れられているわけではない。ロシアの研究者は、イルカなどを死に至らせるモルビリウイルスが大量死の原因ではないかと指摘している。
　ルセフ氏らの研究チームは、論争に終止符を打つため、最近死んでいるのが発見されたイルカからサンプルを採取してドイツとイタリアに送り、結果が出るのを待っている。
　ルセフ氏の国立公園も軍事攻撃を受けており、１００ヘクタールの保護区が焼失した。同氏は、「戦争は恐ろしいものだ。生態系全体に影響を与える。そこには、容易には回復しない種も含まれている。自然のバランスも同じだ。簡単には回復しない」と危機感を示している。【翻訳編集ＡＦＰＢＢＮｅｗｓ】
〔ＡＦＰ＝時事〕（2022/09/06-13:31）

Pacing up and down a beach of fine white sand on the Black Sea coast, 63 year-old Ukrainian scientist Ivan Rusev breathes a sigh of relief: he did not find any dead dolphins today.
A few moments earlier he had rushed towards what he thought was a stranded dolphin. Mercifully it turned out only to be tangled fishing gear.
Rusev spoke to AFP from the Tuzly Estuaries National Nature Park, a protected area of 280 square kilometres (108 square miles) in the Bessarabia region of south-west Ukraine.
Rusev, whose weather-beaten face is shaded by a hat he brought during adventures in central Asia, is the scientific director of the park.
Now his job entails walking every morning along beaches bordered by anti-tank mines in search of the dolphins that have been washing up here since the beginning of the war.
We only found three dolphins over our entire 44 kilometres (27 miles) coastline last year, he tells AFP.
This year, over the five kilometres (3 miles) that we can still access, we already found 35 of them.
Much of the coastline has been off-limits to employees of the park since Ukrainian troops took up positions there to prevent any possible Russian sea assault.
This means Rusev and his team cannot say exactly how many dolphins have been stranded in the park or survey the full extent of the damage.
- Dangerous sonars -
In any case, the death toll is terrifying, says Rusev, who has been keeping an online diary -- now widely followed on Facebook -- about the impact of the war on wildlife.
When dolphins started washing up on the coast in March, Rusev and his team had to get to work quickly to spot dead animals before the many jackals roaming the area got to them.
Then, we reached out to our colleagues in Turkey, Bulgaria, Romania. Everyone witnessed the same thing: a huge number of dolphins have died since the beginning of the war, Rusev said.
The Turkish Marine Research Foundation (TUDAV) warned in March of an unusual increase in dead dolphins washing ashore on the Black Sea coast.
Rusev estimates that 5,000 dolphins have been killed -- about 2 percent of the total dolphin population in the Black Sea.
The Black Sea was home to an estimated 2 million dolphins during the 20th century, but fishing and pollution contributed to their decline.
A survey found there were about 250,000 of dolphins left in 2020.
There's no doubt in Rusev's mind: military sonars used by Russian warships are to blame for the current bloodbath.
The powerful sonars used by warships and submarines interfere with dolphin's hearing systems, he explains.
This destroys their inner ear, they become blind and cannot navigate or hunt, and are more susceptible to lethal disease due to their weakened immune systems, according to Rusev.
The dolphin remains do not show any trace of fishing nets or wounds, which for Rusev is further evidence ruling out the possibility they died any other way.
- Trading blame -
Russia and Ukraine are trading blame even on the environmental toll of the war, so Rusev's theory is disputed.
Russian scientists who looked into the increase in dolphin mortality blamed morbillivirus, a common lethal disease for the species.
Rusev and his team took samples from dolphins that had recently been found and have sent them to Germany and Italy to settle the debate.
Usually Rusev sleeps in a cabin next to the entrance of the park.
Today, the carcass of a dead dolphin lies next to his cabin, in the lagoon's stagnant waters.
Rusev covered it with a fishing net. That way, he explains, fish will eat the flesh, and he can give the remaining skeleton to a museum.
The scientist, sometimes halting conversation to marvel at a white-tailed sea eagle or a flock of pelicans, is visibly worried.
Military strikes have already hit the national park and burned 100 hectares of protected land.
War is a terrifying thing, he said. It impacts the whole ecosystem, including species that won't easily recover.
Nature's balance won't easily recover either.