Barriers erected by Russia to protect the Crimean bridge from Ukrainian attacks have reportedly been washed away by a “storm of the century” that battered the Black Sea region.

The barriers, deployed to protect the road and rail crossing from Ukrainian seaborne drones, have likely been washed away in the storm, an open source researcher reported.

The Crimean bridge, also known as the Kerch Bridge, connects the Russian mainland to the occupied peninsula that Moscow annexed in 2014.

Satellite imagery circulated after the worst of the weather had passed appeared to show the waters close to the bridge unprotected by the floating barriers, according to an analysis by “BrianE6B” shared on X, formerly known as Twitter.

The defences were part of “extensive protection measures” to guard against attacks on the Kerch Bridge, a vital piece of infrastructure for Russian troop movements and shifting equipment into Ukraine.

Pens that once held Russia’s specially trained dolphins deployed to protect the Black Sea naval fleet and Crimea had also likely been washed away in the storm, MT Anderson, a second open source researcher, reported.

HI Sutton, an independent defence analyst, said: “The dolphin pens in Sevastopol harbour are gone as a result.”

He added: “They may have been sunk or washed away. It is plausible that some or all of the trained dolphins have been freed.”

Russian naval forces have used the dolphins to detect elite Ukrainian divers since the beginning of Moscow’s full-scale invasion last February.

British intelligence officials said Moscow had doubled the number of the marine mammals used as part of its complex defence network around Crimea, in a social media post in June.

Ukrainian officials also confirmed that the storm, which pounded the Black Sea region with hurricane-force winds and 30ft waves, had destroyed other Russian defences around Crimea.

Anton Gerashchenko, an adviser to the Ukrainian minister of internal affairs, said: “A storm washed away trenches in occupied Crimea that [the] Russian army dug out on the beaches.

“According to information from Crimean media, in Yevpatoria, the water washed away the defence line on the coast, engineering buildings, and firing positions.”

It emerged last week that Moscow and Beijing have discussed building an “underwater tunnel” connecting mainland Russia and occupied Crimea, amid mounting Russian fears that the Kerch Bridge, which has been successfully struck twice by Ukraine, remains vulnerable.