The corpses of the sea creatures have been washed up along the Tuscan coast or discovered at sea since January.
The most recent was found last Thursday, on a beach at San Rossore, near the city of Pisa.
Autopsies showed many of the animals had stopped eating prior to their death, suggesting they had been hit by a virus, possibly measles.
The virus affects dolphins’ lungs and brains and leads to breathing difficulties as well as skin lesions.
It’s not clear whether it’s related to pollution or other human-related factors.
There was an outbreak of the virus along the Tuscan coast in 2013, which killed many dolphins.
Experts are conducting tests on the carcasses that are not too decomposed and expect to have the first results at the end of August.
They will study the contents of the dolphins’ stomach to see if they had swallowed plastic and will also conduct toxicology tests on their organs.
Dolphins wash up in other parts of Italy but the rate of mortality seems to be particularly high for Tuscany.
The deaths of so many dolphins in the area is even more tragic because the Tyrrhenian Sea off Tuscany forms part of a marine sanctuary that extends to Sardinia and the Tuscan archipelago, which includes islands such as Elba, Giglio and Montecristo.
The Pelagos Sanctuary for the protection of marine mammals, which was created by France, Italy and Monaco in 1999, covers an area of 87,500 square kilometres in total.
