The limitation has been a possibility since the Berlengas nature reserve plan came into force in 2008 and was put in place to protect the fragile ecosystems on the island.

Despite the nature reserve plan, no maximum number of daily visitors was ever established.

The association that represents the 24 boats that travel back and forth to the island also agrees with the limitation.

Some of the boats could not get licences in Peniche so applied in other coastal towns such as Nazaré, São Martinho do Porto and Ericeira, leading to the number of vessels carrying tourists to the island tripling in the last 10 years.

UNESCO classified the archipelago as a Biosphere Reserve in 2011, though it has been a natural reserve since 1981 and was classified as a Special Protection Zone for Wild Birds in 1999.