United Kingdom, June 6 -- Prince William has issued a stark warning over the state of the world's oceans.

In the latest episode of his 'Guardians' YouTube series, The Prince of Wales has highlighted the Sea of Cortez - an area off the coast of Mexico - which was once known as "the world's aquarium" but is now "under pressure" due to "warning waters" and "illegal fishing".

In his introduction, William said: "In Mexico's Sea of Cortez, a place once known as 'the world's aquarium', life is under pressure.

"Warming waters, vanishing species, and the sheer scale of illegal fishing have pushed this ecosystem to the brink."

He went on to introduce boat captain Jose Luis Cesena Calderon, who spent more than three decades fishing illegally bef...