It is not unusual to find groups of rocky islands close to a coastline, but stuck out in the middle of an ocean? That is where you will find the St Peter and St Paul Rocks – in the Atlantic Ocean about 590 miles from northeast Brazil and 1,100 miles from west Africa.
They are 15 small islands that rise to no more than 60 feet above the sea. The total land area is about 160,000 square feet. They are uninhabited, although the Brazilian Navy has established a scientific station and lighthouse on the largest island.
The name comes from the event that led to their discovery in1511. A Portuguese nobleman, Garcia de Noronha, was in charge of a fleet of six caravels on a voyage to India. One of the caravels, “St Peter”, crashed against a rock at night in the middle of the ocean, and the crew had to be rescued by the crew of another caravel, “St Paul”.
The St Peter and St Paul Rocks, despite their apparent lack of importance, are extremely interesting from a geological point of view. They are the very top of an undersea mountain that only just breaks the surface. The technical term for the sort of feature they represent is “megamullion”, this being a ridge that runs at right-angles to a mid-ocean ridge, which in turn marks the point where two tectonic plates are moving apart and allowing new ocean crust to form. The Rocks are the world’s highest megamullion (at 12,000 feet), being composed of mantle rock, and are not an undersea volcano that has reached the surface.
The Rocks were visited by Charles Darwin when on board HMS Beagle in 1832. He noted that they had very little to offer in the way of wildlife, and that he not been able to find a single plant anywhere on the islands. He did find two birds, a moth, a crab and some spiders, but that was about it.
Had Darwin stayed longer, he might have noted the relative richness of the tidal pools, which support sea slugs, shrimps and lobsters. The islands are visited by many migrating seabirds, and the seas surrounding them are populated by some 75 species of fish, including deep-water eels, sharks, and five – including the St Paul’s Gregory – that are found nowhere else.
This is a place that very few people visit, or are ever likely to.