Secca di Washington

The dive

Secca di Washington is the park's own Secca di Spargi, north-west of the island of Spargi and close to the Bocche di Bonifacio. The National Park describes a broad rocky relief whose cap comes up to 6 m below the surface, built of enormous granite blocks weathered above water before the sea rose over them and now surrounded by boulders, rockfalls, tafoni and hollows that at their deepest points go a little past 25 m. Orso Diving gives the shoal a length of 200 m and puts the sand around it at 36 m. Four mooring buoys are anchored to the bottom and come up to about 4 m from the surface, easy to find in anything but bad weather, and the routes across the shoal fan out from them.

The dive is built on a contrast the park itself points out: lit rock covered in a felt of photophilic algae, and shaded rock where thousands of coloured animals crowd every surface. The commonest protected species in the shade is the yellow sponge Aplysina cavernicola, and red gorgonians take over at the deeper end. Scuba Revolution adds that the western flank drops abruptly into vertical walls sheeted with yellow parazoanthus, while the opposite side is shallower and plainer, though that is where eagle rays have been turning up more often in recent years.

Fish are the other half of it, and the park notes they are unusually confident here: large dusky groupers, brown meagre, seabream, common dentex and barracuda that let divers approach. Orso Diving also records conger and moray in the block field. Occurrence records around the shoal include Epinephelus marginatus, Sciaena umbra, Diplodus vulgaris, Serranus scriba, Mullus surmuletus, Coris julis and Chromis chromis, which matches what the park describes.

The catch is the water and the rules. Orso Diving states plainly that the shoal is often beaten by strong currents and is exposed to all winds, and Scuba Revolution rates the current as medium and sometimes intense; there is no lee here. And Secca di Washington is one of four Punti di Immersione Protetti created by the park in July 2011, where access by unauthorised people is prohibited, fishing and night diving are banned, and nothing may be removed. Independent divers can only dive it accompanied by a park-authorised centre.

• Granite blocks weathered above water, now a 200 m shoal topping out at 6 m
• Four park mooring buoys rising to about 4 m from the surface
• Yellow sponge Aplysina cavernicola in the shaded rock, red gorgonians deeper
• Vertical western flank sheeted in yellow parazoanthus
• Groupers, brown meagre, dentex and barracuda that let divers approach
• One of the park's four protected dive points, reachable only with an authorised centre

Conditions

Clear water, which operators rate as excellent. Water temperature runs 14 to 15 C from January to March and 20 to 26 C from July to September. The shoal sits in open water near the Bocche di Bonifacio with nothing to shelter it, so wind and current, not visibility, decide whether the dive happens.

On current: Take the strong reading. Orso Diving's briefing says the shoal is often beaten by strong currents and is exposed to all winds; Scuba Revolution rates the current as medium and sometimes intense. On depth the sources also differ: the National Park describes the shoal's own hollows bottoming a little past 25 m, while Scuba Revolution quotes a 35 m maximum and Orso Diving puts the surrounding sand at 36 m, so the deeper figure is the surrounding seabed rather than the reef.