Secca della Colombara

The dive

The Colombara is a submerged volcanic shoal about a nautical mile off the north coast of Ustica, inside Zone B of the Area Marina Protetta Isola di Ustica, which was Italy's first marine protected area when it was set up in November 1986. The top of the shoal comes up to roughly 3 m, a flat cap of a few hundred square metres covered in brown algae, and from there the sides fall away as basalt walls and rockfalls to about 42 m. It is a big site rather than a single feature: local centres describe several distinct flanks, a broad plateau at the base of the wall around 25 to 30 m, and a rock knob they call the panettone. A typical guided dive covers a few hundred metres of it and leaves most of it unseen.

What people come for is the fish. Ustica's centres describe schooling barracuda circling in the blue, amberjack, dentex and dense sea bream, and grouper in unusual numbers, both the dusky grouper (Epinephelus marginatus) and the red-mouthed Mycteroperca rubra. Moray, both Muraena helena and the brown Gymnothorax unicolor, sit in the rock. On the walls there are red gorgonians, sponges, orange Astroides cups, madrepores and nudibranchs, and operators report the false black coral Gerardia savaglia at about 50 m, below where a recreational dive should go.

Since 2005 the shoal has also held a wreck. The cargo ship ITA, under Panamanian flag and carrying marble with roughly 20 tonnes of diesel in her tanks, struck the Colombara on 21 February 2005; the grounding was treated as a near-miss environmental disaster inside the reserve. She broke up rather than sinking whole, and the pieces are spread around the perimeter of the dive: a dive-travel guide puts the main debris at about 24 m, while an island dive centre describes wreckage as shallow as around 10 m along the wall. The iron is now well encrusted and works as artificial substrate.

Because the site is offshore, exposed, and large, current is the variable that decides the dive. Ustica's own centres warn that it is often running even when the sea looks flat, and that route and depth have to be planned before you go in rather than improvised.

• Barracuda schools and grouper in numbers, both dusky and red-mouthed
• Basalt walls from a 3 m cap down to about 42 m
• Debris field of the cargo ship ITA, wrecked here in February 2005
• Zone B of Italy's first marine protected area, established 1986

Conditions

A boat run out to a shoal that shows as pale rock under the surface on the north side of the island, then a descent onto an algae-covered cap at about 3 m and down a basalt wall. Ustica's operators quote dives of roughly 45 minutes covering a few hundred metres of the shoal, in the 15 to 40 m band. Current is common.

On current: Ustica Diving Center writes that current is frequently present here even on calm days and has to be assessed before the descent; Blue Diving Ustica lists the site as a current-exposed wreck and deep wall dive. Nobody publishes a rate. Because the shoal is a mile offshore on the exposed north side, the practical effect is that the boat picks the sheltered flank on the day, and on a bad one the trip goes somewhere else.