Deep Pinnacles

Meet the site

Deep Pinnacles is the deeper continuation of the outer Lonsdale reef, a field of 'scattered reef and rock bommies rising out of the sandy sea bed' at 16–25 m south-west of Point Lonsdale, in line with the Lonsdale Arches reef and 250 m from Castle Rock. The Scuba Doctor listing (GPS verified) describes the soft calcarenite as 'eroded into lots of little swim-throughs, valleys and overhangs, all topped off with a light scattering of kelp', and the colour as 'yellow zoanthids and awesome colour'. Golden Arch, a natural arch to 23 m, is 137 m to the west on the same line.

The bommies stand a few metres proud of the sand, separated by valleys and linked by short tunnels that the current has bored through the soft rock; the undersides of every overhang are yellow with zoanthids and studded with sponges and jewel anemones, and the kelp on top is thin because of the depth. The listing's fauna – crayfish, blue devils, abalone 'and much more' – is that of the whole outer reef, with the addition of the animals that prefer deeper water: bigger schools of sweep and boarfish, Port Jackson sharks under the ledges, cuttlefish in season, and the occasional sevengill shark or seal passing over the sand.

Because it lies a little further from the entrance than the Arches and Castle Rock the tide is gentler and the listing rates it diveable on any tide as well as at slack; the constraint is Bass Strait swell, and the boat ride out through the Heads. At 16–25 m it is an Advanced site and a natural step up from Castle Rock for divers who have done the shallower outer reef; it is dived by charters on calm 'outside' days and by club boats, and it rewards a torch and a camera.

What you might see

Yellow zoanthids, sponges, jewel anemones, southern rock lobster, southern blue devil, abalone, silver sweep, longsnout boarfish, Port Jackson shark, giant cuttlefish, Australian fur seal, kelp (sparse)

Location

Scattered reef and bommies on the sand just outside the Heads on the Point Lonsdale side, about 1.8 km south-west of the lighthouse in line with the Lonsdale Arches reef; 250 m west-north-west of Castle Rock and 137 m east of Golden Arch.