Lonsdale Bommies

Meet the site

Lonsdale Bommies is a cluster of limestone outcrops on the outer Lonsdale reef, in Bass Strait about a kilometre off Point Lonsdale light and a couple of hundred metres east of Lonsdale Arches. The Scuba Doctor listing gives a depth of 12–18 m, an Open Water rating, an ebb-only tide window, and describes the same nutrient-rich, current-fed environment as the Arches: 'the strong current flow in this area has created a nutrient-rich environment and subsequently prolific marine growth and the associated marine life'. It is also noted, tellingly, as 'a favourite spot for catching crays' – the site lies within the marine national park where taking lobster is now prohibited, but the population that made the reputation is still there.

The bommies are rounded outcrops rising 3–5 m from a sand and rubble floor at 16–18 m, separated by gutters, with undercut bases and encrusted flanks. They lack the arches of the neighbouring site but have more edge, more crevices and, for a photographer, more places to find southern blue devils, cuttlefish, nudibranchs and the ubiquitous crayfish feelers. Above the reef the fish are those of the whole outer reef – sweep, boarfish, magpie perch, wrasse and leatherjackets – and seals drop in from the Point Lonsdale haul-outs.

Operators use the Bommies as the second dive of an 'outside' day after the Arches, or as the first drop when the Arches is crowded. The conditions that apply are the same: ebb slack, no significant south-westerly swell, and a boat that can pick divers up from a DSMB if they finish downstream. The site is easy and the navigation forgiving, and it is a good introduction to Bass Strait reef for divers who have only dived inside the bay. The Scuba Doctor listing also records an alternative Geoff Rodda mark (-38.282283, 144.646533) that is inside the Heads and appears to be an unrelated site.

What you might see

Southern rock lobster, southern blue devil, giant Australian cuttlefish, nudibranchs, silver sweep, longsnout boarfish, magpie perch, bluethroat wrasse, leatherjackets, yellow zoanthids, sponges, Australian fur seal

Location

Rock outcrops on the outer Lonsdale reef in Bass Strait about 1 km from Point Lonsdale light, 200 m east of Lonsdale Arches and 142 m from Twin Bommies.