The Keyhole (Montague Island)

Meet the site

The Keyhole is described by the Marine Life Network as one of the best deep sites at Montague Island. It lies west of the seal colony, with deep sponge gardens from 20 to 40 m featuring large sea fans and schools of pelagic fish. That places it in the zone below the kelp, where rock surfaces are covered in filter feeders and the open-water location attracts fish.

Expect large gorgonian sea fans, sponges of many shapes and colours, sea whips and sea squirts, with bullseyes, nannygai and red morwong on the reef and schools of yellowtail, silver trevally and kingfish in the water column. Being close to the seal colony, divers often have seals for company, and grey nurse sharks from the northern gutters may pass through in summer. Visibility is often good at this depth when the East Australian Current pushes warm blue water south.

This is a deep dive: at 30–40 m, air no-decompression limits are very short and narcosis is significant, so it suits Deep-certified divers with experience, ideally on nitrox or with technical training for the deeper parts. The name suggests a hole or gap in the reef, but no published description explains it. The position is not published, so dive with a Narooma operator. Sharks, including great whites, are occasionally seen near seal colonies, so follow the operator's briefing. Because the site is used only when conditions are right, ask the operator in advance whether a deep day is planned and bring nitrox certification if you have it. A torch or strobe brings out the reds and oranges of the sea fans, which look grey-blue in natural light at this depth.

What you might see

Gorgonian sea fans, sponges, sea whips, sea squirts, bullseyes, nannygai, red morwong, yellowtail, silver trevally, kingfish, fur seals, grey nurse sharks (seasonal)

Location

Deep sponge gardens west of the Montague seal colony with large sea fans and schools of pelagic fish; 20–40 m.

Facilities nearby

Narooma town wharf and marina.