Marengo Reefs is a popular diving and snorkelling site near the Marengo township, just 2.5 kilometres south-west of Apollo Bay, off the world-famous Great Ocean Road (B100). This site is on Victoria's Otway Coast, facing south-east into Bass Strait. It lies in the Marengo Reefs Marine Sanctuary which protects 12.5 hectares of ocean waters. About 150 m (492 ft) offshore, this sanctuary protects the offshore reef system, known as Hayley Reef (aka Little Henty Reef and Marengo Reef).

The inner and outer Hayley Reefs are the only larger islands between Cape Schanck and Peterborough. They offer shelter and protect a foreshore beach that is a great shallow family day out for diving or snorkelling. The outer parts of Hayley Reef, on the exposed sides, offer some challenging diving.

The two sections of Hayley Reef, the inner and outer islands, are usually exposed and separated by a narrow channel known as 'The Gap'. Composed of sandstone they support wonderful intertidal and subtidal reefs which are packed with sea life.

Most of the sanctuary is less than 15 m (49 ft) deep. Both the inner and outer reefs are steep-sided. The eastern shore of the outer Hayley Reef has overhangs and ledges, providing habitat for many marine creatures. The reefs were formed as offshore islands slowly eroded down.

Those exploring the rich intertidal reef areas along the top of the Hayley Reef sandstone islands may come across many invertebrates hidden in the rocks, pools, gutters and ledges. They include a huge variety of sea snails, from large abalone to tiny periwinkles, sea urchin. Numerous filter-feeding animals, such as tubeworms, barnacles and bryozoans (sea-moss) trap floating food brought by the waves.

In slightly deeper waters there are profuse seaweed 'gardens' thriving under the large writhing fronds of Bull Kelp that fringe the islands. The towering brown seaweeds grow luxuriantly, interspersed with beds of the attractive, delicate red and green species.

The channel between the two Hayley Reef islands, known as 'The Gap', is a rare sheltered haven on this wild coastline. The 7–8 metre deep calmer waters support colourful soft corals, sponge gardens and sea urchins. The diverse range of habitats provides resources for a huge range of species.

Bubble Weed is the dominant canopy seaweed in the areas protected from high wave energy by the outer Hayley Reef. Bull kelp dominates elsewhere. Fourteen other species of brown algae and seven species of red algae, including encrusting coralline algae, form an understorey below the canopy.

Around the islands, many kinds of wrasse scoot among the fronds. Schools of black and white Zebra Fish stand out dramatically from the seaweed, and the rotund spiny Globe Fish hovers over the rocks. Leather Jackets, purple wrasse, blue-throated wrasse, red mullet and magpie perch are common. Common invertebrates seen include black-lip abalone, periwinkles and sea urchins. Australian Fur seals use the larger island to sun themselves after foraging far off the coast.

The outer Hayley Reef island has a haul out area for approximately 200 Australian Fur Seals. Walking on the reef is not allowed to avoid disturbing the seals, birds and the intertidal animals.

If you want a way more challenging dive, on a perfect day you could explore the 30+ metre deep gully off the southern tip of the outer Hayley Reef island. For a very rewarding boat dive, Henty Reef lies on the other side of the gully, much further offshore.

Dive Type: Reef Dive

Imported from The Scuba Doctor