A major feature of the Barwon Bluff Marine Sanctuary are the extensive intertidal reefs comprised of both volcanic basalt boulders in the east, and large areas of sandstone in the west. These are covered by the sea and then uncovered twice each day. Reefs that are exposed at low tide are great places to explore as there are many animals and several plants that can survive out of the water for some time.

Conditions for living things on these reefs are harsh with these constant changes in their environments being underwater for several hours, and then exposed to the drying effect of sun and wind. Whilst underwater these reefs are pounded by waves and are also feeding areas for predators like fish, whilst at low tide birds come in to feed.

The animals and plants that live here are well suited to these changing environments and have adaptations to help protect them from drying out, from waves, and from predators.

Rocky shore communities are quite variable across Victoria and several types of intertidal reefs can be seen in different areas of the Barwon Bluff Marine Sanctuary. These vary depending on the rock type, the level of exposure to waves, and its weathering, the presence of rockpools, crevices, and boulders, and the presence or absence of predators.

Rocky reefs that extend into the sea and that are always covered with water are called subtidal reefs and these can be found right along the coast at Barwon Heads including within the Barwon Bluff Marine Sanctuary.

In shallow areas where there is plenty of sunlight these reefs are mostly covered by algae including large brown algae known as kelp. These areas are often described as kelp forests and are rich in a wide diversity of plants and animals that can be found there.

Reefs that are hidden from sunlight in deeper water, or where sunlight is blocked under ledges, often have brightly coloured communities of invertebrates, many of which rival coral reefs for colour and diversity. These sponge gardens contain many animals that filter their food from the water.

They also provide an excellent site for divers and snorkelers to enjoy and experience a huge range of Victoria’s marine life. These reefs are also help the sustainability of some commercially important species such as abalone and rock lobsters that are protected within the Marine Sanctuary, but whose offspring spread outside the park.

Seaweeds that form forests are a special group of large brown algae called kelps. These large plants attach themselves to solid structures such as rock and extend their blades into the waters above them, reaching towards the sunlight.

The large algae in turn create a habitat for smaller algae and a wealth of animals that can either live attached to the rocks beneath the kelps, on the kelps themselves, or in the sheltered waters between individual plants.

In the same way that trees provide shelter and food for many different species, kelp forests are the true forests of the sea.

Because the kelp forest has a dense canopy of blades blocking out light, it can result in shading of the rock surface providing an ideal environment for an understory of encrusting algae and non-moving animals.

Some common algae that form kelp forests within the Barwon Bluff Marine Sanctuary include Bull Kelp (Durvillea potatorum), Crayweed (Phyllospora comosa), and Golden Kelp (Ecklonia radiata).

Sandy habitats are far from being deserts and have a surprising wealth of life.

Many animals such as rays and crabs bury themselves in the sand whilst resting, whilst the small spaces between sand grains are important for a range of small burrowing animals including worms and crustaceans that are food sources for fish and birds.

The beach is another obvious sandy environment and it also provides habitat for animals that live in the sand such as sand hoppers that eat beach washed algae and in turn are important food for birds (at low tide) and fish (at high tide).

Amazing Fact: Scientific surveys have shown that some Victorian sandy environments off Gippsland have the highest levels of animal diversity in the sea ever recorded with over 600 species found in ten square metres!

Some animals that are often found in sandy areas include Smooth Stingrays (Dasyatis brevicaudata), Eastern Shovelnose Stingarees (Trygonoptera imitata), Pipis (Plebidonax deltoides), and Sand Hoppers (Talorchestia sp.).