Flinders-Honeysuckle-Merricks and Cape Schanck
The seaward coastline between Point Nepean and Cape Schanck has some of the most diverse underwater scenery and marine life in Victoria. The amazing array of creatures include the curious weedy sea-dragon, a colourful collection of fish species, crabs and sea stars, set in an equally impressive backdrop of intertidal and shallow reefs, rock pools and caverns.
What are the key natural features of this area?
- This highly exposed part of Victoria’s coast has extensive lengths of intertidal reef, complex shallow reefs constantly scoured by sand and waves. The reefs have many microhabitats such as rock pools, overhanging ledges, boulders, bommies and gutters.
- Vertical reef faces between the Sorrento and Rye back beaches have been significantly eroded over time, forming undercuts, caves and crevices supporting kelp beds, mixed algal habitats and marine life specially adapted to life in caverns.
- From Cape Schanck to West Head (Flinders) there are extensive areas of subtidal reef with outcrops, boulders, ridges and gutters. The reefs support kelp beds. Seaweeds that grow in inshore areas under cliffs and high shores are specially adapted to the low amount of light available.
- Subtidal reefs in the area offer sheltered habitats and food for many fish and invertebrate species. For example, Mushroom Reef Marine Sanctuary has many subtidal pools and boulders. The ancient basalt has been strongly weathered, forming microhabitats that allow marine creatures to hide under loose rocks or within crevices and cracks.
- The complexity of the intertidal area supports a great diversity of invertebrates – Mushroom Reef has the most diverse intertidal rocky reef communities in Victoria.
- There are extensive intermediate depth reefs (15–25 m) offshore from Mornington Peninsula ocean beaches and Cape Schanck. Deeper reefs in the area consist of rubble and bedrock covered by sand washed in by waves. Red algae and sessile (non-moving) invertebrates flourish on barer reefs. Intermediate and deep reefs further offshore support amazing kelp forests and are home to a dazzling array of sessile invertebrates.
- The deep reefs, canyons and pinnacles off Cape Schanck are of high conservation value, but they have not yet been properly surveyed.
- These offshore reefs, which support seaweeds, filter feeding animals and non-moving organisms, are completely unprotected at present. Deep reefs too are not included in any marine protected areas in the region, with ecosystems of very high conservation value present Cape Schanck and West Head. These habitats and communities need to be protected.
- Flinders is another area of high conservation value, with important intertidal and subtidal reef and Amphibolis seagrass beds meadows. The area around Flinders Jetty is home to colonies of Weedy Sea-dragons, Victoria’s marine emblem, and a number of threatened species in the intertidal reef habitats.
- Seagrass beds at Flinders help stabilise sediments and contribute to water quality in the area. They are also important nursery areas for commercially important juvenile fish and invertebrates.
- The flat and shallow Honeysuckle Reef is within a relatively sheltered bay area, and includes intertidal and subtidal reefs and a shallow pool area used extensively by schools of young fish.
- The Flinders-Honeysuckle-Merricks coast has significant reef areas and species-rich seagrass meadows teeming with colonies of the iconic Weedy Seadragon.
- The rocky shores and surrounding reefs at Flinders are famous for the diversity of their marine life, and the area has revealed many animal species not previously known to science. These include sea stars that brood their young in their stomach and other tiny sea star species once thought to be juveniles.
- Crabs, multicoloured Cushion Sea-stars, small spiralled shells of all shapes and sizes and rows of daisy-like anemones are all easily visible. The seafloor in the coves is carpeted in algae and seagrass, and the gutters, ledges and boulders of the subtidal reefs are covered in kelps and smaller brown and red algae. These reefs are home to abundant rock lobster, ascidians, gorgonian fans, sponges and corals. Reef fish such as moonlighters, magpie perch and wrasses, and cartilaginous fish such as Port Jackson and cat sharks, are also commonly seen in the area.
- Sandy areas support large seagrass meadows inhabited by a variety of fish including Saddled Wrasse and Magpie Morwong, and the strange box-like Cowfish.
- Mushroom Reef at Flinders and Honeysuckle Reef at Shoreham support the most diverse intertidal rocky reef communities in Victoria. Part of the beach area adjacent to Honeysuckle Reef is used as a high-tide roost by migratory wading birds.
- This area is also home to a number of rare and threatened invertebrates, including the Snapping Shrimp Alpheus australosulcatus, the Chiton Bassethulia glypta and the Sea-cucumber Apsolidium densum. The threatened sea cucumber is a species found only in Victoria at three locations, two of which are Mushroom Reef and Honeysuckle Reef. The rare chiton has a very restricted distribution, and has only been found in the Port Phillip Heads region and at West Head (Flinders).
- Cape Schanck’s deep reefs, pinnacles and canyons support incredibly diverse communities of sedentary invertebrates like sponges, sea tulips and lace corals.
- Despite their fierce name, sea-dragons are dainty, timid animals that hover slowly and gracefully over the seagrass and seaweed in which they shelter. This fish grows up to 46 cm and is startlingly coloured, with a red body, fine yellow spots, and iridescent blue stripes on their trunk and tail. The most amazing feature of seadragons is the long leaf-shaped flaps of skin that project at intervals along the top and bottom of the fish. This jumble of colours and shapes is for camouflage and they can be very difficult to see. Their tiny fins beat rapidly, enabling them to float without obvious movement. Weedy Seadragons are related to pipe fish and seahorses, although they cannot coil their tails like seahorses. But as with seahorses, it is the male that looks after the eggs. Tiny pink eggs stuck to the tail of male Weedy Seadragons are brooded for two months and then hatch directly into tiny fish which grow rapidly, reaching 7 cm in three weeks.
- All seadragons, seahorses and pipefishes are protected in Victoria, and a permit is required to collect them.
Marine Protected Areas:
Mushroom Reef Marine Sanctuary