Marine Natural Values Study Summary - Parks Victoria

Marine Natural Values Study SummaryChurchill Island MarineNational ParkAustralia’s southern waters areunique. Ninety per cent of ourmarine plants and animals arefound nowhere else on earth.The system of Marine NationalParks and Sanctuaries hasbeen established to representthe diversity of Victoria’smarine environment, itshabitats and associatedflora and fauna.Victoria’s marine environmenthas been classified into fivebioregions according toa nationally agreed schemebased on physical andbiological attributes.Churchill Island MarineNational Park is one of threemarine national parks inWestern Port Bay, whichis part of the VictorianEmbayments bioregion.Image left:The ‘living fossil’ lampshell or brachiopod Magellaniaflavescens on subtidal sediments. Photo by NRE.Image right:Churchill Island Marine National Park.Photo by Chris Hayward, Parks Victoria.DescriptionThe park covers 670 hectares and islocated south of Rhyll on the easternshore of Phillip Island. It extends fromthe high water mark along 11 kilometresof the Swan Bay coastline. The northboundary of the park is between LongPoint on Phillip Island and North Pointon Churchill Island.The intertidal areas of the park canonly be accessed from the cobble andshingle beaches and the rest of thepark by boat.The park is part of three specialprotection areas that cover WesternPort Bay including the WesternPort Ramsar site, the East Asian-Australasian Flyway, and theMornington Peninsula and WesternPort UNESCO Biosphere Reserve.The mudflats, mangroves and saltmarshof Churchill Island and Swan Bay arerecognised as locally significanton the National Trust Register.Within the park a Special ProtectionArea for Natural Values covers thesaltmarsh and mangrove areas,extending seaward from the highwater mark to the edge of theintertidal vegetation.Parks Victoria acknowledges theAboriginal Traditional Owners ofVictoria – including its parks andreserves. Indigenous tradition indicatesthat the park is part of Countryof Boonwurrung.Physical Parameters and ProcessesThe park is influenced by highturbidity in the bay which arises fromdaily reworking and re-suspensionof fine sediment by tidal, wind andwave action.The park is protected from prevailingsouth-westerly winds, but is exposedto some wind-driven waves. Tidalvariation is 2 metres for spring tidesand 0.8 metres for neap tides. Surfacewater temperatures vary betweenan average 20.4°C in the summerand 11.7°C in the winter.The substrate is predominantly softsediment though some gravel-cobblereef occurs in intertidal areas. No riversor creeks flow directly into the park.Active and reflective cliffs indicativeof higher sea levels at Swan Corner,and raised beach and emerged coastalforms between Chambers Point andLong Point are significant geologicalfeatures within the park.Marine Habitat Distributionand Ecological CommunitiesThe main habitats protected by thepark include intertidal and subtidalsoft sediments (including small areas58