Marine Natural Values Study Summary - Parks Victoria

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Physical Parameters and ProcessesThe geology of Port Phillip HeadsMarine National Park is dunecalcarenite (limestone) with somesections covered with sand, thoughPopes Eye has an artificial structureof basalt blocks. The park has a widevariety of exposure. Outside the Headsthe southern coasts of Point Lonsdaleand Point Nepean are exposed tosouth-westerly weather and swells ofBass Strait. They receive ocean wavesaveraging about 1.7 metres, whichbreak on the outer reef flats and arriveon the beach with reduced energyand wave height.Between the Heads is a narrow, deep(100 metres) stretch of water that isvery turbulent due to swell, waves,tides and weather. Tidal currentsthrough the Heads dominate watercirculation in southern Port Phillip Bayand can be as fast as 2.5m/s.The park beaches on the inside coastof the Heads receive low wave energyand are dynamic with natural accretionand attrition of sand, covering anduncovering the reefs and otherhabitats.Further inside the bay, Popes Eye andPortsea Hole have moderate exposureto waves and currents.Point Nepean, looking across the Heads to Point Lonsdale,Port Phillip Heads Marine National Park. Photo by SteffanHowe, Parks Victoria.The islands of Mud Islands createa sheltered lagoon, however strongtidal currents and storm eventscontinually alter the shape of MudIslands and the Great Sands. SwanBay is a large shallow shelteredlagoon, with a constricted connectionto Port Phillip Bay by natural andartificial channels either sideof Swan Island.The park has an unequal semidiurnaltidal pattern, with flooding andebbing having both a higherand lower event per day.Tides vary in the different sectionsof the park, from 1.2 metres springand 0.6 metres neap tides in PointLonsdale and Point Nepean, to 0.7metres spring and 0.1 metres neaptides in Portsea Hole and Mud Islands.Tidal currents diminish before theyreach Swan Bay, with a tidal amplitude
Wet Saltmarsh Scrubland and WetSaltmarsh Herbland with some CoastalTussock Saltmarsh. Within thesecommunities a number of species areconsidered rare or threatened in Victoria.Saltmarsh in Swan Bay is predominatelyoutside the park boundaries but containscommunities of Wet SaltmarshScrubland; Wet Saltmarsh Herbland;Coastal Tussock Saltmarsh; CoastalHypersaline Shrubland; CoastalSaltmarsh; and Estuarine Wetlands.Species include beaded glasswortSarcocornia quinqueflora, creepingbrookweed Samolus repens,Hemichroa pentandra and greyglasswort Halosarcia halocnemoides.Seagrass and UnvegetatedSoft Sediments:The intertidal and subtidal seagrassbeds on the soft sediment in MudIslands and Swan Bay, and on sandcovered subtidal reef in Point Nepean,support abundant invertebrates andjuvenile fish.Intertidal Seagrass and UnvegetatedSoft Sediments:Intertidal seagrass, usually Zosteramuelleri, is an important habitat inthe park, particularly in Swan Bay andMud Islands. The extensive intertidalseagrass beds in Swan Bay alsoinclude Halophila australis, Ruppiatuberosa, Lepilaena marina, andL. cylindrocarpa. Wrack on the shorein Swan Bay can be considerable andcover the inshore seagrass beds.Image left:Western blue devil fish Paraplesiops meleagris on deepsubtidal reef at Point Lonsdale. Photo by Don Love.Image right:Seagrass beds (Zostera muelleri) at Mud Islands.Photo by Mark Rodrigue.Infauna associated with intertidalseagrass beds in Swan Bay isdominated by large numbersof relatively few species. Corophiidamphipods and the amphipodAllorchestes compressa are thedominant crustacea, and thepolychaete fauna is dominatedby capitellids, the nereid Ceratonereispseudoerythraeensis and theorbinid Scoloplos cylindrifer.In unvegetated intertidal soft sedimentsinvertebrate communities are dominatedby oligochaete worms, polychaeteworms Capitella sp., bivalve Myselladonaciformis, gastropod Salinatorfragilis and crane flies Tipulidae.Subtidal Seagrass and UnvegetatedSoft Sediments:Subtidal seagrass is also an importanthabitat the park, particularly in MudIslands and Swan Bay. Mud Islands haslarge persistent beds of Heterozosteranigricaulis in the lagoon and outsidein waters up to 8 metres deep.The extensive subtidal seagrass bedsin Swan Bay include Zostera muelleri,Heterozostera nigricaulis, Halophilaaustralis, Ruppia maritima,R. polycarpa. H. australis is alsofound in deeper water aroundthe Swan Bay jetty area just outsidethe park.The southern deeper end of Swan Bayand near the centre tend to be moredominated by algae such as Caulerpaspp. and filamentous algae thanseagrass.The H. nigricaulis habitat in MudIslands supports at least twenty-sevenspecies of finfish and one speciesof squid.The seagrass assemblages in Swan Baytend to be dominated by large numbersof the spotted pipefish Stigmatoporaargus with other species of pipefishsuch as Vanacampus phillipi. Otherdominant species include the hardyheadLeptatherina presbyteroides, thebridled leatherjacket A. spilomelanurus,the spot-shoulder weed fishHeteroclinus perspicillatus and thecobbler Gymnapistes marmoratus.In the shallow beds, smallmouthhardyheads Atherinosoma microstomaand hardyhead recruits Atherinidaespp. are the most abundant fishspecies along with the wide-bodypipefish Stimatorpora nigra, bridledleatherjacket Acanthaluteresspilomelanurus, little rock whitingNeoodax balteatus, blue spratSparatelloides robustus and spottedpipefish S. argus.In the deeper seagrass beds the mostabundant fish is the wide-bodypipefish S. nigra. Also abundant areleatherjackets, including the bridledA. spilomelanurus, toothbrushA. vittiger and pygmy Brachalueresjacksonianus and the little rockwhiting Neoodax balteatus. TheAustralian giant cuttlefish Sepiaapama has been found in the deeperbeds of H. nigricaulis. Red mulletUpeneichthys vlamingii, little gurnardperch Maxillicosta scabriceps and yankflathead Platycephalus speculator arealso found in the deeper beds.A number of commercially importantspecies, rough leatherjacketScobinichthys granulatus, six-spinedleatherjacket Meuschenia freycineti,and King George whiting Sillaginodespunctatus, settle directly into subtidalH. nigricaulis beds. Skates, rays andstingarees are particularly common38
Page 1 and 2: Marine Natural ValuesStudy Summary1
Page 3: Australia’s southern waters areun
Page 6 and 7: Marine Natural Values Study Summary
Page 8 and 9: Marine National Park form part of t
Page 10 and 11: this habitat is an important feedin
Page 16 and 17: park management plan. Parks Victori
Page 18 and 19: e seen at low tide, though itis gen
Page 22 and 23: (Belloliva leucozona), though thism
Page 24 and 25: (as deep as 50m) including ascidian
Page 30 and 31: caspia, Sternula nereis and Sternas
Page 32 and 33: interpres and the hooded ploverThin
Page 36 and 37: The park is home to twenty-one biot
Page 40 and 41: on the unvegetated sand beds.Specie
Page 42 and 43: Inside the Heads in Point Lonsdalea
Page 45 and 46: Sand patches and associated seagras
Page 49 and 50: Major ThreatsMeasures to address or
Page 51 and 52: anksii, as well as sea lettuce Ulva
Page 55 and 56: at their distributional limits in W
Page 57 and 58: provide habitat for epiphyticfilame
Page 61 and 62: Potentially thirty two species ofma
Page 63 and 64: of Victoria’s migratory waders an
Page 67 and 68: and polychaetes.Subtidal reefs and
Page 73 and 74: The introduced New Zealand seastarA
Page 75 and 76: The marine flora and fauna of thesu
Page 79: organisms. Those that make theirper

Marine Natural Values Study Summary - Parks Victoria

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