PROTECTING MARINE HABITAT A handbook for Victorian waters PROTECTING MARINE HABITAT

VICTORIAN NATIONAL PARKS ASSOCIATION The Victorian National Parks Association (VNPA) helps to shape the agenda for creating and managing national parks, conservation reserves and other important natural areas across land and sea. The VNPA works with all levels of government, the scientific community and the general community to achieve long term, best practice environmental outcomes. The VNPA is also Victoria’s largest bushwalking club and provides a range of information, education and activity programs to encourage Victorians to get active for nature.

REEF WATCH Reef Watch is a Victorian National Parks Association program run in partnership with Museum Victoria. The Reef Watch program was launched in 2002 with the aims of increasing knowledge, awareness and protection of Victoria’s marine biodiversity. Marine citizen scientists are provided with monitoring kits to survey their favourite subtidal reefs, contributing both data and images to an online database and the Atlas of Living Australia. Other Reef Watch projects include ‘Feral or in Peril’, Buddy up with a Blue Devil and the popular annual Great Victorian Fish Count. PROJECT PARTNERS The Protecting Marine Habitat handbook is supported through funding from the Australian Government’s Caring for our Country. The project is also supported by funding from the Victorian Government’s A Cleaner Yarra River & Port Phillip Bay – A Plan of Action through the PPWCMA’s Community Grants Program. ABOUT THE AUTHORS The content for each of the habitats within the Protecting Marine Habitat handbook was researched and written by John Ford. John is an independent consultant at Mezo Research with a background in marine and fisheries ecology. John has spent the last six years at Melbourne University researching rocky reef fish in and around Port Phillip Bay. He has conducted almost 500 dives and become expert on the underwater world around Melbourne and the Victorian coastline. Reef Watch Coordinator Wendy Roberts contributed the text for the introduction, insets and what you can do. Images provided by Museum Victoria, Julian Finn, Mark Norman, John Gaskell, Chris Rowley, Rudie Kuiter, Tim Allen and Bill Boyle. Front cover image: Magpie Morwong and Seastar at Popes Eye, photo courtesy Andrew Newton. Back Cover image: Zoanthids at Beware Reef Marine Sanctuary, photo courtesy Julian Finn. ACKNOWLEDGEMENTS VNPA and the authors wish to thank Simon Branigan, John Sampson and Michael Howes for their assistance in the preparation of this report.

DISCLAIMER Information contained in this publication is provided as general advice only. Reef Watch and the VNPA has taken reasonable steps to ensure that the information contained in the guide is accurate at the time of publication. Readers should ensure that they make inquires to appropriate sources to obtain further up to date information. This publication has been printed on 100% post consumer recycled paper, using non toxic inks and solar power in production, preserving forests, water and environment by Black Rainbow - www.blackrainbow.com.au.

2 A Handbook for Victorian Waters Contents

Introduction ...... 5

Subtidal Rocky Reefs ...... 6

Soft Bottoms & Sandy Flats ...... 8

Seagrass Meadows ...... 12

Rocky Intertidal ...... 16

Mangroves & Saltmarsh ...... 18

A System Under Pressure ...... 20

What You Can Do ...... 22

3 PROTECTING MARINE HABITAT

Zebra Fish form schools in estuaries and coastal reefs. All photos on this page by John Gaskell

Six-spined Leatherjacket in algae. Juvenile Scalyfin shelters under a rocky reef.

4 A Handbook for Victorian Waters Looking after our unique marine life

ictorians are fortunate to live Von the ocean doorstep of an underwater world rich in species diversity. Cool temperate waters combined with a variety of habitats support a high percentage of endemic species not replicated in other areas in the world or in northern waters such as the Great Barrier Reef. From tiny seastars to majestic Humpback Whales, our waters are home to more than 12,000 known species, and more are being discovered each year. Seagrass meadows, rocky algal reefs, sponge gardens and mangrove forests are just some of the marine ecosystems that provide habitats for marine life. Needless to say, healthy and diverse habitats support a greater diversity of marine species, so if we want to protect marine biodiversity in Victoria we need to reduce the negative impacts on and threats to our marine habitats. Many of these threats are from catchment activities, such as pollution, land clearing, dredging, invasive marine species and Southern Calamari with feeding tentacles extended. Photo: Evan Coker overfishing. Others are from the global increase in greenhouse gases where you can find out more about your local reef, writing to local such as CO2, and we are now starting the different types of marine habitats, councillors about the impact of litter to see changes in the distribution some of the species that live there, or stormwater pollution, holding of marine species as a result of the threats to each habitat and how a beach clean-up day, and even increasing seawater temperatures. to minimise these threats. reducing your electricity bill! To help the long-term protection of There are many ways of being We can all ‘be part of the change’ marine life we need to work towards involved in protecting our unique to help our marine environment to minimising the threats to marine marine life. This guide outlines some remain diverse and healthy for future habitats. This guide is a starting point examples, such as photographing generations.

INTRODUCTION 5 PROTECTING MARINE HABITAT Subtidal Rocky Reefs Key features Little is known of the deepest areas of (Girella zebra), while small shoaling these canyons, but remote underwater plankivorous fish such as the Southern ocky reefs come in all shapes and vehicles have catalogued many Hulafish are eaten by resident Rsizes, from spectacular underwater species living at depth, most notably Southern Cuttlefish Sepia( apama) walls and bommies to more modest sponges and hydroids, which do not and visiting Australian Salmon (Arripis platforms or boulder fields. Their need light to survive. species) and Southern Calamari unifying feature is hard substrate – the (Sepioteuthis australis). A number of species are common rock itself – that gives so many plants and animals a surface on which to live. across almost all Victorian rocky reefs The small cracks and crevices in the and provide a very ‘Victorian’ feel. rock provide shelter for many animals The walls and bommies can support a These include: the Eleven-armed you may not see, such as Bullseyes dazzling array of colourful encrusting Seastar (Coscinasterias muricata), (Pempheris multiradiata), or even the invertebrates and algae, with the Common Sea-urchin (Heliocidaris elusive Rockling (Genypterus tigerinus) overhangs and caves homes for a erythrogramma ) and the Southern or dangerous Blue Ring Octopus great diversity of fish and crustaceans. Hulafish Trachinops( caudimaculatus). (Hapalochlaena maculosa). Rock platforms can be completely The food web in rocky reefs can covered by large brown algae, often be very complex and divers and the Common Kelp (Ecklonia radiata) snorkellers are often in a position to Distribution in exposed conditions, Bull Kelp watch predator-prey relationships (Durvillaea potatorum), Phyllospora unfolding before them. Subtidal Rocky Reefs can be found comosa and Macrocystis angustifolia in within Port Phillip Bay, Port Phillip Algae provide foods for territorial the surging surf zone, and Sargassum Heads, Williamstown, Barwon Heads, herbivorous fish such as the Scalyfin and Cystophora species in the more Mushroom Reef, Honeysuckle Reef, (Parma victoriae) and Herring Cale Crawfish Rock, Point Addis, Point sheltered bays and inlets. (Odax cyanomelas), mussels and Danger, Wilsons Promontory, Beware Victoria is also home to some deep barnacles eaten by more transient Reef, Point Hicks and Cape Howe, canyon reefs, most notably in Port bottom feeders such as Pink Snapper Merri Marine Sanctuary. Phillip Heads, but also in the drowned (Cyrsophrys auratus), Morwong river canyons off the coast. (Chielodactylus species) and Zebra Fish

Rocky reefs support important commercial fisheries such as Southern Rock Lobster. Photo: Julian Finn 6 A Handbook for Victorian Waters You little blue devil you

A fish with attitude is something to behold, but don’t be put off by the grumpy face of the Blue Devil. Their beautiful iridescent blue spots make them a favourite among photographers, but few would be aware that the often solitary fish lives Southern Blue Devil fish make rocky reefs their home for up to 60 years. Photo: John Gaskell in the same spot for up to 60 years. can help unravel some of the dredging, stormwater pollution and We now know that the distinctive mysteries about their population size, sediment input. spots on their gill cheeks enable them distribution and life history. So why Conservation efforts to monitor to be individually identified. not ‘buddy up with a Blue Devil’? and protect populations and the There’s still much to learn about Blue Devil homes can be affected habitats in which they live will benefit these fascinating fish and divers by catchment activities such as both Blue Devils and their neighbours.

Importance to us and movement of colour and light, of light. Dinoflagellate and blue-green resident fish and cuttlefish providing algal blooms can starve the water of the ecosystem personality and intrigue. oxygen and cause mass deaths of fish. Rocky reefs are biodiversity hotspots, In the face of these threats, rocky reef supporting an amazing array communities close to cities tend to of brown, red and green algae, Threats and have less species and fewer stands of encrusting invertebrates such as kelp beds. sponges, ascidians and bryozoans, vulnerabilities crustaceans and molluscs both large Rocky reefs are incredibly diverse and Invasive species are also a major 4, with species and small, and many, many fish productive communities, although threat to rocky reefs species. they are under threat from human such as the Japanese kelp Undaria disturbances3. pinnatifida, the fanworm Sabella In fact, rocky reefs support Victoria’s spallanzannii and the ascidian Ciona two highest value commercial In sheltered bays and inlets, pollution intestinalis outcompeting native in the form of stormwater, sewage fisheries – rock lobster and abalone – species in the more disturbed reefs of and agricultural runoff is changing our and are important nursery areas for Port Phillip. recreationally targeted fish such as reef communities. Sediment smothers Pink Snapper and Short-fin Pike1. juvenile macroalgae, preventing the Physical damage or removal of reefs formation of an algal canopy that by coastal development is a more Kelp and algal beds are extremely provides biological structure on a reef. direct threat, and the smothering of productive, almost on par with Turbid water reduces light reaching reefs by dredging spoil is anecdotally seagrass beds, and are valued algae, stunting their growth and reported in many areas of the bay extremely highly for their ecosystem making them less resilient to in past decades. While these latter services and nutrient cycling2. disturbances. Excess nutrients in threats could be considered to be Rocky reefs are also a source runoff promote the growth of faster no-brainers and easily avoided, of wonder for scuba divers and growing algae such as ulva, which can history has told us this is not always snorkellers, each reef with its unique smother other algae and starve them the case.

1. Department Primary Industries 2008. Fisheries Status Report 2008. State Government of Victoria. 2. Constanza et al. 1997. The value of the world’s ecosystem services and capital. Nature 387 pp. 253-260 3. Edmunds et al. 2010. VNPA Nature Conservation Review: Marine Conservation Issues and Priorities for Victoria. Report to Victorian National Parks Association. 4. Hutchinson et al. 2010. Seagrass and Reef program for Port Phillip Bay: Temperate Reefs Literature Review. Fisheries Victoria Technical Report No. 11, 61 pages. Department of Primary Industries, Victoria, Australia. SUBTIDAL ROCKY REEFS 7 PROTECTING MARINE HABITAT Soft Bottoms & Sandy Flats Key features considered nondescript or unexciting, Cystophora, Sargassum or the vivid but soft sediments hide many secrets green Caulerpa. oft sediment bottoms are formed below their surface. by the accumulation of fine Occasionally large areas of drift algae Sparticles of sand, mud and silt. The Underneath the top layer of sand or form over soft sediments1, lasting most dominant marine habitat type mud are complex warrens of worm- weeks (such as filamentous algae on in Victoria, they include the high- holes, clam caves and burrows for mudflats in Corner Inlet) or entire energy sandy beaches with surging small crustaceans. seasons (red algal mats in northern surf zones, the flat tranquil mudflats Port Phillip during summer). of Westernport, and the giant mud Camouflaged under a thin layer of sand, flathead wait for unsuspecting basin that comprises the majority of Port Phillip. prey, flounder hide from predators above, and rays shuffle slowly Distribution While we may not spend much time around, looking for buried food. diving or snorkelling over them, soft Soft sediments and sand flats are sediment bottoms are an extremely Old scallop, mussel and oyster shells common in sheltered bays, estuaries important ecosystem due to their form small anchor points for a variety and inlets. As well as some large size and diversity. They are often of invertebrates such as ascidians areas of open coast such as Ninety overlooked as habitats of interest, or occasionally macroalgae like Mile Beach.

Our vanishing sea forests

We’re used to hearing about rainforests disappearing in tropical regions, but few people would know that towering algal forests are also vanishing in our own southern waters. Home to myriads of marine creatures, these 30m high algal communities Giant Kelp at Popes Eye. Photo Mark Norman are declining at an alarming rate (Tasmania has only 5% of original kelp reasons for the decline are rises in sea fish, and competition for habitat by forests remaining). surface temperatures, an increase in the invasive Japanese kelp, Undaria The Australian Government recently foraging herbivores such as the sea pinnatifida. listed them as a protected community urchin Centrostephanus rodgersii as a under the EPBC Act. Among the result of the decline of large predator

8 A Handbook for Victorian Waters Longsnout Flounder is the most common flounder in Port Phillip Bay. Photo: Julian Finn

Importance to us and the ecosystem The most important aspect of soft sediment environments is what we can’t see with the naked eye – the microscopic layer of bacteria that grow on the surface of the sand and mud. These bacteria are responsible for locking up much of the nutrients that enter the marine environment, and without them we would expect more harmful algal blooms and dead zones devoid of oxygen and life. In Port Phillip Bay these bacteria are especially crucial to the cycling of excess nutrients entering the bay through sewage and stormwater2.

The mussels, oysters, scallops, clams, fanworms and ascidians living in the sediments are also incredibly important in keeping our water clean and healthy. They are all filter-feeders, meaning that they filter out the larger food particles from the water.

This combination of bacteria and An introduced fanworm, Sabella spallanzanii, invades the space of a smaller, more colourful filter feeders forms the lungs of our native fanworm (Sabellastarte australiensis). Photo: John Gaskell SOFT BOTTOMS & SANDY FLATS 9 PROTECTING MARINE HABITAT

A swimmer crab scuttles along the sandy seafloor. Photo: Julian Finn bays and inlets, so don’t forget about them! Soft sediments are also a very productive feeding ground for many of our iconic marine species and some of our more valuable commercial finfish. Stingrays, from the small Banjo Ray to the massive Eagle Ray, all feed on the molluscs and worms found just below the surface. Gummy Sharks cruise for a feed, along with big Snapper aggregating to breed.

Threats and vulnerabilities As they are so large and varied, An ambush predator, the Stargazer waits beneath the sand. Photo: Julian Finn soft sediment environments tend to be very resilient, although they mussels and oysters, and an excess of and widespread in Port Phillip that are often at danger from localised nutrients from sewage and runoff. there is little that can be done to threats. In Port Phillip Bay and other inlets, the greatest threats are those The Northern Pacific SeastarAsterias eradicate it. However, preventing its from invasive species, the decline amurensis is possibly the greatest spread to other bays and inlets is an of native filter feeders, in particular threat, although now it is so abundant extremely high priority. 10 A Handbook for Victorian Waters Southern Sand Flathead populations in Port Phillip have declined by 90% since 2000. Rudie Kuiter Flat out trying to survive

Southern Sand Flatheads were once a Possible impacts are thought Divers are more likely to see common catch for recreational fishers, to be from both recreational and females as they are found in shallow but since the year 2000 scientists commercial fishing, as well as waters – juveniles and males live in have been concerned about their environmental changes in river deeper waters (over 17m) in the Bay. continued decline to around 10% of discharge and long-term climate the original population. fluctuations.

The fanworm Sabella spallanzanii keep Port Phillip Bay clean. it can handle. This can encourage has outcompeted native species on more harmful anaerobic bacteria, The deeper fine sediment basins muddy bottoms and on rocky reefs, receive very little disturbance from which do not require oxygen, to decreasing biodiversity and changing waves or currents, making them flourish, and can create dead zones where other organisms cannot live. ecosystem function. Introduced particularly vulnerable to dredging ascidians such as Styela and Ascidiella operations. aspersa have colonised deeper areas, although these environments are Low numbers of mussels, oysters and scallops in Port Phillip are also seldom visited and we may never of concern, and with fewer shellfish know their real impacts. it follows that there will be a lack of The loss of biodiversity in soft old shells to provide habitat for other sediment environments, whether organisms, or even their own young. from competition with invasive Lastly, the stability of the important species or historical depletion bacterial communities is fragile and through dredging, reduces the we must be careful not to overload capacity to cycle nutrients and the system with more nutrients than

1. Chidgey and Edmunds 1997. Standing crop and nutrient content of macrophytes in Port Phillip Bay, Victo- ria. Port Phillip Bay Enviromental Study Technical Report No. 32 2. Commonwealth Scientific Industrial Research Organisation 1997. Port Phillip Bay Environmental Study 1992-1996. Melbourne Water and State Government of Victoria. 3. Department of Sustainability and Environment 2004. Aquatic pests: treat em’ mean, keep you boat clean. Educational pamphlet. State Government of Victoria. http://www.dse.vic.gov.au/__data/assets/ pdf_file/0008/97091/Aquatic_Pests._Treat_em_mean_keep_your_boat_clean_.pdf

SOFT BOTTOMS & SANDY FLATS 11 PROTECTING MARINE HABITAT Seagrass Meadows

Central Coast: Port Phillip Bay, Swan Key features Bay, Mud Island, Corio Bay, Flinders eagrasses are the true flowering Pier in Westernport Bay, Newhaven Splants of the sea, forming large on Phillip Island, off Williamstown green meadows from the intertidal Beach, Port Phillip Bay. Kirk Point, to depths of about 10m. They grow Point Wilson, Point Cooke, Jawbone on mud and sand by anchoring Marine Sanctuary. themselves with roots, unlike most of East Coast: Corner Inlet. our familiar algae that require a hard surface to attach their holdfast. We are most familiar with the shallow seagrasses in our bays and inlets that Importance to us and may be fully or partially exposed at the ecosystem low tide. Seagrass meadows serve a number These seagrasses are of the Zostera of very important ecological roles and Heterozostera genus and are in our marine environment, and are often referred to as fineleaf seagrass considered the second most valuable or eelgrass, and in slightly deeper habitat on earth for ecosystem areas we may see Paddleweed services1, worth a total of $1.9 trillion (Halophila sp.). These seagrasses are globally2. quick growers and can colonise new Firstly, they provide important areas very quickly from broken-off structure and shelter for a broad fragments that drift to new locations. range of other animals and plants, However, they are also known for particularly in shallow sandy their natural widespread diebacks, environments. They are important evidenced by the large amount of nursery grounds for juvenile fish and seagrass that washes up on beaches crustaceans, most notable whiting in places like Port Phillip. In more and bream, by providing refuge from exposed areas such as the south of larger predators and strong tidal Port Phillip and the open coast, we currents. find the very differentAmphibolis Secondly, seagrasses are primary australis, which more closely producers, just like grasses on land, estimated 10-18% of the total carbon resembles leafy plants from land. and are important food sources burial of the oceans5. Broadleaf Seagrass or Strapweed for creatures such as Garfish and (Posidonia australis) is found in only swimmer crabs. Seagrass systems are one place in Victoria – on the shallow extremely productive, in some cases Threats and sand banks of Corner Inlet. It has a rivalling or exceeding productivity of deep root structure and, much like a terrestrial farming3. vulnerabilities daffodil bulb, grows strongly through Thirdly, the root structure of Seagrasses are one of the most spring and summer before dying seagrass holds together sand banks, threatened ecosystems on earth, back to stubble in winter. preventing erosion and reducing declining at a rate of 110km2 a year water turbidity. and with an estimated 29% of total cover lost since 18792. Lastly, seagrass meadows are a Distribution massive carbon sink, with carbon Locally, Westernport lost around 70% West Coast: Portland Bay, Port uptake rates on average higher than of its seagrass during the 1970s and Campbell Bay, Peterborough terrestrial systems4. They represent an declines have been observed in areas 12 A Handbook for Victorian Waters A Spotted Pipefish hides in seagrass, St Leonards. Photo: Julian Finn

of Port Phillip and Corner Inlet over the past few decades.

Seagrasses naturally experience growth and decline associated with changing environmental conditions including drought and flood cycles, algal blooms and long-term climatic change. However, human activities have increased the severity of many natural environmental cycles and seagrass has suffered as a result. The increase in nutrients and sediment in coastal waterways from human alteration of catchments is the most common and significant cause What’s not to love? A heart-shaped sponge at Flinders. Photo: John Gaskell SEAGRASS MEADOWS 13 PROTECTING MARINE HABITAT

Seadragon heaven

A highlight for any diver, Victoria’s marine faunal emblem the Common Seadragon can be found searching for mysid shrimps and other small crustaceans in seagrass meadows and kelp forests along the coast. In late spring, males brood up to 300 bright pink eggs along their tail. Living for 6 to 10 years, seadragons are known to live within a home range, so any threats to their habitat have an impact on local populations in the area. Threats to seadragons are both Paddleweed can colonise new areas quickly, offering habitat to a myriad of marine creatures. natural and human-induced. As Photo: Mark Norman they are weak swimmers, they are often washed up in flotsam by storms. However, pollution, seagrass loss and collection for of seagrass decline3. dredging activities can either destroy aquariums are thought to be the seagrasses directly or increase main threats. Turbid water starves seagrass of turbidity and starve them of light. light and buries small plants. Excess Seadragons can be seen at Flinders, Portsea, Rye, Queenscliff, nutrients cause algal blooms over These are all real and current threats Point Addis, Warrnambool, seagrass meadows, reducing light to seagrass systems in Victoria, and Portland Wilsons Promontory and and oxygen in the water. more needs to be done to ensure we do not lose such an important Gippsland. Development of the coastline can ecosystem. directly destroy seagrass through the building of seawalls or piers, and

1. Constanza et al. 1997. The value of the world’s ecosystem services and capital. Nature 387 pp. 253-260 2. Waycott, M., et al. (2009), Accelerating loss of seagrasses across the globe threatens coastal ecosystems, Proc. Natl. Acad. of Sci. U. S. A., 106,12,377–12,381 3. Orth et al 2006. A Global Crisis for our Seagrass Systems. BioScience 56:12 pp. 987-996 4. Pidgeon, E. (2009), Carbon sequestration by coastal marine habitats: Missing sinks, in The Management of Natural Coastal Carbon Sinks, edited by D. d’A Laffoley and G. Grimsditch, pp. 47–51, IUCN, Gland, Switzerland. 5. Kennedy et al 2010. Seagrass sediments as a global carbon sink: Isotopic constraints. Global Biogeochemical Cycles 24:4 14 A Handbook for Victorian Waters A male Common Seadragon with eggs. Flinders. Photo: John Gaskell

SEAGRASS MEADOWS 15 PROTECTING MARINE HABITAT Rocky Intertidal Key features ocky intertidal areas are probably Rthe most familiar and well-loved of Victoria’s marine habitats. We have all at one stage fossicked through the tidepools, overturned rocks looking for crabs and tried to catch those little fish that were always a little too quick. These rocky shores support an amazingly hardy community of animals and plants in what is an extreme environment – pounding waves, flooded at high tide and exposed to the hot sun in low tide1. All the plants and animals are adapted to hold on fast and not dry out in the heat, and have some creative ways of doing so. The familiar limpet (Cellana tramoserica) holds on to the rocky surface using the strength of its muscular foot, totally sealing itself away to stop any water loss in the heat. A Waratah Anemone clings to a rocky intertidal reef. Photo: Chris Rowley

Shore Crabs (Paragrapsus quadridentatus) wedge themselves Distribution vast areas clear of seaweed, much as in out-of-the-way cracks, while the a grounds keeper maintains a well- This habitat occurs mainly on rocky manicured golf green. alga Neptune’s Necklace (Hormosira headlands from Portland to Wilsons banksii ) holds water in its bead- Promontory, with some minor Larger animals such as fish enter the like structure and grows clumped occurrences in the far east. rocky intertidal shore during high together to hold moisture – the tide to feed and shelter from larger perfect refuge for many smaller predators. Being warm and full of creatures. Importance to us and sunlight, rockpools are incredibly Commonly encountered critters productive areas, making them include marine snails (Austrocochlea the ecosystem important nursery areas for many fish sp., Bembicium species. sp.), and if you’re Rocky intertidal shores are very lucky there may also be a Waratah important to us on an individual level, The diversity and complexity of Anemone (Actinia tenebrosa), which as they may be the only window into the rocky intertidal community looks like a red jewel tucked into the the marine world many of us see2. is breathtaking – barnacles and cracks and walls of rockpools. cunjevoi filter food from the water, In the broader marine environment, Despite appearing docile and crabs and scavenging snails eat species on the rocky intertidal are an resembling a plant, anemones are detritus and microscopic algae on important part of the food web for predators and fire stinging barbs into the rocks, tiny Red Handed Shrimp deeper subtidal reefs and open water break down waste in shallow rock prey, paralysing them and making communities. them easy to eat. Luckily for us our pools, predatory snails drill holes skin is thick and to us they simply feel The grazers of the rocky shore – in other snails and mussels to get a a little sticky! limpets and herbivorous snails – keep feed, and millions of tiny crustaceans 16 A Handbook for Victorian Waters Red handed Shrimps are common in rocky intertidal pools. Photo: Julian Finn resembling tiny prawns (amphipods) intertidal rocky shores1,4,5. Even away feeding shorebirds like oyster keep the seaweed clean by eating turning over rocks can lead to the catchers7. the smaller algae that threaten to death of sensitive animals that have overgrow it. Pollution from nearby stormwater can found a spot to stay comfortable in increase nutrient loads, promoting during low tide – staying moist and Rocky intertidal shores can also be out of the heat is a matter of life and filamentous algal growth, killing important haul-out areas for seals to off local seaweed and reducing death for residents of a rocky shore. relax, and are feeding areas for many biodiversity. seabirds. Poking, dislodging or damaging intertidal plants and animals can Not many marine pests have

make them lose moisture and lead to conquered our rocky intertidal shores, although the European Shore drying out of many sensitive animals, Threats and Crab (Carcinus maenas) is thought including lace corals and seasquirts. to have invaded over 100 years ago vulnerabilities People and animals walking across and can often be found under rocks, Human disturbance such as intertidal reefs can also trample algae especially in Port Phillip Bay. collection, fossicking, trampling, such as Neptune’s Necklace or crush and littering can be problems for the shells of small snails6, and scare

1. Edgar, G. J. 2001. Australian Marine Habitats in Temperate Waters, Frenchs Forest, NSW, Reed New Holland. 2. Addison, P. F. E., Koss, R. S. & O’Hara, T. D. 2008. Recreational use of a rocky intertidal reef in Victoria: implications for ecological research and management. Australian Journal of Environmental Management, 15, 169-179. 3. Underwood, A. J. & Chapman, M. G. (Eds.) Coastal marine ecology of temperate Australia. Sydney, Australia, UNSW Press. 4. Costa, T. L. (2008) Detecting Anthropogenic Disturbance in the Rocky Intertidal: A Study of Rocky Shores in Victoria. PhD Thesis, Zoology. Melbourne, The University of Melbourne. 5. Keough, M. J., Quinn, G. P. & King, A. (1993) Correlations between human collecting and intertidal mollusc populations on rocky shores. Conservation Biology, 7, 378-390. 6. Povey, A. & Keough, M. J. (1991) Effects of trampling on plant and animal populations on rocky shores. Oikos, 61, 355-368. 7. Pocklington JB, Carey JM, Murshed MDT and Howe SAJ. 2012. Conceptual Models for Victorian Ecosystems: Marine & Estuarine Ecosystems. Parks Victoria Technical Series. ROCKY INTERTIDAL 17 PROTECTING MARINE HABITAT Mangroves & Saltmarsh Key features angroves and saltmarshes are Mboth intertidal habitats occurring on the fringes of bays and inlets, exposed at low tide and inundated at high tide. They are often found side-by-side – mangroves on the lower edge of the coast closest to the water, saltmarsh immediately adjacent before the line of trees or scrub, often paperbark (Melaleuca spp.)1. Saltmarshes do not require mangroves however, and can also exist on the Mangroves during high tide, Westernport. Photo: Bill Boyle edge of tidal rivers, behind sandy shorelines or rocky fringes. crusts. Indeed, this forms the basis for communities between land and sea. salt farming that occurs in areas along Mangroves are highly salt tolerant Not only do they prevent erosion of trees that form dense groves on the Geelong coastline. shorelines, but mangrove roots slow muddy flats in locations such as There are hundreds of both native and water flow, allowing sediment in the northern Port Phillip, Westernport introduced species recorded as living water to drop out and improve water and Corner Inlet. Victoria is home to in saltmarsh, with Shrubby Glasswort clarity. 5177ha of mangroves1, including the (Tecticornia arbuscula) and Beaded Saltmarshes provide a similar service, southern-most limit of mangroves Glasswort (Sarcocornia quinqueflora) where sediment is deposited with worldwide. In Victoria we have only being most prominent. Victoria has each high tide. Both ecosystems are one species, the White Mangrove 19,212 ha of saltmarsh spread along (Avicennia marina highly efficient and effective filtering ). Unlike the the entire coastline, but saltmarsh is tropical mangrove forests of Asia systems and by maintaining good particularly prevalent in western Port water quality, are crucial for the health that can grow up to 10m high, White Phillip, Westernport and the Gippsland of light-dependent ecosystems such Mangroves in Victoria usually grow to coast. less than 4m due to our cold winters2. as seagrass meadows and kelp beds. Mangroves and saltmarsh plants Mangroves are characterised by their breathing aerial roots, called provide food for a great array of pneumataphores, which appear as Distribution organisms – worms, molluscs and crustaceans living in the sediment, as small, round-ended sticks emerging Mangroves and saltmarsh can be from the mud. Oxygen levels in the found at Williamstown, Corio Bay, well as fish that feed there during high mud are often very low and hence Barwon Heads, Westernport, French tides. Juveniles of mullet, flathead, the mangrove will breath instead Island, Inverloch, Corner Inlet, whiting, bream and flounder all directly from the air through its Nooramunga Marine and Coastal use these communities as nursery pneumatophores. Park, South Gippsland and Lakes areas, and adults are often found Entrance. there feeding. Birds and bats use Saltmarsh consists of a range of small these intertidal areas as roosting salt-tolerant shrubs, grasses and and feeding grounds, with birds like succulents. They often appear to be the Little Pied Cormorant roosting very swampy environments, but can Importance to us and in mangrove trees, and White-faced be quite dry on the upper edges, the ecosystem Herons feeding in saltmarshes at low which may only be inundated on very tide. high tides. Small pools may form and Mangrove and saltmarsh are through evaporation may form salt extremely productive buffer 18 A Handbook for Victorian Waters Westernport mangroves and saltmarsh. Photo: Tim Allen

Threats and (particularly along the Gippsland and outside of the system. coast) and erecting seawalls or weirs to prevent tidal movement. The grazing of cattle strips saltmarsh vulnerabilities plants and mangrove leaves, and also There were also many areas where Mangroves and saltmarshes suffer compacts the soil, destroying delicate mangroves were directly removed from a poor public perception, often for development in places like root structures and the many animals considered as nuisance mud holes or Westernport, and for salt and living in the mud. This is equally a smelly swamps. While this opinion is sewerage pond development in concern for human foot traffic and certainly changing, mangroves are western Port Phillip. off-road vehicle use. still under threat, and are often seen as being in the way of expensive Although draining of saltmarsh and Water pollution, especially oil spills, coastal development opportunities clearing of mangroves occurs much are a widespread threat, and even by occupying the premier foreshore less frequently today, there are still too much freshwater can kill off location. many threats to these communities. mangroves.

It is estimated that up to 20% of Mangroves are still under threat from Invasive species such as spartina Victoria’s coastal marsh and wetlands residential coastal development and grasses can dominate coastal marshes, have been lost since the arrival of from residents clearing them to create reducing biodiversity and trapping European settlers3. Regionally the views. excessive amounts of sediment. loss is quite variable, with areas such Saltmarshes are under threat from Lastly, mangroves and saltmarshes will as Port Phillip losing 50% (mainly reclamation by industrial or parkland be highly susceptible to any changes saltmarsh), Koo Wee Rup Swamp developments, and are often the sites in sea level associated with a warming losing 40% (saltmarsh), Anderson of illegal rubbish dumping due to climate. As intertidal communities, Inlet losing 60% (both saltmarsh and their perception as being ‘wasteland’. they will need to migrate to higher mangrove) and Corner Inlet losing Exposure of acidic soils during areas when sea levels rise. Although 55% (mainly saltmarsh). reclamation and development can in many cases this migration will be Most of these declines are a result of also have wide reaching toxic effects blocked by farmland, seawalls and draining wetland areas for farmland on plants and animals both within other barriers.

1. Harty et al 2011. Mangroves of Victoria Information Kit. Seasearch and Parks Victoria. 2. Boon et al 2011. Mangroves and Coastal Saltmarsh of Victoria: distribution, conditions and threats. Institute for Sustainability and Innovation, Victoria University. 3. Sinclair and Boon 2012. Changes in the area of coastal marsh in Victoria since the mid 19th century. Cunninghamia 12:2 pp.153-176.

MANGROVES & SALTMARSH 19 PROTECTING MARINE HABITAT A System Under Pressure

of their largely unaltered state, but existing community, whether rocky 1. Nutrients and we can’t be complacent – other bays reef, seagrass or the soft sediment sediments from land and inlets are easy targets for future community of worms, clams, mussels spreads. Although often not obvious, excess and scallops. Surface dredging for sediment and nutrients flowing into commercial fishing is a lower impact our marine environments represent but often more frequent disturbance, the major threat to Victoria’s 3. Coastal foreshore shifting communities in favour of marine habitats. Sediment smothers organisms that prefer finer sediments, plants and animals and reduces development more disturbance and often lower light levels. the available light to algae and The removal or destruction of habitat seagrasses. Nutrients promote the for development is the most basic growth of filamentous algae that and direct threat to our marine smother and shade, and also of toxic habitats. 5. Trampling by dinoflagellate and blue-green algal blooms, and give the edge to some Development around our foreshores humans, animals and invasive species that outcompete is still a reality, particularly in less vehicles natives. well regarded habitats such as saltmarsh and mangrove. We are only Trampling is probably the most The threat is greatest close to the now realising the cost of historical overlooked of all threats, often coast and near rivers, streams and reclamation of saltmarsh for building because we feel that the impact stormwater with human habitation development or farmland, as the of a single person or animal is or intensive farming. Our coastal marine system loses an important insignificant. However, the cumulative bays and inlets, and especially the water quality filter and nursery impacts of thousands of people ‘big four’ – Port Phillip, Westernport, habitat. trampling on a rocky platform Corner Inlet and Gippsland Lakes during summer, or cattle grazing in – are all significantly threatened by Rocky reefs and seagrass are still saltmarsh every week, can be quite nutrient and sediment runoff. under threat from marina, breakwall and jetty developments proposed in destructive. Plants and animals are the coastal zone and often located physically crushed by the weight, for human convenience rather than broken off or inundated if the ground 2. Invasive species environmental sensitivity. is compacted underneath them. Most of Victoria’s marine habitats Unfortunately degradation through are lucky to have experienced very trampling can create a downward few introductions of invasive or pest spiral where the more trampling species. Port Phillip, on the other 4. Dredging damage there is in a habitat, the hand, is one of the most invaded Dredging significantly disturbs lower it is valued and the more our marine systems in the world. Many marine habitats, whether it’s for concern over trampling is reduced. channel and port deepening or native species have been out- This is very apparent in saltmarsh competed for space, light or food, for fishing activities. Large-scale systems, which in any case are often and are associated with lower dredging releases plumes of considered wasteland and used for biodiversity. sediment that can settle on habitats, smothering plants and animals and rubbish dumping and off-roading. Invasive species often thrive because reducing light for algae and seagrass. they are better adapted to the environment than native species, and The immediate effects of dredging this has generally occurred due to are catastrophic for anything living 6. Climate change the degradation of the natural state in the material – it is unlikely that It is very difficult to predict the to one that better suits invasives. anything dredged up and moved will effects of climate change on our Open coast marine habitats are survive the battering. The dumping marine communities, but they are therefore at much lower risk because of dredge material smothers the likely to be widespread and serious. 20 A Handbook for Victorian Waters An invasive Northern Pacific Seastar attacks a Rough Rock Crab. Photo: Julian Finn

Major threats Mangroves & Saltmarsh Rocky Reefs Seagrass Soft Sediments Rocky Intertidal Nutrients and sediments from land r r r r Invasive species r r r Coastal foreshore development r r r Dredging r r r Trampling (humans, animals and vehicles) r r Climate change r r r r r

Like ecosystems on land, marine inputs to coastal waters, although in ecosystems will need to migrate to some cases drought conditions may more suitable climates and conditions be beneficial to marine habitats. as temperatures and sea levels rise. However, with intertidal communities Associated ocean acidification is like saltmarsh and mangroves there likely to affect many shell-forming organisms such as molluscs and may be barriers to their migration shorewards such as seawalls, or even crustaceans, potentially significantly affecting soft sediment communities, a road or cafe! intertidal rocky shores, and the Seagrasses may be affected by higher productivity of open water diatoms, water temperatures and greater an important food source at the exposure to the sun, and will also bottom of the food chain. need to migrate to appropriate depths. Changing rainfall patterns may affect the sediment and nutrient A SYSTEM UNDER PRESSURE 21 PROTECTING MARINE HABITAT What You Can Do

he diver on the opposite page a part in decreasing greenhouse gas three projects with more to come. Twas photographed while taking production and the harmful impacts You can even start your own! part in the Great Victorian Fish Count. associated with climate change. There are countless ways you can be Along with her dive buddies, she If you love being out on top of the actively involved in protecting our volunteered to survey 25 selected water, then there is a lot you can do marine life. fish species in what has become an to limit the spread of invasive species. annual census of Victoria’s temperate Join a local Friends group of a marine reef fish. Following the Department of protected area or take part in a Environment and Primary Industries’ Through her efforts she has clean-up day at your local beach. easy steps when washing your boat contributed to building our and gear, removing all animal and Share your underwater discoveries understanding of the types and plant matter from the anchor and with others, such as at your child’s numbers of species to be found desposing of it safely. This will reduce school, or write an article for your at different reef sites each year. the chances of you translocating a local newspaper. This is just one of the many ways marine pest to another area or bay. the community can contribute If you are really concerned about to increasing our knowledge and Check out the Reef Watch ‘Feral or an issue that is affecting a habitat, awareness of Victoria’s marine in Peril’ program to learn how to species or your local reef, then write species and habitats. identify marine pests that have made a letter to your local councillor or Port Phillip Bay home. Oh, and with politician. Let them know you think Out of the water there are other that boat anchor, be sure not to it’s important to protect Victoria’s ways you can be ‘part of the change’ drag it over reefs or through fragile marine life. to protect our marine habitats and seagrass meadows! species, you don’t even have to leave The VNPA is leading the way in home. If your hobby is photography, then making sure there is a healthy marine why not add your images of the environment for future generations, Just by being mindful of stopping species you see on your dives to a the soapy suds from your car both through the Reef Watch national database that can be used wash making it into our drainage program and our marine and coastal by everyone, including scientists and system, or fertilisers from your campaign work. To find out more, marine and coastal managers. Yes, garden reaching stormwater drains get involved, become a member or you too can be a citizen scientist just you are playing an important part donate, visit www.vnpa.org.au. by uploading an image with a date in decreasing the nutrients and and a location to Bowerbird pollutants reaching our reefs. (www.bowerbird.org.au), the social Right: A diver takes part in the Great Leaving your car at home or trying to science website of the Atlas of Living Victorian Fish Count. reduce your energy use will also play Australia. Reef Watch has started Photo: courtesy Jane Bowman

22 A Handbook for Victorian Waters 23