Chapter 3.3 — of southeastern Australia • 276

3.3 Seagrasses of southeastern Australia

Robert J. Williams1, P. R. Scanes2 and James Udy3 1Senior Research Scientist (retired), NSW Department of Primary Industries (Fisheries), Australia 2Senior Team Leader Estuaries and Catchment Science, NSW Office of Environment and Heritage, Australia 3Chief Scientist, Healthy Waterways, Australia

Abstract The southeast portion of Australia has a high energy coastline that generally prohibits growth of seagrasses except in sheltered bays and estuaries. is also the most densely populated portion of the country, meaning that seagrasses are subject to pressures from agriculture, industry, and urban activities. Yet the maintenance of healthy meadows is critical to the economy of these regions as it forms a critical link in the food chain of many recreational and commercial fish species as well as providing other functions. In order to generate a better understanding of these pressures and derive appropriate economic and environmental outcomes, an understanding of the biology of seagrasses and their value to the community is critical. This chapter presents an overview of the seagrass habitats of SE Australia as well as the differing management approaches in Queensland, and . It also provides an overview of the role of community monitoring projects in providing important information for management of these critical habitats. Chapter 3.3 — Seagrasses of southeastern Australia • 277

Introduction of the ever growing population pressure to use the locations in which seagrasses live – the shallow The body of knowledge about seagrasses in inshore waters of bays, lagoons and estuaries. Australia, and at the global scale is extensive (see texts in the supplementary reading list). Recent The objectives of this chapter are to provide: output from a National Working Group (see ACEAS • an introduction to seagrass biology and its (Australian Centre for Ecological Analysis and implications for conservation management; Synthesis)) has differentiated three main Australian bio-regions for seagrass: Tropical and Sub-tropical • a simple comparison of the basis for Northern Australia, Temperate SE Australia, management between three principal Temperate SW Australia. This chapter focuses management authorities along the southeast on the seagrasses of the temperate southeast sector of the mainland (southern Queensland, Australian coast, defined somewhat arbitrarily New South Wales, eastern Victoria); and based on the north-south orientation of the coast • a differentiation of the types of community as stretching from the Noosa River (Queensland) monitoring that has been and might be to Corner Inlet in Victoria. The extensive meadows initiated to assist in determining the well being of seagrass in the Great Barrier Reef and those of of beds of seagrass in southeast Australia. Western Port, Port Philip Bay and western Victoria deserve mention at another time. Relative to the There are many species of seagrass, most of which entire Australian coastline this represents less have a specific shape, distribution and behaviour, than 10% of the coastline, but with more than and so it is more apt in scientific and management 80% of Australia’s population. The distribution terms to refer to “seagrasses” rather than seagrass. of seagrasses in the south-east also differs from This is particularly so in the management sense other parts of the continent, being confined with as there is a need to understand better their estuaries and bays rather than forming extensive individual conservation needs. (The same situation offshore meadows as occurs in southern and also prevails with “mangroves”, Chapter 3.4; and . Each of the states within the “saltmarsh”, Chapter 3.5). southeast sector recognises the value of seagrass At the global scale there is considerable concern (e.g. Queensland: AquaBAMM, Clayton et al. about the present management of seagrasses 2006) and various initiatives are in place to assess and their long term fate (Orth et al. 2006; Global seagrass condition for protection and planning Seagrass Trajectories Working Group 2009). Within purposes (e.g. Queensland: seagrass depth range Australia there is a recent effort to identify and monitoring in ). Further, there are synthesise current knowledge and threats to state-wide reviews based on extensive local seagrasses to support management actions aimed literature (e.g. Victoria: Warry and Hindell 2009). at maintaining healthy meadows. This Seagrass Although the importance of seagrass in protecting Working Group (online), supported by ACEAS, has community values for estuaries and coastal regions initiated two review papers. The first explores the was poorly understood in the past, the role seagrass different spatial and temporal scales at which plays in supporting coastal fisheries and reducing anthropogenic and natural processes impact on coastal erosion is becoming more understood seagrasses and will provide managers with an and appreciated by the wider community. This understanding of the most appropriate monitoring increased awareness has been assisted by many approaches to assess seagrass condition. The different approaches. One that has assisted greatly second paper will update a previous assessment of is the involvement of community associations, the distribution of seagrass around the Australian such as Coastcare and other local groups that have Coast (Mount and Bricher 2008), provide conceptual become actively involved in the monitoring of understanding of the major processes important for these habitats and the role of seagrasses in coastal maintaining seagrass habitats in the different bio- ecology. Community awareness continues to grow regions of Australia and provide a risk assessment as a result of research efforts to understand better framework for the sustainability of seagrass along the biology of seagrasses and the translation of the Australian coast. those outputs into protective legislation, policy and guidelines. This chapter provides an overview of the management of seagrasses in the southeast “Seagrasses” are a diverse group of aquatic sector of Australia. This sector is instructive because that evolved from terrestrial counterparts millions of years ago to inhabit shallow coastal Chapter 3.3 — Seagrasses of southeastern Australia • 278

and estuarine waters across the globe. All species region, from Noosa to the Qld/NSW border of seagrass are flowering plants (angiosperms). is a transition zone that includes both tropical They are not grasses in the true sense of the word and temperate species. However, in NSW and but are distantly related to lilies and gingers. Victoria the seagrass meadows are dominated Seagrasses have leaves and rhizomes – a type of by temperate species. Progressively more robust root that anchors the plants in sand or mud. sophisticated techniques in anatomy, biochemistry Fine roots, with hairs, emerge from the rhizomes and genetics have in recent times distinguished providing structural stability and providing for between similar looking species within these the uptake of nutrients. The leaves contain the families, but studies are underway to reduce chlorophyll necessary for the photosynthetic uncertainty, for example, with regard to the process, which uses light to turn carbon dioxide distribution of species in the and water into the complex molecules of growth. (Sainty et al. 2012, p. 127, p. 129, p. 131). Even though the flowers produce seeds, the main The five families contain at least 12 species with mechanism by which most species of seagrass different distributions (Table 3.3.1). sustain and expand themselves is through their australis is the sole species within the family rhizomes. There are many reviews of the complex Posidoniaceae to be found along the southeast anatomical and physiological features of seagrasses coast (Other species within this genus occur along (e.g. Vermaat 2009). the southern and western coasts of Australia.). There are nearly 70 species of seagrass worldwide, Three species are within the family : with some having restricted distributions but Zostera capricorni, Zostera muelleri and Zostera others occurring globally. Some species are found nigricaulis. The Hydrocharitaceae family includes in nearshore oceanic waters (bays and coastal Halophila australis, Halophila decipiens and lagoons) whereas others grow in estuaries, within Halophila ovalis. Within the are habitats ranging from near marine channels to tridentata and Halodule univerus. brackish upstream locations. Three species belong to the Family Ruppiaceae: Seagrasses should not be confused with maritima, Ruppia megacarpa and Ruppia macroalgae or “seaweeds” which are simple polycarpa. These are usually found in the upper plants with no root system or flowers. (The portions of estuaries where salinity is low. The excellent photos provided by Sainty et al. (2012) plants in this family have a distinctly different life readily distinguish seagrasses from macroalgae; history from other seagrasses – they have emergent other estuarine plants are also identified in this flowers that are pollinated in the air. For other valuable text.) seagrass species this reproductive function takes place under water. All seagrasses fall within the Order , a large group of approximately 4,500 species with Some seagrasses, such as Posidonia australis, an aquatic lifestyle, either living underwater or in the Halodule and Halophila species are found marsh habitats. Of the nearly 70 species of seagrass exclusively in sheltered bays and near the entrances currently recognised worldwide, Australia has the to estuaries where tidal exchange offers clear world’s highest diversity, having approximately half oceanic water of high salinity. Posidonia australis of the total number of species (Butler 1999). is found no further north than Wallis Lake, NSW (West 1983), and in a few bays and permanently The stretch of coast between Noosa and Corner open estuaries south along the coast to Corner Inlet includes sub-tropical and temperate climates. Inlet, Victoria (Warry and Hindell 2009). Other Relative to other parts of Australia the southeastern species, such as Zostera, are found not only near sector has relatively few species of seagrass and estuary entrances in Queensland, NSW and Victoria less extensive meadows than other sections of but further upstream as well and are therefore the coastline (Kirkman 1997). Many of the species assumed to be able to tolerate variation in light in this sector are found elsewhere in Australia as regime, salinity and temperature. well as globally (Table 3.3.1). The seagrasses of the southeast are usually found in estuarine and Seagrass distributions can change over time. Some inshore waters less than 15m deep. offshore beds migrate naturally, a phenomenon recognised off the West Australian coast where Five Families of seagrass occur along the beds have leading and trailing edges that appear southeast sector of Australia: Cymodoceaceae, to respond to the movement of sand. As the wave Hydrocharitaceae, Posidoniaceae, Ruppiaceae and energy off the southeast coast is extreme, no Zosteraceae (Table 3.3.1). The northern part of this Chapter 3.3 — Seagrasses of southeastern Australia • 279

Table 3.3.1. Characteristics of NSW seagrasses within the Order Alismatales (after Kuo et al. 2012).

Genus and Common Southeast Australian Family Characteristics species name distribution A short stem at each Tropical Indo-Pacific rhizome node with slender Halodule extending to Wallis Cymodoceaceae – (<1.5mm) leaves to 150mm tridentata Lake (NSW). Estuarine/ length with tridentate tip. marine. Estuarine/marine. Narrow (<4mm) leaves at each rhizome node Tropical Indo-Pacific Halodule with leaves to 150mm extending to Sandon Shoal Weed univerus length with tridentate tip River (QLD). Estuarine/ having two well-developed marine. lateral teeth. Largest leaved of the Halophila genus. Paired bright green or brown oval Halophila Victoria. Estuarine/ Hydrocharitaceae Paddleweed leaves 6-15mm in width australis marine. to 70mm in length with smooth margins. Thin whitish surface rhizome. Paired bright green or brown oval leaves more Most widely distributed Halophila elliptic than above, 5mm in Paddleweed seagrass on the globe. decipiens width, 25mm in length with Estuarine/marine. small toothed margins. Thin whitish surface rhizome. Paired green or brown oval leaves more elliptic than above, <15mm in width, Indo-Pacific to Victoria Halophila ovalis Paddleweed <45mm in length with Estuarine/marine. smooth margins. Thin whitish surface rhizome. Southwards from Wallis Long green leaves 10mm Lake in permanently in width and 300-600mm Posidonia open estuaries and Posidoniaceae Strapweed in length, robust (20mm) australis bays to Corner Inlet. rhizome. Occurs below Estuary entrances/ Mean Low Tide. marine. Leaves 0.5mm in width and Global distribution. Ruppiaceae Ruppia maritima Sea Tassel 150mm in length. Rivers, Rivers, lakes and lakes and estuaries. estuaries. Leaves <1mm in width and Sea Tassel Southeastern Australia. Ruppia <250mm in length. Flowers or Widgeon Rivers, lakes and megacarpa pollinate on surface of Grass estuaries. rivers, lakes and estuaries. Leaves 0.5mm in width and Southeastern Australia. 150mm in length. Flowers Ruppia polycarpa Sea Tassel Rivers, lakes and pollinate on surface of estuaries. rivers, lakes and estuaries. Chapter 3.3 — Seagrasses of southeastern Australia • 280

Table 3.3.1. (cont.) Characteristics of NSW seagrasses within the Order Alismatales (after Kuo et al. 2012).

Genus and Common Southeast Australian Family Characteristics species name distribution Most common of NSW Zostera Eelgrass or seagrasses. Olive green or Eastern Australia. Zosteraceae capricorni Ribbon Weed brown leaves (<500mm) Estuaries and bays. with round tip. Southwards from Jervis Dwarf Smaller than above with Bay to the Victorian Zostera muelleri Grass-wrack notched leaf tip. border. Estuarine/ marine. Southwards from Zostera Eelgrass or Leaves arise from an Port Stephens to nigricaulus Ribbon Weed upright stem. the Victorian border. Estuarine/marine. such bed movement is seen unless in the lee of currents allowing particles to fall from suspension, islands. However, small-scale fluctuations in the in turn enhancing water clarity. The rhizome mats areal extent of seagrasses have been reported in of seagrass bind sediments and provide protection sheltered waters of Queensland (Udy, unpublished against wave-induced erosion. data), Victoria (Blake and Ball 2001) and NSW Seagrass canopies modify what would otherwise (Williams et al. 2003) over the past several decades. be featureless substrata to provide a high value Another reason for change in distribution is ecosystem: canopy structure supports more diverse that species migrate with changes in global invertebrate assemblages and higher community temperature and sea level. At the height of the primary production than bare mud or sand, last Ice Age (18,000 years ago) the shoreline of facilitating numerous food web linkages to higher southeastern Australia was 15 to 20km further trophic levels, including fish, turtles and . east of where it is today with sea level 120 to 130m Some small plants (epiphytes) attach themselves lower than it is at present. While knowing the to seagrass leaves, as do some small encrusting distributions of seagrasses thousands of years ago animals (epizoa). Species of fish graze on these is problematic, it could be hypothesised that species attached organisms, inadvertently consuming confined to the southern Queensland coast during seagrass leaf material. Seagrass beds and meadows the last Ice Age migrated to NSW as warming have often been referred to as “nurseries” for many progressed and sea level rose. Shifts of distribution, species of small fish, crustaceans and molluscs as possibly due to global warming, are continuing well as the juveniles of larger species. Large fish at present, with Halodule tridentata and Halodule invade seagrass beds during their hunt for food, and univeris now found in estuaries of northern NSW some juvenile fish, after being sustained in the beds where they had not previously been described for the early part of their lives will be harvested by (Sainty et al. 2012, p. 97, p. 99). Species present in commercial and recreational fishers. subtropical Queensland can be expected to move One of the processes that sustains the nursery further south with global warming, and temperate function of seagrass beds is the production of species, such as Posidonia australis, presently found detritus. Leaves that are lost from the plants either along the NSW coast can be expected to retreat to due to age or are broken off during occasional cooler latitudes. storms are colonised by fungi, bacteria and Functions of Seagrasses other microorganisms that degrade the dead leaf material creating ever smaller particles and Seagrass leaves capture carbon dioxide, offer releasing nutrients into the water column. The a three dimensional habitat for plants and fungi and bacteria in turn provide sustenance animals, and are a source of food for many for larger organisms such as phytoplankton, and animals, either directly or through detrital then through the food chain larger individuals of pathways. Leaves act as baffles, slowing down zooplankton provide food for juvenile and small Chapter 3.3 — Seagrasses of southeastern Australia • 281

adult fish, crustaceans and molluscs. In some cases levels are especially of concern in estuaries and seagrasses are directly consumed by herbivorous semi-enclosed bays where land use practices can fish, and in Queensland by dugong and turtles. cause erosion of sediments or deliver nutrients that enhance algal densities in the water column Sampling of fishes in shallow estuarine waters or epiphyte growth on seagrass leaves. In either shows a greater diversity in estuaries where case the amount of light reaching seagrasses is seagrass is present. For example, the Hunter diminished and the depth at which seagrasses can River, NSW has been reported to have no seagrass survive is reduced (Dennison et al. 1993). (Williams et al. 2004) and has of the order of 40-50 species of small adult and juvenile fishes, Direct damage arises from dredging, reclamation, while other estuaries of the same type, with mooring blocks and chains, anchors, keels, seagrass meadows (Clarence, Richmond and propellers, bait digging and shading from structures Shoalhaven Rivers), have between 70-80 species like jetties and berthing areas. Indirect damage (Williams, unpublished data). The conservation comes about via changes in catchment landuse of seagrass would seem to be of fundamental as well as agricultural, industrial and urban importance for the support of commercial and pollutants. An invasive algae, Caulerpa taxifolia, recreational fisheries. It has often been remarked: has appeared in a number of NSW estuaries and “No habitat means no fish!”. may pose a threat to the survival of seagrasses (NSW Department of Primary Industries 2009), and A conservation issue that is becoming more topical another invader, the algae Codium fragile ssp. fragile is the role seagrasses (and other marine plants) play also occurs in seagrass beds in Corner Inlet and Port in removing CO from the atmosphere and binding 2 Phillip Bay (S. Howe, pers. comm., 2013). The rise it up in long-lived biomass. This has been referred of sea level will alter the distribution and extent of to in popular texts as “blue carbon”. The research beds of seagrass, with the lower margins receiving in this arena is in its infancy but inroads have been reduced sunlight and possibly dying off and the made (e.g. Macreadie et al. 2012). If blue carbon upper margins moving further upslope as water can be utilised for this purpose it will make an even depth increases if suitable habitat exists. stronger case for seagrass conservation. Threats to Seagrasses Seagrasses in South East Australia Australia has extensive areas of seagrass with Mechanical damage to seagrasses moorings, from the largest meadows in Western Australia, dredging and reclamation, and the insults from followed by the Torres Strait (e.g. Kirkman 1997). pollutants such as herbicides are more readily Nevertheless, there are ecologically important recognised and dealt with in environmental studies areas of seagrass along the southeast coast, a high and management plans than in the past. energy, geomorphically complex environment. Of particular importance along the southeast As a consequence, meadows are smaller than coast is increase in water turbidity and its effect in other parts of Australia, being found almost on photosynthesis. Sunlight falling on seagrass exclusively in bays and estuaries where protection leaves stimulates photosynthesis, whereby carbon is afforded from storms and currents. This pattern dioxide taken from water is converted into of distribution puts the southeast seagrasses at tissue. The degree of photosynthesis is therefore particular threat because agricultural, industrial contingent on the amount of light travelling and urban pressures on coastal habitats are through the water column and reaching the leaves. greatest in estuaries. Different species have to contend with differing In NSW, at least one species of seagrass is found light regimes. Some species grow at much greater in about 110 of the 184 recognised estuaries depths than others due to innately different (NSW DPI unpublished data; West et al. 1985). The physiologic characteristics (Table 3.3.1), and most distribution of seagrass is, however, not consistent can survive short term reductions in water clarity among different types of estuary in the south-east. from rainfall and runoff events. Some seagrass is found in every large embayment Persistent reduction in water clarity will (e.g. Moreton Bay, Botany Bay, Jervis Bay, Twofold result in seagrass loss. Turbidity is increased Bay, Corner Inlet) or drowned river valley (e.g. when the concentration of inert sediments in Hawkesbury River, Clyde River) along the southeast the water column increases (for example by Australian coast. Seagrass is also found in over 85% dredge operation) or where sediments are kept of coastal plain rivers and large coastal lagoons that in suspension (e.g. vessel movement). Turbidity Chapter 3.3 — Seagrasses of southeastern Australia • 282

Additional Information sparsely established due to dense coverage of filamentous algae. The lagoon had been Sydney Olympic Park, situated in the upper artificially constructed in early 1950s using portion of the estuary of the Parramatta River, dredge spoil from Homebush Bay. Tidal will never host species such as P. australis or exchange was enhanced in 2006 by installing those in the Halodule and Halophila genera as an automated tidal gate, and Ruppia quickly these plants, found in sheltered bays and near disappeared and has not been detected since. the entrances of estuaries (e.g. Sydney Harbour), Nevertheless, the primary aims of restoration at occur in water of high clarity. In contrast, species the Waterbird Refuge were fully realised. of the genus Zostera, while commonly found at entrances of estuaries, are also found in upper In 2001, Ruppia was identified at another semi- estuarine locations. Decades ago, Tarban Creek detached estuarine lagoon, the Newington (Hunters Hill) was the most upstream location Nature Reserve Wetland. As this lagoon is of Zostera in the Parramatta River (West et al. separated by a walkway from the adjacent 1985) but more recently Zostera has been found Parramatta River’s only tides over 1.6m can further upstream (West et al. 2004). Upstream enter the wetland. Ruppia was detected in a few migration may have occurred between the two disturbed pockets of the wetland, and appears to surveys as water pollution controls became have thrived at those sites to the present day. more and more stringent in the Parramatta River In 2010, Ruppia maritima was identified in a through the 1980s and 1990s. Alternatively, totally unexpected water body within Sydney there may have been small patches of Zostera Olympic Park – a leachate treatment pond in not identified in the earlier survey. Wilson Park (S. Paul, pers. comm., 2013). This There is no record of Zostera in Sydney Olympic pond, also adjacent to Parramatta River and Park precincts, either along the Parramatta River separated from it by a walkway, was constructed or in Homebush Bay, and this may relate to in 1999 to assist in bioremediation of tar seeps. sediment movement and high turbidity levels The pond has a water impermeable liner, and, to brought about by vessel traffic. enhance treatment of leachate, water is always in motion inside the pond. Ruppia maritima Ruppia megacarpa (hereafter Ruppia) has been was detected along the shallower edges of the located intermittently in Sydney Olympic Park approximately 2.0m deep pond, and appeared (S. Paul, pers. comm., 2013). It was identified healthy with relatively long stems, perhaps due in 1997 in an estuarine but almost detached to the continuous movement of water. lagoon (known as Waterbird Refuge) at Bicentennial Park, Homebush Bay. It occurred in the shallower parts of the Refuge but was

are mostly open to the sea. In these estuaries, the 1960s and 1970s to 90ha (Williams and Meehan area covered by seagrass is less than 10-15% of the 2001). The most recent estimate (Creese et al. water surface area. 2009) indicates cover in Port Hacking has stabilised at 90-100ha. There are distinct management In contrast, only 30 to 50% of intermittently open implications for these large variations in cover that estuaries and coastal lagoons have any seagrass will be discussed below. Large losses of seagrass (OEH, DPI Fisheries unpublished data). This is have also been seen in the Parramatta River (West thought to be due to extremes of temperature and Williams 2008) and in other NSW estuaries and/or salinity that come about when a berm (Williams et al. 2003). prevents tidal flushing and/or evaporation creates hypersaline conditions, particularly during Management droughts. Sometimes Ruppia species are seen to survive in these fluctuating conditions. The relatively small cover of seagrasses in southeast Australia (compared to other parts of Australia), Large losses of seagrass have been documented coupled with the important functions seagrasses for some estuaries. The cover of seagrass in Port contribute, mean that protection of meadows Hacking, NSW was consistently of the order of should be the first priority in management. This 180ha between 1930 and 1950, but declined in the priority is reinforced by the fact that restoration Chapter 3.3 — Seagrasses of southeastern Australia • 283

techniques such as seagrass transplanting are The ambit of a monitoring program is directly in their infancy (see below). All Australian states influenced by extent of disturbance and the scale of have expressed concern for the conservation of impact on seagrasses. seagrasses but some states are more explicit with In circumstances where funds for conservation their legislative and policy initiatives. managers and researchers are diminishing, Queensland and New South Wales have legislation new models for natural resource monitoring specifically designed to protect seagrass (Table are required. One new model is to establish 3.3.2). The primary difference between the two partnerships between professional seagrass states is that the Queensland Fisheries Act 1994 biologists and community volunteers, a model that protects all marine plants in all waterways, can be mutually beneficial as it brings sophisticated public and private, whereas in NSW the Fisheries skills and equipment to a site(s), as well as Management Act 1994 deals principally with enhances the labour pool. seagrass, mangrove, saltmarsh and macroalgae In situations where no professional expertise (seaweeds) in all public waters. In Queensland, is available there still are standard measurements New South Wales and Victoria seagrasses are that volunteers can use to contribute to local or also managed within marine protected areas and even regional understanding of the ecological aquatic reserves. Under the terms of the NSW processes of seagrasses. A localised loss (or gain) Fisheries Management Act 1994, P. australis has of seagrass can be monitored with simple been declared as having “Endangered Populations” equipment: measuring tape, GPS, permanent in the Sydney metropolitan and Central Coast marking fixtures. The Sea Search Manual (Browne regions (NSW Fisheries Scientific Committee 2009). et al. 2013) provides a set of criteria for selecting Except for the proposal to list P. australis under the best indicators for monitoring programs. the Commonwealth’s Environment Protection and These range from ‘easy’ to “difficult” to provide for Biodiversity Conservation Act 1999, no other use of volunteers with different skill levels and interests that act has been applied to protect and manage and to help ensure data are of sufficient quality to seagrasses in a national context. inform management. It is the aim of legislation, policies and guidelines Major factors to consider in the planning to safeguard beds of seagrass from direct and/or phase include: indirect damage. • objective of the project; Monitoring • geographic extent of a project; The monitoring of seagrasses is a complex issue that is sometimes best approached with a series • number of persons available; of questions: is there a perceived problem? What • skill base of the persons are the needs of management (e.g. early indicators involved: professional scientists of impact vs. long-term meadow scale effects)? or community volunteers; What resources are available? Monitoring to detect early indications of impact necessarily occurs at • type of equipment available; the time scale of hours, weeks or months, and at • logistic constraints; the spatial scale of individual plants or patches • data quality; of plants, taking the form of measuring rates of photosynthesis or changes in carbohydrate stores, • data management; actions that in the past have been the domain of • framework to implement professional scientists. Similarly, if a series of yearly management response; status reports of the cover of seagrass in one or more estuaries was desired such that a decadal • feedback to volunteers; and trend of gain or loss could be produced, airphoto • budget. imagery, appropriate hardware and software, and skilled operators to assemble and interpret the data These factors might need to be iterated several would be needed. In contrast, monitoring to detect times to match the objective with the capacity to natural variability in cover and/or density (months, execute the project, and the final objective must seasons, years) at a local scale (individual beds), be made explicit to all participants. One logical is readily undertaken by community volunteers. starting point is to determine whether a project is strategic or tactical in nature. The former may Chapter 3.3 — Seagrasses of southeastern Australia • 284

Table 3.3.2. State legislation relevant to seagrass management in southeast Australia.

State Queensland NSW Victoria Fisheries Management Act 1994 National Parks Act 1975 Legislation Fisheries Act 1994 Fisheries Management Fisheries Act 1995 (General) Regulation 2010 National Parks Act: “for the protection and preservation The destruction, damage of the natural environment or disturbance to seagrass . . . ” (and other marine plants: Prevent “harm” to Fisheries Act: “protection mangrove, saltcouch, seagrass (and mangrove, Objective and conservation of fisheries algae, sampfire, melaleuca saltmarsh and seaweed resources, habitats and and coastal she-oak on all whether alive or dead) ecosystems including the coastal lands whether alive maintenance of aquatic or dead) ecological processes and genetic diversity” Private, leasehold or Jurisdiction Public land Public land public land “Harm” is defined as “gather, cut, pull up, destroy, poison, dig up, “cut, trim or remove, injure, prevent “Preserve and protect Provisions for remove seagrass” light from reaching or indigenous flora” otherwise harm the marine vegetation or any part of it.”

Permit required to National Parks Act: Yes Yes Yes “harm” Fisheries Act: Yes

Corporate penalties Yes Yes Yes

Individual penalties Yes Yes Yes

Policies and Yes Yes Yes guidelines available

Environment Protection Act 1970 Water Act 1989 Threatened Species Flora and Fauna Guarantee Associated Sustainable Planning Conservation Act 1995 Act 1988 legislation Act 2009 Environmental Planning Planning and Environment Act and Assessment Act 1979 1987 Land Act 1958 Conservation, Forests and Lands Act 1987 Chapter 3.3 — Seagrasses of southeastern Australia • 285

be to assess natural variation in bed or meadow execute projects where the ultimate goal is to dynamics and will certainly be long term. A tactical integrate various data sets into decision-making study might attempt to investigate impacts framework. Some assistance on this issue will come of a perceived disturbance. In the latter case, from an Australia-wide study to determine the monitoring will ideally be initiated before change applications of “citizen science” by identifying the (e.g. dredging) occurs at a specific location, and major factors which influence the provision and have an appropriate experimental design, including use of data collected by volunteers (C. Sbrocchi, such features as multiple control or reference sites pers. comm., 2013). (e.g. Underwood et al. 2000) so that change can All monitoring programs, whether conducted unequivocally be attributed to the disturbance. by scientific professionals or by members of the Seagrasses can change their characteristics community, require clear objectives that lead to naturally over time, with some changes occurring appropriate field methods. Community projects on a predictable cycle, as for example with the need to be framed in the first instance by objective, loss of leaves during winter months. Other natural and then by the resources at hand. It may be changes occur intermittently, such as storm erosion necessary to scale down what is proposed in a of seagrass beds, but beds can be expected to project so that it can actually be done. When the regrow, although more quickly for some species objective is clear the hard but important question than others. However, other types of stressors needs to be asked – is it still worthwhile to proceed such as land clearance that alters the runoff of (the effect size issue) or is some other objective sediments and nutrients, thereby increasing more appropriate? In some cases an over-exuberant turbidity, will reduce photosynthetic capacity of launch of a community project has wound down seagrass. Discharge of pollutants into estuarine over time due to inadequate person-power or or nearshore waters can produce immediate other logistic difficulties. Projects that require and persistent disturbance. Of critical interest to regular field sampling are often derailed in the conservation scientists and managers is being winter months or during inclement weather when able to differentiate between change brought volunteers become less than willing to expose about naturally and that brought about by human themselves to the elements. disturbance. Such discrimination is difficult given Other issues that can prove troublesome are that seagrass ecology is complex, and a matter of the degree of quality control exercised during interest to professional scientists is “effect size”, data collection. If collection techniques are which asks the question “How much effort must be flawed, appropriate management action cannot used to differentiate a real change (which may be be demanded or expected due to uncertainty small but critical) from natural variation? One way about conclusions. A dedicated budget is needed to envision the issue is to contemplate the number to consolidate, archive and summarise data for of quadrats needed to determine average % cover. managers and volunteers. Endless data sets How many quadrats should be used at a site? How without archival facilities or without resources many sites should be used to describe a location to provide summary statements have limited (large bed or meadow)? Resolving questions such as value. Volunteers need feedback to sustain these to determine effect size is a statistical matter interest and engagement. that requires appropriate skills. Unless a mentor is available to resolve statistical issues such as these Nevertheless, there are means by which higher it would be more appropriate for volunteers to deal order monitoring can be undertaken by the with matters such as presence/absence of species, community, and some well established methods number of beds in a meadow, and depth of the are being used along the southeast Australian coast deepest seagrass margin. (Table 3.3.3). These methods include determination of total area, species abundance, per cent ground The use of community volunteers in monitoring cover, shoot density, growth rate (e.g. above- projects has wide-ranging outcomes which are ground biomass), or, available seed bank. Sediment highly beneficial to natural resource managers. composition, as it is readily determined, is often However, how these programs are integrated added to field observations. into Natural Resource Management (NRM) across the southeast sector of Australia can be highly “Seagrass Watch”, operating since 1988, initially variable. As local programs can differ in its scale in tropical Queensland but then expanding to and purpose, it is a challenge for natural resource other states, has promulgated manuals that managers to determine the best ways to plan and identify objectives and procedures for community Chapter 3.3 — Seagrasses of southeastern Australia • 286

involvement in seagrass monitoring (McKenzie et management (Browne et al. 2013). Parks Victoria al. 2003). A number of scientific reports have been rangers oversee each project and are responsible for produced from Seagrass Watch. data quality and continuity. A number of scientific reports have been produced from Sea Search. “Sea Search”, sponsored by Parks Victoria with commercial partners, university and community A community project being run by Great Lakes volunteers, monitors seagrass and other coastal Council is using recreational divers to collect and resources in that State (Koss et al. 2005; Browne deploy artificial seagrass to monitor the overgrowth et al. 2013). One of its objectives is to engage by algae (I. Strachan, pers. comm., 2013). Data from the community and this is done via fieldwork to this exercise have been analysed and are the basis determine the condition of seagrass beds in marine for a longer term project. national parks and sanctuaries. A technical manual Along the southeast coast the location of the for field procedures and data entry protocols was largest of seagrass meadows have been identified developed in 2005 (Koss et al. 2005, Table 4). The albeit at a coarse scale (West et al. 1985; Mount program was updated in 2012 to include a broader and Bricher 2008; Creese et al. 2009). One type range of methods with varying levels of difficulty of community monitoring could take the form of to provide opportunities for a range of volunteers locating smaller units, i.e., the beds and patches. As with different skill levels and interest, and to help an adjunct operation, species can be differentiated ensure data quality is sufficient to help inform

Table 3.3.3. Differential approaches to seagrass monitoring projects.

OPERATOR SCALE OBJECTIVE WHEN HOW COMMENTS (Who) (Where) (What) Quality Assurance/ Individuals or Locate new GPS: surface Quality Patch or community groups patches and/or Once off and underwater Control (QA/ meadow (e.g. NGO) meadows surveys QC); Data repository needed Quarterly/ Determine change annually QA/QC; Data Patch or in perimeter, (as GPS repository meadow depth or location resources needed allow)

Mentored groups (e.g. university diving Locate new GPS: surface QA/QC; Data Patch or club, recreational patches and/or Once off and underwater repository meadow fishers, commercial meadows surveys needed fishers) Quarterly/ Determine change annually QA/QC; Data Patch or in perimeter, (as GPS repository meadow depth or location resources needed allow) Determine Can be for change in species Transects, quadrats, macroalgae composition, lab samples as well as density, seagrass abundance Chapter 3.3 — Seagrasses of southeastern Australia • 287

Table 3.3.3. (cont.) Differential approaches to seagrass monitoring projects.

OPERATOR SCALE OBJECTIVE WHEN HOW COMMENTS (Who) (Where) (What) Professional At Enhance Various genetic scientists (university, Cell, leaf, or appropriate As funding understanding of and biochemical federal, state, local plant temporal allows seagrass function techniques government) scales Locate new sites For and determine macroalgae, Patch or change in Quadrats, Photo epiphytes meadow perimeter, depth quadrats, transects and epizoa as or location at appropriate known sites Ecosystem Remote sensing via Ascertain (lagoon, satellite and/or air degree of bay, photo images dieoff estuary)

Remote sensing via Ascertain Ecoregion satellite and/or air degree of photo images dieoff via texts that facilitate field identification (e.g. shore-based surveys of bed location and extent Sainty et al. 2012). A second step, contingent on are undertaken. It was recognised some time ago strategic or tactical needs, is determining the (Kirkman 1997) that offshore beds of seagrass beds centroid and/or the extent of individual patches, can be constantly moving but maintain their overall beds and small meadows. As seagrasses occur in mass and therefore any measurements of extent irregular distributions that can change over time, need to be carried out over lengthy time intervals. and as the time necessary to fix the location of all For a community project that aims to determine patches or beds within a meadow may be lengthy, whether the outer margin of a seagrass bed(s) is a minimum size of the seagrass area of interest changing due to: might need to be adopted. Alternatively, in the face of a forecast disturbance, it might be crucial • turbidity increase/decrease in light, to generate location and extent measurements • erosion due to a change in current direction for even the smallest of patches/beds, particularly or velocity, or where a meadow is already under stress and might be fracturing into smaller and smaller beds. • health stressors Direct measurement of change in area or shape of regular distance measurements either from fixed seagrass beds can, where water is clear and where shore stations or by the application of a GPS can be appropriate facilities are at hand, can be readily used. As a small change over a short time interval assessed by the inspection of aerial photographs might reflect a natural disturbance, management (Williams et al. 2003). Deakin University and Parks intervention might not be needed in the first Victoria are comparing aerial photography (with instance and repeated measurements would be near infrared) and satellite imagery (plus LiDAR) for required. A question arises that in some ways is mapping seagrass beds in marine national parks in difficult to answer: what is the degree of change Victoria. Recent advances in satellite sensors and that should stimulate management intervention? If software capacity mean that routine monitoring a bed were to contract shoreward by half its width of the extent and condition of seagrass beds is this would almost certainly be an intervention becoming more feasible (Dekker et al. 2005; Anstee trigger, but what about a relatively small change? et al. 2009). In other locations, such as Moreton Further, if a bed were to maintain its size but shift Bay where water clarity is reduced, boat and/or its location would this be important? These issues Chapter 3.3 — Seagrasses of southeastern Australia • 288

Table 3.3.4. Differences between seagrass monitoring projects in southeast Australia.

Program NSW DPI Seagrass Watch Sea Search Australia wide - selected Victorian marine parks and Ambit NSW locations only sanctuaries Objective Whole-of-state trend Regional and local trends Regional and local trends Coordinator NSW DPI (Fisheries) Parks Victoria Operator NSW DPI (Fisheries) Community groups Community groups Reference Creese et al. (2009) McKenzie et al. (2003) Browne et al. (2013) Site visit details X X X Photographs (Air photo images) X X Substratum X X Seagrass cover X X X Species composition X X X Leaf length X X Shoot density X Macroalgal cover X X Epiphyte cover X Animals X X Voucher specimen X Seagrass Watch Data repository NSW DPI Parks Victoria Coordinator Seagrass Watch Data outputs NSW DPI Parks Victoria Coordinator must be examined within the site-specific context As indicated, water clarity is an important feature (e.g. occurrence of recent bottom scour due to for the sustainability of seagrass beds, with long flooding, or modification of run-off due to a change periods of high turbidity a threat to survival in land use) and may require outside advice. of meadows, and it is the deeper parts of the meadows that are most at risk. In Queensland the An initiative underway in NSW (Office of monitoring of turbidity is an important part of Environment & Heritage) is the derivation of the government’s Healthy Waterways Ecosystem conceptual models of the consequences of stresses Health Monitoring Program. In NSW the monitoring on seagrasses (Figure 3.3.1). OEH is also developing of turbidity levels in estuaries is a primary indicator predictive models that can be applied to anticipate in the state’s Monitoring Evaluation and Reporting the likely occurrence of seagrass at any location framework (Roper et al. 2011). in large estuaries such as Lake Macquarie and Tuggerah Lakes; other models under development More complex measurements such as the deal with seagrass growth and seagrass health. determination of growth rate, tissue composition, Each of these models recognises the primary turbidity and incident light (photosynthetically importance of light regime, bottom stress (erosion/ active radiation - PAR) are employed by seagrass sedimentation due to wind and tidal currents) scientists to assess changes in seagrass distribution and sediment chemistry and provides an ability and abundance. The time periods over which these to understand the effects of changes to these techniques are applied have to be sufficiently long variables. The models are subject to revision as to determine natural and human-induced variation. more data about ecological processes are acquired. Chapter 3.3 — Seagrasses of southeastern Australia • 289

Figure 3.3.1. At its deeper margin (X) the distribution of seagrass is mainly affected by light. The amount of light can be changed by turbidity of the water from external sources (brown dots), or due to re-suspension of sediments (brown arrow), algal growth (green dots) or shading. At its upper margin (purple arrow), chemical factors such as concentration of sulphides and oxygen, as well as exposure and desiccation, are important. Physical removal (dark green arrow) by waves and currents can also strongly affect seagrass distribution.

In NSW, as part of the NRM monitoring program, beds. There appears to have been no projects in a regular census of area of macrophytes is carried southeastern Australia which have successfully out in 15 estuaries on a five yearly basis. Estuaries engaged this approach. This is in part because of were prioritised on the basis of previous mapping cost as well as the limited Australian success of exercises (Roper et al. 2011) and a range of seagrass transplant projects (Ganassin and Gibbs techniques are used to identify and confirm the 2003). However, one apparent success comes location of seagrass (and mangrove and saltmarsh). from a multi-party exercise in Western Australia On the basis of comparative imagery studies in that ranks itself as the world’s most successful Victoria (mentioned above) similar assessments of transplant operation. Cockburn Sound and several area are expected to begin on meadows of seagrass locations near Albany have seen over 3.1ha and in marine parks (S. Howe, pers. comm., 2013). 1ha, respectively, transplanted with high survival rates four years after planting (Oceanica 2011). The Hence, “monitoring” as a facet of management techniques used in Western Australia may have can be complex, requiring sophisticated skills merit elsewhere in Australia, but until such time and equipment. Alternatively, if an appropriate as transplantation and its associated issues (e.g. objective is formed and a suitable understanding impact on the donor bed) are resolved it is far better of the need for, and type of, monitoring is achieved, to conserve seagrass in the first instance. monitoring can successfully be done by community volunteers. Any type of monitoring, whether Conclusions strategic or tactical, whether done by professional scientists or community volunteers, is all too The seagrasses of southeast Australia: often made irrelevant by the failure to address the • are limited in their distribution mostly to bays questions of what is to be monitored and why the and permanently open estuaries. monitoring is to take place, as well as associated matters dealing with the logistics of field sampling, • are susceptible to an increasing population data storage and data summary. Community density from Melbourne to Brisbane and need projects that have scientific mentors or careful management to maintain the services co-ordinators have shown themselves to be they provide such as foreshore protection and capable of deriving considerable scientific data provision of habitat. on the extent and health of seagrass beds. • occasionally are damaged by storms but can generally be expected to regrow. Rehabilitation • are susceptible to direct damage such as The transplantation of seagrass is sometimes dredging and/or reclamation. invoked as a means by which to rehabilitate denuded areas or create new meadows as offsets • are also susceptible to indirect damage in coastal projects that pose threats to existing occasioned by reductions in light due to increased turbidity from inert particles. Chapter 3.3 — Seagrasses of southeastern Australia • 290

• are susceptible to indirect damage occasioned sanctuaries. Available at http://parkweb.vic.gov. by reductions in light due to increased turbidity au/__data/assets/pdf_file/0008/602279/Sea_ from enhanced nutrient concentrations. Search_Manual.pdf. • are susceptible to climate change: sea level Butler, A. J. (1999). Seagrass in Australia: Strategic rise, increased sea surface temperature, Review and Development of an R & D Plan, FRDC increased air temperature (especially for Project 98/223. intertidal species). Clayton, P. C., Fielder, D. F., Howell, S., and Hill, • can benefit from community monitoring C. J. (2006). Aquatic Biodiversity Assessment projects provided well-reasoned objectives can and Mapping Method (AquaBAMM). p. 77. be obtained from appropriate field techniques. (Environmental Protection Agency: Brisbane.) • may benefit from transplantation techniques Creese, R. G., Glasby, T. M., West, G., and Gallen, C. developed elsewhere, but the first priority (2009). Mapping the habitats of NSW estuaries. should be to conserve these species wherever Industry & Investment NSW – Fisheries Final Report they occur. Series No. 113. p. 95. Acknowledgements Dekker, A. G., Brando, V. E., and Anstee, J. M. (2005). Retrospective seagrass change detection Swapan Paul of Sydney Olympic Park has been in a shallow coastal tidal Australian lake. Remote on the lookout for seagrass in the SOP precincts Sensing of Environment 97, 415–433. since 1998 and to date has encountered Ruppia megacarpa on an intermittent basis. Carla Ganassin Ganassin, C., and Gibbs, P. J. (2008). A review has an excellent understanding of the subtleties of of seagrass planting as a means of habitat practical seagrass management and is thanked for compensation following loss of seagrass meadow. a review of the text. Steffan Howe of Parks Victoria NSW Department of Primary Industries – Fisheries added immensely in setting out the state of play Final Report Series No. 96. p. 41. in Victoria for community volunteers and making Global Seagrass Trajectories Working Group the text more relevant. We hope Carla Sbrocchi’s (2009). National Center for Ecological Analysis and thesis will provide additional impetus for “Citizen Synthesis, Project 10002. Science”. Greg West of NSW DPI, Port Stephens Kirkman, H. (1997). Seagrasses of Australia. State of Fisheries Centre mapped the extent of P. australis at the Environment Australia, Technical Paper Series, Broughton Island in 2005 (unpublished data). Estuaries and the Sea. p. 33. References Kirkman, H., and Kuo, J. (2012). Seagrasses of South- Anstee, J., Botha, E., and Dekker, A. (2009). Study on east Australia, An Introduction. In ‘Estuary Plants the remote sensing of estuarine macrophytes and and What’s Happening to Them in South-eastern saltmarsh vegetation in Wallis Lake. CSIRO Water Australia’. (Eds G. Sainty, J. Hosking, G. Carr and P. for a Healthy Country National Research Flagship Adam.) pp. 78–91. (Sainty and Associates Pty. Ltd: report CSIRO. Potts Point, NSW.) Australian Centre for Ecological Analysis & Koss, R., Bunce, A., Gilmour, P., and McBurnie, J. Synthesis Seagrass Working Group (online). Last (2005). Sea Search: Community-Based Monitoring updated 11 April 2013. of Victoria’s Marine National Parks and Marine Sanctuaries - Seagrass Monitoring.Parks Victoria Blake, S., and Ball, D. (2001). Victorian Marine Technical Series No. 16, Parks Victoria, Melbourne. Habitat Database: seagrass mapping of Port Phillip Bay. Geospatial Systems Section Marine Kuo, J., Kirkman, H., Sainty, G., and Jacobs, S. and Freshwater Resources Institute Report No. (2012). Seagrasses. In ‘Estuary Plants and What’s 39, Marine and Freshwater Resources Institute, Happening to Them in South-eastern Australia’ Queenscliff. (Eds G. Sainty, J. Hosking, G. Carr and P. Adam.) pp. 92–131. (Sainty and Associates Pty. Ltd.: Potts Browne, M., Pocklington, J., Franklin, A., Howe, Point, NSW.) S., Rodrigue, M., et al. (2013). Sea Search Manual, A guide for community based monitoring of Victoria’s marine national parks and marine Chapter 3.3 — Seagrasses of southeastern Australia • 291

Macreadie, P. I., Allen, K., Kelaher, B. P., Ralph, P. J., in NSW. Technical Report for the NSW Natural and Skillbeck, C. G. (2010). Paleoreconstruction Resources Monitoring, Evaluation and Reporting of estuarine sediments reveal human-induced (MER) Strategy. weakening of coastal carbon sinks. Global Change Sainty, G., Hosking, J., Carr, G., and Adam, P. (2012). Biology 18, 891–901. ‘Estuary Plants and What’s Happening to Them in McKenzie, L. J., Finkbeiner, M. A., and Kirkman, H. South-eastern Australia.’ (Sainty and Associates Pty. (2001). Methods for mapping seagrass distribution. Ltd.: Potts Point, NSW.) In ‘Global Seagrass Research Methods’. (Eds. F. T. Underwood, A. J., Chapman, M. G., and Connel, S. Short and R. G. Coles.) pp. 101–122. (Elsevier Science D. (2000). Observations in ecology: you can’t make B.V.: Amsterdam.) progress on processes without understanding the McKenzie, L. J., Campbell, S. J., and Roder, C. A. patterns. Journal of Experimental Marine Biology (2003). ‘Seagrass-Watch: Manual for Mapping & and Ecology 250, 97–115. Monitoring Seagrass Resources by Community Vermaat, J. E. (2009). Linking clonal growth (citizen) volunteers.’ 2nd edn. (Queensland Fisheries patterns and ecophysiology allows the prediction Service, Northern Fisheries Centre: Cairns.) of meadow-scale dynamics of seagrass beds. Mount, R. E., and Bricher, P. J. (2008). Estuarine, Perspectives in Plant Ecology, Evolution and Coastal and Marine (ECM) National Habitat Map Systematics 11, 137–155. Series Project Report February. Spatial Science Warry, F. Y., and Hindell, J. S. (2009). Review of Group, School of Geography and Environmental Victorian seagrass research, with emphasis on Port Studies, University of Tasmania. Report to the Phillip Bay. Arthur Rylah Institute for Environmental Department of Climate Change and the National Research. Department of Sustainability and Land and Water Resources Audit, Canberra, ACT. Environment, Heidelberg, Victoria. NSW Department of Primary Industries (2007). West, G., and Williams, R. J. (2008). Preliminary Seagrasses. Primefact 629, NSW Department of assessment of the historical, current and future Primary Industries. Available at: http://www.dpi. cover of seagrass in the estuary of the Parramatta nsw.gov.au/data/assets/pdf/file/0019/203149/ River. NSW Department of Primary Industries – seagrasses-primefact-6a9.pdf. Fisheries Final Report Series No. 98. p.61. NSW Department of Primary Industries (2009). West, G., Williams, R. J., and Laird, R. (2004). Caulerpa taxifolia. NSW Department of Primary Distribution of estuarine vegetation in the Industries. Available at: http://www.dpi.nsw.gov. Parramatta River and Sydney Harbour, 2000. Final au/fisheries/pests-diseases/marine-pests/species/ report to NSW Waterways Authority – Fisheries caulerpa-taxifolia. Final Report Series No. 70. p. 33. NSW Fisheries Scientific Committee (2009). West, R. J. (1983). The seagrasses of New South Proposed Determination: The seagrass Posidonia Wales estuaries and embayments. Wetlands australis as Endangered Populations in Port (Australia) 3, 34–44. Hacking, Botany Bay, Sydney Harbour, Pittwater, Brisbane Waters and Lake Macquarie (NSW). West, R. J., Thorogood, C. A., Walford, T. R., and Williams, R. J. (1985). An estuarine Oceanica (2011). Seagrass Research and inventory for New South Wales, Australia. Fisheries Rehabilitation Plan – Synthesis Report July 2003 Bulletin 2. Department of Agriculture, New South to June 2010. Prepared for Cockburn Cement Wales. p. 140. Limited, Department of Commerce by Oceanica Consulting Pty Ltd, Report No 520_001/3, Perth, Williams, R .J., and Meehan, A. J. (2004). Focusing Western Australia. management needs at the sub-catchment level via assessments of change in the cover of estuarine Orth, R. J., Carruthers, T. J. B., Dennison, W. C., Duarte, vegetation, Port Hacking, NSW, Australia. Wetlands C. M., Fourqurean, J. W., et al. (2006). A global crisis Ecology and Management 12, 499–518. for seagrass ecosystems. BioScience 56, 987–996. Williams, R. J., Meehan, A. J., and West, G. (2003). Roper, T., Creese, B., Scanes, P., Stephens, K., Status and trend mapping of aquatic vegetation in Williams, R. J., et al. (2011). Assessing the NSW estuaries. In ‘Coastal GIS 2003: an integrated Condition of Estuaries and Coastal Lake Ecosystems approach to Australian coastal issues’. (Eds C. D. Woodroffe and R. A. Furness.) pp. 317-346. (Wollongong Papers on Maritime Policy, No. 14.) Chapter 3.3 — Seagrasses of southeastern Australia • 292

Williams, R. J., Watford, F. and Balashov, V. (2004). Kooragang Wetland Rehabilitation Project: History of changes to estuarine wetlands of the lower Hunter River. NSW Fisheries Final Report Series No. 22. p. 87. Additional reading den Hartog, C. (1970). ‘The Sea-grasses of the World.’ (North Holland Publishing Company: Amsterdam.) Larkum, A. W. D., McComb, A. J., and Shepherd, S. A. (Eds) (1990). ‘Biology of Seagrasses.’ (Elsevier: Amsterdam.) Larkum, A. W. D., Orth, R. G., and Duarte, C. M. (Eds) (2006). ‘Seagrasses: Biology, Ecology and Conservation’. (Dordrecht, Springer: the Netherlands.) Parks Victoria (2013). Sea Search website: http://parkweb.vic.gov.au/get-involved/volunteer/ sea-search.