Corner Fish Habitats 2007

Julia Kent, Leanne Gunthorpe and Guy Werner (Editors)

May 2011

Fisheries Assessment Report Series No 60

Corner Inlet Habitats 2007

If you would like to receive this Authorised by the Victorian Government, information/publication in an 1 Spring Street, accessible format (such as large Published by the Department of Primary Industries. print or audio) please call the Copies are available from the website: Customer Service Centre on: www.dpi.vic.gov.au/fishing 136 186, TTY: 1800 122 969, General disclaimer or email This publication may be of assistance to you but [email protected] the State of Victoria and its employees do not guarantee that the publication is without flaw of © The State of Victoria, Department of Primary any kind or is wholly appropriate for your Industries, 2011. particular purposes and therefore disclaims all This publication is copyright. No part may be liability for any error, loss or other consequence reproduced by any process except in accordance which may arise from you relying on any with the provisions of the Copyright Act 1968. information in this publication. Preferred way to cite this publication: Kent, J., Gunthorpe L. and Werner G (Eds.) (2011) Corner Inlet Fish Habitats 2007. Compiled by the Fish Habitat Assessment Group. Fisheries Victoria Assessment Report Series. Report No. 60. 27 pp. (Fisheries Research Branch, Queenscliff). ISSN 1329‐7287 ISBN 978‐1‐74264‐790‐6 (print)

Corner Inlet Fish Habitats 2007 ii Table of Contents

Executive Summary...... vii

Introduction...... 1

Goals, Objectives and Strategies for Maintenance of Fish Habitats ...... 2 Strategic Directions ...... 2 Strategic goal ...... 2 Strategic objectives...... 2 Strategic activities ...... 2 Policy and Legislative Context ...... 2

Corner Inlet...... 3 Background...... 3 Fisheries of Corner Inlet...... 3 Management Responsibilities...... 3 Stakeholders ...... 3

1998 Assessment ...... 6 Status...... 6 Management Implications ...... 6 Research Priorities...... 6

The 2007 Assessment ...... 8 Aims, Objectives and Strategies of the Assessment ...... 8 Boundaries of estuaries ...... 8 Definition of a Fish Habitat...... 8 Methods...... 8 Assessment Methods...... 8

Key Fish Species and Their Habitat Requirements ...... 10 Targeted Fish Species...... 10 Key Fishery Species and Habitat Links...... 10 King George Whiting ...... 10 Rock Flathead ...... 11 Southern sea garfish ...... 13 Greenback flounder...... 13

Corner Inlet Fish Habitats 2007 iii Calamari ...... 14 Important Fisheries Habitat Summary ...... 14

Status of Important Fish Habitat...... 16 Water...... 16 Seagrass ...... 16 Unvegetated Soft Sediments...... 17 Threats...... 17 Sedimentation and Turbidity ...... 17 Hydrodynamics...... 18 Water Quality ...... 18 Spartina...... 18 Management Implications...... 18

2007 Assessment Summary...... 20 Status ...... 20 Research Needs...... 21

Acknowledgements ...... 22

References ...... 23

Glossary...... 26

Corner Inlet Fish Habitats 2007 iv List of Tables Table 1. Management agencies with responsibility for Corner Inlet...... 4 Table 2. Stakeholders with an interest in Corner Inlet...... 5 Table 3. A threat matrix for fish habitats in the western minor in 1998...... 7 Table 4. Research needs for the fish habitats in Corner Inlet in 1998 ...... 7 Table 5. Fish species targeted by recreational and commercial fishers within Corner Inlet ...... 10

List of Figures Figure 1. Recruitment of rock flathead showing observed recruitment and recruitment predicted using an environmental‐recruitment model based on winter flow from the Franklin River...... 12

Corner Inlet Fish Habitats 2007 v Corner Inlet Fish Habitats 2007 vi Executive Summary

The sustainable harvest of any fishery resource is • Which of these habitats drive the production dependent on maintaining the integrity of the of the targeted species? habitats, environmental conditions and The assessment concluded that seagrass habitat is ecological processes that support the production crucial for driving fisheries production in Corner of that resource. Fisheries Victoria has Inlet, as seagrass‐based food webs contribute a established a formal Fish Habitat Assessment large proportion of the nutrition for King George process to provide scientific information on the whiting and southern sea garfish. identity and status of marine fish habitats. This information is essential for facilitating protection The CI HAG identified four threats to the of important fish habitats and thus continued habitats within Corner Inlet: production of fish. • Increasing sediment deposition rates and Corner Inlet is an internationally recognised erosion Ramsar wetland, containing a rich biodiversity of • Changes in hydrodynamics associated with flora and fauna, and supports both commercial climate change and recreational fisheries. • Decreased water quality The inaugural meeting of the Corner Inlet Fish • The ongoing presence of Spartina. Habitat Assessment Group (CI HAG) was held in In relation to these threats, the CI HAG posed the 1998. The second meeting occurred on 29 May following questions: 2007 at Foster. • How do the threatening processes impact on The CI HAG identified fish species that are or the factors that link fish to habitat? have been historically targeted by fishers in the • Which, if any, of these processes are Corner Inlet: significantly decreasing fisheries production • King George whiting in the inlet? • rock flathead The CI HAG concluded the threats may cause: • greenback flounder • Decreased availability of food • southern sea garfish • Reduction in habitat for seagrass dependent • calamari. species • A change in primary production from These species are resident in the inlet throughout seagrass to opportunistic algae. their life or depend on habitats within the Inlet at critical life stages. In the opinion of the CI HAG it was unclear to what extent these threats affect fisheries The CI HAG identified four known habitat production. These identified the following requirements of each life stage of these species research priorities: within Corner Inlet, namely: • Determine the critical habitat dependencies • pelagic of early life history and biology of rock • seagrass flathead, flounder and calamari and to a lesser extent • Identify settlement timing and critical habitat • unvegetated sediments for juvenile King George whiting • . • Determine the relative importance of the macro‐algae, micro‐algae, phytoplankton, To determine which of these habitats were seagrasses (all species) and epiphytes in crucial to King George whiting, rock flathead, sustaining the production of King George greenback flounder, southern sea garfish and whiting, garfish, flounder and rock flathead calamari in these river estuaries, the CI HAG posed the following questions: • Identify “slub” (a single‐celled, brown‐green, filamentous algae which extends from the • What are the factors that link key fisheries shore into the inlet, overgrowing both species to these habitats? i.e. Are all equally vegetative and non‐vegetative habitats) and important?

Corner Inlet Fish Habitats 2007 vii determine its reliance on anthropogenic nitrogen sources • Determine the impact of eutrophication on fisheries production and dynamics of seagrass habitat.

Corner Inlet Fish Habitats 2007 viii Introduction

A fishery is dependent on maintaining the The objectives of the fish habitat assessment integrity of the habitats, environmental process are to: conditions and ecological processes that support • Identify fish habitats in Victorian waters production of target fish populations. that are important in supporting production Management of fisheries includes identification of key fishery target species of, and advocacy for, management actions • Assess the current status of key fish habitats needed to protect and where possible enhance • Determine processes threatening these fish ecosystems that support production of fishery habitats resources. To do this it is necessary to know: • Make recommendations on fish habitat • The type, location and extent of habitat and research and monitoring needed to assist in environmental conditions that are important the management of fish habitats. for production and/or survival of key target fish species within the system Corner Inlet, as the second largest and inlet fishery in Victoria, contributes significantly to • The links between particular commercial and recreational fishing activities habitat/environment conditions and conducted in Victoria. production/survival of stocks of key target species This fish habitat assessment report is divided • The current status and historical trends in into the following sections: the condition of key fish habitats • A summary of the goals, objectives and • The main threats (whether from fishing or strategies in place to maintain fish habitats other non‐fishing human activities) to the • A summary of the outcomes of the previous integrity of each key fish habitat. assessment In 1995, Fisheries Victoria established a formal • Details of the aims and objectives of the 2007 fish habitat assessment process to provide Corner Inlet fish habitat assessment, and an scientific information on the location and status explanation of the methods and processes by of key marine and estuarine fish habitats as an which the assessment was conducted input to the development or review of fishery • Identification of the key fishery target species management arrangements. This process in the Inlet involves the participation of stakeholder • An update of what is known of their habitat representatives, scientists and fishery managers requirements in fish habitat assessment workshops, and the • The identification of habitats in the Inlet that publication of workshop findings in the Fisheries Victoria Assessment Report Series. support the production of the key target species Information and advice provided by these fish • An assessment of the likely main threats to habitat assessment groups (HAGs) complement the well‐being of the identified key fish the matters and issues dealt with by formal habitats stock assessment and fishery assessment • The possible fisheries management processes, and inform the development or review of habitat protection objectives in Fishery implications of the identified threats to fish Management Plans for specified waters. habitat • A summary of the assessment of fish habitats in Corner Inlet and the prioritising of research/monitoring projects required to improve future assessments of fish habitats in the Inlet.

Corner Inlet Fish Habitats 2007 1 Goals, Objectives and Strategies for Maintenance of Fish Habitats

Strategic Directions Policy and Legislative Context There is increasing evidence worldwide that the The Victorian Government and the Department sustainable use of any fishery resource is of Primary Industries are committed to applying dependent not only on controlling the direct the principles of Ecologically Sustainable impacts of fishing on fish stocks, but also on Development (ESD) to fisheries management. maintaining the integrity of the aquatic habitats, These principles are: environmental conditions and ecological • To provide for equity within and between processes that are crucial for the production generations in the use of natural resources and/or survival of target fish species. This is • To enhance individual and community well‐ particularly so in inshore marine, estuarine and being by following a path of economic inland waters facing increasing pressures from development that provides optimum current human population growth and associated benefits while safeguarding the resource use agricultural, industrial, urban and tourism options of future generations development. • To protect biological diversity and maintain Strategic directions for fish habitat assessment ecological processes and systems which are relevant to the deliberations of habitat • To adopt a precautionary principle, so that assessment groups are as follows. where there are threats of serious or Strategic goal irreversible adverse effects on resources or • To secure the future of Victorian fisheries by habitat, lack of full scientific certainty should advocating the protection and maintenance of not be used as a reason for postponing essential fish habitats. measures to prevent resource depletion or environmental degradation. Strategic objectives • Identify critical fish habitats and threatening The Fisheries Act 1995 recognises these principles processes in conjunction with stakeholders by including the following stated objectives: • To protect and conserve fisheries resources, • Lead and facilitate the development of management arrangements that maintain or habitats and ecosystems including the enhance the productive capacity of key fish maintenance of quality ecological processes and genetic diversity habitats. • To provide for the management, Strategic activities development, and use of Victoria’s fisheries, • Commission focused habitat assessment, aquaculture industries and associated monitoring and research programs biological resources in an efficient, effective • Establish partnership arrangements to and ecologically sustainable manner. influence the management of non‐fishery The Fisheries Act 1995 also specifies that a Fishery threats to key fish habitats Management Plan declared for a given fishery • Develop and implement fish habitat must identify critical components of the restoration programs in priority waters ecosystem relevant to the fishery, current or • Establish a community based fish habitat potential threats to those components, and protection focus across Victoria existing or proposed measures to protect or maintain key fish habitats. • Identify funding opportunities for fish habitat improvement and cooperate with other agencies in accessing these funds • Review legislative and policy frameworks to support fish habitat protection.

Corner Inlet Fish Habitats 2007 2 Corner Inlet

The main recreational species are King George Background whiting, sand flathead and yank flathead with Corner Inlet is an internationally recognised smaller quantities of southern sea garfish, Ramsar wetland supporting a rich diversity of snapper, Australian salmon, estuary perch and plants and animals. A description of the Corner gummy shark. The recreational fishery is Inlet region was presented to the 1998 Corner substantial, but highly seasonal with most Inlet (CI) HAG (Gunthorpe and Hamer 1998). fishing occurring in summer. This report described the Inlet, surrounding rivers and creeks, and the two basins of which Management Responsibilities Corner Inlet is composed. Responsibility for the management of Corner Inlet is shared between 16 agencies (State Fisheries of Corner Inlet Government Departments, Local Government Corner Inlet supports productive recreational Agencies and Statutory Authorities). The and commercial fisheries. responsibility of each agency or Authority is The commercial fishery produced 284 tonnes in listed in Table 1. 2005/06 with a wholesale market value of $1.7m. This is the second most valuable bay and inlet Stakeholders fishery after Bay. Those who use or have an interest in the fisheries of Corner Inlet are diverse and can be The commercial catch and value of the main classified into three broad groups (Table 2), species in 2005/06 were rock flathead (54 tonnes, based on the types of activities that are $0.24m) southern sea garfish (49 tonnes, $0.3m); conducted. These range from non‐profit King George whiting (43 tonnes, $0.5m); recreational activities such as swimming, southern calamari (24 tonnes, 0.2m); silver boating and fishing to enterprises that are reliant trevally (20 tonnes, $0.06m); greenback flounder on the Inlet for commercial activities. (16 tonnes, $0.1m); and gummy shark (12 tonnes, $0.1m). One group of stakeholders includes the Government Agencies, Local Authorities and The recreational fishery in Corner Inlet is almost Peak Bodies that represent or regulate the wide entirely based on boat anglers, but there are range of groups that use the estuarine reaches of several charter boat operators and a small hand‐ the rivers. The management agencies listed in spear fishery for flounder which is conducted Table 1 are also stakeholders in the Inlet. mostly at night at low tide. The main boat access points are at Port Albert, Port Welshpool, Yanakie, Toora, McLoughlin’s Beach and Mann’s Beach.

Corner Inlet Fish Habitats 2007 3 Table 1. Management agencies with responsibility for Corner Inlet Agency Responsibility

Department of Innovation, Industry and Regional • Primarily as funding source for construction of Development public infrastructure. Fisheries Victoria, Department of Primary Industries • Management of the fisheries. Department of Sustainability and Environment • Management of catchments, coastal crown land and national/coastal parks. West Gippsland Catchment Management Authority • Management of catchments and rivers. South Gippsland Region Water Authority • Management of water supplies and sewerage systems. Environment Protection Authority (Victoria) • Protection of water quality of Corner Inlet. Gippsland Coastal Board • Provision of coordinated strategic planning and management of Corner Inlet. Victorian Environmental Assessment Council • Provision of recommendations to the Victorian Government about public land (including marine, estuarine and coastal) to provide for its balanced use. Esso Australia Ltd • Management of the shore facility at Barry’s Beach Gippsland Ports • Management of navigable channels for Port Albert, Port Welshpool and Barry’s Beach. Committees of Management • Management of coastal lands eg Port Franklin. Parks Victoria • Management of other channels. • Management of Ramsar wetlands. • Management of national coastal parks and marine national park. Local Government – Wellington Shire Council, South • Management of local municipalities around Gippsland Shire Council. margins of Corner Inlet. • Management of town and roadside drainage. Marine Board • Issuing of licences for operation of various types of commercial water vessels. State Boating Council • Provision of funding for infrastructure such as boat ramps and jetties. Water Police • Ensuring the compliance of the public to fisheries acts, maintaining water quality, responsible boating.

Corner Inlet Fish Habitats 2007 4 Table 2. Stakeholders with an interest in Corner Inlet Stakeholder

Community • Coast Action / Coast Care • Conservation groups and organisations. • Consumers of seafood from Corner Inlet. • Ecotourists. • Landcare • Private land holders • Recreational boating. • Recreational diving, snorkelling and other passive users. • Recreational fishers. • Recreational swimmers and beach goers. • Waterwatch Industry • Corner Inlet Fish Habitat Association. • Cattlemen’s Association. • Agriculture. • The charter industry (tourism and recreational fishing). • The commercial fishing industry, retail outlets of local seafood and seafood restaurants. • The diving and snorkelling industry. • The recreational fishing and boating industry. • The recreational fishing and boating media. • The tourism industry. • Waste dischargers. Non Management Government Agencies, Statutory Authorities and Peak Bodies • Department of Treasury and Finance. • Department of Premier and Cabinet. • Fisheries Co‐Management Council. • Victorian Recreational Fishers Peak Body. • Seafood Industry Victoria. • Victorian National Parks Association.

Corner Inlet Fish Habitats 2007 5 1998 Assessment

• relative contribution of certain habitats to Status fisheries production. Insufficient information was available to assess quantitatively the status of fish habitats and A major threat to fish habitat in Corner Inlet in threatening processes in Corner Inlet in 1998. 1998 was posed by the spread of Spartina onto Very few studies had been conducted on the estuarine and intertidal habitats. The potential flora and fauna of the Inlet, and those that had existed for a significant loss of fish habitat to been undertaken were nearly ten years old. occur. The risk to fish habitat from the exotic macroalga Codium was not known. Although if It was the belief of the CI HAG, based on limited another outbreak was to occur, significant scientific information and on the observations of reduction to unvegetated sediment habitats is HAG members, that the fish habitats within likely to be the result. The expansion of this Corner Inlet were in fairly good condition. species across unvegetated habitats in Corner Corner Inlet appeared to be affected little by Inlet had been linked anecdotally to the decline human activities when compared with other in flounder catches. The risk of introductions of Victorian inlets. other destructive exotic species through There was no evidence (scientific or anecdotal) shipping remains. of major habitat degradation in Corner Inlet. Sedimentation was implicated in the loss of 25% There had been historical clearing of mangroves of the seagrass habitat in Corner Inlet during the and saltmarsh habitats resulting in loss of 1980s, though extensive recovery of this habitat habitat. Wetland habitat was also lost through was evident in 1998. The draft Corner Inlet land reclamation activities. The extent of overall Fisheries Management Plan stressed the loss was unknown. importance of catchment management to reduce The biomass of fish taken from the Inlet sediment inputs in the future. The loss of shallow unvegetated and seagrass habitats appeared to be stable (MacDonald 1997) though the species composition had changed. Little was through sedimentation would be expected to known about the causative agents of these affect most of the fish species in Corner Inlet to varying degrees. compositional changes, though it is possible these were a result of natural events, rather than Physical disturbance caused by boating as a result of human impacts. activities, bait collection and dredging were also identified as threats, particularly on a local scale. There was evidence of major seagrass fluctuations within the Inlet, though at the time of the 1998 assessment, seagrass coverage was Management Implications extensive and apparently healthy. Again the The management implications of the major causes of these fluctuations were not known. threats to Corner Inlet fish habitat are: The CI HAG identified a lack of scientific • Restriction and loss of habitat, which may information relating to habitats and their threats result in decreased food availability, within the Inlet. More specifically, the HAG increased vulnerability of fish to identified information gaps in the following competition, and which may also restrict areas: recruitment to the fisheries • nutrient status of waters and sediments • Deterioration in the quality and suitability of habitats for fish species, which may result • immediate threats posed by exotic species in altered community structures, reduced and toxicants. fish abundance and decreased spawning Concerns were also expressed about the lack of and nursery habitat. information on: • fish/habitat links Research Priorities • fish biology (all life stages) It was not the intention of the CI HAG to downplay the importance of or the need for any of the monitoring, research and management

Corner Inlet Fish Habitats 2007 6 actions identified in the assessment. They felt The lack of knowledge concerning the value of some priority should be assigned to those many habitats to fish was also seen as a threat to processes that posed the greatest threat to the the effective management of fish resources in most habitats within the Inlet. Corner Inlet. Suggestions for immediate research needs based on the 1998 assessment of The CI HAG developed a threat matrix for the Corner Inlet fish habitats were given (Table 4). habitats discussed in the assessment (Table 3). From this table it is evident that excessive nutrient input and sediment deposition / turbidity posed the greatest threat to fish habitat.

Table 3. A threat matrix for fish habitats in the western minor inlets in 1998 THREAT HABITAT TYPE 1 2 3 4 5 6 7 seagrass unvegetated pelagic estuaries macroalgae reef sediments Nutrients ••• •• ••• ? ••• ? •? •? Sedimentation/tur ••• •? •? ••• ? ••* •? bidity Exotic species •• ••• ? ••• ? ••• ? Toxicants •?* •?* •?* •?* ? •?* •?* Water abstraction ‐ ‐ ‐ •• ‐ •? ‐ Physical ••* ‐ ‐ •• •? •• • disturbances

Both threats and habitats types are listed in order of their importance for the western minor inlets. Dots indicate priorities as follows; ‘•••‘ High; ‘••‘ Medium, ‘•‘ Low and ‘?’ unknown or uncertainty. “*” indicates localised areas of threat, ‘‐’indicates the threat is not applicable to the habitat.

Table 4. Research needs for the fish habitats in Corner Inlet in 1998 Priority Research High Water quality assessment. Sediment quality assessment. Biological data for the older juvenile life stages of targeted fish species. Develop a hydrodynamic model to be used to determine fish recruitment patterns and to evaluate the spatial extent of impact from nutrients/sediments. Determine relationship/links between fish life stages and habitats.

Medium Determine impact and presence of exotic species. Determine natural dynamics of seagrasses habitats within the inlet. Determine the impact of broccoli weed (Codium) on fish habitat and fish distribution.

Low Determine the impacts of toxicants on fish life stages. Value of habitats for fish production: • estuaries • mangroves • macroalgal • hard substrates.

Corner Inlet Fish Habitats 2007 7 The 2007 Assessment

Aims, Objectives and Strategies of the Assessment Aims high water mark along the outer or seaward • To update data on the status of estuarine shoreline of the Nooramunga Islands that enclose reaches of rivers within Corner Inlet upon Inlet, crossing the entrances at which fisheries resources are dependent McLoughlins Beach, Manns Beach, Kate • To identify management actions and Kearney’s and Port Albert with a straight line recommend future directions for habitat between the mean high water marks on the research. seaward extremities on each side of each entrance, continuing along the mean high tide Objectives water mark on the outer or seaward shoreline of • Identify habitats important to key target Snake Island to the westerly point on Bentley species in Corner Inlet Point (approximately latitude 38°46’5S longitude • Provide up‐to‐date summaries of research 145°59’6E) thence a straight line to the mean high and monitoring programs water mark on Wilsons Promontory.” • Assess the current state of crucial fish In the rivers and creeks that enter the Inlet, the habitats area is bounded by the limit of tidal penetration • Identify processes which pose major threats and does not include the freshwater reaches. to key fish habitat habitats • Provide a qualitative risk assessment of the Definition of a Fish Habitat main threats to crucial fish habitats For the purposes of this assessment, a habitat • Identify management issues for crucial fish was defined as the ecological processes, broad habitats physical structures, zones and biological • Identify research and monitoring needs to communities that support fish. The emphasis of assist in the management of each habitat. this report is on those habitats which support fish Strategies targeted by recreational fishers and key prey • Characterise the important habitats for each species. of the fisheries resources of Corner Inlet Particular attention was given to those target beginning with King George whiting and species that are most reliant on Corner Inlet. rock flathead • Establish archival databases of all relevant Methods research and monitoring material for each Data important fish habitat in Corner Inlet A literature search was undertaken to provide • Synthesise available data, identify the major information on Corner Inlet and the habitats threats to each critical habitat and provide contained therein published since the last options to reduce these threats in Corner workshop was held in 1998. Inlet. Information was also obtained from published papers and reports, and unpublished data and Boundaries of estuaries reports held by various State Government For the purposes of this assessment the area research agencies and statutory authorities. defined in the Draft Fisheries Management Plan was considered and is detailed below: Assessment Methods The workshop began by updating the previous “…. the waters of Corner Inlet are defined as the assessment, incorporating scientific data, total area of all the bays, inlets and entrances, anecdotal information and management actions, bounded by a line running generally south which provided information on the current status westerly from the mean high water mark on the of fish habitats within Corner Inlet. south westerly end of the Ninety Mile Beach (McLoughlins Entrance) which follows the mean

Corner Inlet Fish Habitats 2007 8 An assessment of the status of each habitat was undertaken. The main threats to each habitat were then identified and their implications for fisheries management detailed. Finally the future research and monitoring needs for each habitat were identified.

Corner Inlet Fish Habitats 2007 9 Key Fish Species and Their Habitat Requirements

Targeted Fish Species King George Whiting King George whiting is a demersal species The inaugural 1998 CI HAG identified eighteen found from northern to the species of fish as important components of the south‐west coast of West Australia, including recreational and/or commercial fisheries of the north coast of (Paxton et al. 1989). Corner Inlet (Gunthorpe and Hamer 1998). Of Juvenile fish are restricted to bays and inlets these species, five are either specifically targeted while adults are found in bays and inlets and by fishers or have been an important component open coastal waters (Kailola et al. 1993). of Corner Inlet’s fisheries in the past (Table 5). King George whiting have a life expectancy of The 2007 CI HAG focused on King George 15 years and are thought to reach sexual whiting, rock flathead, southern sea garfish, maturity at three years when fish are 35 cm in flounder and calamari because: length (Jones et al. 1990). King George whiting • These species are or have been historically from Victorian waters spawn from May to July targeted by fishers (Jenkins and May 1994). While it is known that • Many are resident within the Inlet this species does not use bays or inlets for throughout their life spawning (Jenkins 1986), the spawning • Several have critical life stages, and are location(s) or habitats of King George whiting dependent on habitats within the Inlet are not known. Research suggests that spawning • Most are resident or habitat–dependent fish may take place in coastal waters to the west of and are thought to provide a good indicator Victoria’s major bays and inlets, and that a of environmental ‘health’. proportion of Victoria’s King George whiting population may be spawned in South Australian Key Fishery Species and Habitat waters (Jenkins et al. 2000). In , spawning King George whiting have been Links found in waters near Kangaroo Island and at the The 2007 workshop updated the known habitat tip of the Eyre Peninsula (Fowler and McGarvey requirements for the five key species and the 1997). habitat requirements of each life stage were identified. King George whiting eggs are buoyant, and hatch within two days of fertilisation (G. Jenkins This information: pers. comm.). The larval stages may spend from • was based on the literature where it is about 90 to 150 days drifting in coastal waters referenced and for Corner Inlet specifically, before entering Victorian bays and inlets during when unreferenced, from the experience spring, at a size of around 20 mm long (Jenkins and knowledge of HAG participants and May 1994). King George Whiting larvae are • supplements that presented in the 1998 not found in Corner Inlet. Assessment (Gunthorpe and Hamer 1998).

Table 5. Fish species targeted by recreational and commercial fishers within Corner Inlet Species Common Name Fish targeted by* Sillaginodes punctata King George whiting com, rec Platycephalus laevigatus rock flathead com Hyporhamphus melanochir garfish, sea com Rhombosolea tapirina greenback flounder com bycatch, rec minor Sepioteuthis australis calamari com, rec * Recreational target species are indicated by ‘rec’ and commercial target species are indicated by ‘com’.

Corner Inlet Fish Habitats 2007 10 Juvenile and fishery sized whiting predominate Rock Flathead in Corner Inlet. The source of these fish is not Rock flathead spend their entire life‐cycle within known. shallow bays and inlets. These are seagrass– Juveniles remain closely associated with shallow associated fish. seagrass and algal habitats for four to five Rock flathead are generally long lived. Females months after settlement before moving to tend to be larger and older than males and can unvegetated sand patches amongst vegetated live to be 21 years old (56 cm in length), while habitats (Jenkins and Wheatley 1998). With this males can live to 16 years old (49 cm). Maturity change in habitat use diet also changes from tiny occurs at 1.8 years for males (23 cm length) and crustaceans to polychaetes and larger 1.4 years for females (26 cm length) (Koopman crustaceans, which are sourced from bare sand 2003). and mud patches near seagrass and reefs. Most rock flathead are in spawning condition all Older juveniles venture into deeper water, year. In Corner Inlet, spawning has been where they are more common over sandy, observed to commence in October and be muddy areas with patchy seagrass and algae (G. completed by February (Gary Cripps pers. Jenkins pers. comm.). comm.). In Corner Inlet, whiting (27 to 35 cm) feed over Spawning has been observed to occur over sand sand during the night and move onto seagrass spits near broad‐leaf seagrass (Posidonia) and during the day. Fish (< 25 cm) often disappear near the junction of channels. In Corner Inlet during winter, though smaller fish (20 cm) at rock flathead require sand (unvegetated this time can be found in shallow areas. Larger substrate) near seagrass. The fish come out of fish (40 cm) are associated with deeper channels seagrass onto sand to spawn. This occurs at the in Corner Inlet, but can also be found over top of the incoming tide and may be a strategy seagrass. It is not clear whether these fish are to disperse eggs throughout the inlet. moving throughout the inlet at different times, or whether they display specific habitat Observations of local fishers suggest that preferences at different ages. spawning is strongest on days when there is a fresh easterly blowing and the water is a little King George whiting are also found in murky. The spawning runs are not as strong macroalgal beds, and this species appears to when the water is clearer under south‐westerly actively prefer macroalgal habitats in Corner winds. In Corner Inlet this spawning activity Inlet at certain times of the year. It is thought usually peaks over a month and a half – this preference reflects the availability of food. normally October and November. King George whiting migrate out of bays and The eggs may be negatively buoyant, sinking to inlets at approximately four years of age (Jones the bottom. In Corner Inlet, fishers report seeing et al. 1990). velvet crabs in greater numbers and more often No work has been done on feeding of early during spawning. larval stages in coastal waters. In Port Phillip No information is available concerning the Bay, the diet of late‐stage planktonic King larval biology of this species. George whiting larvae is composed primarily of planktonic calanoid copepods; however, a range Recruitment of juvenile rock flathead in Corner of other zooplankton are also important (G. Inlet has been observed during December by Jenkins pers comm.). The diet of young juveniles Jenkins et al. (1993a). Jenkins et al. (1993a) found is dominated by benthic and epifaunal that newly‐settled rock flathead show a organisms such as harpacticoid copepods and preference for unvegetated habitats while older amphipods, and a range of other small juveniles and adults prefer seagrass. A similar crustaceans that live near the bottom (Robertson pattern has been observed in 1977; Edgar et al. 1993; Jenkins et al. 1996). As (Edgar et al. 1993). individuals grow, their diet expands to include Recruitment of rock flathead in Corner Inlet is larger benthic organisms such as polychaete variable. Koopman et al. (2003) used river worms, ghost shrimp (Callianassa), molluscs and discharge and SOI data to determine if there was peanut worms (Sipuncula) (Robertson 1977). a correlation between recruitment and Polychaetes may dominate the diet of the larger environmental variables. Recruitment was King George whiting in Victorian bays (Parry et significantly correlated with total discharge al. 1995).

Corner Inlet Fish Habitats 2007 11 from the Franklin and Agnes Rivers (Figure 1), Adult rock flathead are found almost and the relationship was particularly strong exclusively with seagrass (G. Cripps pers. during winter. Nearly 60% of the variation in comm.). recruitment could be explained by river flow. Adult rock flathead are known to feed on fish, The relationship was negative, so that years of squid, shrimps, and crab in Port Phillip Bay. higher discharge also had poorer recruitment. Nutrition is derived from brown algae, Possible causal mechanisms for this relationship epiphytes, red algae, benthic microalgae, green are unknown. algae, phytoplankton and seagrass. This broad Strong recruitment events occurred during 1994, range of primary producers gives resilience to 1997 and 1998, while poor recruitment occurred the fishery, as the loss of any one food source during 1992, 1993 and 1996. can be compensated by others. In a system where seagrass dominates, the level of reliance In Corner Inlet, commercial fishers report first offered may be reduced in the instance of a observing 1+ rock flathead when they are about basin wide dieback of seagrass, as other primary 10–12.5 cm. This size rock flathead are found producers are neither widespread nor abundant. over broad leaf and fine leaf seagrass (Heterozostera/ Zostera), often in intertidal areas. This size has not been observed in the channel habitats.

4 Observed relative abundance of recruits Predicted relative number of recruits

3

2

Relative abundance 1

0 1992 1993 1994 1995 1996 1997 1998 1999

Figure 1. Recruitment of rock flathead showing observed recruitment and recruitment predicted using an environmental‐recruitment model based on winter flow from the Franklin River.

Corner Inlet Fish Habitats 2007 12 Southern sea garfish Western Port have an unusual diet that consists Southern sea garfish is a pelagic species found primarily of plant matter, in particular seagrass from Eden in New South Wales to Kalbarri in (Zostera sp.), during the day and planktonic West Australia, including Tasmania (Kailola et al. crustaceans during night (Klumpp and Nichols 1993). Southern sea garfish are most common in 1983). bays and coastal waters but may also occur in Greenback flounder estuaries. This species is a schooling fish and is Greenback flounder are commonly found in generally found in surface waters (Kailola et al. estuaries, bays and inshore coastal waters from 1993). southern New South Wales to the east coast of Southern sea garfish may live for up to 10 years West Australia, including Tasmania (Gomon et (Jones 1990) and reach 50 cm in length (Collette al. 1994). Greenback flounder are demersal and 1974). Sexual maturity occurs when fish are two are most common on unvegetated sediments to three years of age and are 25 to 30 cm in length (Hutchins and Swainston 1986; Kuiter 1993). (Ling 1958; Jones 1990). Southern sea garfish Greenback flounder can tolerate a wide range of spawn in late spring and summer, with the peak salinities and water temperatures (Kailola et al. spawning period reported to be from October to 1993). November (Ling 1958; Jones 1990). Greenback flounder may live for three to four The eggs have adhesive filaments that are used years reaching a maximum size of 40 cm in for attachment to filamentous algae (Mills et al. length and reach maturity at sizes of between 19 1997) and possibly seagrass (Ling 1958). The and 30 cm long (Kailola et al. 1993). Spawning is importance of seagrass beds as spawning areas is thought to occur in offshore waters from March yet to be confirmed; Mills et al. (1997) have found through to October (Kurth 1957; Crawford 1984) sea garfish eggs attached to filamentous algae and the presence of eggs and recently hatched (drift) in Tasmania at depths of two to six metres. larvae in Port Phillip Bay indicates that spawning It is possible that the major spawning grounds also occurs in coastal bays during winter (Jenkins for this species occur offshore in coastal waters. 1986). In Corner Inlet, roed fish have been caught While it is not known if sea garfish spawn within in channels and in shallow areas, though little is Corner Inlet, eggs from an unidentified fish known about the spawning behaviour in this species have been reported in seagrass, and Inlet. The amount of roe increases significantly female sea garfish with roe have been caught in after May. the Inlet in October and November. The eggs Eggs are planktonic and hatch about four days hatch 30 days after fertilisation (Mills et al. 1997). after fertilisation (Crawford 1984). In Port Phillip Larvae and small juveniles appear in Port Phillip larvae may spend a month or more drifting in the Bay during summer (Jenkins 1986; Neira and Tait water column (Jenkins 1987) before 1996; Hamer et al. unpublished data) though little metamorphosing and settling onto shallow else is known about these early life stages. While inshore sand and mud flats during late winter it is known that the larvae are pelagic, the areas and early spring at about 10 mm length (May within the inlet that are important to garfish and Jenkins 1992). larvae are not known. Intertidal unvegetated areas are important Larger juveniles have been found in low nursery areas for juvenile greenback flounder numbers over seagrass beds (Heterozostera) in (Jenkins and Wheatley 1998; Jenkins et al. 1997 b). Corner Inlet but little is known about the habitat Areas with patchy macrophyte cover are also preferences of this life stage. Very few juveniles likely to be important nursery areas. This is due have been seen in Corner Inlet, though to the increased food availability resulting from historically juveniles were reported in organic enrichment of the sediments by mangroves. Juveniles are pelagic and the degree macrophyte detritus (Shaw and Jenkins 1992). to which various other habitats, such as Greenback flounder move into deeper mangroves, provide food, is not well understood unvegetated habitats as they grow, but may still (Hamer, pers comm). occur in shallow areas as older juveniles. Larvae and small juvenile sea garfish probably Historically, thousands of juvenile fish were feed on a range of zooplankton and reported from the mangrove habitats around phytoplankton, although there is no detailed Corner Inlet. information on the diets of these life stages. Adult flounder can be found throughout Corner Larger juveniles (>10 cm long) and adults in Inlet, in both shallow and deep water usually on

Corner Inlet Fish Habitats 2007 13 bare substrates near seagrass beds (particularly are resident within the Inlet and depend Posidonia). Adult flounder are generally not throughout their life history on the quality of the found in macroalgal habitats. environment within the Inlet. Larval stages may feed on dinoflagellates and Building on the broad habitats identified in the zooplankton such as bivalve veligers, copepods previous assessment, the 2007 CI HAG identified and nauplii (Jenkins 1986). The diets of juveniles four habitats used by King George whiting, rock and adults are primarily composed of sediment‐ flathead, southern sea garfish, greenback associated organisms such as diatoms, plant flounder and calamari within the Inlet (Table 4). material, polychaete worms, nematodes, small These are: bivalve molluscs, harpacticoid copepods and • water amphipods (Shaw and Jenkins 1992; Rigby 1984). • seagrass Calamari • bare sediments Southern calamari are found along the • mangroves. southerncoast of Australia from Brisbane in to Dampier in To determine which of the habitats are crucial to (Kailola et al. 1993). Calamari can be found in fish production in Corner Inlet, the 2007 CI HAG bays and inlets and along the shallow coastal posed the following questions: margins. • What are the factors that link these species to these habitats? i.e. Are all equally important? While calamari are thought to spawn throughout the year, spawning peaks in summer, though the • Which of these habitats drive the production timing does vary from state to state (Kailola et al. of the targeted species? 1993). Peak spawning occurs in summer and winter in South Australia and from August to January off Victoria (Kailola et al. 1993). Calamari are thought to spawn in Corner Inlet though there is no direct evidence for this. In other inlets and embayments, spawning takes place over seagrass (Heterozostera) and macroalgal habitats. Eggs are contained in capsules (4 to 5 per capsule) and attached to the benthic substrate (Kailola et al. 1993). Egg masses can contain up to several hundred capsules (Parry et al. 1990) and are protected by adults. The egg masses are susceptible to physical disturbance (e.g. seine nets). Larval calamari are planktonic, swimming to the surface after hatching, where they remain in the plankton until they reach 7 cm in mantle length (Jones et al. 1990 in Kailola et al. 1993). Adults are found throughout the year in Corner Inlet and display no obvious habitat preferences. Southern calamari live for approximately two years. They are quick growing and attain sexual maturity at 12 months of age (Kailola et al. 1993). Calamari are visual predators and feed on fish, prawns (Kailola et al. 1993) and when in aggregations may cannibalise other smaller calamari (Jones et al. 1990 in Kailola et al. 1993). Important Fisheries Habitat Summary The 2007 CI HAG focused on King George whiting, rock flathead, southern sea garfish, greenback flounder and calamari as these species

Corner Inlet Fish Habitats 2007 14 Table 4. Summary of habitat usage by each life stage of key fish species in Corner Inlet. Life Habitat stage King George whiting Rock flathead Flounder Southern sea Calamari garfish Spawning does not occur in the Inlet Out of seagrass bare ? ?Ripe gars in CI on veg. lower parts of substrate. At head of Ripe flounder in ‐ inlet, well flushed junction between 2 CI marine waters, also channels. On sand spits outside inlet

Eggs & does not occur in the Inlet ? Pelagic? ?seagrass Lower parts of inlet, larvae well flushed cool, marine waters

NS juv does not occur in the Inlet ??? Shallow sand & ?: CI. Small juveniles? mud flats?

0+ juv Sparse Seagrass/sand then Shallow sparse seagrass unvegetated areas ? bare sand amongst (broard & Narrow) (intertidal – 2 m) vegetation Patchy seagrass First observed at 8 cm in ?mangrove winter in CI

1+ juv Deeper when warm, bare Bare substrates ~ Pelagic with patchy seagrass, Seagrass near seagrass Over seagrass Nutrition all species seagrass Affected by river flow Mangroves? & epiphytes Çflow È recruitment

adults >4 years leave the inlet Seagrass Wide range of p. Bare substrates Pelagic + seagrass, highly mobile producers algae (red, near seagrass Food derived from predator, pelagic brown, green micro) mangrove Eiphytes + seagrass plankton, seagrass Wide range of p. producers algae Where ? indicates unknown or uncertainty and NS indicates newly settled juveniles

Corner Inlet Fish Habitats 2007 15 Status of Important Fish Habitat

In the Gippsland Natural Resources Report were not thought to be problematic except at Card for 2007 (West Gippsland Catchment three sites (see below). Management Authority 2007), which is an Nutrients in water exceeded quality objectives assessment of overall environmental condition set by the EPA at all sites, but more frequently at based on land, water, biodiversity and air Franklin and Yanakie, with ammonia and nitrate indicators, Corner Inlet was given a condition levels being exceptionally high at Yanakie. rating C. This means that some environmental Phosphate levels did not exceed EPA trigger values are indicated as poor, but are levels at any of the sites examined, and silicate recoverable. Corner Inlet has had a condition levels were usually highest at sites with rating C since it was first assessed in 2006. significant riverine input. Since 1998, to the knowledge of the CI HAG Where metal contaminants were measured, participants, two scientific studies have been toxicants in water were lower than detection undertaken in the Corner Inlet region to limits for most metals. Pesticides in water were determine the current status of its fish habitats. all below detection limits (Hindell et al. 2007). This information is detailed below and has been A number of drains and wastewater outfalls augmented by the observations of the discharge into Corner Inlet, allowing pollutants participants of the 2007 GH HAG. and/or raw sewage to impact on water quality. Water Many of these are untreated and unmonitored, Monitoring of water quality was carried out at so their effect is unknown. six sites in Corner Inlet between January 2005 Seagrass and January 2007 (Hindell et al. 2007). Basic There are four species of seagrass in Corner water quality attributes (salinity, temperature, Inlet: Heterozostera nigricaulis, Zostera muelleri, DO, turbidity, and phytoplankton) varied Halophila ovalis, and Posidonia australis. strongly through time and among sites, but

1998 2005 2006 1998 2005 2006 1998 2005 2006

1998 2005 2006 1998 2005 2006 1998 2005 2006

Figure 2. Summary of the proportional changes in areas of unvegetated sand, sparse and dense seagrass at study sites in Corner Inlet between 1998 and 2006.

Corner Inlet Fish Habitats 2007 16 Aerial photography analysis indicates ‘Slub’ (a single‐celled, brown‐green, filamentous substantial seagrass loss in some regions of algae which extends from the shore into the Corner Inlet (Figure 2). The greatest losses have inlet, overgrowing both vegetative and non‐ been in the northwestern area (Franklin, Foster, vegetative habitats) algae has been reported in and Toora) which suffered over 90% decline Corner Inlet, and can extend up to 5 km north‐ between 1998 and 2006 (Hindell et al. 2007). west and west from the shore, particularly following rainfall. Where this occurs it can be Only one site, Yanakie, showed an increase in extremely detrimental to seagrass and seagrass– seagrass area. Where a Posidonia loss is dependent species. identified this is likely to be long lived as re‐ colonisation takes decades, if it occurs at all. Threats Baseline monitoring of seagrass beds between The 2007 CI HAG identified four threats to fish July 2000 and June 2001 was conducted along habitats within Corner Inlet: the southeastern end of Corner Inlet, where intertidal banks support both Posidonia australis • Increase in sediment deposition rates and and Heterozostera tasmanica beds (O’Hara et al. erosion 2002). • Changes in hydrodynamics associated with climate change Posidonia beds underwent a clear seasonal cycle • Decreased water quality associated with with long leaves (to 1000 m) and dense cover in sedimentation and eutrophication summer to shorter (to 300 mm) leaves in winter (possibly due to winter storms), and also • Ongoing presence of the noxious weed supported a single faunal and floral community spartina. (O’Hara et al. 2002). At sites where there was Sedimentation and Turbidity evidence of haul‐seining, the height and cover of Sediment inputs into Corner Inlet peak during Posidonia was reduced, and there was a lower periods of high rainfall and river flow. Less abundance of associated fauna. Heterozostera terrestrial vegetation as a result of recent climate beds did not show a seasonal pattern and conditions has led to increased sediment run‐off, remained approximately 200–300 mm in length and the prediction of more frequent and severe during the study period (O’Hara et al. 2002). storms poses a further risk of erosion. Recent research (Hindell et al. 2007) has Long‐term strategies are being implemented to demonstrated seagrass habitat is crucial for combat erosion, but in the short‐term current driving fisheries production in Corner Inlet. sediment loads are likely to be maintained. Seagrass and the epiphytes contributed up to Initiatives like the Golden Creek and Jack and 90% of the total nutrition of key fisheries species Albert Rivers Riparian Restoration projects have in Corner Inlet. While few of these species involved the design and construction of erosion directly eat seagrass or epiphytes, these plants control structures to slow water flow and are eaten by small animals that are eaten by encourage sediment to settle before it reaches larger animals, which in turn are eaten by the the inlet. Vegetation buffers also act as a filter target fish. Given this reliance, large‐scale for run‐off from cleared grazing land. change in seagrass cover will significantly affect High sediment loads during flood events are a Corner Inlet’s fisheries production. concern and have led to higher levels of Unvegetated Soft Sediments turbidity in Corner Inlet, which are associated Metals and pesticides do not appear to be a with seagrass decline. Sedimentation was significant issue in Corner Inlet, except around implicated in the loss of seagrass in the 1980s, as the marinas at Franklin and Welshpool, which it reduces the light available for photosynthesis had high levels of lead (and on one occasion and smothers the seagrass. Results from the copper) in the sediments. recent water quality monitoring (Hindell et al. 2007) further support these assumptions, as the Nutrient levels in sediments throughout Corner sites with the highest turbidity levels were the Inlet were lower than those recorded in the sites where most dense seagrass had been lost. , but significantly higher than High loads of sediment in the water are also those found in Port Phillip Bay (Hindell et al. likely to increase rates of sedimentation on the 2007). banks which could eventually result in higher mud banks which do not retain water at high tide, leading to seagrass desiccation.

Corner Inlet Fish Habitats 2007 17 Dredging, associated with port operations is not known, but stable isotope measurements taking place in areas around Corner Inlet (Lewis suggest primary‐treated terrestrial effluent is a Channel, Port Welshpool, Barry Beach) which likely cause (Hindell et al. 2007). It is plausible could cause localised increases in turbidity. It is that the contamination of Yanakie could have assumed that these operations are being occurred by the delivery of nutrients via the controlled and there is no threat posed to groundwater. fisheries production; however the exposing of Nitrogen isotopes can be used to distinguish substrate means the potential for invasion by between sources of effluent, as effluent which is exotic species. To minimise damage to fish terrestrial in origin is isotopically light habitats, dredging operations should adopt the compared to marine values. The stable nitrogen EPA ‘Best Practice Environmental Management isotope values of the common fisheries species Guidelines For Dredging’. King George whiting, yellow‐eye mullet, and Hydrodynamics southern sea garfish were depleted in Corner Climate change predictions include rising sea Inlet compared with samples from Western Port levels and more frequent and extreme storm and Gippsland Lakes. This was also the case for events. Changes in hydrodynamics brought on seagrass stable nitrogen isotope values (Hindell by climate change may affect larval delivery and et al. 2007). These results suggest that the connectivity with nursery habitats, which could unidentified input of nutrients somewhere on have a large impact on fisheries production. the western shore of Corner Inlet is influencing trophic dynamics at a whole‐of‐system scale. Water Quality Around 30 stormwater and agricultural drains A further indicator of elevated nutrients in and three treated wastewater outfalls (Toora, Corner Inlet is the presence of ‘slub’. It is especially detrimental to seagrass as it may Foster and Welshpool) discharge into Corner Inlet, all which may allow effluent and fertilisers reduce the amount of light available to the to enter the inlet, and have the potential to alter seagrass, which in turn may reduce photosynthesis below survival levels. When this water quality (Parks Victoria 2005). Many of these drains are untreated and not monitored so occurs there is a risk of a change in primary the risk of impact is high. Raw sewage can also production from seagrass to opportunistic algae, which also poses a threat to any other species be discharged via stormwater drains into Corner Inlet from septic systems in Port Welshpool which are seagrass dependent, and potentially during floods (Parks Victoria 2005). The need for altering fishery production. improved management regimes for existing Spartina septic tanks in unsewered coastal areas has been Spartina anglica is a major environmental weed identified by the Integrated Coastal Planning for and a declared noxious aquatic species under Gippsland Coastal Action Plan (Gippsland the Fisheries Act 1995 (Vic.). In the past it has Coastal Board 2002). been widespread in Corner Inlet, but a Land use in the catchment, including urban continuing control program initiated in 1997 has development and agriculture, has increased the seen a major decline of the species. Spartina still sediment and nutrient loads discharged into has a scattered abundance in Corner Inlet and is Corner Inlet, particularly during high rainfall being controlled by spraying, but is currently events (GRWMP 2002). Dairy farms produce not a major threat to fisheries production. large amounts of concentrated effluent which has the potential to pollute surface and Management Implications groundwater. In relation to the threats described above and in Water samples taken between January 2005 and the 1998 CI Assessment, the 2007 CI HAG posed January 2007 from three sites in Corner Inlet the following questions: (Port Franklin, Welshpool and Yanakie) were • How do the threatening processes impact on ‐1 found to have consistently high (>30 μg l ) the factors that link fish to habitat? levels of ammonia and nitrate/nitrite. Nitrogen • Which, if any, of these processes are levels in Yanakie exceeded those recommended significantly decreasing fisheries production in the 2003 State environment protection policy in Corner Inlet? environmental quality objectives by as much as twenty times the acceptable level (Hindell et al. Since the 1998 assessment there has been 2007). The precise sources of these nutrients are substantial seagrass decline in Corner Inlet,

Corner Inlet Fish Habitats 2007 18 particularly in the north‐western areas. • Change in primary production from Seagrass‐based food webs have been identified seagrass to opportunistic algae. as the main source of nutrition for several ‘icon’ The management implication is that these fish species in Corner Inlet. It is not clear to what threats have the potential to decrease the extent the seagrass loss has impacted upon these productivity and quality of fisheries in Corner species. Inlet. The threats may cause:

• Decreased availability of food • Reduction in habitat for seagrass dependent species and epiphytes

Corner Inlet Fish Habitats 2007 19 2007 Assessment Summary

• Processes by which eggs and larvae of Status flounder and rock flathead are retained The 2007 Corner Inlet Fish Habitat Assessment within Corner Inlet (CI HAG) was held in Foster on 29 May 2007. • Settlement habitats for rock flathead, The 2007 workshop focused on the habitat flounder and garfish requirements of: • Relative contributions of epiphytes and each • King George whiting species of seagrass to fish production within Corner Inlet. • rock flathead • southern sea garfish Since 1998 seagrass distribution and density has • flounder declined across Corner Inlet. These losses appear to be most pronounced in the north • calamari. western areas. Both Zostera and Posidonia beds The workshop posed three questions: have been affected. • What habitats are crucial for the production The loss of seagrass habitats would be expected of these species in Corner Inlet? to affect most of the fish species in Corner Inlet • How do threatening processes impact on the to varying degrees. factors that link fish to these habitats? • Which, if any, of these processes are Two main threats were thought to play a crucial significantly affecting fish production in role in limiting the production of fish from Corner Inlet? Corner Inlet. These were: The 2007 assessment identified: • sedimentation • euthrophication. • Seagrass is important spawning and settlement habitat for rock flathead and Sediment inputs into Corner Inlet peak during garfish, and spawning habitat for calamari periods of high rainfall and river flow. While • Bare sediments are important habitat for long‐term strategies are being implemented in older juvenile and adult flounder the catchment to reduce erosion, in the short‐ • Bare sediments near seagrass beds at the term at least, the current sediment loads are junction of channels are thought to be likely to be maintained. Future projections for important spawning habitat for rock climate change indicate that there is an flathead. increasing erosion risk in the catchments. Sedimentation was implicated in the loss of While these habitats are important for spawning seagrass from Corner Inlet in the 1980s. and settlement, recent research has indicated that fisheries production in Corner Inlet is There is significant pollution by an unidentified primarily based on seagrass and epiphytes. effluent into Corner Inlet, which is influencing Food webs derived from seagrass and epiphytes trophic dynamics. The effluent source appears contribute up to 90% of fish nutrition in Corner to be located in the north western area of Corner Inlet. Inlet. Also indicative of euthrophication is the appearance of “slub” – a brown‐green It was also evident from the HAG deliberations filamentous algae that extends from shore into that the specific habitat and ecological the inlet, overgrowing both vegetative and non‐ dependencies of some of the life stages of fish in vegetative habitats. this inlet are not known scientifically, particularly: In the opinion of the 2007 CI HAG, there was still insufficient knowledge about habitat • Spawning habitat for flounder and rock linkages and the environmental and ecological flathead processes which underlie fish production in this • Location and extent of spawning habitat region to quantify the impact these threats will (seagrass) for calamari and garfish have on fish production.

Corner Inlet Fish Habitats 2007 20 Research Needs seagrasses (all species) and epiphytes in sustaining the production of King George The 2007 CI HAG identified that the following whiting, garfish, flounder, and rock flathead research is required to determine the habitat, • and environmental and ecological processes Identify the source of pollution along the driving the production of fish: western shore of Corner Inlet, determine how it is entering the system, and quantify • Determine the critical habitat dependencies the level of contamination of early life history and biology of rock • flathead, flounder and calamari Identify “slub” and determine its reliance on anthropogenic nitrogen sources • Identify settlement timing and critical • habitat for juvenile King George whiting Determine the impact of eutrophication on fisheries production and dynamics of • Determine the relative importance of the seagrass habitat. macro‐algae, micro‐algae, phytoplankton,

Corner Inlet Fish Habitats 2007 21 Acknowledgements

This report was prepared by the Fish Habitat Assessment Group from discussions and a compilation of contributions by members of the group. Participants at the 2007 Corner Inlet fish habitat assessment workshop held on 29 May 2007 at Foster are listed as follows:

Graeme Jackson

Joel Sedgewick

Trudy Schmidt

Ross Winstanley

Murray MacDonald

Harry Houridis

Andy Stevens

Gary Cripps

Jonathon Stevens

Brett Millington

Leanne Gunthorpe

Corner Inlet 2007 22 References

Collette, B.B. (1974). The garfishes Journal of Marine and Freshwater (Hemiramphidae) of Australia and New Research, 37, 507‐520. Zealand. Records of the Australian Jenkins, G.P. (1987). Comparative diets, prey Museum, 29, 11‐105. selection, and predatory impact of co‐ Crawford, C.M. (1984). An ecological study of occurring larvae of two flounder Tasmanian flounder. Ph.D. Thesis, species. Journal of Experimental Marine University of Tasmania, Hobart. Biology and Ecology, 110, 147‐170. Edgar, G., Hammond, L. and Watson, G. (1993). Jenkins, G. P., Watson, G. F., and Hammond, L. Consequences for commercial fisheries S. (1993). Patterns of utilisation of of loss of seagrass beds in Southern seagrass (Heterozostera) dominated Australia. Final report to the Fisheries habitats as nursery areas by Research and Development Corporation commercially important fish. Final (FRDC), No. 88/91, Victorian Institute of Report to FRDC Project 89/2. Victorian Marine Sciences. Institute of Marine Sciences Technical Report. 19. pp. 101. Victorian Institute of Fowler, A.J. and McGarvey, R. (1997). King Marine Sciences, Melbourne. George whiting (Sillaginodes punctata) South Australian Fisheries Assessment Jenkins, G.P. and May, H.M. (1994). Variation in Series No. 97/6, 93pp. settlement and larval duration of King George whiting, Sillaginodes punctata Gippsland Coastal Board (2002). Integrated (Sillaginidae), in , Victoria, Coastal Planning for Gippsland Coastal Australia. Bulletin of Marine Science, 54, Action Plan. 281‐296. Gomon, M.F., Glover, C.J.M. and Kuiter, R.H. Jenkins, G.P., Wheatley, M.J. and Poore, A.G.B. (1994). The Fishes of Australia’s South (1996). Spatial variation in recruitment, Coast. Adelaide, State Prin. growth and feeding of post‐settlement GRWMP (2002). So what’s going into Corner King George whiting, Sillaginodes Inlet and where’s it coming from? punctata, associated with seagrass beds Report prepared by the Gippsland of Port Phillip Bay, Australia. Canadian Regional Water Monitoring Partnership Journal of Fisheries and Aquatic coordinator for South Gippsland Water. Sciences, 53, 96‐105. Gunthorpe, L. and Hamer, P. (1998). Corner Jenkins, G.P., Black, K.P., Wheatley, M.J., and Inlet Fish Habitats 1998, Fisheries Hatton, D.N. (1997a). Temporal and Victoria Assessment Report No. 20. spatial variability in recruitment of a Compiled by Fish Habitat Assessment temperate, seagrass‐associated fish is Group. (Fisheries Victoria: East largely determined by physical Melbourne). processes in the pre‐ and post‐ settlement phases. Marine Ecology Hindell, J., Ball, D., Brady, B. and Hatton, D. Progress Series, 148, 23‐35. (2007). Establishment of a monitoring program to assess estuarine water Jenkins, G.P., May, H.M.A., Wheatley, M.J. and quality and its effects on seagrass health Holloway, M.G. (1997b). Comparison of in Corner Inlet. Department of Primary fish assemblages associated with Industries, Queenscliff, Victoria. seagrass and adjacent unvegetated habitats of Port Phillip Bay and Corner Hutchins, B. and Swainston, R. (1986). Sea Fishes Inlet, Victoria, Australia, with emphasis of Southern Australia. Swainston on commercial species. Estuarine Publishing, Perth. Coastal and Shelf Science, 44, 569‐588. Jenkins, G.P. (1986). Composition, seasonality Jenkins, G.P. and Wheatley, M.J. (1998). The and distribution of ichthyoplankton in influence of habitat structure on Port Phillip Bay, Victoria. Australian

Corner Inlet 2007 23 nearshore fish assemblages in a Kurth, D. (1957). An investigation of the southern Australian embayment: I. greenback flounder, Rhombosolea tapirina Comparison of shallow seagrass, reef‐ Gunther. Ph.D. Thesis, University of algal, and unvegetated sand habitats, Tasmania. with emphasis on their importance to Ling, J.K. (1958). The sea garfish, Reporhamphus recruitment. Journal of Experimental melanochir, (Cuvier and Valenciennes) Marine Biology and Ecology, 221, 147‐ (Hemiramphidae), in South Australia: 172. breeding, age determination, and Jenkins, G.P., Black, K.P. and Hamer, P.A, growth rate. Australian Journal of (2000). Determination of spawning areas Marine and Freshwater Research, 9, 60‐ and larval advection pathways for King 110. George whiting in southeastern MacDonald, C.M. (1997). Corner Australia using otolith microstructure Inlet/Nooramunga fin fisheries – 1994. and hydrodynamic modelling. I. Fisheries Victoria Assessment Report Victoria. Marine Ecology Progress No. 3. Compiled by Fish Habitat Series, 199, 231‐242. Assessment Group. (Fisheries Victoria: Jones, G.K. (1990). Growth and mortality in a East Melbourne). lightly fished population of garfish May, H.M.A. and Jenkins, G.P. (1992). Patterns (Hyporhamphus melanochir), in Baird Bay, of settlement and growth of juvenile South Australia. Transactions of the flounder Rhombosolea tapirina Royal Society of South Australia, 114, determined from otolith microstructure. 37‐45. Marine Ecology Progress Series. 79, 203‐ Jones, G.K., Hall, D.A., Hill, K.M. and Staniford, 214. A. (1990). The South Australian marine Mills, D., Jordan, A. and Ewing, G. (1997). scalefish fishery: stock assessment, Preliminary findings on spawning economics, management. South distribution, egg and larval Australian Department of Fisheries development in the southern sea garfish Green Paper. 186pp. Hyporhamphus melanochir. Kailola, P.J., Williams, M.J., Stewart, P.C., ASFB/FARMAA Conference, Darwin. Reichelt, R.E., McNee, A. and Grieve, C. Neira, F.J. and Tate, S. (1996). Ichthyoplankton (1993). Australian Fisheries Resources. survey in Port Phillip Bay, Victoria, Bureau of Resource Sciences and the 1995‐1996: preliminary results. Marine Fisheries Research and Development and Freshwater Resources Institute, Corporation, Canberra Australia. Queenscliff. Internal Report. pp. 12. Imprint Limited, Brisbane. Marine and Freshwater Resources Klumpp, D.W. and Nichols, P.D. (1983). A study Institute, Queenscliff of food chains in seagrass communities O’Hara, T., Norman, M. and Staples, D. (2002). II. Foods of the rock flathead, Baseline monitoring of Posidonia Platycephalus laevigatus Cuvier, a major seagrass beds in Corner Inlet, Victoria. predator in a Posidonia asutralis seagrass Museum Victoria, Melbourne. bed. Asutralian Journal of Marine and Freshwater Research, 34, 745‐754. Parks Victoria (2005) Corner Inlet Marine National Park Management Plan Koopman M, Morison AK, Troynikov V (2003) September 2005. Parks Victoria, ʹPopulation dynamics and assessment of Melbourne. sand and rock flathead in Victorian waters. Final report to Fisheries Parry, G.D., Campbell, S.J. and Hobday, D.K. Research and Development Corporation (1990). Marine Resources off East Project No. 2000/120.ʹ Primary Gippsland, Southeastern Australia, Industries Research Victoria, Technical Report No. 72. Department of Queenscliff. Conservation and Natural Resources, Melbourne. Kuiter, R.H. (1993). Coastal Fishes of South Eastern Australia. Crawford House Parry, G.D., Hobday, D.K., Currie, D.R., Officer, Press, Bathurst, New South Wales. R.A., and Gason, A.S. (1995). The

Corner Inlet 2007 24 distribution, abundance and diets of demersal fish in Port Phillip Bay. Port

Phillip Bay Environmental Study, Technical Report No. 21. (CSIRO: Canberra).

Paxton, J.R., Hoese, D.F., Allen, G.R. and

Hanley, J.E. (1989). Zoological catalogue of Australia: Volume 7, Pisces. Petromyzontidae to carangidae. AGPS, Canberra. 664 pp. Rigby, B.A. (1984). The ecology of fish inhabiting estuarine seagrass habitats in the Gippsland Lakes, Victoria. M.Sc. Thesis. University of Melbourne, Melbourne. Robertson, A.I. (1977). Ecology of juvenile King George whiting Sillaginodes punctata (Cuvier and Valenciennes) (Pisces: Perciformes) in Western Port, Victoria. Australian Journal of Marine and Freshwater Research, 28, 35‐43.

Shaw, M. and Jenkins, G.P. (1992). Spatial variation in feeding, prey distribution and food limitation of juvenile flounder Rhombosolea tapirina Gunther. Journal of Experimental Marine Biology and Ecology, 165, 1‐21. West Gippsland Catchment Management Authority (2007) Gippsland Natural Resources Report Card for 2007,http://www.ginrf.org.au/reportcard /list.asp

Corner Inlet 2007 25 Glossary

Algae: A large group of non vascular plants, Ecologically sustainable development: The many are microscopic, and live in water. management of resources to meet the needs of the present generation without Anoxic: Devoid of oxygen. compromising the ability of future Anthropogenic: Changes resulting from human generations to meet their own needs. activities. Ecosystem: The physical, chemical and biological Aquaculture: Farming of plants or animals in environment of a community of organisms, water. and all the interactions among those organisms and between organisms and their Benthic: Belonging to the sea floor. environment. Benthos: Organisms living on or in association Effluent: An outflow usually wastewater (eg with the sea floor. sewage). Bioaccumulation: The concentration of Epiphyte: A plant growing on top of another substances (especially toxicants) in the surface (eg crab shell, pier pylon, seagrass). tissues of plants and animals. Estuary: That area within the mouth of a river Biota: All living organisms in a region. which is influenced by the sea. Bivalve: a type of mollusc possessing two shell Eutrophication: An increase in the nutrient valves joined by a hinge (eg scallops and status of a water body, and consequently the mussels). rapid growth of plants, both natural and as a Bloom: Microalgae occurring in dense numbers result of human activity. Excessive plant in a water body. production may deplete oxygen and suffocate animals. Catchment: The area of land from which run‐off from rain enters a waterway. Exotic species: Any species that is not of natural origin to a location. Chronic: Over a long period of time. Opposite of acute. Fauna: All kinds of animals. Community: In the biological sense, a Filter feeder: An animal that obtains food by community is a group of plants and animals filtering particles from water. that live together in a particular habitat. Fish: (a) live, fresh, imported or processed Often they are critically dependent on each aquatic invertebrates with gills including other, with a loss of one species leading to crustaceans, molluscs and all other forms of an impact on others. animal life other than reptiles, amphibians Contaminant: A substance out of place (also and mammals. pollutants). (b) Fish products or any part of the fish. Crustacean: Animals living in water which have Fishery: The taking of fish described by reference a hard outer surface and jointed limbs and to the species taken, the gear used and the belong to the Crusteacea. purpose of the Fishery. Demersal: Used for fish that live on or near the Fishery resources: The stock or stocks which sea floor. support the fishery. Detritus: Non‐living organic matter (eg dead Flora: All kinds of plants. seagrass). Food chain: The sequence of consumption of Ecology: The study of living of organisms and plants by animals and those animals by their relationships to one another and the other animals. environment. Food web: A complex of food chains.

Corner Inlet 2007 26 Groundwater: The part of rainfall which seeps Salinity: The salt content of the seawater. into the ground and moves slowly in a Seafood: The edible marine organisms. horizontal direction. Seagrass: A group of flowering vascular plants Habitat: The place where a plant or animal lives. which live in seawater. They take root in the Heavy metals: A general term for cadmium, sea floor. copper, iron, mercury, nickel, manganese, Sediment: The solid material that sinks to the lead, zinc, arsenic and selenium. substrate. Hydrocarbons: Compounds of hydrogen and Sewage: Loosely applied to any waste sent to a carbon such as petroleum. treatment plant. Ichthyoplankton: Fish eggs and larvae which Stakeholder: An individual or organisation float in water. interested in and able to influence the Infauna: Animals living within the sediment on management of (in this instance) Corner the sea bed. Inlet and its fisheries. Inputs: Substances entering a water body. Stormwater: Run‐off during storms. Invertebrate: Animals without a backbone. Substrate: A surface on which organisms live or into which they burrow. Larvae/Larval Fish: Early stage(s) of the life‐cycle of fish. Often fish drift in the upper layers of Sustainability: A characteristic of a process or a the water column with varying degrees of state that can be maintained indefinitely. swimming ability. Sustainable development: Improving the Macrophyte: A seaweed. capacity to convert a constant level of physical resource use to the increased Microalgae: Single celled plants. satisfaction of human needs. Mollusc: An invertebrate animal with a shell (eg Sustainable growth: A term applied only to mussel) and belonging to the phylum renewable resources. It means using them Mollusca. at rates within their capacity for renewal. Nutrients: Substances required for plant growth Suspended matter: Particles suspended in water. (eg fertilisers). Toxic: Poisonous. Organism: A living entity. Toxicant: A poison. Organochlorines: Complex organic molecules with chlorine atoms attached (eg pesticides). Trophic: Related to food chains and food webs. Pelagic: The water column. Turbidity: Cloudiness caused by sediments suspended in water. Phytoplankton: Microalgae that live in the water column. Wastewater: Water that has been used and discarded. Plankton: Aquatic, free‐drifting suspended organisms, generally but not always Zooplankton: Small animals which live in the microscopic. water column. Pollutant: A substance in excess or not belonging. Glossary compiled from definitions Producer: An organism that can create living contained in matter out of inorganic or inanimate matter. Port Phillip Bay Environmental Study : Final Productivity: The magnitude of a producer’s Report (Harris et al. 1996). activity. Port Phillip Bay Fisheries Management Plan: Recreational use: The harvesting of fish or any Background Paper (Fisheries Victoria 1996). other aquatic resource for personnel use.

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