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State of the Marine Environment Report for Australia: State and Territory Issues - Technical Annex 3

Edited by Leon P. Zann and David Sutton
Great Barrier Reef Marine Park Authority, Townsville Queensland
Department of the Environment, Sport and Territories, Canberra (1996)
ISBN 0 642 23012 9


Issues in the Tasmanian Marine Environment

Chris Rees
Prepared for the Parks and Wildlife Service
Department of Environment and Land Management
Tasmania

Introduction

Although Tasmania has been described as a region of low level development, with extensive areas of its coastline still largely intact (DELM 1991), from an ecological viewpoint little of the coastal zone has remained unchanged since European occupation. The environmental impacts of the issues described here have arisen from our centres of population, agriculture, industry, recreation, and exploitation of living and nonliving resources.

This review is restricted to the impacts of both land and sea based human activities on the marine component of the coastal zone. These activities are grouped according to type, looking at polluting activities, extractive activities, some problems arising from development and management issues, and actual changes to the coastal marine ecology. Because of this focus on problems, the overall picture is a negative one by design. It is therefore important to acknowledge that many people and organisations are engaged in reducing these impacts and working towards the ecological sustainability of our activities.

Characteristics of the Tasmanian marine environment

Around the main landmass of Tasmania are a number of small to medium sized islands, giving the State a considerable coastline with a wide range of coastal environments. The coastal climate is temperate maritime, but there are significant differences between various regions of the State. These are due to the nature of the prevailing winds, offshore currents, rainfall in adjacent catchments, tidal patterns, water and air temperatures. Tasmania's marine flora and fauna have been placed in the Maugean subprovince, but the northern and north-eastern coasts are also influenced by the Flindersian and Peronian provinces of south-eastern Australia.

Major features include: headlands interspersed with sand beaches and lagoons in the north-east; cliffed coast, sheltered bays and drowned river valleys in the south-east; cliffed coast and sand beaches in the south; sand beaches, headlands, river estuaries and harbours in the west; and open coast and river estuaries with numerous islands in the north.

Mean summer coastal water temperatures in the south approach 18C and in the north 19C. In winter, southern mean temperatures are 12C, and in the north 13C. Inshore water bodies experience a broader range of temperatures. The prevailing wind direction for Tasmania is north-westerly. These winds are strongest in winter and spring. Air temperatures for the State range from mean summer maxima of 17C to 23C, and mean winter minima of 3.1C to 7C. Tidal ranges vary from maximum of around 0.8 m in the southern Tasmanian region to as much as 3.3 m in parts of the Bass Strait.

Coastal water may be diluted for some distance offshore by the large volumes of fresh water flowing from some of the State's rivers. This is particularly true on the west coast where the annual rainfall averages around 3700 mm compared to 500 mm on the east coast. There is also heavy tannin staining in rivers on the west and north-east coasts, derived from organic soils.

Polluting activities

Many of the State's estuaries have urban and industrial development and associated coastal water pollution problems. The principal marine contaminants are localised in parts of the north coast such as the Burnie area and Tamar River, on the west coast in Macquarie Harbour and the Pieman River catchment, and the Derwent estuary in the south-east. These are the major centres of population and industry, or mineral extraction. Locations mentioned in the text are shown in Figure 1.

Mining

Most mining is concentrated in the west of the State in the Pieman catchment which drains directly into the sea [Renison (tin), Rosebery (tin, lead, zinc), Savage River (iron ore), Que River (tin, lead, zinc - now closed)], and the King river catchment which drains into Macquarie Harbour [Mt. Lyell (copper)]. The adverse effect on the marine environment is the release into rivers of dissolved and particulate waste, including chemical contaminants and heavy metals.

Figure 1

Tasmanian Coastline

In addition, some west coast mines, in particular Rosebery, Que River, and Mt. Lyell, are engaged in the mining of sulphide ore bodies. Waste dumps and exposed ore faces can continue to oxidise indefinitely from these mines to produce acid mine drainage (AMD). Worldwide this is recognised as a serious environmental problem, and once it is established there is at present no practical way to eliminate it. The lowered pH of AMD mobilises metals bound up in the ore body and sediments. At Mt. Lyell approximately 700 tonnes of copper leaves the site in AMD each year (Wood 1991).

The Pieman River was subject to an environmental monitoring program following a large fish kill in the lower river in March 1990 (Koehnken 1992), and reports of arsenic dumping and a tailings spill in the same period. The fish deaths were subsequently shown to have been caused by the release of a large volume of oxygen-depleted water from the Pieman dam.

Some 25% of water discharged at the mouth of the Pieman is derived from tributaries affected by mine discharges. The greater part of the sulphate, heavy metals, and suspended sediments carried comes from mining operations. Metal levels in fish caught in the Pieman catchment were within National Health and Medical Research Council (NH&MRC) guidelines (Koehnken 1992). Impacts of human activity in the Pieman catchment on the adjacent marine environment have not been researched.

Mineral processing

Mineral processing requires large industrial plants. The three major processing sites in Tasmania are in estuarine or coastal areas, and include Tioxide near Burnie on the north west-coast, COMALCO and BHP-TEMCO on the Tamar, and Pasminco EZ Ltd. on the Derwent.

Derwent River

Situated on the Derwent River just north of Hobart, Pasminco EZ Ltd. has been processing zinc ore since 1916. Prior to the 1970s the bulk of the waste from the plant was flushed into the Derwent River where much still lies in the sediments (H. Bloom, pers. comm. 1990).

A change from river to ocean dumping of waste by Pasminco EZ began in 1973, with approximately 200 000 tonnes per annum dropped 25 nautical miles south-east of Tasman Island. This is under a Commonwealth Government permit that expires on 31/10/95. Called Jarosite, the waste mixture contains mostly iron and ammonia (NH3) with various anions (e.g. NO3 & SO4). The dumping is within the range of the major fisheries. Pasminco EZ is proceeding with a program leading to enhanced extraction of metals from Jarosite and land based disposal methods.

North-west coast

The release of effluent from the Tioxide plant at Heybridge east of Burnie results in the deposition of a plume of iron oxide waste into Bass Strait. This settles out on the sea bed over a large area, locally suppressing the benthic biota and altering the marine biodiversity. Another major impact is to cause turbid conditions which reduces the growth of marine algae. A ministerial exemption on Tioxide's Bass Strait discharges is due to cease in 1994.

Tamar River - Bell Bay

Bell Bay has been targeted by the State Government as an industrial zone. In this area BHP-TEMCO produces specialised ferrous alloys using iron and manganese ores, and COMALCO operates a large aluminium smelter. Both operations were attracted to Tasmania by low electricity prices. There is only limited knowledge about pollution from these plants in the Tamar River or nearby marine environments , although COMALCO does have atmospheric fluoride emissions which may precipitate into the aquatic environment. Despite levels of wastewater treatment at both sites, there is still potential for heavy metal contamination from diffuse emissions draining into the river. An environmental baseline program for Bell Bay has been outlined by the Department of Environment and Land Management, and is expected to provide comprehensive data on the estuarine and marine biota of the Lower Tamar.

Other major industries

Pulp and paper mills

A pulp mill owned by Australian Paper Mills (APM) operated intermittently at Port Huon from 1967 to 1987. The mill contributed to the general loading of dissolved nutrients and particulate waste in the lower reaches of the Huon River. In particular, a substantial buildup of solids occurred in Hospital Bay, immediately adjacent to the mill. Since the mill's closure, this blanket has retreated

There were concerns from salmon farms a short distance downstream from the mill that wood fibres being washed from the foreshore loading areas could lead to fish gill irritation. In response to these concerns, the company installed foreshore bunding around the loading areas.

The Huon Estuary is the focus of periodic toxic dinoflagellate blooms. The dinoflagellates appear to have been introduced through ballast water discharges in the estuary, and ships visiting the Port Huon pulp mill may have contributed to these discharges. An increased movement of shipping into the estuary as a consequence of a proposed woodchip mill development at Whale Point will give rise to a greater risk of discharge of additional exotic organisms that may be toxic to aquaculture species and the estuarine biota.

ANM Ltd. operates a newsprint mill at Boyer on the Derwent River, which until recently has been responsible for considerable wood fibre (prior to 1988 between 80 to 140 tonnes per day) and chemical contamination of the river, including mercury. Effluent quality has now been improved, and should continue to do so with the commissioning of a secondary treatment facility in 1996.

A summary of the Derwent River Phase 2 Study of Wood Fibre Rich Sludge in the Derwent River Estuary, Spring 1991 and Summer 1992 (Derwent Estuary Advisory Committee, Department of Environment and Land Management 1992, p. 1) noted that:

`Major deposits of sludge studied in Spring 1991 and Summer 1992 were found to occur in four areas: in the mixing zone for 200 to 300m below the ANM Ltd outfall; between Green Island and Bridgewater Causeway intermittently on both shores; between Whitestone Point, Austins Ferry Bay and Dragon Point mostly on the western shore; extensively in Elwick Bay.

A limited number (11) of core samples of upper Derwent estuary sediments was obtained in Summer 1992 by means of a Pelva "bomb" sampling device. The maximum thickness values of the sludge layers of 900 mm in the mixing zone and 150 to 350 mm in various areas downriver were found to be considerably less than in cores examined in earlier studies, viz. up to 2.3m in the mixing zone in 1990, and 1 to 1.3m between Bridgewater Causeway and Bilton Bay in 1989. These results also suggested that the quantity and nature of the woodfibre load discharged by ANM Ltd at Boyer has decreased considerably since 1990.

A first (crude) estimate of the volume of sludge in the Derwent estuary in Summer 1992 was 571 500 m3 (tonnes) consisting of 82 500 m3 (tonnes) between the ANM Ltd outfall and Green Island, and 489 000 m3 (tonnes) between Green Island and Bowen Bridge. These estimates represented decreases of ~20% and ~40% respectively in these areas compared to their values in 1990.'

Overall, the upper Derwent estuary appears to be continuing to recover slowly from the severe impact previously caused by effluents containing excessive woodfibre discharged by ANM Ltd. Limited microscopic observations of sludge showed an increased abundance of viable microalgae and decreased abundance of bacteria compared to earlier studies. The abundance of organisms higher in the food chain, however, was not investigated.

Associated Pulp and Paper Manufacturers (APPM), owned by North Broken Hill Peko, have two factories on the north coast at Burnie, and Wesley Vale near Devonport. The Burnie plant produces paper, whilst Wesley Vale is currently involved with coating paper from Burnie.

The Burnie plant bleaches the paper using chlorine. Organochlorines from this process together with fibres, organic staining and plant washings form a `turbid, coloured and odorous' effluent which is discharged into Emu Bay just below the tide line. A ministerial exemption applies to the plant's discharges. Wesley Vale similarly has the potential to use chlorine bleaching, and ocean discharges include kaolin clay, wood fibre, organics and hosings. A clarifier was installed to remove solids from the effluent at the time of the recent proposal to build a much larger mill nearby.

Food processing

Most waste disposal from food related industries is adequately treated, though there are some areas of concern (J. Wood, DELM, pers comm.). Fish processing plants at Margate, Glenorchy and Triabunna treat their waste on site, while abattoirs in the State direct their waste to sewage treatment plants (STPs). However, waste from Edgells at Ulverstone enters the offshore outlet from the STP downstream of the treatment, and has high nonfiltrable residues (NFR). For this reason the STP requires an exemption.

The Cadbury factory on the Derwent discharges some dairy waste with a high biochemical oxygen demand (BOD) into the Derwent under ministerial exemption. However, an on-site treatment plant is being built which will discharge into the Cameron Bay STP.

Agricultural and urban pollution

Landfill

Urban and industrial waste is discarded in landfills in all municipalities except those which buy landfill space in adjacent areas. The siting of landfills on river banks at Huonville, Ulverstone and Queenstown, and on reclaimed wetlands at Lauderdale is no longer an acceptable practice. At least two of the riverside sites are due to be closed in the near future.

A number of the smaller rural landfills are unsupervised and the extent of contamination from hazardous wastes into groundwater systems, waterways and the coastal receiving waters is not known. The pollution risk to coastal waters from these sources requires research. The site at Lauderdale fails to meet the majority of DELM requirements, and wind blow plastic waste and ground water contamination is a pollution risk to adjacent coastal areas.

Run-off

Urban and agricultural run-off are sources of nutrient enrichment, and other forms of pollution in numerous estuaries and coastal water bodies around the State. Examples include the Derwent estuary, Tamar River, North West Bay, Duck Bay, Georges Bay, Pittwater, and numerous smaller sites.

Most piggeries, chicken farms and feed lots have no discharge into coastal waters, but the State's largest piggery at Penguin discharges its effluent directly into the sea and carries a ministerial exemption. Many rivers and ultimately the coastal waters of the north-west receive effluent from dairy farms and processors in the area, and fertiliser and pesticide run-off from intensive commercial vegetable growing. The overall extent and impact of this run-off is largely unresearched, although remedial action is being taken with some dairy farms (see `Existing and planned marine environment monitoring programs, Dept of Primary Industry', this paper) (J. Wood, DELM, pers. comm.). An example is the statewide survey of dairy sheds and intensive piggeries, and improved effluent control practices.

Sewage

Statewide, 45 STPs discharge directly into coastal, estuarine or bay receiving waters. Of these, 13 have ministerial exemptions covering effluent levels, including 4 that discharge directly into the Derwent river. The exemptions are due to cease by the 30th June 1994, although the lack of progress in the city of Hobart suggests that compliance with regulations may not be achieved in that time. State regulations for sewage discharge into receiving waters are listed in Table 1.

Upgrading of STPs has concentrated on installing secondary treatment stages to existing plant. Some community groups argue that no discharges should be permitted into rivers and coastal waters, and that a valuable resource is being wasted that simultaneously degrades the State's waters. It is now, however, becoming generally accepted that recycling and waste minimisation is the preferred approach, including reuse of the effluent. Some councils (e.g. Riverside and Scamander) are now investigating these options and guidelines have been released.

Marine accidents and spillages of hazardous materials

Disaster/contingency plans for oil spills

All oil products imported into Tasmania are in their refined state. Tank ships visit three ports on the north coast (Burnie, Devonport and Georgetown), and Hobart in the south. King and Flinders Islands also receive occasional deliveries of oil products. Hobart also services Macquarie Island and the Antarctic bases with oil products. The movements of tank ships in Tasmanian waters is relatively light compared to some large mainland ports. Average annual tank ship visits for each port are Hobart (20), Georgetown (12), Devonport (12), Burnie (18), Lady Barron (Flinders) (nil), Naracoopa (King Island) (1), and Port Latta (1).

Although considered a low risk, a major marine oil spill is always a possibility in Tasmanian waters. This could occur through collision at sea, collision or grounding close to the coast, minor collisions or spills in port, or illegal discharge of bilge water or tank washings. Under the Tasmanian Supplement to the National Plan to Combat Pollution of the Sea by Oil, coastal features at risk have been identified, and the State Marine Pollution Control Committee has contingency plans for all local port and harbour authorities in the event of maritime accidents, particularly oil spills. However, Tasmania does not have the facilities to cope with more than a minor spill, and plans for a major spill assume considerable assistance from other States as provided for under the National Plan. The Tasmanian Pollution of Waters by Oil and Noxious Substances Act 1987 provides for the management of marine oil pollution by shipping in the State.

Table 1: Ambient quality for water receiving sewage discharge

Receiving waters BOD

( mg/L)

NFR

(mg/L)

Faecal Coliforms

(/100 ml)

Grease & Oil Dissolved oxygen
Bays & estuarine 20 30 1000 visually free not reduced below 50%
Coastal no limit 200 no limit visually free not reduced below 50%

BOD - Biochemical oxygen demand
NFR - Nonfilterable residues

Oil exploration

There is currently no oil exploration in Tasmanian waters, although a production well for oil and gas is likely to be installed in the near future in the Yolla field 140 km north of Burnie. There is a further possibility of drilling on the continental shelf off the west coast near Strahan in the future. Possible exploration of oil bearing formations in the south Bruny Island area are unlikely to involve offshore drilling.

Tar deposits found on west coast beaches have been chemically linked to exposed oil-bearing formations in Indonesian waters, and are a natural phenomenon.

MARPOL

The International Convention for the Prevention of Pollution from Ships (MARPOL) annexes I (oil), II (noxious liquid substances) and V (garbage) are in force in Tasmania as throughout Australia. To date there have been no successful prosecutions in the State. This may be attributed to the complexity of Commonwealth/State administrative arrangements associated with MARPOL, a lack of resources to regulate the MARPOL system, and the need to provide better information about the Convention and its requirements.

Activities exploiting living resources - Fisheries

Some fisheries (e.g. shark, scallop, rock lobster and barracouta) are in decline, with a reduction in fishing effort recognised as being needed, while most others are being fished at rates that present knowledge cannot guarantee are ecologically sustainable. Where catch levels have been maintained it is usually due to increased effort and improved technology. The causes of decline include at least one of the following: heavy or over-exploitation, degradation of food sources, loss of breeding and nursery grounds, pollution, habitat degradation, and natural fluctuations. Also, the consequences of the by-catches of some practices on marine ecosystems is little understood. At present no allowances are made for possible long-term consequences of environmental change, even though, for example, the decline of the macroalga Macrocystis pyrifera in Tasmania is thought to be due in part to ocean warming (Sanderson 1987) (see `Ecological impacts, Habitat degradation/modification, Macrocystis pyrifera - string kelp', this paper).

In general, despite considerable research into individual fisheries in Tasmanian waters and the acceptance of the need for an holistic ecosystems approach to fisheries management, it is still not possible to predict ecologically sustainable levels of exploitation. Both commercial and recreational sectors of the industry tend to lobby decision makers to maintain the status quo until research proves that reductions are essential. The ever increasing list of over-exploited species indicates that a more cautious approach is necessary for the ecological sustainability of our marine ecosystems.

Regulation and policing of recreational and commercial fishing are problems due to lack of resources, and the perception by the fishers that penalties are small even if apprehended. Recently, penalties have significantly increased with a maximum fine from $2000 up to $500 000. The courts have also been given the option of jailing, for up to 2 years, repeat serious offenders.

General issues and commercial fisheries

Examples of fisheries where an accurate assessment of fish populations is lacking include crayfish, abalone, jack mackerel, orange roughy, and the inshore trawl fishery. Some species show a short- or long-term variability that may be environmentally induced, e.g. barracouta and jack mackerel. Others have almost certainly been over-fished. For example, the serious decline in school and gummy shark populations is leading to severe restrictions on further exploitation and the increased protection of nursery areas. Similarly, the scallop fishery has been closed since 1987 due to the collapse of the population through over-exploitation. At present there is little sign of any recovery. As part of the development of a new legislative basis for fisheries management in Tasmania, the management of all fisheries within Tasmanian fishing waters is being reviewed. This is being done through the development of individual fisheries management plans that will specifically consider the environmental impact of the activities managed under the plan. Management measures contained in the plans will additionally undergo a period of public comment before their introduction.

Jack mackerel

Jack mackerel have been fished industrially off the east coast since 1985. In 1991-92 the total allowable catch was set at 42 000 tonnes. In the previous year the catch was of 27 300 tonnes. The impact that the jack mackerel fishery has on the marine ecology is little understood, although it is known that the species is an important food source for some marine mammals, seabirds and other fish species.

Rock lobster (Jasus edwardsii)

The Tasmanian rock lobster fishery harvests the crayfish Jasus edwardsii. In the commercial fishery 10 532 pots are distributed amongst 340 vessels, with an additional 10 000 amateur licences issued annually. Current yields are considered unsustainable, with catch rates declining and the residual biomass of legal sized fish falling. Size limits must also be reviewed, as females in the north of the State do not become sexually mature before they reach the legally fishable size. A Rock Lobster Task Force has been established to study future options for the fishery (DPIF 1993) and a reduction in the fishing season has now been implemented by the Department of Primary Industry and Fisheries.

Scallop dredging and demersal trawling

Anecdotal information suggests that commercial scallop dredging in D'Entrecasteaux Channel severely degraded the substratum by exposing anoxic muds that were previously covered by sand and shell material, and that the lack of commercial scallop recruitment in recent decades is due to the altered habitat rather than overfishing itself. Whether true or not, the use of dredges which dig into the seabed clearly has the potential to cause sustained ecological damage off the eastern and northern coasts of Tasmania. This problem has only recently begun to be properly investigated in Victoria and New South Wales.

The effect of demersal trawling on the substratum, and the flora and fauna found there, is of concern both within the fishing industry and in general. The extent and impact of any effects are unknown, however, and both DPIF and the CSIRO have begun a research program into this issue.

Cockles

Some sediment dwelling bivalves, collectively referred to as Cockles, are presently being targeted for recreational and semicommercial exploitation. The harvesting of cockles can lead to the disturbance of large areas of tidal flats, where the underlying anoxic sediment is brought to the surface. This can have significant impacts on the flora and fauna of the tidal flats and the estuaries as a whole. Popular sites are Ansons Bay, Georges Bay and Recherche Bay. Commercial harvesting of clams and cockles has been banned except via limited (3) exploratory licences.

Reefs

Reef communities are targeted at all trophic levels by both recreational and commercial fishing. Examples of target species include algae, abalones, wrasses and other fish, urchins and crayfish. There is little data on interspecific interactions in reef communities.

Recreational fishing

Recreational fishing by line, net or collection is a popular pastime in Tasmania with the high level of boat and beachside shack ownership. Because of the lack of any economic restraints on recreational fishing activity, and loyalty to `traditional' fishing spots, the depletion of local fish populations may be severe, and taking undersized fish is not uncommon. Additionally, some operators can be said to fish semicommercially, with large boats and sophisticated fish location technology. The area of greatest concern is the recreational gill net fishery.

Recreational fishing using gill nets is comparatively unregulated in Tasmania, a situation the government is now trying to change, as this practice has been recognised as decimating reef fish stocks and is banned or heavily controlled in all other States and Territories in Australia. Gill netting is permitted without a licence, with three nets allowed per person, and no lower age limit on gill net ownership. There are also no controls over the length of time a net is set, or requirements for nets to be tended. Any number of nets may be set from one boat, provided the required ratio of people is present. The Division of Sea Fisheries estimates net numbers at between 15 000 and 45 000, each up to 50 m long. The maximum length of deployable net in the State may therefore be 2250 km.

The Division of Sea Fisheries is concerned at the lack of data on this practice. There is currently a draft management plan under public discussion (DPIF 1992). Gill net use has the potential to deplete reef fish communities. If poorly set or left untended they can catch indiscriminately, causing large bycatches, or if lost can `ghost fish' indefinitely. The impacts of, and practices used in, gill net fisheries, both commercial and recreational, on the reef fish communities around Tasmania are of concern. These issues are being addressed through the development of fisheries management plans and codes of practice for commercial and recreational gill net fishing.

Aquaculture

The aquaculture industry is based on the farming of finfish and shellfish. These operations generally occupy leases in sheltered coastal waterways and intertidal areas principally in the south-east of the State (see Figure 2).

Figure 2

Tasmanian Coastline

This Industry is one of the fastest growing areas of primary industry and has further potential to expand, providing new jobs and economic growth. In recognition of the benefits of aquaculture, the Department of Primary Industry and Fisheries is undertaking a major program to produce Aquaculture Development Plans (or planning schemes) that introduce a zoning system for all marine farm growing regions. Special planning legislation has been developed to support these schemes. Plans will be completed for the major growing areas in south-east Tasmania (e.g. Huon River/D'Entrecasteaux Channel) by the end of 1994. Key environmental factors are being taken into account in the delineation of aquaculture zones. Environmental management plans for each aquaculture zone and Codes of Practice to guide the operations of farms are also being introduced.

Finfish farming

Salmonid species have been farmed in Tasmania since 1984. The industry has evolved structurally and technically after an initial rush of speculative capital in the early years, and competition for suitable lease sites. These were granted in many otherwise undeveloped inshore waterways. Atlantic salmon and sea-run rainbow trout are the species farmed, with research into farming Striped Trumpeter in progress. The current state of knowledge in relation to potential environmental impacts include:

(1) adverse interactions with wildlife, with small numbers of seals and seabirds being shot. This is now very rare due to improved netting and cage design;

(2) some sea bed degradation and localised high nutrient loadings due to faecal waste: the routine rotation of cages to leave sites fallow, and minor adjustment of leases to improve natural flushing have lessened this problem. Woodward et al. (1992) in a two year study found that salmon farming was having no detectable impact on algal blooms and nutrient cycling in the Huon estuary. Localised loss of benthic biodiversity may be an issue with some groups, however, this loss is not viewed as irreversible.

(3) their visual impact in otherwise unobstructed waterways. Visual pollution, noise and loss of amenity have been common objections to the expansion of existing farms or the granting of new leases, and the alienation of the adjacent foreshore by the building of facilities is a problem in some areas;

(4) some reliance on the Jack Mackerel fishery off Tasmania's east coast for feed stock (see `Activities exploiting living resources, General issues, Jack mackerel', this paper), in addition to imported feed stocks;

(5) the impact on coastal marine ecosystems of feral fish. Some anecdotal evidence suggests that feral salmon and trout consume many juvenile native fish and other organisms, however, there is no scientific support for this view. Unpublished inspections of gut contents of many salmon specimens indicates that escaped salmon are more likely to starve, perhaps due to their habituation to pelletised food (N. Barrett, pers comm.).

There have been 36 finfish leases granted (DPI 1992), although not all these are operational. A moratorium on new salmon leases is due for review in November 1993. Some operators are presently seeking enlargements of existing leases. However, most future growth in the industry will tend to use offshore deepwater sites where there will be less impact on inshore ecosystems.

Shellfish farming

Shellfish farming includes oysters, mussels and, on a small scale, abalone. There are 91 leases granted for Pacific and/or flat oysters, though not all are occupied (DPI 1992). Shellfish farms are usually less obtrusive than finfish farms, the major points of conflict with the human community being the loss of navigable water, visual impact and noise from harvesting operations. Impacts on the coastal marine ecology are less clear. Locally there may be a loss of food for other plankton feeders, and a decline in seagrasses in the immediate vicinity of intertidal racks due to algal growth, shading and turbidity caused by boat activity. However, there is no clear scientific evidence to date in relation to these possible impacts. There is also some suggestion that seagrasses are coming back in some areas where there are oyster farms , for example Little Swanport and Moulting Bay.

Coastal and catchment management and development activities

In the postwar decades there has been considerable development of the coastal zone in many parts of the State. This includes urban and industrial development, wetland drainage, forest clearance, road building, and holiday shack development often on fragile shore land such as dune systems. Many municipal authorities have permitted coastal subdivisions in response to the demand for waterfront holiday properties. Planning and administrative problems in the coastal zone have been discussed in detail in State and Commonwealth government reports (DELM 1991; RAC 1993), and a newly established coastal policy unit within the Department of Environment and Land Management is focussed on developing an integrated coastal policy for the State. Two development issues affecting the coastal marine environment are briefly considered here.

Manipulation of hydrological cycles

The majority of the State's rivers in all regions have been dammed or modified for the production of hydro-electricity, irrigation, or domestic and industrial water supply. On the north-west coast almost all rivers are intercepted by farm irrigation dams; the west coast rivers are dominated by hydroelectric schemes, as is the Derwent flowing to the south-east; the Coal River has been dammed for a major irrigation scheme in the south-east; some east coast rivers, such as the Meredith, Prosser and Scamander, are dammed for town water supplies; and the South Esk and Tamar system supports irrigation, town water supplies and a hydroelectric scheme.

These modifications have tended to alter natural seasonal flow patterns, reduce total discharges, cause deeper penetration of saline water into some rivers, and subject some rivers to unseasonal releases of fresh water. The ecological impacts on the coastal marine environment are largely unresearched, but may result in loss of habitat, altered sedimentation patterns, and disruption to natural breeding and migratory patterns.

Port and jetty development and operations

Potential port development problems include the modification of the environment by landfill, construction and maintenance works, and the disposal of dredge spoil. These activities are usually in areas already highly modified such as Burnie, Port Dalrymple, and Hobart, but may prevent the recovery of habitat. On a small scale there are many new jetties and boat ramps added to the shoreline annually, often related to aquaculture activities or holiday shack development. Each has only a small and very local impact, but in total amount to a significant intrusion into inshore waters. An incremental loss of habitat and additional point sources of debris are possible results.

Lighthouse destaffing and implications

Under cost-cutting measures by the federal administrating body AMSA, Tasmania's lighthouses have been progressively destaffed over recent years, and replaced with automatic beacons. In many sites, particularly on the Tasmanian mainland and close to human habitation there has been no decline in safety due to the improved navigation technology of shipping. However, there are other important functions in having a human presence in remote areas that are not fulfilled by an automatic beacon.

The lighthouse on Maatsuyker Island off the south coast provides the only administrative presence in a dangerous and remote area frequented by many fishing vessels and recreational craft. Up to the minute weather reports and prognoses are obtainable from the lighthouse staff, and relief coordination in the event of mishaps at sea. Additionally, the fragile flora of nearby islands and the adjacent coastline of the World Heritage Area of south-west Tasmania has been subject to numerous deliberate fires, and local seal colonies have been regularly harassed. The official presence on Maatsuyker Island provides a significant deterrent to these illegal activities. Similar issues apply to the lighthouse on Deal Island in Bass Strait. AMSA plans to destaff and automate both these sites.

Ecological impacts

Habitat degradation/modification

Other activities discussed elsewhere contribute to degradation and modification of habitats. Described here are specific examples of ecological change.

Seagrasses

Seagrass beds in Tasmania have declined significantly in a number of areas close to large human population centres (Rees 1993). Five species of seagrass occur in Tasmanian coastal waters. In the Furneaux Group on the north coast, particularly among the islands of the north-west, there are extensive areas of Posidonia australis, and smaller areas of Amphibolis antarctica and Heterozostera tasmanica. On the east coast and in the south-east of the State, seagrasses are confined to sheltered bays and estuaries, and tend to be dominated by H. tasmanica, but include Halophila australis and Zostera muelleri.

In many cases these water bodies have been receiving waters for urban, industrial and agricultural waste, which have added nutrients and suspended solids to the water column. These have been identified as causes of seagrass decline in other parts of Australia (Larkum et al. 1989). Recent research has shown significant losses in the Hobart and D'Entrecasteaux region, Triabunna and St. Helens on the east coast, and the Tamar, Port Sorell, and Duck Bay near Smithton on the north-west coast. A strong relationship between seagrass decline in these coastal areas and the presence and abundance of algal epiphytes on seagrass beds has been demonstrated (Rees 1993).

Macrocystis pyrifera - String kelp

Macrocystis pyrifera is a brown alga and the largest of the kelps, forming dense stands offshore along suitable rocky coastlines. Plants may grow up to 30 m long, forming an upper canopy over smaller native species They thus increase both habitat complexity and refuge for fish and invertebrate species, including larval lobster and abalone. Urchin divers claim their best catches come from within Macrocystis beds.

Macrocystis is also highly productive. A company was established in the 1960s to harvest this alga on the east coast, on the basis of earlier estimates of the growth rate and standing biomass by Cribb (1954). Harvesting in most areas realised a single crop per year rather than the three anticipated, and the largest annual yield was 9000 tons. With a decline in the amount of alga, the enterprise became unviable and closed in 1972. Another proposal to harvest Macrocystis was rejected by the Division of Sea Fisheries in 1986. A survey had estimated a biomass of 10-12 000 tonnes. Since then Macrocystis has continued a dramatic decrease.

This decline over recent decades has corresponded with a rise in mean annual seawater temperatures (Sanderson 1987), although other factors have been suggested as possibly being implicated. These include:

(1) extra run-off and siltation from forestry activities affecting recruitment;

(2) earlier scallop dredging silting up inshore reefs;

(3) frond damage from boat traffic;

(4) competition from the introduced alga Undaria pinnatifida which occupies a similar ecological niche; and

(5) fishing pressure on rock lobsters, a predator of sea urchins may have lead to an ecological imbalance where the populations of sea urchins have increased, thereby impacting on the Macrocystis, one of their foods. There is no evidence, however, of a significant increase in sea urchin numbers or that they are eating out the Macrocystis.

Introduction of exotic organisms

As in the terrestrial environment, the marine ecology of Tasmanian coastal waters is being rapidly modified by the introduction of exotic species. Some of these are having serious long-term impacts on the biota, out-competing indigenous species with little prospect for control of their spread.

Some species, noted below, have been introduced by the discharge of ballast water from visiting bulk carriers in Tasmanian ports.

Gymnodinium catenatum - toxic dinoflagellate

Vessels collecting woodchips from terminals at Long Reach in the Tamar, Triabunna on the east coast and Port Huon in the south are the likely source of the toxic dinoflagellate Gymnodinium catenatum. These first appeared in 1971, soon after the first woodchip exports from the area. Blooms of these organisms threaten shellfish farms in the Huon. In 1986, 15 farms were closed for 6 months, leading to financial hardship. The situation is monitored by the Department of Community and Health Services through a $120 000 per annum program that also samples the bacterium Escherchia coli and other organisms in shellfish (G. Hallegraeff, pers. comm.). The Government has recently set up a `The Harmful Algal Bloom Task Force' which will report in July 1994 and make recommendations on the management and research options needed to deal with harmful algal blooms and the requirements for environmental monitoring.

Undaria pinnatifida - Japanese Kelp

In 1988, the first plants of the exotic seaweed Undaria pinnatifida were found at Rheban on Tasmania's east coast (Sanderson 1990), although it may have been introduced in ballast water as early as 1982 (Sanderson & Barrett 1989). In New Zealand, plants have been found attached to ships hulls and as a consequence transported to other harbours around the country (Hay 1990). This alga is a member of the Laminariales or `kelps'. It is an annual and can grow to 2 m in height. It can attach to a variety of substrates to depths of 15+ m, and will out-compete a number of native algal species important to the abalone and urchin fisheries. In some areas it shades 100% of the ocean floor, having profound effects on the inshore marine ecology. Temperature tolerances of critical phases of the plant's life cycle indicate its potential to spread from Woolongong (NSW) to Cape Leeuwin (WA).

So far, in Tasmania, the distribution of the alga has been confined to an area of coast from Triabunna to the southern tip of Maria Island, a distance of approximately 25 km. Undaria cannot be eradicated, but some control may be possible through commercial harvesting programs, since the species is an important mariculture crop plant in Japan. Local and Japanese markets could be established taking advantage of Tasmania's pollution-free image.

Predatory starfish

Another likely ballast water introduction, now well established in south-east Tasmanian waters is the Northern Pacific Seastar, Asterias amurensis. A predator of scallops, mussels, oysters, crabs, barnacles, and some gastropods including juvenile abalone, Asterias poses a serious threat to the marine ecology in the State. In Japan, Asterias is a serious pest to commercial scallop growers, and is a threat to the trawl fishing industry. The female seastars breed prolifically, and can produce up to 25 million eggs annually. They can live at depths from 1 to 200 m.

While a majority of the farms in the south are affected by the seastars, these infestations are being controlled by physical means. Asterias has no known predators, though the gonads are eaten by some Japanese communities. Harvesting is the most suitable management option and the University of Tasmania is investigating ways of using seastars as compost. However, toxins remain in seastar bodies and this may prevent the development of a fertiliser market.

The Tasmanian and Commonwealth Governments have recognised the potential impact of the Northern Pacific Seastar and have established and funded the National Seastar Task Force. The Task Force is to develop a national approach to the seastar problem and to fund research into various control measures.

A second large predatory starfish that is common on exposed reefs on the eastern, southern and western coasts, Astrostole scabra, has also probably been introduced to the state, as it was first recognised in Tasmania in the later 1960s but is abundant in New Zealand. A major prey of this species is abalone.

Spread of Pacific oysters

The Pacific oyster, Crassostrea gigas, was introduced to Tasmania in the 1950s, and is now extensively cultured in the State. The oysters have now become established in the wild, and encrust some rocky shorelines in the south-east and Tamar regions. Rocky intertidal habitats are considerably altered by the oysters, with an unknown impact on intertidal communities.

Maoricolpus roseus - the Rosy Screw Shell

The Rosy screw shell is believed to have been introduced into the state from New Zealand amongst live oysters imported by boat in the 1920s.

Since its arrival, this gastropod has gradually spread in massive numbers up the east coast and has now reached southern New South Wales. In many areas, including the D'Entrecasteaux Channel, it has completely altered the structure of the benthos because the substrate is now covered with a carpet of live and dead shells in contrast to the former sand or mud. A variety of other New Zealand species were probably also introduced at the same time, including the crab Cancer novaezelandiae and Petrolistes elongatus, the chiton Amaurochiton glaucus and the seastar Patiriella regularis. The effects of none of these species on the local biota is known.

Impacts on wildlife

Marine debris

Tasmanian coasts are increasingly polluted with debris from oceanic sources, implicating activities such as fishing, boating and shipping. A large proportion of this debris is potentially harmful to wildlife. Australian fur seals have an entanglement rate of 1.7%, approximately 500 seals at any one time. Other vulnerable species include other marine mammals, fairy penguins, gannets and other seabirds.

A statewide survey conducted at a representative geographic sample of 88 coastal sites between January 1990 and June 1991 assessed the composition and source of the debris (Slater 1991). Plastics made up 65% of all debris, of which 40% was related to fishing and aquaculture (rope, nets, line, bait straps, oyster spat bags, buoys and floats). Green mesh trawl net has only been used in recent years, yet forms a major component of the fishing net debris found (71%). Some 59% of debris was potentially harmful to wildlife. The proportion of fishing debris on Tasmanian beaches appears to be significantly higher than elsewhere in the world.

Educational programs are concurrently aimed at the fishing industry, the recreational fishing and boating community, and schools who play a major role in beach surveys. The development and marketing of a strapless bait box in Tasmania is helping to reduce the number of potentially lethal straps discarded by fishing vessels.

Seals

Ten species of seals inhabit or visit Tasmania's coast. These are all protected by law, but are still threatened by illegal shooting, entanglement and ingestion of marine debris, and reductions in prey species through fishing. Conflicts with fish farms have now been greatly reduced by improved cage and protective net design (DELM 1991) following earlier research (Pemberton 1989).

Some haul out sites are subject to disturbance in the breeding season by tourist boats and illegal shooters.

Seabirds

Seabird populations in Tasmania have generally declined. Pressures include the impact of feral animals, destruction or disturbance to nesting sites by development, off-road vehicles, pets and walkers, ingestion or entanglement with marine debris, and direct poisoning or loss of food sources by pollution (Woehler 1989, and pers. comm. 1993)

Wildlife interactions with fisheries

There is a high mortality of sea birds and mammals from longline fishing within the 200 nautical mile zone (i.e. as close as 20 nm offshore). Albatrosses, gannets and seals are particularly vulnerable. Entanglement in marine debris is another cause of mortality (see `Activities exploiting living resources, General issues' this paper), and competition for commercial fish is a likely, though unquantified source of pressure on sea birds and mammals (see `Activities exploiting living resources, General issues, Jack mackerel' this paper). Gill nets in the Pacific are also a cause of seabird mortality. Estimates suggest that as many as 280 000 short tailed shearwaters leaving Tasmania are drowned in Japanese gill nets each year. The northern Pacific squid fisheries also kill unknown numbers.

Gannets are a favourite bait for cray fishers, and their population on Cat Island in Bass Strait has dropped from 10 000 pairs to less than 10 as a result of this activity (Woehler 1989). Fairy penguins are also in decline statewide due to killing for cray bait, nesting habitat destruction, and competition with fisheries for food.

Climate change

During the past 30 years there has been a general increase of about 1.5oC in mean water temperature in the Tasmanian region (Harris et al. 1987). Because of the retraction of the subtropical convergence to higher latitudes, there has been a substantial decrease in nutrient levels and plant productivity associated with the temperature increase. Major consequences of this change seem to include a reduction in the productivity of pelagic systems including a decline in jack mackerel stocks, loss of Macrocystis beds (see above) and perhaps the extinction of other algal species (e.g. Adenocystis utricalis, which has not been recorded in Tasmania for several decades). Any further increase in global water temperatures will presumably have a greater effect on Tasmanian than other Australian marine communities because of the formerly high productivity in this area and the lack of a refuge further south into which cool water species can move.

Areas containing chronically disturbed zones

Some regions of the State have a concentration of human activities whose effects over time have compounded to seriously degrade what was, only 200 years ago, a pristine marine environment. The most evident of these are discussed below (for locations see Figure 1).

D'Entrecasteaux Channel and North West Bay

The population of this area has increased by 33.7% between 1971 and 1991, putting increased pressure on the marine environment, already considerably altered since European occupation due to activity on land and in the waterways. Marine living resources have been depleted through overfishing, resulting, for example in the collapse and closure of the D'Entrecasteaux scallop industry. Increased sedimentation from land clearance and forestry, agricultural run-off, and effluent from urban and industrial development all continue to impact on marine vegetation such as seagrass beds and macroalgae, degrading coastal marine habitats. Some coastal wetlands have been degraded, used as illegal waste disposal sites or reclaimed for development (see Figure 2).

Water quality is of prime importance to the increasing mariculture of salmonids and shellfish in the region. An aquaculture management plan and water quality monitoring program do not yet exist for the area.

Derwent River

The Hobart area has a population of only 172 000 people and only three major industries discharging effluent into the Derwent River, yet the river was described in 1973 as one of the most polluted rivers in Australia (Bloom 1973). Studies on the biota have indicated that shellfish throughout the estuary are unfit for human consumption, while finfish are within standards but to be treated with caution due to heavy metal accumulation.

Principal contaminants in the river include treated and untreated sewage, nutrients, food wastes, wood processing by-products, resin acids, sulphides, chlorine, chlorinated organic compounds, dyes, contaminants from urban run-off and wastewater, and heavy metals (zinc, manganese, arsenic, cadmium, mercury, copper, and lead) both in the water column and in sediments. These have reduced water quality especially in shallow bays and in the upper estuary, have affected the aquatic biota, diminished recreational and commercial use of the estuary and contributed to long-term environmental degradation. Bloom (1975) found mercury levels in sediments near Pasminco EZ works (1130 g/g) were at the time exceeded only by Minimata Bay in Japan. This study has now been repeated (see `Existing and planned marine environment monitoring programs, DELM Environmental Management Division', this paper), and published results indicate a significant improvement since that time.

The results of government monitoring programs have been published in DOE (later DELM) annual reports which were tabled in parliament. The earlier broadwater sampling strategies by the DOE have now been abandoned in some cases in favour of more comprehensive studies of heavy metals and organic contaminants using biological indicators such as mussels and oysters (Mytilus edulis and Ostrea angasi).

In general, however, surveys have been too narrowly based. The result is that the environmental systems of the Derwent have been poorly understood, and cause/effect influences and pathways have not been mapped. Even now, effective development, planning and pollution control strategies have yet to be put in place (Chapman 1992).

Of the 14 sewage treatment plants discharging into the estuary 4 still have exemptions. All are required to provide full secondary treatment with disinfection by 1994, although it has been argued that the haste required in meeting this timetable may be detrimental to producing the most desirable outcome. Bacterial levels in the river are often high, and most popular swimming beaches have had to be closed from time to time, and activities restricted at others.

Major industries on the river have greatly reduced discharges in compliance with the lifting of ministerial exemptions in 1994. ANM has greatly reduced its effluent (see `Polluting activities, Other major industries, Pulp and paper mills', this paper), and Pasminco EZ has similarly been reducing the metal load in its effluent so that the current ministerial exemption will not be required. Prior to the construction of an effluent treatment system significant quantities of zinc and cadmium were discharged into the river. In future these metals in wastewater will be recovered.

In general, the direction of State and local government and industry has been to reduce the levels of pollutants to within `acceptable' limits. Community groups on the other hand are calling for zero discharges of all pollutants into the Derwent (Friends of the Derwent, Greenpeace). The DELM Discussion Paper on the review of the Environment Protection Act: Future Directions for Regulations and Standards noted that: `Tasmania should seek to move in that direction - zero discharge as a long-term goal, particularly for persistent bio-accumulative toxicants' (DELM 1991).

Macquarie Harbour

The Mount Lyell mine in Queenstown, owned by Renison Goldfields Consolidated, began releasing tailings into the Queen River in 1922 with the introduction of flotation technology to preconcentrate the ore. This discharge has continued to the present. In December 1974 the mine was granted a pollution exemption with no specified limits. Currently, 1.5 million tonnes of mine tailings and an undocumented quantity of acid mine drainage is discharged annually into the Queen River.

The highly alkaline tailings (pH 10.1) pass from the Queen River into the King River and out into Macquarie Harbour where heavier particles drop out of suspension. A 250 ha delta has formed. Finer particles remain in suspension for some months as a plume on the harbour. The tailings and acid drainage contain a cocktail of heavy metals including manganese, cadmium, nickel, copper and zinc. Much of this is in particulate phase and is deposited in the delta. At present the alkalinity of the tailings neutralises the acid mine drainage. There is concern that when the mine ceases operation in June 1995, the un-neutralised acid drainage will liberate the heavy metals in the delta into the environment for an indefinite period.

Dissolved heavy metals have been irregularly monitored in the King River by the DOE and DEP since 1974, and in 1975 a DOE study looked at heavy metals in mine residues (DOE 1975). Recently metal levels have been studied for the first time in fish (de Blas 1992). Copper in oysters from the harbour have shown 5 times the NH&MRC standard of 70 g/g. De Blas found mercury levels in some fish species 2 to 3 times NH&MRC standards (brown trout and dogfish respectively). As a result of these findings, in April 1993 the Department of Health advised the public not to eat some species of fish from Macquarie Harbour more than once per fortnight. Although the mining company dispute that they are the source of this contamination, figures cited in DOE (and DEP) annual reports indicate that copper and mercury levels in the Queen River rise dramatically below the tailings outfall.

A CSIRO report (Carpenter et al. 1991) found the concentration of dissolved heavy metals in the harbour to be 100 times that of coastal of seawater. The total concentration of manganese, cadmium, nickel and zinc were found to be two orders of magnitude higher, and copper three orders of magnitude higher in the lower King River than in the Gordon River which also drains into Macquarie Harbour.

In February 1993, a steering committee was formed to coordinate a 3 year scientific investigation of pollution in Macquarie Harbour. This included representatives from the Division of Environmental Management, the Division of Sea Fisheries, the Hydro Electric Commission, and the Mt. Lyell Mining and Railway Company Ltd. The Macquarie Harbour Study is designed to examine the fate of sediment and metal dispersion in Macquarie Harbour, particularly in relation to the King River. It will assess the possible impacts of future changes to activities in the King River Catchment, including alterations to inputs from the Mt Lyell Mine and the operation of the King River Power Station. As part of the study, there will be an assessment of metal contamination of fish caught in the harbour.

Stage I will incorporate technical investigations into the physical and geochemical processes controlling sediment and metal dispersion in the freshwater and estuarine environments, and the status of sediments throughout the Harbour. The information obtained from Stage I will provide the technical basis for future environmental policy directions in Macquarie Harbour. Stage II should commence in the first half of 1994 and will examine the broader environmental management issues relating to the Harbour, together with broader community concerns. Analysis of farmed fish shows no evidence of elevated metal levels.

North-west coast - Burnie and surrounds

In the region of Burnie on the north-west coast of Tasmania a number of industries impact on the marine environment. A polluted zone extends from Table Cape in the west to Point Sorell in the east (Tasmanian Department of Environment and Land Management annual reports). Pollutants include chemical contaminants, nutrients, and suspended solids which may significantly increase turbidity.

Australian Pulp and Paper Manufacturers (APPM) commenced production in Burnie in 1938. The effluent of this plant is released directly into the sea. Other sources of pollution in the area include:

(1) acid-iron waste from Tioxide Australia Pty. Ltd. dispersed through a pipeline off Heybridge (see Newell 1986; Ritz et al. 1985);

(2) residual contamination from the Emu Bay ocean dumping site of North West Acid Pty. Ltd. prior to their 1979 closure, and;

(3) partially-treated sewage, urban run-off, quarry washings, and spills and discharges from harbour and shipping activity.

There are also towns to both the east and west of Burnie, plus light industry, agricultural run-off and the effluent from the Wesley Vale pulp mill situated about 55 kilometres to the east.

Some aspects of the impact of human activity on the littoral, benthic and marine biological communities of this coastline have been documented in various reports (Ritz et al. 1985; AEC 1982; DOE 1981, 1978, 1974). There remains a need for studies into the synergistic effects on the marine environment of combined effluents in Bass Strait, particularly in the Burnie area.

Orielton Lagoon

Orielton lagoon was created in 1953 by construction of a causeway which divided it off from Pittwater. Tidal exchange with Pittwater was limited. The northern section of the lagoon is an internationally recognised wetland, important for migratory wading birds.

The introduction of primary treated sewage in 1969 exacerbated an increasingly eutrophic environment previously dominated by extensive seagrass beds. The lagoon is now devoid of seagrasses, and has become dominated by phytoplankton and the rapid growth and die-off of a few species of macroalgae; in 1993 there was a toxic blue-green algal bloom. The visual impact and odours produced by decomposing algae affect the local residents in Midway Point and Sorell, and cause frequent complaints.

A remediation program is following the recommendations of a consultant's report, as a component of an integrated catchment study commenced by the State government and the local council. Solutions to the problem include land disposal of the effluent, increasing the tidal exchange, and a range of catchment management practices. A comprehensive monitoring program has been initiated to ensure no detrimental impact to Pittwater and the valuable oyster industry there.

Tamar River

There is only limited knowledge of the state of the environment of the Tamar River valley. The river is the site of major urban, industrial and agricultural development, with attendant pollution problems from each of these sectors. A dam above Launceston forms Lake Trevallyn which reduces freshwater flow. Some 13 sewage treatment plants discharge into the Tamar and its tributaries. Industries in the Bell Bay/George Town area include the COMALCO aluminium smelter, the Southern Aluminium wheel foundry, the BHP-TEMCO ferrous smelter, an oil-fired power station, two wood chip mills and wharfs at Bell Bay and Beauty Point, and the Sea Cat terminal at George Town.

Pollution also enters the river from urban run-off and trade wastes from Launceston, old mine workings at Beaconsfield and on the South Esk river, a tributary of the Tamar, and also silt and other contaminants from agricultural run-off. The South Esk receives effluent from a variety of sources, including a 3000 cattle feed lot, a sewage plant and dairy at Fingal, and sewage ponds at Longford. There is also drainage into the South Esk River from tailings at the now abandoned mining operations in the catchment.

DELM is currently coordinating an environmental baseline program for the lower Tamar in the Bell Bay region. This will identify many of the environmental parameters that at present remain unquantified.

Existing and planned marine environment monitoring programs

Monitoring programs are listed here under the State or Commonwealth agency responsible. (ref: RAC 1993).

Department of Environment and Land Management, Parks and Wildlife Service

The Division has data bases relating to recreational facilities, flora and fauna, and is establishing a GIS covering its activities. Specific marine programs include:

(1) Muttonbird and Seal Monitoring Program;

(2) Marine Debris and Pollution Program;

(3) Environmentally Friendly Fishing and Boating Campaign;

(4) Marine Reserves Program (baseline monitoring under Ocean Rescue 2000);

(5) Introduced Marine Invertebrate Study (with Tasmanian Museum);

(6) capture/relocation of seals for fish farm protection;

(7) recording of whale sightings, and sampling of stranded pods for heavy metals and other data, and;

(8) monitoring of seabird colonies and populations.

Department of Environment and Land Management, Environmental Management Division

This Division is responsible for licensing polluting industries and installations under the Environmental Protection Act 1973, including STPs, landfills, factories and food processing operations discharging into rivers and coastal waters. The most polluting of these generally carry exemptions granted under the provisions of the Act. Monitoring programs are gradually moving towards testing ambient levels and biological indicators rather than point discharges, although a comprehensive program of indicator monitoring proposed for Victoria (VIMS 1991) has not been developed in Tasmania.

Several air and water monitoring programs are conducted by the Division, including:

(1) West Coast Monitoring Program, a continuation of the Pieman River study sampling 36 sites in the catchment for heavy metal levels;

(2) Derwent River Monitoring Program, repeating Bloom's 1975 study of metals in fish and shellfish (now complete);

(3) Derwent River Nutrient Study, a 12 month program looking at nutrients in water and sediments;

(4) ongoing sampling of bacteria and faecal coliforms in the Derwent River;

(5) involvement in a current program in Macquarie Harbour looking at the distribution of mine tailings and the consequences of mine closure;

(6) various air monitoring programs, including the Launceston Air Study, air fallout at some major industrial sites, and monitoring lead in air, and;

(7) incident response monitoring of spills and other polluting accidents.

The Industrial Operations Branch run no specific monitoring programs but receive data from a range of industries that have monitoring obligations under their licensing conditions. These include Tioxide, APPM, ANM, COMALCO, TEMCO and EZ. Similarly, the Waste Management Branch requires industries and local authorities to conduct monitoring regimes and submit data to the agency. The emphasis is thus on increasing the auditing role of the agency rather than running costly monitoring programs itself, although these are undertaken randomly as a safeguard. A database is held of environmental monitoring results. The Bell Bay Environmental Baseline Program is similarly coordinated by the Division, but is contracted out.

In recent years the Division has developed comprehensive solid and hazardous waste management strategies. These have an emphasis on waste minimisation, reuse and recycling, and appropriate treatment and disposal practices.

Department of Primary Industry, Division of Sea Fisheries (DFS)

Evaluation and monitoring are central to fisheries management, and include:

(1) collection and analysis of catch statistics;

(2) baseline research and monitoring in Marine Reserves (with DPWH);

(3) research relating to commercially and recreationally fished species;

(4) environmental monitoring of marine farms;

(5) algal bloom monitoring and biotoxin levels in shellfish.

Department of Primary Industry, Water Resources Division

The Division has overall responsibility for the State's water resources under the Water Act 1957, but no powers over tidal waters. However it has powers to control water pollution in rivers (in cooperation with local government) and may affect the marine environment through irrigation works, river management and drainage, and foreshore protection works. Of importance is the Dairy Effluent Project, initiated in 1991 to reduce the levels of dairy effluent entering rivers in the north west of the State (see `Polluting activities, Agricultural and urban pollution, Run-off', this paper) (due however to high Escherichia coli levels in shellfish farms in Duck Bay rather than a wider environmental concern).

Department of Health

The Department has extensive powers over many areas of human activity with its overall mission to `promote, protect and maintain the health of the people of Tasmania'. It has overriding control over development and health issues, and delegates many of these powers to local government.

The Department's activities include:

(1) management of the Tasmanian Shellfish Quality Assurance Program;

(2) administration of the Food Standards Code (including seafoods) which sets maximum permissible levels of harmful substances;

(3) monitoring recreational water quality, including swimming beaches;

(4) setting standards for on-site wastewater disposal, and prescribing effluent quality criteria.

CSIRO

CSIRO does not conduct ongoing monitoring programs as such, but carries out specific research projects that may be self-initiated or requested by DASET, usually in the context of licensing agreements for particular industries. Research projects are sometimes undertaken cooperatively with industry, and the results are often confidential. The organisation sees its role as an impartial research body, yet despite this is reluctant to make available its findings in the public domain for fear of being drawn into controversial political issues.

In Tasmania, CSIRO research has been conducted into Bass Strait water movements off Wesley Vale as part of the National Pulp Mill Program, Derwent and Storm Bay pollution studies, offshore Jarosite dumping, research on the south-eastern trawl fishery, and heavy metal studies in Macquarie Harbour.

Inadequate knowledge, research and community awareness

Community interest and response to issues relating to the marine environment has increased greatly in recent years. The majority of the State's population live on or near the coast. Many own or have access to a boat or beachside shack, and perhaps enjoy fishing or other water-based activities. Public education programs have aimed at minimising the impact of some of these uses of the coastal zone, but have also encouraged many people to participate in ongoing monitoring and impact reduction campaigns. Examples of this include:

(1) Adopt-a-beach, where communities, schools and organisations collect litter and marine debris, and conduct some monitoring (particularly of wildlife) on a chosen beach. This ties in with;

(2) marine debris surveys, which have gained considerable community support and have provided data enabling some sources of debris to be identified and addressed;

(3) fishing education campaigns, using booklet distribution in schools and the community, aimed at reducing undersized catches, overfishing, illegal fishing, littering and other damage, and improving safety;

(4) cleanup campaigns, such as the Derwent, organised by nongovernment organisations and community groups who also play a lobbying role against polluters;

(5) work with the fishing and aquaculture industry on seal and seabird issues. The questions of illegal shooting of seals and seabirds and gun control on boats will need to be addressed.

Although these are generally limited programs, each has required skill and resources to establish and maintain, and has served to increase overall public interest and awareness. Their ongoing funding is, however, uncertain.

The introduction of marine reserves also has reinforced the concept that the marine environment can be protected and not just exploited. The current reserves are arguably too small to play a significant role in the conservation of marine ecosystems, but with funding for improved interpretation material and education campaigns the community may support additional marine reserves. The baseline biological monitoring of the existing reserves is an essential part of this process and deserves ongoing financial and logistical support.

Other ecological issues discussed in the text requiring urgent research include:

(1) Undaria pinnatifida - Japanese Kelp;

(2) Asterias amurensis - Pacific seastar;

(3) Macrocystis pyrifera - String kelp;

(4) environmental impacts of marine farming;

(5) loss of seagrass beds in specific areas, and;

(6) comprehensive monitoring of environmental indicators.

A comprehensive range of physical and biological indicators derived from the Tasmanian marine environment needs to be adopted along the lines of the Victorian program (VIMS 1991). A commitment to funding the regular monitoring of these indicators should be a priority. The State Policies and Projects Act 1993 establishes a legislative requirement for State of the Environment Reports to be prepared for Tasmania.

Data management in the State also needs addressing. Much data has been gathered independently by many agencies, consultants, academics and independent researchers, and concern a wide range of issues relating to the marine environment . However, there is currently no strategic plan to produce an integrated marine database. To build such a database would require agreement on standardisation of data storage and the free exchange of information between organisations. The result would enhance the value of present knowledge, enable limited research funds to be more effectively allocated, and improve the quality of management decisions by all relevant agencies.

Whilst the importance of raising awareness of marine environment issues through properly resourced public education campaigns is acknowledged, sanctions are also required to deter those who would flout regulations. These must adequately reflect the serious damage to the marine environment that some actions can cause. Such regulations relate to fisheries, effluent discharges, attacks on wildlife, and dumping of debris. However, there is not yet the community perception that regulations will be enforced in the courts. Therefore, legal sanctions need to be reviewed and policed with an allocation of resources that reflects the economic, cultural and ecological importance of Tasmania's marine environment.

Many polluting operations, both publicly and privately owned, have in recent decades been allowed to exceed regulations through the granting of exemptions by ministers of the day. The repeated renewal of these ministerial exemptions reflects poorly on the priorities of these past decision makers. These exemptions are now being phased out, but the environmental legacy of some of these operations remains at odds with a growing national and international perception that Tasmania has a clean and pristine environment.

Increased public awareness and debate of marine environmental issues is a desirable outcome of access to information, with the community enabled to make quality decisions over its relationship to the marine environment. The commencement of a State of the Environment Reporting program in Tasmania by the Department of Environment and Land Management will support public awareness and understanding of the issues.

References

AAEC 1982, A Report to Tioxide Australia Pty Ltd on the dispersion of ferric hydroxide in Bass Strait, Lucas Heights Research Laboratories Report AAEC/C25, Australian Atomic Energy Commission.

Bloom, H. 1975, Heavy metals in the Derwent Estuary, Chemistry Department, University of Tasmania.

Carpenter, D., Butler, E.C.V., Higgins, H.W., Mackey, J.D. & Nichols, P.D. 1991, `Chemistry of trace elements, humic substances and sedimentary organic matter in Macquarie Harbour, Tasmania', Australian Jounal of Marine and Freshwater Research , vol. 42, pp. 625-54.

Chapman, J.D. 1992, Controlling pollution in the Derwent Estuary, Masters thesis, Centre for Environmental Studies, University of Tasmania, Hobart.

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The technical paper by Mr C. Rees was reviewed by Dr G. Edgar, Zoology Department, University of Tasmania.