T. Petr
27, McLeod Street, Toowoomba 4350, Australia
ABSTRACT
The rapid growth of recreational fisheries in inland waters of Australia has been made possible by the development of artificial breeding methodologies for native fish species. Large-scale production of seed/fingerlings since the 1970s, but especially since the 1980s, has made it possible to stock fish species into many Australian waters formerly devoid of fish of interest for anglers, and to increase the species diversity in other water bodies. Inter-basin translocations allowed the stocking of water bodies in distant regions, such as the transfer of several species from eastern Australia to Western Australia. The demand for more fish is growing with the increasing number of anglers, with almost one sixth of the Australian population now fishing fresh waters. This increases the demand for more stocking. Catch-and-release fishing is gaining support due to changing attitudes; anglers now tend to keep only fish needed for immediate consumption, rather than keeping them all to prove their success. As methodologies for artificial breeding of other native species are developed, more species are added to those already regularly stocked, further enriching the spectrum of fish of interest to anglers and enhancing fish stocks. On the other hand, the very high stocks of the exotic but so-called ‘noxious’ common carp are barely touched and there is great potential for their commercial exploitation. In recent years each state government has revised the fishing laws and regulations in order to satisfy the growing demand of anglers, but also to prevent overexploitation of fish stocks.
1. BACKGROUND
Australian freshwater fisheries are administered by the individual states, therefore obtaining an overall picture of the success of enhancement measures in boosting and/or maintaining the desired fish stocks requires putting together a mosaic from the approaches of the individual states. During the past few years, each state fisheries administration has been undergoing restructuring, which in some states has led to significant changes in management and to the introduction of new jurisdictional measures.
Most Australian freshwater fishery management measures are aimed at satisfying the demands of recreational and sport fishermen. Surveys by the national body Rec-Fish Australia estimate that 5.5 million, out of the total population of 18 million Australians, are anglers. In 1995, in the state Victoria 49% of anglers fishing from boats fished inland waters. Anglers spend, on average, 12.5 days a year fishing (the sea and inland waters), and spend an average A$ 91 a year on equipment and bait, and once boats, rods, reels, terminal tackle, bait, books and clothing are included, it adds up to a recreational fishing industry worth an estimated A$ 3.5 billion a year. Thirty-five percent of fishers are now female, and more than half of all anglers are aged between 18 and 39. More than half of all homes have a fishing rod. Television fishing shows regularly earn top ratings, fishing books and videos sell rapidly, and fishing information sites on the Internet outnumber football pages seven to one. Among the recent changes in attitude to fishing is the support by amateur anglers for catch-and-release fishing, as compared to the mentality 5 to 10 years ago when the success of a fishing trip was measured by the number of packets of fillets in the freezer. Now anglers aim to keep only those fish that they can eat that day, and most of the captured fish are released.
Fishery administrators in the individual states of Australia are aware of the need to rationalise the existing recreational fisheries laws and regulations. The industry is moving towards support for a compulsory recreational fishing licence. This should raise A$ 50 million for the employment of more fisheries inspectors to prevent overfishing.
In New South Wales, new trout laws were introduced on 30 September 1995. They recognise the need to conserve the NSW trout fishery in a climate of rapidly increasing angling pressure. Some streams are now given a two trout/day bag limit, in others only catch-and-release fishing is allowed. In NSW angling laws for freshwater native fish have also been reviewed with a view of providing support for long-term sustainability of the freshwater native fishery. The new proposals include reduction in present bag limits and increased size limits. Such measures are paralleled by continuing the policy of enhancing the stocks of native fish through stocking, with nearly 5 million of them released in public waters in the last decade.
Current proposals for reviews of fishery laws in the Australian Capital Territory recommend changes to ensure that recreational fishing is fair, equitable, enjoyable and sustainable.
In the State of Victoria, there has been a call for improvement of the inland fishery management. The request for an overall state-wide management plan for Victoria's inland fisheries resources and habitats is the result of realising that the current approaches are still fragmented. It is hoped that such an overall plan would allow the development of detailed management plans for individual waters and catchments. The Victorian Fisheries released the draft strategy for public comment in July 1996. The draft represents a move towards co-management of inland fisheries, with greater involvement of anglers in management issues. Such liaison is expected to result in better agreements on fish stock enhancement (e.g. stocking rates), regulations and other aspects of inland fisheries.
On the other side of Australia, in the state of Western Australia, which has a scarcity of fresh waters, a freshwater fishing section within the West Australian Field and Game Association was established only in 1994, although the W.A. Trout and Freshwater Angling Association has been in existence for some time.
Queensland, like the other states of Australia has a Fisheries Management Authority (QFMA), an agency responsible for the management, use, development and protection of the state's naturally occurring fisheries resources. The Authority is committed to ensuring that fisheries resources are used in an ecologically sustainable way, that optimum benefits are obtained from them and that access to the resource is fair. In 1996 the QFMA for the first time drew together the many and varied aspects of Queensland's freshwater fisheries into a single management plan, with the aim of ensuring the sustainability of Queensland freshwater fisheries (Discussion Paper No.4, 1996). The Queensland Discussion Paper discussed in depth two management measures for sustainability and enrichment of fish stocks, largely for the purpose of providing anglers with a good fish catch. These are: translocations, and fish stocking.
Tasmania's freshwater recreational fisheries has been under some form of administrative control since 1862. Close contacts are maintained between the Inland Fisheries Commission and angling organisations with the result that satisfaction with management performance is generally quite high compared with other states of Australia. Efficiency of operation is also ensured by financial arrangements. All recreational fisheries management functions are funded from angling licence fees and include administration, research, management and enforcement (Fulton and Sanger, 1994). Licence fees have been loosely linked to the Consumer Price Index.
2. INLAND FISHERIES ENHANCEMENT
This section discusses the success of enhancement measures in some Australian states and their inland water bodies. This is largely based on information available in the recently published proceedings of workshops and symposia, organised by the Australian Society for Fish Biology, supplemented by information from draft reports and the Freshwater Fishing journal. It should be considered as the first step towards a more comprehensive evaluation on the topic at a later date.
Stocking, protection of fish habitats, and in the past translocations have been the three major measures for maintaining and enhancing fish stocks in inland water bodies in Australia.
2.1 Translocations
The practice of interbasin transfer of fish, i.e. translocations, as a tool for improving fish stocks in selected water bodies, has been much in retreat lately. In Queensland, it is specified that fish enhancement using translocations of species can be considered only where a clear potential economic, social or conservation benefit can be demonstrated, and where no alternative native species in the drainage basin have similar potential (Discussion Paper No.4, 1996). It is not permitted in catchments where the integrity of native fish communities remains substantially intact and/or where there are one or more threatened species of fish, and/or where there are several native fish species of value. Translocation of species accorded threatened status because of habitat loss is supported. With the exception of threatened species, preference is to be given for translocating species that will not reproduce in their target environment. Release of fish into farm dams, where the risk of escape into natural waterways is high, should not be permitted in priority conservation catchments or in catchments in which translocations are considered unnecessary. All potential translocations are to be subject to a disease risk assessment to minimise the risk of disease transfer.
In Queensland, translocations of the recreational angling species (Australian bass (Macquaria novemaculeata), golden perch (Macquaria ambigua), silver perch (Bidyanus bidyanus), southern saratoga (Scleropages leichardti) have occurred as part of the Queensland Government's Freshwater Fishing Enhancement Programme, initiated in 1986/87. For Queensland, recommendations for translocations (or no translocations) basin by basin, providing a rationale for each case, are given in the Discussion Paper No.4 (1996).
In Western Australia, a state with hardly any native fish species of significance for angling, the Recreational Fishery Advisory Committee conducted a seminar and workshop in 1994 in order to discuss the translocations of various freshwater fish in west Australian waters. The meeting learned that several private land owners and crayfish marron (Cherax tenuimanus) farms have already translocated several species regardless of environmental and disease risks. The meeting gave strong support to the proposal for introduction of golden and silver perch and black bream (Acanthopagurus butcheri) in selected waters. The local waters already harbour the exotic carp (Cyprinus carpio), redfin (Perca fluviatilis) and gambusia (Gambusia holbrooki). In the past these fish, and trout (Onchorhyncus mykiss, Salmo trutta) and marron have been liberated into hundreds of farm dams and rivers in the south-west of Western Australia without any environmental studies being done to ensure that no harm would result. Stocking of trout in impoundments, rivers and streams has been a common practice in WA, with 238,500 of mostly rainbow trout released in 1995 into 18 different water bodies.
2.2 Stocking
Stocking is well recognised as a tool for creating or improving fisheries, as well as for conservation of threatened species, and it can contribute to the rehabilitation of fish stocks after a major fish kill (Discussion Paper No.4, 1996).
In Australia, recreational anglers are getting more involved in improving freshwater fisheries, through various approaches, such as raising money to buy from private fish hatcheries fingerlings for release into their favourite waters, and establishing their own native fish hatcheries.
2.2.1 Impoundments and lakes
In Queensland, the stocking of fingerlings was the objective of the Queensland Government Recreational Fishing Enhancement Programme, which began in 1986. Before the introduction of this programme, most stocking yielded limited results. After 1986 there was a dramatic improvement in the quality of freshwater fishery, particularly in impoundments. The program was complemented by an almost equal stocking effort from local communities, through their stocking organisations. Advances in the development of artificial propagation and rearing techniques have provided the basis for the production of native fish species, including barramundi (Lates calcarifer), Murray cod (Maccullochella peelii peelii), Mary River cod (Maccullochella peelii mariensis), yellowbelly (golden perch), silver perch, Australian bass and saratoga. At present techniques are being developed for the production of several other fish species, including mangrove jack (Lutjanus argentimaculatus), whiting, bream and flathead. In southern Queensland, the dominant fish stocked is yellowbelly, accounting for almost half of all fingerlings released, followed by silver perch (34%) and bass (12%). Other stocked species include saratoga, sleepy cod (Oxyeleotris lineolatus), Murray cod, Mary River cod, barramundi and sooty grunter (Hephaestus fuliginosus) (Hamlyn and Thomas, 1995). The major species stocked in north Queensland are barramundi, sooty grunter and sleepy cod (Hogan, 1995). Ongoing release of fingerlings is necessary because the fisheries based on stocked fingerlings are largely of a put-grow-and-take nature. Most of the stocked species do not reproduce in impoundments and must be replaced continually. Since 1986 some 15 million fingerlings have been stocked in Queensland. Some 70 stocking groups are now established throughout Queensland. The stocking groups play a crucial role in the stocking programme, particularly by raising funds in the local community for the purchase of fingerlings from private hatcheries.
The broad objective of Government-driven fish stocking over the last 20 years has been to upgrade the quality of the freshwater recreational fisheries in Queensland streams and impoundments (Hogan, 1995). During the mid-1980s, emphasis was placed on the creation of an inland recreational fishery resource to improve the quality of life for people living in the bush. Another reason advanced was to divert angling pressure from estuaries, and to attract tourists. Stocking groups were set up and it was hoped the locals would look after the local fisheries. But other reasons were also given: fish for forage, for pest control, for environmental improvement, for conservation of endangered species, for maintenance of genetic diversity, for stock enhancement above normal levels and to overcome the overfishing. These days the mechanism for managing stocking of crown waters is through issuing permits by the QFMA, which stipulates conditions relating to numbers, species, location and monitoring. At the end of the stocking season, the permit holder is required to advise the Authority of the actual numbers of fish stocked, the dates when stocked and the release sites. Farmers and graziers currently do not require a stocking permit. The issue of controlling fish stocking in farm dams is being addressed.
Apart from finfish, crayfish have been stocked in several impoundments. The recreational redclaw (Cherax quadricarinatus) fishery has become very popular over the last few years, although the redclaw stocks are quickly fished out with a minimal fishing effort and are unlikely to sustain a viable commercial fishery. This has been accompanied by concern about the potential for the redclaw to spread outside its natural range. Many farm dams have been stocked, and there are at least 25 commercial redclaw farms in Queensland. However, to establish a population large enough to attract fishermen may require a long time and several large stocking inputs, as experienced in Tinaroo impoundment in north-eastern Queensland. Eels are a major controlling factor in the distribution of redclaw, and redclaw occur naturally only in streams which are free of eels.
Several creel surveys undertaken on impoundments in Queensland provided details of the ratio of the number of fingerlings stocked to the number of fish caught. Such information is still lacking for rivers and estuaries where natural populations exist in parallel with the stocked ones of the same species. To separate them, and thus to be able to assess the degree of stocking success, requires tagging of the stocked fish. This would assist in better understanding of whether stocking can actually improve the fishery and provide a reasonable return to the fisher, whether commercial or recreational.
In Tinaroo impoundment archer fish (Toxotes chatareus) and sleepy cod were stocked in fairly small numbers, but they established self-sustaining populations. And 1136 stocked sooty grunter fingerlings released into the Pioneer River produced a successful fishery within ten years (Hogan, 1995). The optimal stocking density for golden perch and sooty grunter, fish which do not reproduce in impoundments, was 400 per hectare. Stocking above this rate didn't result in better catches. Barramundi, being four times the size of the above species, is stocked at 100 fish per hectare. Repeated experiments with barramundi have shown that the survival of the traditionally stocked 50 mm fingerlings was as high as that of 20 mm, but the survival of fingerlings below 17 mm was nil. Barramundi of 200 mm stocked in Tinaroo impoundment had low survival, as they formed schools which were immediately attacked by pelicans. A shadow to these fish brought up in hatcheries meant food, not danger. Pondreared sooty grunter of 50 mm behaved in a similar way and also had no danger instinct which would protect them against bird predators. Now only 20 to 25 mm fingerlings of barramundi and sooty grunter are stocked in north Queensland waters.
Impoundments, where escape is limited and there is no natural recruitment, provided a better means of measuring the results of stocking than did open systems. Examples of creel survey data for two Queensland impoundments (Leslie and Cooby) showed returns of one fish for each 8 to 10 fingerlings of golden perch stocked and there were equal, respectively lower returns of silver perch in these two dams. In Cooby Dam, Murray cod returned one out of 19 fingerlings stocked, which is considered an exceptionally good return. In Moogerah impoundment there was an excellent return of bass (one per each 3.5 fingerlings stocked), and a lower one of one per 13 and one per 15 for Sommerset and Wivenhoe impoundments, respectively. Returns of silver perch were very poor in Moogerah (173:1) and Wivenhoe (442:1) impoundments (Hamlyn and Thomas, 1995).
An example of economic benefits is available for Leslie impoundment, where some 200 anglers were interviewed in 1992. Average expenditure within 30 km of the area was A$ 15.30 per angler day. Based on the estimated 36,000 angler days for the season, this represented a direct benefit to the local community of A$ 314,000 a year (Hamlyn and Thomas, 1995). The cost-benefit of stocking, based on an average community stocking expenditure of A$ 17,500 a year, represents a ratio of 1:18, that is, a direct return to the community of A$ 18 per every A$ 1 spent on stocking.
Most impoundments are understocked because sufficient resources have not been available to stock to optimum levels, especially in the larger impoundments. The limited data available from some of the more heavily stocked impoundments suggest an optimum level of between 500 and 600 fingerlings per hectare, with an annual maintenance stocking level of 100 to 200 fingerlings per hectare (Hamlyn and Thomas, 1995). Creel surveys give an indication of how many stocked fish were harvested. In Leslie impoundment the estimated annual harvest for 1994–95 was 10,500 stocked fish. It was estimated that 84,000 fingerlings were needed to replace the harvested fish. However, the currently used figures are still largely theoretical, and future stocking rates may have to be adjusted as more information becomes available from regular monitoring of catches (Hamlyn and Thomas, 1995).
In Queensland most stocking to date has been either for enhancement or to create new fisheries in impoundments where there are few or no existing recreational fisheries. Barramundi is an example of a species which has been stocked for both purposes (Russell, 1995). With the development of technology for the culture of barramundi in the mid-1980s, there was considerable community pressure first to create impoundment fisheries and later to enhance stocks in coastal streams where existing stocks were perceived to be at very low levels. Habitat degradation and overfishing appear to be the major factors contributing to the decline of the fishery despite concerted management efforts. It is not yet clear how many hatchery-raised fish survive after being released, and whether stocking of hatchery fish increases abundances rather than displacing wild stocks (Russell, 1995). Where stocks are being enhanced, at present the most effective method of assessing success is mark/recapture.
The impact of trout stocking was demonstrated in two cold-water impoundments of New South Wales. Prior to 1981, Lake Eucumbene maintained brown and rainbow trout stocks through natural reproduction of fish released in 1957. When in 1981 the catches of rainbow trout suddenly declined, a total of 380,000 rainbow fingerlings were released in this and the following year. As a result, not only the catches of rainbow increased by 83% by 1986, but there was an increase in brown trout as well. It was explained that the competition from rainbow has pushed the browns into the shallow margins more often in search of food. The increased catches were sustained for 10 years, without additional stocking.
In Victoria, in attempt to re-establish self-sustaining populations in the wild, the Department of Conservation and Natural Resources has, since 1986, been stocking Murray cod in 15 waters, trout cod (Maccullochella macquariensis) in seven waters, and golden perch (Macquaria ambigua) in six waters (Gooley, 1992). The protocol adopted has been to stock a particular water for 4–5 years, then undertake post-stocking surveys to determine whether any natural recruitment has occurred. Once a viable breeding population becomes established no further stocking will be undertaken.
In Tasmania most major lakes contain self-supporting populations of brown trout. Similarly, river fisheries are self-supporting. If any lakes do require additional recruits the first resort is for improvement of spawning habitat. Other lakes that do not have suitable spawning habitat may be stocked regularly. Rainbow trout are frequently stocked in impoundments closer to population centres to provide a readily catchable resource for the less dedicated angler or for those without the means to travel to the lakes. Waters that do not provide reasonable returns generally receive minimal attention. Angler involvement in stocking is encouraged either through assistance at time of release of Inland Fisheries Commission-reared stock or through club participation in regional rearing units. The rearing units obtain trout fry free of charge from the Commission and rear them to a more advanced stage prior to release in certain waters (Fulton and Sanger, 1994).
2.2.2 Coastal rivers
The northern Queensland Johnstone River was stocked to enhance the stocks of local fish, particularly barramundi. Tagged fish in two size classes were released in three subsequent years' breeding seasons. Recaptured fish (over 50, out of the almost 50,000 released) showed that the stocked fish appeared to move freely through the river system, including tidal waters. Preliminary data suggest that stocked fish make up at least 17% of all barramundi caught in the appropriate size range. The cost/benefit of stocking was evaluated both for the recreational and commercial fishers (Russell, 1995). Using estimates made by Rutledge et al. (1990) that the average fish costs a recreational fisher A$ 50, and a commercial fisher about A$ 25, one concluded that only 400 of the fish originally released (less than 1%) would have to be captured to recover the purchase price of the fingerlings (A$ 12,500). The results suggest that enhancement of barramundi stocks in coastal waters has the potential to provide important economic benefits to local communities.
2.2.3 Farm dams
The provision of conditions suitable for fish is not generally a major consideration in construction of Australian farm dams (MacKinnon, 1989). While fish will survive in most farm dams, many different factors interact in individual dams to determine the success of stocking programmes. Under the provision of the Fisheries Act 1976–89 it was still permissible to stock farm dams with Australian native fish originating from other areas, providing the dams are adequately screened to prevent the escape of fish or their eggs. This practice is no longer encouraged.
There is an excellent range of native finfish species which are ideal for growing in farm dams, especially where water temperatures exceed 18 degrees C. Golden perch are the most popular for stocking such dams. They exhibit very good growth rates, reaching table size (300 grams+) in 18 months to two years. They have extremely good temperature tolerance (3–30 degrees C) and are therefore ideal for stocking in most areas. They do not breed in farm dams (O'Sullivan, 1991). Murray cod are Australia's largest and most highly prized freshwater fish. They grow best in dams greater than 0.2 hectares and reach table size in 2–3 years. They also do not breed in farm dams. Silver perch are also very popular for stocking in farm dams, and have similar temperature tolerance as golden perch. However, they do breed in farm dams. Barramundi may reach 3 kg in less than two years in farm dams, and Australian bass grow up to 1.5 kg, with table-sized fish available in 3 years' time. Other species stocked in farm dams are eeltailed catfish (Tandanus tandanus), straight-backed catfish (Neosilurus spp), spangled perch (Leiopotherapon unicolor), sooty grunter, sleepy cod, Mary River cod, archer fish and saratoga.
In New South Wales, Murray Cod Hatcheries is a commercial enterprise supplying fingerlings of silver and golden perch, catfish and Murray cod to farmers for stocking dams on their properties, and to anglers groups to restock rivers and popular fishing spots. The Narrandera Fisheries Centre of the NSW Fisheries has produced over 10 million native fish in 11 years, including 1.5 million Murray cod and golden perch in 1995.
Collection of broodstock for aquaculture
For the Queensland freshwater fisheries the conditions for collection of broodstock are spelled out in Discussion Paper No.4 (1996). Responsibility for the culture of fisheries products and the issuing of aquaculture licenses lies with the Department of Primary Industry, while the responsibility for the collection of culture stock lies with the QFMA. However, the DPI issues general fisheries permits for culture stock collection on behalf of the QFMA.
Licensed aquaculturists are permitted to take fish from the wild to use as culture stock for the production of fish for human consumption, for fish stocking and for the aquarium fish trade. There are some 290 aquaculturists (fish farms and hatcheries) in Queensland and of these about 90 may collect broodstock (both fish and crustaceans) from fresh waters.
The recommended maximum numbers of broodstock collected from the wild that may be held in possession for aquaculture purposes are: Mary River cod (20), Murray cod (20), saratoga (20), Australian bass (30), Welch's grunter (Bidyanus welchi) (40), silver perch (40), mangrove jack (40), barramundi (40), eeltailed catfish (60), sleepy cod (Oxyeleotris lineolatus) (60), yellowbelly (golden perch) (60), sooty grunter (60), redclaw crayfish (100). For freshwater aquaria fish the recommended numbers are 30 for species considered to be threatened or restricted and 60 for species considered to be common. These numbers are for general guidance only and may be increased if there is a legitimate need for an aquaculture licence holder with a general Fisheries Permit for Culture Stock Collection to increase the number of broodstock for a particular species. The numbers reflect the needs to safeguard wild stocks from over-harvesting and to discourage the illegal sale of wild-caught fish, but at the same time to enable replacement of broodstock on a regular basis, which is important for ensuring good genetic mixing in broodstock used to provide progeny for stocking programmes (Discussion Paper No.4, 1996).
2.3 Protection of fish habitat
Another important aspect related to the implementation of fish stock enhancement in Australian inland waters is the need for maintaining good quality freshwater habitats. The Workshop on Sustainable Fisheries through Sustaining Fish Habitat (1992) focused on the need for fishery legislation which, apart from targeting harvest control would also include the needs of habitat control. Mader (1991) pointed out that the habitat/fish linkage may not become evident until we refocus on habitat management as the cornerstone of sustainability, for example, as the European Economic Community is initiating.
Compared to marine fisheries, freshwater fish management is even more closely linked and vulnerable to human activities, particularly land and water management. In many Australian river catchments the development and exploitation of natural resources has had an impact on the quality and quantity of freshwater fish habitat. Threats have arisen among others from wetland loss, land and water use impacts, and introduction of exotic fish species.
The regulation of water in the Murray-Darling River system, draining large parts of four Australian states, has had an adverse impact on the native fish species. In order to improve the fish habitat, the Murray-Darling Basin Commission has developed Fish Management plan which provides a practical framework for remedial action aimed at reversing the decline of native fish stocks in the system (Lawrence, 1991). The Plan provides for the manipulation of river operations to better meet the needs of native fish within the constraints imposed by other demands on water resources, such as irrigation and domestic supply. The Plan also sets priorities for the Commission's fish research programme, which currently includes investigations such as enhancing native fish recruitment in the lower Murray by flow manipulation; fish mitigation and fishway performance; and fish response to flooding in a floodplain forest. As a resulting management measure floodplains of the Murray downstream of Lake Victoria were flooded through manipulated releases in November 1991, and this triggered Murray cod spawning on the adjoining floodplains. Re-establishment of species in modified environments which are productive or have been restored or are in the process of being restored is high on the priority list for the Murray-Darling River system (Cadwallader and Lawrence, 1994).
The Queensland Fisheries Act 1994 provides several fish habitat protection measures, including: declaration of closed waters for the protection of fishery resources, declaration of Fish Habitat Areas in which works can be controlled by permit and permitted activities can be subject to a management plan, and the issuing of restoration notices to those responsible for pollution and degrading fish habitat. Land use and development controls available under the Local Government (Planning and Environment) Act 1990 provide scope for protecting freshwater fish habitats. After significant fish habitat areas are mapped, protective measures can be incorporated in the Development Control Plans of local authorities. A number of other acts are available and can be used to counter threats to freshwater fish habitats. These can be used for prevention of: soil erosion, vegetation clearing (which may lead to increased sedimentation and salination), riparian vegetation loss and bank erosion, water pollution, degradation of wetlands, hydrological changes, fish migration, spread of exotic aquatic plants, harmful gravel and sand extraction, overfishing.
Impoundments are artificial water bodies for which habitat rehabilitation is no alternative to stocking if the objective is to create recreational fisheries. However, even in impoundments, habitat protection and rehabilitation have a role to play in the establishment and maintenance of fish stocks. In many instances habitat rehabilitation presents the opportunity to provide a long-term solution for dwindling fish stocks. Where habitat impacts have resulted in the loss or reduction of nursery areas, fish stocking may be required to maintain sufficient recruitment levels to meet the carrying capacity of a catchment or particular habitat area. However, every effort should be made to rehabilitate nursery habitats (Tait, 1995). In Australia, as elsewhere, habitat management has emerged as a critical issue in relation to stocking and hence to fish stock enhancement.
There is an effort to amend the existing legislation so as to ensure that it encompasses the needs of freshwater habitat protection. Mapping of freshwater habitats is in progress and when completed protective measures will be incorporated in the Development Control Plans of local authorities.
3. DISCUSSION
An unregulated resource can reflect an attitude of government or community that the resource is either unlimited or indestructible, or, alternatively, useless and valueless. Where recreational fishing is concerned, state fisheries determine how the resource is to be regulated. In Australia, the approach to regulation (or non-regulation) differs from state to state. Although the individual states have legal responsibility for management of fisheries, each of the states has a different approach to funding, and also may have a different mixture of management strategies. This is quite logical, as each state has different climate, different types of water bodies with different species, as well as different distribution and concentration of human population. There is a need for specific and detailed fisheries management plans for specific fisheries in specific areas.
Some anglers have been complaining about declining catch rates, with commercial fishing normally perceived as the cause. As a great majority of inland waters are only fished by anglers, the decline in angler catch rates is mostly directly attributable to the increase in the total angling effort. In several cases where commercial catches have declined, for example bream (Fluvialosa erebi) in the Richmond River, this decline is almost certainly due to increased total recreational catch which now accounts for more than 90% of the total catch from that river. Increased stocking rates may not always compensate for the rapid growth in the number of anglers and catching intensity, and the existing regulatory measures need to be revised and followed by enforcement. An example of this is the new trout fishing law in NSW. In Australian waters allocation of fish species within and between competing user groups is emerging as an important fisheries management policy issue of the near future (McLeod, 1994), although it would appear to be an issue of immediate concern for coastal rather than inland waters.
The Workshop on Recreational Fishing, held in Canberra in 1994, showed a great need for improvement of statistical data. A figure of 50,000 tons captured annually by recreational fishermen (including those fishing the seas) was accepted as a guesstimate at the meeting. The shortage of information on the catch and effort represents an obstacle for developing more precise stocking strategies. In most Australian fisheries it is not known what the sustainable yield and the current catch are (Recreational Fishing in Australia, 1994). Such shortage of information makes enhancement of fish stocks in the individual water bodies more guesswork than result of a scientifically based management policy.
Recreational fishery is now by far the greatest user of fish stocks in Australian inland waters and estuaries. In the South Australian section of the Murray River allocation of fish stocks has been progressively towards the recreational fishing sector, as the commercial fishery declines through retirement and subsequent withdrawal of licences. In the Northern Territory, the Government closed the Mary and East Alligator River systems to commercial fishing, restricted access to the Daly River system, but at the same time imposed a bag limit on recreational catches to protect valuable stocks.
In the Murray River system, the decline in commercial fisheries for native fish species could be partially overcome by targeting non-native species. Carp is a wide-spread species, which has invaded many Australian waters. While it is considered as being a low-value table fish by most Australians, and a pest by fishery managers and anglers, the sheer quantity and ease of catching it makes this fish an easy target both for anglers and commercial fishermen. There are very few commercial fishermen in Australia who fish carp, partly because the governments of the individual states prefer the fish to be destroyed rather than utilised. To obtain a license for carp fishing in New South Wales requires approval from the NSW Fisheries, Department of Water Resources and private land owners. Only one commercial fisherman delivers captured carp once a week to Sydney Fish Market. Using electrofishing in irrigation canals, up to 4 tons of carp can be fished out in three hours. More carp could be utilised by processing it into pet food, fish pellets, garden fertilisers, and food additives for cattle, chickens and emus, carp fillets for the export market, crayfish bait, skins for leather products and pituitaries for induced breeding. Lack of commercial interest is a major obstacle to better utilisation of this considerable, and non-utilised fishery resource. Once better utilised and more intensively fished, the fish currently labelled as noxious could become a valuable commodity.
The National Recreational Fisheries Working Group has emphasised the need to manage the recreational fishery in Australia as part of the total fisheries resource to ensure quality fishing, and to maintain fish stocks and their habitats for present and future generations of Australians (Recreational Fishing in Australia, 1994). Australian fisheries should also be managed within an ecosystem management framework. The document addressed the issue of enhancement through stocking but emphasised the need for allowing natural reproduction and recruitment to take place where possible. It felt that stocking should not be seen as a substitute for loss of natural reproduction and recruitment caused by habitat degradation.
The need for fish stock enhancement has been included among the priority areas for additional funding. A broad estimate indicates that the total amount required for recreational fishery management is in the order of A$ 44 million at 1993 prices. This is only a fragment of the A$ 3.5 billion estimated to flow on from recreational fisheries to businesses and local communities. Other areas for additional funding include research, policy development, community education, resource monitoring, enforcement, recreational fisher representation and further development of recreational fishing opportunities (Recreational Fishing in Australia, 1994).
4. CONCLUSIONS
Australia is a continent surrounded by oceans. With the majority of population settled along the coasts, from the very beginning of the settlement of Australia through immigration, fishing took place predominantly in coastal waters. For a long time the native freshwater fish were considered to be of minute importance. In the mid-1800s trout were imported from Europe and successfully introduced in cold waters. With a few exceptions, until recently, trout fishing dominated the recreational fisheries. Enhancement of trout stocks, both brown and rainbow, was a duty of hatcheries, most of which were situated in the states of Victoria, New South Wales and Tasmania.
In the past, introductions of exotic fish and translocations of Australian fish were important enhancement measures. Most of the translocated species could not breed in new environments, thus requiring restocking at regular intervals to satisfy anglers' demands.
The success with artificial reproduction of a number of native fish species since the 1970s, but especially since the 1980s has led to stocking of a great number of water bodies, especially impoundments with fish species absent from them. Prior to that, most impoundments either lacked or had only few fish of angling significance The regular stocking of water bodies with native fish has become the major factor behind the explosive growth of recreational fisheries in inland waters. At present, one out of three Australians goes fishing, and one out of six fishes fresh waters. Today, stocking of native fish is the major management tool for enhancement of inland water fish stocks. Hatchery-bred stocks can play an important role in the conservation of threatened native fish in the Murray-Darling basin, provided stocking is undertaken in conjunction with habitat restoration and appropriate protective legislation to ensure the continued survival of the stocked fish (Cadwallader and Lawrence, 1994). The individual states of Australia and the local recreational fishery organisations, assisted by stocking societies, carry the responsibility for maintaining healthy fish stocks in many inland waters. Each state government now closely collaborates with angler societies, stocking societies and seed producers in optimising fishing conditions in inland water bodies. While the number of anglers is rising, the number of commercial fishermen is in decline.
There is a potential for increasing the number of native fish seed producers as in some areas shortage of stocking material keeps certain waters well below their production capacity. The government also supports further diversification of suitable fish for angling, and as methodologies for artificial breeding and production of other native fish are perfected, more species are being released into waters as their hatchery seed production gets under way. Further potential rests with the development of fishery for carp, an exotic fish widespread and very common in a large number of Australia inland water bodies. This fish, which is currently on the list of noxious species and subject to a number of attempts at its eradication, could be processed into a variety of products. This is a major fishery resource awaiting skilful entrepreneurs.
Recreational fisheries for native and exotic freshwater fish is expected to grow for some time to come. Consequently demand for better management of recreational water bodies will continue. The increased demand for fish has recently led the individual states to revise their fishing laws and regulations, with more restrictions being placed on bag size, size limits, fishing seasons, etc. This is one way to satisfy the growing number of anglers. In some water bodies the angling pressure has resulted in reallocation of the resource, with commercial fishermen becoming the losers. Anglers are encouraged to use a catch-and-release approach to preserve the fish stocks. There is also a growing number of managed private water bodies which allow fishing for a fee.
In conclusion, one must again highlight the major achievement in advancing and perfecting the induced breeding of native fish species, the most important factor for enhancing fish stocks in inland waters of Australia and a major driving force for the expansion of recreational fisheries in inland waters, especially where conditions are not suitable for trout fishery. Introducing a larger diversity of fish species and maintaining their required stocks through regular stocking to sustain the angling pressure, has also resulted in considerable benefits to local economies arising from this leisure sport.
ACKNOWLEDGEMENTS
Thanks to Dr. Phil Cadwallader, Prof. K. Walker, Dr. Bryan Pierce and Allan Haines who drew my attention to a number of documents and thus made easier my task of compiling this paper.
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