Sustainable management of natural resources requires robust and timely information inputs, particularly in multispecies or cross-jurisdictional fisheries such as the Murray-Darling Basin's (MDB) recreational fishery. Innovative data collection and monitoring approaches, management tools and cooperative efforts enable the requirements of fisheries managers to be met efficiently and cost-effectively. This paper considers a number of pioneering initiatives operationalised under the Native Fish Strategy that have helped inform sustainable management outcomes for the recreational fishery in the MDB.
Recreational fishing is an important leisure activity worldwide (Cooke & Cowx 2004) and a valued pastime of the Australian community, offering significant economic and social benefits (Henry & Lyle 2003; McManus et al. 2011). The importance of recreational fishing to communities in the Murray-Darling Basin (MDB) specifically was highlighted by a recently published study, which reported that 430 000 Basin residents aged >5 years recreationally fish each year, contributing approximately $1.3 Billion per annum to the economy and supporting an estimated 10 950 jobs (Ernst & Young 2011). Of the 57 recognised fish species found in the MDB (Lintermans 2007), 18 (12 native and 6 introduced) are either targeted or captured unintentionally by recreational fishers. A variety of techniques are employed by fishers (e.g. lure and fly casting, trolling, bait fishing) for both sport and food throughout approximately 6835 km of waterways comprising both riverine and impoundment habitats. Fishers target both wild and stocked fish that are managed by any one of five state/territory governments.
The fishery has undergone significant changes over the last 20–30 years, especially the Murray Cod (Maccullochella peelii) fishery (Rowland 1989, 2005). Foundational research in the 1970s–1990s led to changes in management arrangements such as the closure of commercial fisheries, minimum size limits, bag and gear restrictions and seasonal closures to protect breeding stock. The development of a comprehensive stocking program in a number of jurisdictions also established several productive impoundment fisheries, as well as aiding recovery of some stocks in river systems such as Trout Cod (Maccullochella macquariensis) and Murray Cod (Allen et al. 2009; Koehn et al. 2013). These programmes have the potential to serve as an effective adjunct to other restoration activities, such as habitat restoration (Nicol et al. 2004) and the provision of environmental flows (King et al. 2010; Koehn et al. 2014).
Analysis of data collected between 1994 and 2011 indicate an increase in Murray Cod abundance by 740% across NSW in the last 17 years (D. Gilligan, NSW DPI, unpublished data, cited in Rowland 2013). Consequently, in contrast to the situation in the 1970s where the capture of a Murray Cod was noteworthy, recreational fishers now have a more than reasonable expectation of success in many locations (Fig. 1), and these improvements have seen the fishery grow to one of the Australia's most important recreational fisheries (Ernst & Young 2009). Notable improvements have also been reported for some (although clearly not all) of the MDBs threatened species, particularly Trout Cod (Koehn et al. 2013). Nevertheless, MDB fish species still face considerable challenges from degraded habitats and reduced flows, and recent studies have shown that bottlenecks still exist in natural recruitment processes for some species/stocks. For example, in contrast to reported recovery in other areas of the Basin, in South Australia, Murray Cod have experienced ongoing population declines with very little evidence of recruitment (Ye & Zampatti 2007). It is clear that ongoing work is required.
Current approaches to recreational fishery management rely largely on regulatory restrictions to limit fishing mortality (see Arlinghaus et al. 2010) and stocking of hatchery-produced fish to increase populations (Cowx 1994). Information requirements for effective fisheries management include available biomass and size/age structure, population dynamics (rates of migration, births and deaths) (King 1995), estimates of natural and fishing mortality (including released fish), and data to differentiate stocked and wild recruits in populations. This can be expensive to obtain, particularly over large spatial scales, necessitating development of innovative data collection and monitoring approaches. Strong stakeholder engagement provides a useful adjunct to traditional scientific data collection for cost-effective monitoring (Stenekes & Sahlqvist 2011) and offers additional benefits such as engendering understanding and support among fishers for fisheries regulations required, leading to higher compliance levels (Kuperan et al. 2008).
A suite of projects funded under the Native Fish Strategy (NFS) (Murray-Darling Basin Commission 2004) has helped inform sustainable recreational fisheries management outcomes for the MDB. In this study, we describe several key examples and consider their contribution to sustainable and well-supported recreational fishing outcomes in the MDB into the future.
Fish Populations and Management Predictions
Modelling offers the ability to formally articulate interactions between management and biological/ecological outcomes, using available knowledge and data (Hilborn & Mangel 1997). In this way, the efficacy of alternative management strategies is able to be compared in terms of population risk (risk of quasi-extinction: see Burgman et al. 1993) and abundance or fishery yield (Smith et al. 1999). Importantly, an interactive modelling process can also help engage key stakeholder groups in the identification of management actions required (Burgman et al. 1993).
Management of some species such as the Murray Cod, which is both a threatened species and of significant value to recreational fishers, requires a balance between conservation and resource utilisation objectives. The need to predictively ‘test’ management options for this species led to the development of population models able to be used for this purpose (Allen et al. 2009; Koehn & Todd 2012). While the use of commercial fishery models (e.g. Sainsbury et al. 2000) and species conservation models (e.g. Todd et al. 2004) is common, to date they have usually been employed separately.
The Murray Cod models were built using the best available knowledge of the species’ biology and life history, with structure and inputs explicitly agreed to by stakeholders. The cumulative impacts of multiple threats on fish populations are complex and rarely considered (Cowx & Van Zyll de Jong 2004), but importantly, recognition and inclusion of other (nonfishery) impacts (such as injury/mortality of larvae at weirs) assist in the ‘real world’ evaluation and are in line with multimanagement rehabilitation actions for native fish populations (Murray-Darling Basin Commission 2004; Koehn & Lintermans 2012). A range of other relevant impacts (e.g. fish kills, stocking, thermal impacts, habitat changes) were also incorporated (National Murray Cod Recovery Team 2010).
The interjurisdictional management arrangements for Murray Cod necessitate a coordinated approach with a high level of collaboration between individual state conservation and fishery agencies and their stakeholders (including recreational fishers, indigenous community, conservation group representatives and others). Consultative workshops that included conservation and fishery interests were conducted to engender trust and ownership of the Murray Cod modelling process and outcomes. These workshops were used to update knowledge, guide the model development and reach agreement on management scenarios and then to refine and test the model. A user's manual was developed to accompany the software, which was also made available as ‘freeware’ in an effort to further enhance adoption and ownership (Todd & Koehn 2010), (see http://www.dse.vic.gov.au/arthur-rylah-institute/publications/software).
These models have been used to consider suitable alternative management arrangements for this species, including alternative minimum legal length limits (MLL) and harvest slot length limits (HSLL), and indicate that risks of decline to Murray Cod populations can be substantially reduced and catch rates increased through use of HSLL rather than MLL. Both a 600–1000 and a 400–600 mm HSLL were found to provide lower risk of decline and greater catch rates than a 500 mm MLL (Koehn & Todd 2012).
Murray Cod is only one of many freshwater fish species, for which population models would be useful. Todd et al. (2011) determined there was sufficient life cycle information and data parameters to construct age population models for nine MDB species, with Silver Perch (Bidyanus bidyanus), Macquarie Perch (Macquaria australasica), Trout Cod, Freshwater Catfish (Tandanus tandanus) and Golden Perch (Macquaria ambigua) identified as priorities (Todd et al. 2011). Such models should be formally integrated into fish management and species’ recovery plans, set within an adaptive management framework where the models can help set a structured learning environment and be used to assess potential outcomes from management actions (Todd et al. 2011).
Marking Hatchery Produced and Stocked Fish
Estimates of recruitment into populations are critical as input parameters for fisheries models. Generation of such estimates requires a good understanding of natural spawning and recruitment, as well as the effects of artificial stocking. More than 60 million fish produced by private and government hatcheries having been stocked into waterways over the past 30 years with Golden Perch comprising approximately 65% and Silver Perch and Murray Cod making up most of the remainder (Gillanders et al. 2006). The vast majority of stocking in the MDB is targeted towards improving recreational fishing. Despite the large scale of stocking activities, to date, there is little information regarding the effects of stocking on native fish populations or the receiving ecosystems.
A major impediment to understanding the effects of fish stocking in the MDB has been the lack of methods for discriminating hatchery fish that are suitable for implementation in large-scale hatcheries. The majority of stocked native fish in the MDB are released as fingerlings of 20–50 mm total length (TL), and it is common for hatcheries to produce batches of 100 000 or more fish. Consequently, methodologies that require handling of individual fish (e.g. fin clipping, tagging) have to date been considered impractical except for specific research programmes (Russell & Hales 1992; Ingram 1993).
A suite of methods were developed and evaluated for routine chemical batch marking of fingerlings with funding from the NFS. These methods included external and otolith marking of fingerlings with the fluorescent compounds calcein and alizarin red S (Crook et al. 2007, 2009), trans-generational marking of the otoliths of progeny by injecting nonradiogenic isotopes into brood fish (Munro et al. 2009) and otolith marking of larvae and fingerlings via immersion in solutions of nonradiogenic isotopes (Munro et al. 2008; Woodcock et al. 2012). All of these methods were specifically designed to be suitable for use in large-scale hatcheries. For example, 20 000 or more fingerlings can be marked using calcein in approximately 15 min using the osmotic induction technique described by Crook et al. (2009). Marked fish can then be discriminated by use of a fluorometer, specialised glasses or examination of otoliths under a fluorescence microscope (Crook et al. 2012a,b; Figs 2a–d.)
Field studies involving stocking of chemical marked Golden Perch in the Murrumbidgee River, Edward River and Billabong Creek and then sampling resident fish communities over 5 years showed that the proportion of stocked fish varied greatly between rivers and across years (Crook et al. 2012). For example, stocked fish released into the Edward River in 2003 comprised 22% of their year class, whereas in Billabong Creek 100% of the 2005 year class was stocked.
Successful implementation of fish marking protocols in hatcheries is essential to improve understanding of outcomes achieved through fish stocking (Rowland 2013). Among hatchery operators, willingness to adopt marking methods depends on a range of considerations, including costs of associated equipment and consumables, staff availability and logistics, any effects on the health, quality or quantity of fish produced, any associated environmental or human health issues, and the administrative tasks involved. It is important, therefore, that procedures for marking hatchery fish accord as much as possible with the requirements of hatchery operators and fisheries managers. It is also critical that privately run operations are not financially or otherwise disadvantaged; willing participation in marking programmes is essential to adoption of marking protocols.
More than 3 million calcein marked fish from more than 10 species have now been stocked across Australia as part of research on the outcomes of stocking for recreational and conservation purposes. With development of chemical batch marking methods, as well as recent advances in genetic techniques for identifying hatchery fish (e.g. Rourke et al. 2011), there is now the potential to gain a detailed understanding of the effects on fish populations and the cost/benefits of native fish stocking in the MDB.
Building an Oral History of River Health and Fish Communities
It can be assumed that Australia's native fish have evolved adaptations to natural conditions that are most suitable to sustain their populations (Poff & Allan 1995). Consequently, sustainable management of wild recreational fisheries requires that (among other things) environmental conditions necessary to support spawning, recruitment and growth be maintained. Where fish populations decline over time, comparison to undisturbed systems can help inform consideration of appropriate rehabilitation measures. Unfortunately, however, the long history of riverine modification in Australia, and particularly the MDB, makes identification of undisturbed systems difficult (Bayley 1995). Consequently, temporal comparisons of the occurrence and abundance of native fish species and habitat condition that can play a crucial role in identifying changes in fish communities and developing recovery strategies (Davies et al. 2008) are lacking.
Contemporary ecological studies and population modelling approaches provide useful insights to inform fisheries management (e.g. Nicol & Todd 2004; Lintermans 2007), but there are limitations to these sources of information. For example, it was not until the twentieth century that broad-scale ecological research into the fish and rivers of the MDB commenced, by which time many changes attributable to the arrival of Europeans had already occurred. This may therefore limit our understanding of optimum conditions to sustain native fishes.
Observations by anglers of changes to fish populations in the MDB by 1880 were the catalyst for management of the fishery and research into the biology of native fish (NSW Government 1880). J. O. Langtry's post-WW2 survey of fish populations incorporated ‘anecdotal’ oral history information, creating a record of environmental change used to inform management practices (Cadwallader 1977). Recently, the concept of ‘historical triangulation’ to validate oral history using multiple lines of evidence such as photographs and newspaper stories has helped reinforce credibility of such information (Robertson et al. 2000; Boulton et al. 2004). This approach has been applied to create narratives describing changes to fish populations and habitats in several catchments within the Basin (Roberts & Sainty 1996; Frawley et al. 2012) and Gwydir (Copeland et al. 2003) catchments and to map the original distribution and abundance of fish species across large areas of the MDB (Trueman 2011).
Other historical information sources such as aboriginal oral histories also provide valuable and as yet underutilised data to inform management. Aboriginal people were originally viewed as hunter-gatherers moving from place to place as resources became available or were depleted. This view has changed, however, with increasing evidence that aboriginal people were environmental managers with at least some habitats being dependent upon their practices such as ‘firestick’ farming (Bird et al. 2008). There is also historical evidence of their managing fisheries by regulating their take, enhancing habitat, creating fish sanctuaries and carrying out translocation activities (Gilmore 1934; Humphries 2007). It may be that some fisheries benefit from historical aboriginal management practices in similar ways to terrestrial environments.
Native fish played a prominent role in the lives and spirituality of the first Australians. The collection of historical information on their practices, apart from potentially aiding the management of fisheries, allows the aboriginal community to revive their connections to their ancestors and country. Knowledge of the relationship between aborigines and fisheries in the general community may also serve to foster the process of reconciliation and enhance broader community connection with the environment.
Historical information on fisheries also provides an important political impetus for restoration and management. It is through comparison to historical documented evidence that communities are able to recognise changes that have transpired, and the reduced ecosystem services afforded by degraded habitats. Further, public awareness of the total loss of some past fisheries (e.g. Trout Cod, Macquarie Perch) reinforces foregone angling opportunities and the threat of future losses in the absence of effective intervention (Fig. 3). Perhaps, the most valuable application of historical information can be to catalyse the process to restore lost fisheries.
Historical accounts such as Trueman (2011) have challenged contemporary thinking of preferred habitat and conditions for key species, including Trout Cod and Murray Cod which were found to exist at higher altitudes than previously thought. Findings from this and other historical research have been actively utilised by fisheries managers wishing to understand the abundance and distribution of native species throughout the Basin (C. Westaway, pers. comm). Such knowledge has informed development of a classification program for managing waterways as recreational fisheries and for native fish recovery in Victoria (Department of Primary Industries 2010), the development and prioritisation of recovery actions for threatened species recovery (National Murray Cod Recovery Team 2010) and providing baseline information for ongoing monitoring programmes (Davies et al. 2012). It would be valuable to continue to build narratives from historical information on the precondition of our waterways and fish stocks and continue to integrate such information in future decision-making and rehabilitative strategies. This is particularly true of knowledge held within indigenous communities.
Co-management in Practice: the Murray Cod Fishery Management Group
Meaningful engagement between management agencies, researchers and the fishing community is an important precursor for the achievement of effective fisheries management outcomes for multijurisdictional fisheries such as the Murray-Darling Basin's Murray Cod recreational fishery (Kuperan et al. 2008; Koehn & Lintermans 2012). This species is both highly valued by recreational fishers (Ernst & Young 2009), and a nationally listed species, for which a recovery plan has been produced (National Murray Cod Recovery Team 2010). Fishery and conservation objectives are largely compatible; however, it is also important to ensure compatibility of actions implemented to pursue population recovery and fishery enhancement (Cowx et al. 2010; Koehn 2010).
Initiation of a collaborative model for management of Murray Cod through the Murray Cod Fishery Management Group (MCFMG) has facilitated continued progress in the recovery of this species and optimisation of fishing outcomes at a basin scale. The MCFMG comprises researchers, managers and recreational fishers from each basin jurisdiction, as well as representatives of the Murray Cod Recovery Team. The body was established under the auspices of the Australian Fisheries Management Forum (AFMF) to enhance Murray Cod recreational fisheries outcomes across the MDB through improved collaboration and alignment of management and research across the basin.
The group oversees implementation of an action plan formulated as an output of a collaborative workshop, which articulates strategic priorities to aid enhancement of Murray Cod populations (Murray Cod Fishery Management Group 2011, 2012). This process has helped to improve communication between jurisdictions, unify diverse interest groups behind a single cause, facilitate targeted investment in research and development for this species, and leverage significant co-investment. The MCFMG also provides a collaborative forum for developing a shared vision for management of Murray Cod within which the values and experience of recreational fishers are considered alongside research expertise and management input. A basin-wide monitoring program to assess the status of this species using angler-derived information alongside fishery-independent data sources was recently initiated through co-investment from the Fisheries Research and Development Corporation, NSW and Victorian recreational fishing trusts, and state management fisheries agencies.
Recognising that the co-management model developed in the MCFMG has wider prospective application, AFMF recently endorsed expansion of its terms of reference to incorporate other basin native fish species. It is expected that additional efficiencies will be realised through this approach to multispecies management of fish stocks in the Basin.
Conclusion and Recommendations
The management of recreational fisheries within the MDB has been enhanced through the availability of better tools and techniques, a more cooperative approach, increased consideration of the historical context and the input of data from nontraditional sources. Building upon existing relationships and scientific information, the NFS has provided a vital unifying structure under which strategic research relevant to the recreational fishery in the MDB could be identified, prioritised and delivered. This has helped overcome cross-jurisdictional issues that are often encountered in the delivery of research and development at large spatial scales and has helped avoid short-term, responsive and fragmented approaches to freshwater fisheries research that can occur in the absence of an overarching structure.
There will be an ongoing need for applied research and development to inform sustainable fisheries management in the Basin following discontinuation of the NFS in 2013. Hence, it will be necessary for research providers, managers and other stakeholders to adopt a similarly unifying, strategic and collaborative process for the prioritisation and delivery of applied research for this purpose. An ongoing commitment to engaging the recreational fishing community in this process will be vital to delivery of effective outcomes.
The authors would like to thank Fern Hames for her assistance in reviewing this manuscript. With the exception of Cameron Westaway, all authors have either worked for or delivered projects in a paid capacity for the Murray-Darling Basin Authority's Native Fish Strategy.
Matt J. Barwick is the Director of Greenfish Consulting Pty. Ltd. (36 Sydney Street Labrador, Gold Coast, QLD 4215; Tel: +61 422 752 789; firstname.lastname@example.org) and Program Coordinator for Recfishing Research
John D. Koehn is a Principal Research Scientist with the Arthur Rylah Institute for Environmental Research (Department of Sustainability and Environment, 123 Brown St, Heidelberg, Victoria, 3084, Australia
David Crook is a Principal Research Fellow with Research Institute for the Environment and Livelihoods, Charles Darwin University (Darwin NT 0909, Australia
Charles R. Todd is a researcher with Victoria's Arthur Rylah Institute
Cameron Westaway is a Senior Fisheries Manager Inland with NSW Department of Primary Industries (3/556 Macauley St, Albury NSW 2640 Australia
William Trueman is a private consultant (P.O. Box 494 Gordonvale Qld 4865, Australia; email@example.com). This project arose from a need to summarise how research funded under the Native Fish Strategy has been useful in informing fisheries management in the Murray-Darling Basin