Commercial and recreational fishers are permitted to use gillnets in Tasmania. There are several classes of gillnet distinguished by mesh size - commercial gillnets include, small mesh, graball and shark nets, while recreational gillnets include mullet and graball nets. During the past 5 years around 150 commercial operators each year have reported gillnet use, for an average catch of 200 tonnes of scalefish. Recent information for the recreational sector is limited though recreational netting remains popular, with over 10,000 net licences issued in 2009. Previous surveys indicate that recreational fishers target much the same species as commercial operators.

Over the past decade there have been several management initiatives, including a prohibition on night netting for most areas and, more recently, the introduction of maximum soak times. These initiatives have been designed to improve gillnetting practices, and reduce wastage and impacts on non-target species. Despite this, there have been conspicuous declines in the abundance of several key gillnet species along with increasing community concern about the ecological impacts of gillnetting. This concern has been particularly evident in the debate surrounding the introduction of marine protected areas, with gillnetting identified as a key threat to biodiversity. Furthermore, in the 2009 Scalefish Fishery review DPIPWE identified the need to develop strategic policy in relation to no-netting areas to address issues including resource sharing, wildlife interactions and stock management.

In view of the above, there is an urgent need to better understand how recent management initiatives have influenced netting practices, and to objectively assess the risks and impacts on target and non-target species. Ultimately such an understanding will be pivotal in informing the on-going debate over the future management of gillnetting in Tasmania.

Liitle is known of the movement patterns of most commercial reef species, an aspect that is crucial for evaluating the effectiveness of spatial management and interpretation of local stock dynamics. By undertaking a broadly applicable movement study drawing on examples over an Australia wide scale and using model species representing differing life histories, we will address a key issue identified in several national strategic priorities (SCFA Research Priorites for Australian Fisheries and Aqauculture - Program 4). These priorities include understanding the ecosystem effects of fishing and the need to assess the merits and performance of spatial management. They were identified at the Aquatic Protected Areas R&D workshop (Cairns), and in a recent spatial management discussion paper by Smith et al. (2003).

In Tasmania, defining movements of commercial finfish species (e.g. banded morwong) between and within reefs, has been identified as an important research issue by the Scalefish RAG, and essential for understanding local stock dynamics and interpreting CPUE data. Current fishing practices target juvenile trumpeter species, and spatial ‘nursery area’ closures may be one option of ensuring a significant proportion of fish reach maturity before becoming vulnerable to the fishery.

In the Northern Territory the black jewfish is an important species for both commercial and recreational fisheries, yet it appears to be particularly vulnerable to overfishing due to a mix of aggregating behaviour and an increasing knowledge by fishers of the location of these aggregations. Understanding the nature of these aggregations and the threat posed by fishing has been identified as the number one priority for fisheries research and knowledge of fish movements with respect to these aggregations is an important component required for development of effective management plans.

Smith, D., Sainsbury, K., Buxton, C., Morris, L., Hough, D., Haddon, M. & Moore, M. 2003. Development of an R&D response to ecosystem based management: Spatioal management of fisheries and the role of MPAs. FRDC Final Report 2003/073. 51pp

In concert the establishment of MPAs around the world and the current push to increase the number an size of no-take areas it has been argued that these areas may be of benefit to fisheries management. Included are moving fisheries harvests towards more sustainable yield, rebuilding depleted stocks, an insurance against stock collapse and the protection of essential habitat.

But as with all management tools, potential and real benefits need to be rigorously assessed. This knowledge base is currently lacking.

The proposed project will make a major theoretical contribution to the general understanding of MPAs for fisheries management as it will incorporate several new parameters in the model, including:- effort displacement; existing management tools (input controls and TAC); larval dispersal where possible (research on larval dispersal of rock lobster has focused on Tasmania); fleet dynamics; and spatial variation in biological parameters.

The plan to establish a National System of Marine Protected Areas in Australia has been resisted by the fishing sector because of a percieved loss of yield proportional to the area of the closure and the lack of critical evidence to support the proposed benefit to fisheries (including insurance against stock collapse, sources of eggs and larvae and improvement in yield). To resolve this conflict we urgently need to model the potential impacts and provide the empirical ground-truthing of the effects of area closure on the fishery.

Given that most commercially-exploited reef species are long lived and that MPAs require several years for the effects of closure to manifest themselves, there is a need to provide baseline information on the status of proposed sites. This information can then be used to evaluate MPA objectives in the future.

Equally there is a need to maintain adequate assessment of the changes that occur once an area has been closed. Monitoring of existing reserve sites in Tasmania has been ongoing for a period of five years. It is important to continue this work because analysis after five years of initial survey provided no indication that population changes of exploited species had stabilised. The biomass of rock lobsters within reserves, for example, continued to increase throughout the five years of the study. Clearly there is a need to continue the survey in order to properly document longer term changes that occur as a result of closure. This information is fundamental to the evaluation of MPAs as a coastal management tool.

The project chooses to focus on relatively sedentary species for several reasons:

While intuitive benefits in terms of stock recovery of sedentary species have been demonstrated, other benefits are far from predictable and the scant information on this subject yields results that are species specific and dependent on the behaviour of the species. There is a growing awareness that generalised models are inappropriate and each case needs examination on its own merit. Furthermore, the size of the no-take areas under consideration mitigates against the study of the benefits for highly migratory species, which range freely between protected and unprotected sites. Finally, empirical confirmation of models based on sedentary species is most likely to be achievable (recognising that models for migratory species are not well advanced at this stage).

PRIORITISATION

To address possible funding constraints we have prioritised the tasks as follows:

1. Modelling the effects of closure on the fishery
2. Survey of the proposed reserve sites in Tasmania, including the industry proposed sites
3. Ongoing survey of established sites in Tasmania
4. Survey of proposed sites eslewhere Australia
5. Survey methods workshop