Characteristics of traditional dugong and green turtle fisheries in Torres Strait: opportunities for management

The management of dugongs (Dugong dugon) and green turtles (Chelonia mydas) is a complex social and ecological problem. Dugongs and green turtles are protected by Australian national and sub-national conservation legislation. Both species are important cultural, spiritual and economic (i.e., subsistence) resources for Indigenous Australians. In Australia, Aboriginal and Torres Strait Islander Traditional Owners may hunt these species to satisfy personal, domestic, or non-commercial communal needs. Torres Strait, not only has the largest population of dugongs in the world and one of the largest breeding populations of green turtles, but also has high rates of Indigenous hunting compared to other parts of Australia. Consequently, management of the traditional Torres Strait dugong and green turtle fisheries needs to include social–ecological considerations and involve Torres Strait Island communities. The ecological scales at which dugongs and green turtle operate are large. Dugongs undertake large-scale movements and green turtles undertake breeding migrations, which means the populations that are hunted by Torres Strait Islanders are also hunted or impacted by threats in other countries and in waters off mainland Australia. Thus, management of these populations needs to occur at local, state, national and international scales.\ud \ud To inform the development of management arrangements for the traditional dugong and green turtle fisheries in Torres Strait I aimed to provide an overall context for management at different spatial scales and investigate opportunities and challenges associated with co-management, particularly community-based monitoring.\ud \ud The development of a participatory research process, particularly the research agreement, cultural reference group and employment of Indigenous research counterparts was integral to the study being resilient to external perceptions of hunting reported in the media that threatened to cause hunters to withdraw their participation from the project. Without a process to establish trust, hunters were concerned that the information they provided would be used against them to stop them from hunting. Hence, the process I undertook confirms the importance of strong, resilient co-management partnerships.\ud \ud The risk to dugongs from hunting was evaluated based on spatial data about hunting patterns and dugong distribution and relative abundance. More than 60% (10,690 km²) of the areas supporting very high and high densities of dugongs are at low risk from hunting because hunting is largely restricted to areas close to inhabited islands (i.e., within 30 km). Nevertheless, the areas accessed by hunters also include a substantial amount (6,007 km²) of the very high and high dugong density areas, most of which are the 'sea country' of individual communities. A spatial decision framework based on knowledge of jurisdictional arrangements suggested that different types of management will be appropriate in different parts of the Torres Strait region and that the relative importance of different co-management partners changes with spatial scale.\ud \ud Hunters and elders from Hammond Island were interviewed regarding the need for local management, their perceptions of different management tools and multi-scale co-management from a community perspective. The Hammond Islanders considered some management tools, such as quotas and spatial management, appropriate to incorporate into co-management plans, but that other tools, such as seasonal closures and sex/size-based limits, were inappropriate because of social and cultural factors. Community-based management approaches were considered important especially the application of: (1) cultural norms to the development of tools to achieve compliance and enforcement within the community; and (2) consensus-based decision-making, with regard to the use of more formal rules. The need for cooperation with other communities and stakeholders across spatial scales was also recognised, particularly with regard to enforcement. Overall, the results suggested that co-management is likely to be a more appropriate approach for managing dugongs and green turtles in Torres Strait than either community-based management or government-driven management.\ud \ud Re-analysis of data from two catch-monitoring projects previously conducted in Torres Strait to collect catch statistics and/or life-history parameters on dugongs: (1) occasional sampling and (2) census by an outsider showed that occasional sampling would not provide robust catch-estimates at the individual community level as required for community-based management. I investigated an alternative strategy that considered hunter as the sampling unit. Hunters in the Kaiwalagal communities of Hammond Island and Thursday Island recorded information on datasheets on the number of animals taken, demographic information about the animals taken and information on hunting patterns. Indigenous research counterparts recruited hunters to participate, distributed and collected datasheets, collected biological samples from harvested animals and helped provide feedback to hunters and their communities about the results and progress of the project. The results suggest that a community based approach, such as hunter self-monitoring, will be a more reliable and cost effective approach for determining catch-estimates for dugongs and green turtles to inform co-management at the community level than alternatives such as occasional sampling or census by scientists (e.g., professionally-based monitoring). Hunter self monitoring has fewer limitations and more benefits than the alternatives with respect to: accuracy and precision of the catch estimates, financial costs, trust by communities and capacity to feedback results to communities in a timely manner.\ud \ud Determining the sustainability of the catch requires demographic information about the animals taken as well as the number of animals taken. Hunters recorded information that was more straightforward (e.g., sex) more often than information that was more complex (e.g., reproductive status) and specimens were rarely collected. In addition, hunters did not record unsuccessful trips and therefore an understanding of catch-per-unit-effort could not be obtained. The amount and complexity of information to be collected should ideally be increased in stages as hunters become more proficient, with training in the provision of information at each stage.\ud \ud Collection of information about hunting patterns, including social and cultural considerations, can provide important insight about hunting pressure, which can be useful for guiding decisions regarding the choice and application of management tools. Some of the management options included in the Community Dugong and Turtle Management Plans of other Torres Strait communities, such as stopping spotlighting of green turtles at night, could be effective in reducing catch, but could be difficult to implement. Dugongs and green turtles were caught mostly for general consumption. Therefore, management strategies that limit hunting to ceremonies may be difficult to implement due to the social pressure on hunters, particularly the few prolific hunters who are regularly asked by others to hunt for them. Thus, efforts to change beliefs and behaviours regarding hunting management needs to go beyond hunters to the broader community.\ud \ud Although community-based catch-monitoring will be more appropriate than occasional sampling by professionals to inform co-management of the Torres Strait dugong and green turtle fisheries, there are significant challenges to its implementation. Obtaining insights into the population status and sustainability of the catch will require monitoring temporal trends in a series of indicators using a framework, such as developed in this thesis, to assist in accessing and coordinating the functions necessary to develop and implement a catch-monitoring project. Such a framework could be used by a coordinating organisation such as the Torres Strait Regional Authority to access the necessary technical skills and plan a monitoring project, including highlighting where capacity-building is needed