by Wendy Noreña
Indigenous communities around increasingly finding that their traditional fishing practices clash with new, externally-imposed conservation policies and societal expectations. Finding an appropriate answer to these disagreements is difficult, especially since there are not enough data about most traditional, or even modern, marine fisheries to be able to create accurate scientific models that could help guide potential management strategies. Marsh et al. (2015) investigate the indigenous Dugong harvest in the Torres Straits, an area that spans the ocean space between Papua New Guinea (PNG) and the Northern Australian coast. Based on Marsh et al.’s preliminary research, the harvests here have been taking place for 4,000 to 7,000 years and have been “substantial,” for 400 to 500 years. With concerns about the conservation of ecosystems becoming more prevalent and politically involved, more and more people in Australia and PNG are calling for a ban or for restrictions to Dugong harvests. So far, regulations have already been set in place to limit hunting in certain areas and with certain equipment, but, because of the Australian Native Title Act, the Torres Strait islanders are lawfully allowed to hunt in what is known as their, “sea country,” as long as they follow a few restrictions. Marsh et al. argue that previous studies which stated that dugong harvests are largely unsustainable are actually incomplete due to the absence of good population and hunting data. Marsh et al. estimate that the Dugong harvest is sustainable and suggest that typical conservation methods should not be used to manage the Dugong harvests. Instead, they suggest that until sufficient data is available to use more popular management methods, a cultural reinforcement strategy currently in use, which involves ancient, traditional limitations on when, where, and how many Dugong can be harvested, should be implemented to manage this harvesting activity. These cultural reinforcements, driven by the indigenous communities themselves, must be coupled with detailed hunting reports as well as collaborations between government officials and indigenous leaders to create a more efficiently tailored management system for the dugong harvest.
The data for this study were collected using aerial surveys of dugongs between 1987—2013, consistently conducted over the same grid system consisting of areas called blocks. Using the information collected during these flights the authors were able to calculate relative Dugong density, create spatial models, report the percentage of calves seen, and analyze spatial hunting patterns and, “take areas.” Marsh et al. found that, overall, 13.9% of Dugongs seen were calves, a rate higher than any other habitat on the Australian coast. In the study region, 5268 km2 were capable of supporting a high density of Dugongs, a fact that is important in order to determine how well Dugongs can thrive despite the harvest. With the current culturally-enforced regulations put in place for Dugong hunting, only 5—7.9% of the hunt occurs in very high density or high density areas. Additionally, the Dugong population in this area is the most genetically diverse group, likely due to some migration between this region and the Great Barrier Reef, and the relative density was highest in the very last year of the aerial surveys.
Based on the information collected, Marsh et al. suggest that it will take at least five years to generate enough data to create the models necessary to draft appropriate total allowable catch limits. For now, the study finds that the culturally-inclusive method currently in use is highly effective at maintaining a sustainable harvest. Marsh et al. go on to argue that this cultural management method should be further expanded and explored by reinforcing and encouraging indigenous traditions of harvest. Overall, this study is an interesting way in which to look at the management of indigenous activities; it demonstrates that sometimes the best way to regulate potentially unsustainable yet ancient natural activities is by working with and facilitating the traditions of the community itself.
Marsh, H., Grayson, J., Grech, A., Hagihara, R., Sobtzick, S., 2015. Re-evaluation of the sustainability of a marine mammal harvest by indigenous people using several lines of evidence. Biol. Conserv. 192, 324–330.