Using Indigenous and scientific knowledge in wildlife harvest management

: mangrove clams harvest in a remote Indigenous community

Abstract

Subsistence resource users often possess an extensive knowledge of their natural environment that has been developed over many generations. Throughout the world, there is increasing recognition of the value of combining this knowledge with scientific information to develop sustainable management strategies. This thesis documents Indigenous Ecological Knowledge and scientific information of the mangrove clam, Polymesoda erosa. This estuarine bivalve makes a substantial contribution to the subsistence economy of remote communities in central Arnhem Land, and may have potential for commercial exploitation. Oral history interviews with Indigenous people of the Maningrida region of central Arnhem Land were used to document and explore biological knowledge, customary management strategies and attitudes toward the possible commercial harvest of the species. This is combined with preliminary information on the harvest rates, density, distribution and growth rates of the mangrove clam in the Maningrida region. Results demonstrated that Indigenous Ecological Knowledge of mangrove clam biology and customary harvest of the species was reasonably widespread amongst Indigenous people at Maningrida. Mean harvest rate of mangrove clams was found to be 84.1 clams per person per hour (SE=11.1), which was substantially higher than the rate observed in 1972. Interviewees expressed concern that a commercial harvest of the mangrove clam would threaten their subsistence use of the species, and that they may be excluded from receiving any benefits from sale of clams. The mangrove clam is locally abundant, with a mean density of 0.69 clams per m² (SE=0.14). Its distribution is widespread throughout estuarine rivers and creeks in the Maningrida region. The size class frequency of harvested mangrove clams matched that of the available surface population indicating that harvest is non-selective, and most harvested clams were reproductively mature. Current subsistence harvest levels may be able to tolerate some additional harvest for commercial purposes but this should not be considered without further consultation with local people. The combination of Indigenous and scientific data allows a more holistic approach to harvest management.

Date of Award	May 2004
Original language	English
Supervisor	Anthony Griffiths (Supervisor)