The economic contribution of seagrass to secondary production in South Australia

The valuation of seagrass habitats, and indeed many natural resources, has been the focus of many researchers with differing approaches. This study presents an estimate of the value of seagrass habitats in terms of the contribution to secondary production of some important South Australian fish species in a broad scale domain. The approach we take considers the relationship between primary production estimates for seagrass habitats in temperate and subtropical coastal waters and estimates of commercial, recreational and discarded catch figures. The paper briefly describes models which link expected harvest of different species to seagrass area and the consequent expected reduction in catch given seagrass decline. We estimate that the economic contribution of seagrass habitats to secondary production in the gulf waters of South Australia is of the order of $A114 million per year. Furthermore, we estimate in a particular example that the economic cost of a 16% decline of seagrass in one small area was $235,000 per year in lost production.