MANAGING THE AQUATIC ENVIRONMENT

The primary objective for managing eutrophic waterbodies must be to re duce the level of available nutrients. However, where diffuse agricult ural runoff is the principal source of nutrients, this is slow and dif ficult to achieve. In the meantime symptoms - principally the excessiv e growth of algae - must be managed in the interests of nearby human p opulations and of the ecosystems themselves. The management measures c urrently employed in large coastal waterbodies in southwestern Austral ia are mainly mechanical collection and disposal of algal accumulation s. These do not significantly reduce nutrient levels. However, removal of the algae allows smothered seagrasses to regenerate and prevents t he release of nutrients from anoxic surface sediments under decaying a lgal masses. Other measures appropriate to smaller water bodies includ e the use of algicides, chemical treatment, and dredging. The channel from Harvey Estuary to the sea (under construction) has the potential to significantly reduce nutrients and algal growth in Peel-Harvey estu ary by increasing exchange with the sea.