A strategy for management has been developed following the consideration of a large number of options; the main details have been published elsewhere (Humphries and Croft, 1984; Kinhill Engineers, 1988). Measures have been taken to reduce the amount of phosphorus entering the estuary from the catchment, and a proposal is under discussion to construct a new channel to the ocean, at the north west of Harvey Estuary. The channel would increase water exchange with the ocean and so enhance phosphorus loss, would reduce the period of year when salinities are suitable for Nodularia,and reduce phosphorus loss from the sediment to the water column at critical times of year.
As management proceeds, it will be important to continue to monitor the estuary, and so review the effectiveness of the techniques. Interest will attach to seeking a deviation of the relation between chlorophyll and minimum salinity, as phosphorus concentrations fall in river water. It will also be important to examine the relationship between macroalgal biomass and light penetration, as in the short term the relation will continue to hold, with an increase in biomass, but in the longer term we would expect a diminution in macroalgal biomass as the nutrient status of the estuary is depleted.