MER program measures estuary condition in 30-40 estauries per year. These represent 3 types of estuary and low, medium and high levels of catchment disturbance for each estuary type. Estuaries are grouped into 3 regions and one region is sampled each year. 8 sentinel estuaries are sampled every year. Chlorophyll is used as an intergrating indicator of condition(Scanes et al. 2007). Chlorophyll was measured with a field fluorometric probe, supplemented by a subset of samples where chlorophyll was determine by acetone extraction.