Table 1. Characteristics of the 4 estuaries sampled.

	Area Rocky Reef (km2)	Total Area (km2)	Mean Tidal Flow (106 m3)	Estuary Classification
Port Stephens	1.36	128.36	157.50	Wave
Broken Bay	0.01	47.47	195.00	Wave
Port Jackson	0.52	50.47	82.33	Tide
Botany Bay	0.49	38.31	No data	Tide

Mean flow rate is the mean volume of water that flows into and out of the estuary during flood and ebb tides, measured close to the oceanic entrance. Estuary classification indicates the dominant force shaping the hydrodynamics of the estuary. Data are from the Ozcoasts database (http://www.ozcoasts.org.au, accessed 2012).