Coastal and marine environment

The coast, estuaries and adjacent marine waters are a unique part of the South Australian environment. Over 90% of South Australians live within 50 kilometres of the coast (ABS 2002), and many commercial, industrial and recreational activities rely on coastal and marine resources.

The coast and adjacent marine waters are subject to a diverse range of pressures including pollution from wastewater and stormwater, physical development (residential, marinas, ports), commercial and recreational fishing, shipping and aquaculture. The good news is that the quality and reuse of treated wastewater is increasing as is the capture and reuse of stormwater (SA Water 2013). Better regulation and management practices have seen a decrease in impacts arising from aquaculture from nutrients, disturbance and waste, even though the area occupied by aquaculture is increasing.

There is a strong correlation between human disturbance and the ecological health of the coastal zone. An assessment of the six coastal regions found the extent and condition of coastal ecosystems (including foreshore, rocky reefs, seagrass, saltmarsh and mangroves) is highly variable and declining.

As with terrestrial species and ecosystems, climate change is starting to have major impacts on coastal and marine species and ecosystems. This includes an increase in ocean temperature and acidity, changes in ocean salinity and currents, rising sea levels, saline incursion through permeable coastal geologies and the introduction of new pests.

In summary

Component	Summary	Assessment grade				Confidence
		Very poor	Poor	Good	Very good	In grade	In trend
Recent Trend Improving Stable Deteriorating Unclear Level of confidence Evidence and consensus too low to make an assessment Limited evidence or limited consensus Adequate high-quality evidence and high level of consensus Grades Very Poor Poor Good Very Good
Extent and condition of coastal and marine ecosystems	The extent and condition of coastal ecosystems (including foreshore, rocky reefs, seagrass, saltmarsh and mangroves) are declining.
Disturbance and pollution	The quality and use of treated wastewater are increasing. The capture and reuse of stormwater are increasing. The area occupied by aquaculture is increasing. Human population in the coastal zone is increasing. The quality of coastal and marine waters is improving.
Threatened species and ecosystems	Marine protected areas have increased in size and number. New fishery recovery strategies have been implemented. There has been an increase in some species (e.g. New Zealand fur seal and southern right whale). Ocean salinity and currents are changing. Ocean acidity is increasing. Sea level is rising. Coastal and marine ecosystem extent, condition and diversity are variable and declining. There is a decline in some species (e.g. giant cuttlefish and little penguin).
Pest plants and animals	Port handling and shipping traffic has increased, which increases the risk of pest species incursions.

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