West coast water quality monitoring
The EPA’s marine biologists recently travelled to the west coast to collect monitoring data for the region’s first set of nearshore marine Aquatic Ecosystem Condition Reports (AECRs).
Monitoring along the 350 km stretch of water from Coffin Bay to Point Bell near Fowlers Bay is logistically difficult. Exposed coasts and long distances between monitoring sites make the daily site selection dependent on the weather forecast, access points for safe launching and shelter from the exposed seas.
The region’s nearshore environment condition is typically expected to be some of the best in South Australia. At many locations, extensive dense seagrass meadows and rocky reefs covered in large brown algae were found. However, in some of the sheltered bays close to the small townships, there was evidence of nutrient enrichment suggesting that even small populations can start to have an impact on the nearshore marine environment.
This monitoring work will help the EPA and local communities to intervene early and prevent future seagrass loss. In many circumstances seagrass loss can lead to significant economic impacts on local fisheries and sand stability. Often the seagrass can never regrow, resulting in a permanent economic cost to the state.
As well as completing the nearshore assessment, the EPA team visited a group of offshore islands recently declared a Sanctuary Zone in the state’s Marine Park program, including St Francis Island which is a part of the Nuyts Archipelago Wilderness Protection Area. These remote locations are useful references as they reveal information about the condition of habitats where there is very little human activity. This understanding of reference conditions will enable informed decisions about what is impacted and whether some activities need to be regulated differently in affected areas.
The AECR program uses extensive information on the biology and the water chemistry of a location to determine the condition of the nearshore marine environment. Summaries from the program are used for State of the Environment reporting, while finer-scale results inform whether the region is being impacted by high nutrient loads or poor water clarity. The findings of this program assist the regulation of discharges—through EPA licensing, and the work of other agencies such as NRM.
Now it is back to the desk for the marine biologists, to analyse the data, interpret the findings and generate the AECRs for publishing in mid-2015.