On the map, zoom in and click on the dots to view underwater video at each site.
Dense and continuous seagrass meadows dominated by Posidonia spp. with sparse Amphibolis spp.. Very little epiphytes were recorded on seagrasses suggesting as very low nutrient environment.
Rocky reefs were densely covered in large brown canopy algae with diverse coarse branching and encrusting red algae present in the understory.
Area map
About the Biounit
The Fowlers Biounit is located in the Murat bioregion and is the western most biounit monitored in the EPA’s nearshore marine program. The biounit spans from Cape Adieu in the West to Point James near Davenport creek west of Ceduna.
Fowlers’ experiences high wave energy along the rocky limestone coast with headlands jutting into the sea and isolated sandy beaches. In the lee of the rocky headlands there are small relatively sheltered bays. The rocky headlands and reefs support diverse red macroalgal communities, while in the lee of the rocky headlands, seagrasses can thrive particularly Posidonia spp. and Amphibolis spp.
The adjacent land use is primarily cereal and modified pasture crops and there are areas of coastal conservation park. There are few permanent residents in Fowlers, but what dwellings there are, would treat sewage via on-site septic tanks which, in high densities, have the potential to introduce nutrients into shallow groundwater. There is a large saltfield near Penong, at Lake McDonnell, which evaporates seawater to harvest salt. The evaporation encompasses the bitterns waste which results in no discharge to the marine environment.
The Nuyts Archipelago Marine Park is the largest marine park in South Australia and aims to protect examples of the unique diversity of sea life arising due to the warm water currents arriving through the Leeuwin current from tropical Western Australia.
The assessment of identified threats to the nearshore habitats predicts that the Fowlers biounit is likely to be in Excellent condition.
In summary
Sites sampled showed that seagrass habitats were dense and intact and had very little epiphytes. Similarly the reef habitats were comprised largely of large dense brown canopy algae with diverse communities of red algae.
Findings
The condition of habitats in waters between 2–15 m deep throughout the Fowlers biounit was assessed based on monitoring data collected during autumn and spring 2014. There are some areas within the biounit that are deeper than 15 m which are not included as a part of this assessment.
The isolation and exposure of this biounit resulted in only 2 sites assessed in autumn and spring of 2014. The waters were relatively high energy, even in the shelter provided by the rocky headlands.The interpretation and assessment of condition has taken this into consideration for the whole biounit.
East of Point Bell (m0449) was located in the lee of the prominent rocky headland at Point Bell. This site was dominated by dense and largely continuous Posidonia spp. seagrass meadows with sporadic sparse Amphibolis spp. Throughout the site there was very little epiphytic algae on the seagrass recorded in autumn or spring, which could be related to the higher energy of the site.
Inside Lounds Reef (m0444) is a relatively deep (~13m) low profile rocky reef, exposed to the southern ocean swells. The site was dominated dense communities of Cystophora spp, and Ecklonia radiata with sparse foliose and encrusting red algae present in the understory.
The water chemistry was predictably very low in nutrients for the two sites sampled however the biounit is occasionally subjected to very high turbidity which was observed in spring. This is likely to be due to the very high wave energy which, given the habitat quality observed, is unlikely to occur in a frequency sufficient to cause a significant impact on the habitats.
This assessment indicated that Fowlers was in Excellent condition with the structure and function of the habitats in a natural or unimpacted state.
The findings presented here are explained more thoroughly in the Eyre & Murat Assessment Report.
Pressures and management responses
There are no known pressures acting on the Fowlers Nearshore Marine Biounit; this area of marine environment is considered to be unimpacted by human activities. As such, management responses have also not been established for this biounit.