Nuyts Nearshore Marine Biounit
2019 Aquatic Ecosystem Condition Report

The site sampled showed that seagrass habitats were dense and intact and in general had very little epiphytes. Similarly the reef habitats were comprised largely of large dense brown canopy algae with diverse communities of red algae.

The condition of habitats in waters between 2–15 m deep throughout the Nuyts biounit was assessed based on monitoring data collected during autumn 2019. There are some areas within the biounit that are deeper than 15 m which are not included as a part of this assessment. The score classifies sites on the ecological condition based on habitat integrity outlined in the Methods Report. This score does not reflect suitability of the sites for other purposes including aquaculture production.

Site	2019
	Condition	Trend
m0435, Franklin Is. South	Good
m0450, Franklin Is. North	Good

The sites are on the northern side of Franklin Is. and are well away from anthropogenic pressures from the mainland. Seagrass habitats across these sites are mostly comprised of Posidonia sp. with little change in cover between years for both sites. Epiphytes and opportunistic algae, which are considered to indicators of nutrient enrichment, are were present in relatively low amounts at Franklin Is. South. At Franklin Is. North (m0450) the 2014 showed similarly low epiphyte (21.6%) in 2014, but in 2019 over 40% of seagrass leaves covered in epiphyte. At this stage the epiphyte does not appear to be impacting negatively on seagrass and may be reduced through natural senescence of seagrass leaves and water movement.

There were no direct pressures identified to sites monitored in Nuyts.

• Download the Methods Report for the nearshore marine ecosystems monitoring, evaluation and reporting program.

These pages outline the statistical analysis undertaken for the Nuyts biounit. It should be read in conjunction with the AECR for that biounit. The methods used for the collection of the information can be found detailed in marine methods.

The habitat variables; total seagrass cover, bare sand, epiphyte and opportunistic algae were used to compare sites using Primer v7 with the PERMANOVA add-on^[1]. The data was square root transformed and all transects in a site were analysed for each year of monitoring. The multivariate PERMANOVA test was used to determine if the data showed a difference between sites and years.

There were insufficient number of sites to undertake a principal coordinates ordination (PCO) as such interpretation has been limited to site based comparisons.

The sites were consistently dense and continuous Posidonia seagrass with low epiphyte loads (Figure 1). The PERMANOVA test showed no statistical difference between the composition of sites between years (Table 1). Similarly the Fp ratio and the size classes indicating phytoplankton community composition suggest an oligotrophic environment at the time of sampling (Figures 2 and 3). Indicating that the offshore regions of Nuyts are in very good condition.

Table 1  PERMANOVA was performed on sqrt transformed 2014 and 2019 habitat data (total SG, bare sand, epiphyte and opportunistic algae). P values of less than 0.01 were considered significant.

Figure 1  Benthic habitat composition at each site in the Nuyts biounit for all years monitored.

Figure 2   Fp ratios for each site in Nuyts. Higher ratios are more typical of increasing level of nutrient enrichment with oligotrophic conditions broadly considered to have an Fp ratio less than 0.3, mesotrophic conditions are above 0.3 and less than 0.7, and eutrophic conditions are signified by an Fp ratio above 0.7.

Figure 3   Size class composition of phytoplankton communities in the Nuyts biounits in 2019.

While the AECR score is developed from a set of metrics outlined in the Methods document. This document outlines the key information used and additional statistical analysis undertaken to interpret the results of the AECR for these sites. It provides the confidence that the AECR score is consistent with the scientific interpretation and attempts to understand the pressures acting on the system.

This document does not outline all data collected for this program, additional data (eg: water chemistry) can be downloaded on the download data tab on the website or by contacting the EPA.

^[1] Anderson, M., Gorley, R. and Clarke, R. (2008) Permanova+ for Primer: Guide to Software and Statistical Methods. Plymouth, UK.: Primer-E Ltd.