The Coral Index score remained ‘poor’ in 2023 with no improvement following a period of recovery from 2014 to 2020. Since 2020, scores for Juvenile coral and Macroalgae at 5 m depths have declined. Conversely, the Coral cover score has slowly improved since 2020 but remains within the ‘moderate’ range and this improvement was not consistent among reefs. Since the impacts of floods and storms that drove the Coral Index to a ‘very poor’ low point in 2014, the Macroalgae score has remained ‘very poor’ while Cover change, Coral cover and Composition have all improved.
Overall, the seagrass condition score for the Fitzroy NRM region slightly deteriorated and remained poor in 2022–23. Both condition indicators, abundance and resilience scored poorly. For the third year in a row, inshore seagrass meadows in the region have experienced a decline, despite gradual improvement from 2012-13 to 2019-20 after years of climate-related impacts. There are local-scale impacts and processes that are negatively affecting a few sites, while others within the same habitat are improving. Due to the limited number of sites in the Fitzroy region, changes in one site can have a significant influence on the overall score in comparison to other regions.
Seagrass abundance score marginally improved from the previous period, but this was driven by only one site (estuarine intertidal). Average abundances for all other sites continued to slightly decline, however, the overall score was unimpacted. Abundances remain very low at over half the sites in the region, particularly the reef intertidal sites.
The seagrass resilience score in the Fitzroy region showed a decrease to the second lowest level recorded. However, the trend varies depending on the habitat and site. For estuarine and coastal habitats, one site showed an improvement while the other declined. Increased resilience was noted in sites that were dominated by foundational species. In reef intertidal habitat, resilience fell to the lowest level in three years.
The annual condition WQ Index has scored water quality as ‘good’ since its inception in 2020, with the 2022–23 year receiving a ‘good’ score.
The WQ Index is divided into three categories: Water Clarity which includes Turbidity, Secchi Depth and Total Suspended Solids (TSS); Productivity which includes Chlorophyll-a (Chl-a) and Nitrogen Oxides (NOx); and Particulate Nutrients which includes Particulate Nitrogen (PN) and Particulate Phosphorus (PP).
Water quality showed trends along the sampling transect (cross-shelf gradient in northerly direction). Sites located nearest to the river mouth had high concentrations of Chl-a, NOx, TSS, and particulate nutrients, which declined with distance away from the river mouth, reaching low levels in mid-shelf waters. Secchi depths were low at sites near the river mouth and increased with distance from the river mouth. These spatial patterns are generally consistent with those that are typically observed in the region.
This year, seasonal differences in Chl-a, TSS, PN, and PP were observed, where concentrations were higher during the dry than the wet season. These seasonal differences tended to become less pronounced further offshore. Secchi depth and NOx were generally similar along the transect between wet and dry seasons. These seasonal differences may be driven by strong physical forcing rather than by river discharge events given this was a year of near-median discharge.