Inshore Central

The northern boundary of the Central inshore reporting zone area extends north-east from Cape Grafton just south of Cairns to the offshore boundary and includes enclosed coastal, open coastal and mid-shelf waters.

The southern boundary of the Central zone extends due eastward from the mainland just south of the Moresby River at Double Point to the boundary of the offshore waters.

The major rivers discharging into the central zone are the Mulgrave River the Russell River and Johnstone River. The Moresby River discharges into the southern coastal area of the Central zone. Numerous smaller waterways drain coastal sub catchments that discharge into the Central zone.

Water quality in the Central zone is affected by plumes of sediments, nutrients and pesticides from rivers discharging directly into the zone but also from the plumes of southern rivers, particularly the Tully/Murray, which are carried north by prevailing currents.

The area includes Fitzroy Island to the north, the High Island Group some 12km north-east of Deeral, the Frankland Island group approximately 16 km due east of Deeral and Normanby Island located between the High Island group and the Frankland Island group. These islands provide fringing shallow water environments that support coral reef ecosystems.

Key results for 2024-25

The score for the Central zone increased from 54 to 55 and the grade remained ‘moderate’.

• Water quality for the Central inshore zone remained ‘good’ and scored 62, increasing from 61 in the previous year.
• Water clarity remained ‘good’ with both total suspended solids (TSS) and turbidity graded ‘good’.
• Nutrients improved from ‘poor’ to ‘moderate’, with oxidised nitrogen (NOx) improving from ‘very poor’ to ‘moderate’, particulate nitrogen (PN) improving from ‘very poor’ to ‘poor’ and particulate phosphorus (PP) remaining ‘moderate’.
• Chlorophyll a grade declined from ‘good’ to ‘moderate’.
• Coral condition remained ‘moderate’ with the score unchanged at 48.
• The coral cover indicator remained at the lower threshold of ‘good’ with a very slight decrease in score to 61.
• The cover change indicator has remained ‘moderate’ over the last three years, with scores declining each year reflecting reduced rates of recovery in hard coral cover between disturbance events.
• The composition indicator has been ‘moderate’ for the last four years. Composition scored zero at three of the 13 sites which typically indicates a low representation of Acropora.
• Macroalgae score has remained ‘poor’ after a continued decline in score since 2020-21 when the grade was ‘good’. Over this period of declining score, increased macroalgae cover has occurred at both 2m and 5m depths and has been characterised by persistent dense mats of red macroalgae, particularly at Franklands West.
• The juvenile coral score remained ‘poor’. While there is substantial variation of juvenile density across sites, the trend for reefs at 2m has been a decline since 2020-21.
• Crown-of-thorns starfish densities at above outbreak levels were recorded at Fitzroy East, High East and Franklands East. Feeding scars are typically present at all reefs surveyed in the Central zone. In addition, a single large individual was recorded at Fitzroy West. There were 678 and 71 individuals removed from the Frankland group and Fitzroy Island, respectively, during 2024–2025 by the Crown-of-thorns Starfish Program. More information on the Crown-of-thorns Starfish Control Program including latest results is available from the project dashboard.

The diagram below shows the detailed results for each indicator by year. Click on the timeslider to see data from previous years.