Inshore Palm Islands

The northern boundary of the Palm Island Inshore reporting zone extends east from the north-west bank of the Seaforth Channel mouth, just south of Hinchinbrook Island, to the offshore boundary and includes enclosed coastal, open coastal and mid-shelf waters.

The southern boundary of the Palm Island zone extends eastward from the southern boundary of the Herbert River Basin to just east of the Palm Island Group and runs north to the Wet Tropics NRM marine region boundary at the junction with the offshore waters boundary.

The major river discharging into the Palm Island zone is the Herbert River. Several sub-catchments, including the Seymour River, also discharge into the Palm Island inshore zone.

Water quality in the Palm Island 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 Burdekin River the mouth of which is approximately 180 km to the south-east.

The area includes the Palm Island group located approximately 17 km east of the mainland. The Palm Island Group includes Orpheus Island, Pelorus Island, Fantome Island, Palm Island, and Havannah Island. These islands provide fringing shallow water environments that support coral reef ecosystems and reef seagrass meadows.

Key results for 2024-25

The score for the Palm Island zone decreased from 57 to 41 and the grade remained ‘moderate’.

• Water quality declined from ‘good’ to ‘poor’ and the score decreased from 69 to 40.
• Water clarity declined from ‘good’ to ‘moderate’, with total suspended solids (TSS) declining from ‘very good’ to ‘poor’ and turbidity remaining ‘good’.
• Nutrients declined from ‘good’ to ‘poor’ with oxidised nitrogen (NOx) declining from ‘‘very good’ to ‘poor’, particulate nitrogen (PN) remaining ‘poor’, and particulate phosphorus (PP) declining from ‘good’ to ‘poor’.
  All three nutrient forms showed correlation between peak concentrations and the February 2025 flood events.
• Chlorophyll a improved from ‘poor’ to ‘moderate’ although the score only increased slightly from 39 to 41.
• During the summer of 2024-25, the coral reefs of the Palm Island zone were impacted from a localised severe storm with high winds and damaging waves, and from floodwater inundations in February 2025, when heavy rainfall and flooding events occurred in the catchments to the south including the Burdekin, and the adjacent Herbert River catchment.
• Coral condition remained ‘moderate’ with the score decreasing from 45 to 43.
• The coral cover indicator decreased substantially in score and declined from ‘moderate’ to ‘poor’. This was a result of exposure to low salinity floodwaters from the extreme rainfall events and high river discharges, and from physical impacts of wind and waves from the storm event.
  The most extreme impacts on coral cover occurred at Lady Elliot Reef, with 90% of hard corals at 2m depth, and 22% of hard coral at 5m depth killed by floodwaters.
• The cover change indicator remained ‘poor’ but varied considerably among sites.
• The composition indicator remained ‘moderate’ but decreased from 58 to 45. This decline is associated with a lowering of Acropora representation within the hard coral community.
• The macroalgae indicator improved substantially from ‘poor’ to ‘good’ with scores increasing at most sites. Macroalgae indicator scores increased markedly at Pandora, Lady Elliot Reef and Havannah Island, however the reduction of macroalgal cover was a result of lowered salinity due to floodwater exposure and from storm damage.
• The juvenile coral indicator remained ‘poor’ but declined in score. Whilst juvenile density was high at select sites, particularly Pandora North, density was poor and declines have occurred at most of the sites.

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