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.

The overall grade for Palm Island zone in 2023-24 declined from ‘good’ to ‘moderate’ and the score decreased from 61 to 57 since the previous year.

Key results

• The water quality grade in 2023-24 for the Palm Island inshore zone remained ‘good’ whilst the score decreased from 75 to 69 since the previous year.
• Turbidity declined from ‘very good’ to ‘good’ and chlorophyll a, declined from ‘moderate’ to ‘poor’, since the previous year.
• Grades for nutrients (oxidised nitrogen (NOx), particulate nitrogen (PN), particulate phosphorus (PP)) were the same as the previous year.
• The coral condition index remained ‘moderate’ whilst the score decreased from 47 to 45 since the previous year.
• For the Palm Island zone impacts on coral cover included thermal bleaching from high water temperatures and moderate localised damage to coral from Tropical Cyclone Kirrily which made landfall as a category 1 south of the Wet Tropics region in January 2024.
• Coral cover grade remained ‘moderate’, but the score declined from 51 to 48.
• Coral composition reduced at Havannah North and resulted in a decline from ‘good’ to ‘moderate’ for the zone.
• Macroalgae cover decreased at three sites and the zone improved from ‘poor’ to ‘moderate’.
• The Juvenile coral indicator declined from ‘moderate’ to ‘poor’ and was linked to declines in abundance as a strong cohort of juveniles either died or have grown beyond juvenile size classes.

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