Inshore North

The northern boundary of the North Inshore reporting zone extends north-eastward from the mainland just north of the Bloomfield River along the boundary of the Wet Tropics NRM marine region to the boundary of the offshore waters and includes enclosed coastal, open coastal and mid-shelf waters.

The southern boundary of the North zone extends north-east from Cape Grafton just south of Cairns to the offshore boundary. The major rivers discharging into the North zone are the Daintree River, the Mossman River and the Barron River.

The Bloomfield River discharges at the northern most extent and Smiths Creek discharges through Trinity Inlet at the southernmost extent. Numerous smaller waterways draining the catchments of the often steep eastern slopes of the Great Dividing Range also discharge into the North zone.

Water quality in the North 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 Russell/Mulgrave and the Tully/Murray, which are carried north by prevailing currents.

The area includes Snapper Island, some 3.7 km east of the Daintree River mouth, the low Isles 11km south-east of Snapper Island, and Green Island, approximately 27 km north east of Cairns. These islands provide fringing shallow water environments that support coral reef ecosystems and intertidal reef seagrass meadows. Subtidal and intertidal coastal seagrass meadows also occur close to the mainland including Cairns Harbour and Yule Point approximately 10km south of Port Douglas.

The overall grade for the North zone in 2022-23 remained ‘good’ and the score increased from 64 to 66 since the previous year.

Key results

• The water quality grade for the North inshore zone remained ‘very good’ in 2022-23, and the score increased from 81 to 82.
• For total suspended solids (TSS) and chlorophyll a, the grade declined from ‘very good’ to ‘good’, whilst for particulate nitrogen (PN) the grade declined from ‘good’ to ‘moderate’.
• Pesticide monitoring and reporting re-commenced in 2022-23. High scores and a grade of ‘very good’ for pesticides, due to the very low pesticide toxicity risk, contributed to the increase of the water quality index score.
• The coral condition index in the North zone remained moderate and score increased from 51 to 54.
• For coral, the composition score increased substantially from 30 (‘poor’) to 50 (‘moderate’), mainly due to the re-emergence of Acropora at all reefs in the zone. Macroalgae remained moderate whilst the score decreased from 55 to 47. Macroalgae cover varied substantially across depths and reefs. 
• Seagrass in the North zone improved from ‘moderate’ to ‘good’ and reached its highest score since the report card commenced in 2016.

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