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 remained ‘moderate’ and the score declined from 60 to 57 since 2019-20.

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

WATER QUALITY

The water quality grade for the North inshore zone improved from ‘good’ in 2020-21 to ‘very good’, and the score increased from 72 to 81.

Water quality grades are based on water quality guideline trigger values established for the waters of the Great Barrier Reef Marine Park that, if exceeded, identify the need for management responses. The guidelines are not targets or an assessment of pollutant loads entering the marine environment. The results are derived from in-situ water samples taken at six locations from inshore waters extending from sites adjacent to Cape Tribulation in the north to sites adjacent to Cairns in the south.

The water clarity score increased from 69, graded ‘good’, in 2020-21 to 84, graded ‘very good’ and is comprised of a total suspended solids (TSS) score only. Turbidity was not monitored in the North Zone.

Nutrients scored 75 and increased from a score of 60 in 2020-21 with the grade remaining ‘good’. Nutrients were graded ‘very good’ for oxidised nitrogen (NOx) which improved from ‘moderate’, ‘good’ for particulate nitrogen (PN) which was unchanged, and ‘good’ for particulate phosphorus (PP) which improved from ‘moderate’.
The chlorophyll a score was 83 and decreased from 86 in 2020-21 and the grade remained ‘very good’.

Pesticide scores from 2019-20 onwards have not been available due to the suspension of pesticide logger deployment in the North zone.

CORAL

The overall coral grade in 2021-22 for the North inshore zone was ‘moderate’. The score increased from 44 the previous year to 51. The coral index grade in the north zone has remained ‘moderate’ since 2014-15.

The coral grade is comprised of the density of juvenile hard corals score of 38 (‘poor’), the macroalgae cover score of 55 (‘moderate’), the coral cover score of 65 (‘good’), the change in coral cover score of 70 (‘good’), and the coral community composition score of 30 (‘poor’).

In the North zone coral cover has continued to increase, whilst macroalgae cover remained high at two Snapper Island sites but was very low at the other sites.

More information is available in the latest Marine Monitoring Program inshore coral report.

SEAGRASS

The overall seagrass grade in 2021-22 for the North inshore zone remained ‘moderate’ with the score increasing from 57 in 2020-21 to 60.

The Marine Monitoring Program updated the indicators for assessing seagrass condition for 2020-21 onwards. The seagrass indicators have changed with the removal of tissue nutrient status and the replacement of the reproductive effort with a more holistic resilience indicator. Information on these updates is available in the methods and results technical reports.

The seagrass grade is comprised of the seagrass abundance score of 63 (‘good’), and resilience score of 41 (‘moderate’) from the Marine Monitoring Program (MMP) in addition to the seagrass biomass score of 73 (‘good’), the meadow area score of 84 (‘very good’), and seagrass species composition score of 94 (‘very good’) from the Queensland Ports Seagrass Monitoring Program (QPSMP).

Seagrass condition for inshore QPSMP monitoring meadows (Cairns Harbour) continued to improve after the La Niña associated declines in 2009 – 2011. The average grades for all condition indicators (biomass, area, species composition) were all good or very good in the past 3 years. Overall condition scores for MMP sites improved at the Green Island in the past year, with intertidal seagrass in good condition and subtidal sites in very good condition, whilst seagrass at the Low Isles remained very poor for the fourth year.

More information on seagrass condition in the North zone is available from QPSMP reports and the Marine Monitoring Program reports.

FISH

The fish index is currently under development and will be available in future report cards.

See the detailed reports for further information on the methods used to produce the scores and grades and the detailed results.