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.

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very good








very poor

insufficient data

Confidence surrounding the data used in the circle diagrams has been assessed using a multi-criteria framework.


Water quality

Hover over each segment for indicator scores and data confidence.

Water quality in the North inshore zone is graded ‘good’ in 2016-17 with a score of 69.

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 assessments 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 and from passive pesticide samplers located at the Low Isles.

The water clarity score of 69 (‘good’) in the North zone is comprised of a total suspended solids (TSS) score only. Turbidity was not monitored in the North Zone.

Nutrients scored 68 (‘good’) in the North zone, comprising of ‘very good’ for oxidised nitrogen (NOx), a ‘moderate’ for particulate nitrogen (PN) and a ‘moderate’ for particulate phosphorus (PP).

The chlorophyll a score in the North zone is 47 (‘moderate’).

Using the Photosystem II herbicide equivalent concentrations method, pesticides received a score of 93 (‘very good’).

The water quality index score in North zone changed from 79 in 2015-16 to 69 with the largest decreases occurring for chlorophyll a and PN.



Hover over each segment for indicator scores and data confidence.

The overall coral grade for the North inshore zone in 2016-17 is ‘moderate’ with a score of 46.

The coral grade is comprised of the density of juvenile hard corals score of 40 (‘poor’), the macroalgae cover score of 40 (‘poor’), the coral cover score of 42 (‘moderate’), the change in coral cover score of 67 (‘good’), and the coral community composition score of 42 (‘moderate’).

The coral index grade in the north zone has remained ‘moderate’ since 2014-15 and the index score of 46 remains unchanged from 2015-16.

In the North zone the impacts of the 2017 bleaching event differed considerably between sites although the combined results for the zone showed a halt to the increases for the coral index score between 2014-15 and 2015-16. An increase in macroalgae cover (as represented in decline in the macroalgae score) may indicate high nutrient availability as a factor limiting coral community condition at Snapper Island.

More information is available in the Marine Monitoring Program inshore coral report by Thompson et al. (2018).


Hover over each segment for indicator scores and data confidence.

The overall seagrass grade for the North inshore zone in 2016-17 is ‘poor’ with a score of 30.

The grade for seagrass is comprised of the seagrass percent cover score of 52 (‘moderate’), the tissue nutrient score of 35 (‘poor’), and reproductive effort score of 0 (‘very poor’) from the Marine Monitoring Program in addition to the seagrass biomass score of 52 (‘moderate’), the meadow area score of 70 (‘good’), and sea grass species composition score of 48 (‘moderate’) from the Queensland Ports Seagrass Monitoring Program.

There have been considerable signs of improvement and recovery in seagrasses in the North zone, however this varied somewhat between sites and locations and overall seagrass condition was rated as ‘poor’. Indicators related to seagrass abundance such as biomass, percent cover and area of meadows increased for the majority of inshore locations.

For monitoring conducted at smaller fixed transect sites, ‘very poor’ scores for reproductive effort had a significant effect on the overall scores, with all of these sites receiving a zero score despite four of the seven sites having ‘good’ or ‘very good’ abundance (percent cover). Permanent transect site monitoring in the Reef habitats had ‘poor’ or ‘very poor’ scores for percent cover (abundance) at Low Isles and the sub-tidal Green island site in 2016-2017.

For larger meadow scale monitoring locations considerable improvement in seagrass condition was recorded. Expansion of meadow area continued at Cairns’ coastal meadows for the second consecutive year in 2016-2017. Biomass also increased in two of the three meadows assessed.

The recovery of Cairns meadows since historical lows in 2010-2012 has coincided with favourable light and climate factors driven by El Nińo weather conditions.

Despite the improvement in seagrass condition, seed banks in the intertidal 'Zostera muelleri' meadow CN34 have declined, with no seeds present in samples from March 2017. It is likely the newly recovered plants require more time to reach sexual maturity before the seedbank can be replenished and meadow resilience restored.

Species composition had yet to return to pre-disturbance state for some meadows. This resulted in meadow CN13 remaining in ‘very poor’ condition due to the foundation species 'Z. muelleri' still absent from the meadow in 2016-2017, despite large expansion in area.
More information on seagrass condition in the North zone is available from the Marine Monitoring Program report by McKenzie et al. (2017) with further updates soon to be published for 2016-17.


Hover over each segment for indicator scores and data confidence.

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


McKenzie, L.J., Collier, C.J, Langlois, L.A., Yoshida, R.L., Smith, N. and Waycott, M. 2017, Marine Monitoring Program: Annual Report for inshore seagrass monitoring 2015-2016. Report for the Great Barrier Reef Marine Park Authority, Great Barrier Reef Marine Park Authority, Townsville, 247pp.
Thompson A, Costello P, Davidson J, Logan M, Greg Coleman, Gunn K (2018) Marine Monitoring Program. Annual Report for coral reef monitoring: 2016 to 2017. Australian Institute of Marine Science, Townsville.148 pp.


Further information on the methods used to produce the scores and grades and detailed results can be found here.