Moresby Estuary

The area of the Moresby estuary reporting zone can be defined by the pre-cleared extent of mangrove and saltmarsh remnant vegetation which is characterised by species that require periodic inundation of sea water. This area extends approximately 3.3 km north and 2 km south of the river mouth along the coastline and extends approximately 12 km inland. The area includes numerous tributaries that drain into the main river channel. Land use within the Moresby estuary area is dominated by cropping and pond aquaculture with some residential development. The Moresby locality is on the western fringe of the estuary area. The Port of Mourilyan is located near the mouth of the estuary and exports raw sugar and molasses from a loader, wharf and handling facility.

Scroll down for further detailed results for each indicator group.

Grading

gradesa1

very good

gradesb1

good

gradesc1

moderate

gradesd1

poor

gradese1

very poor

insufficient data

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

confidence

Water quality

Hover over each segment for indicator scores and data confidence.

The overall water quality grade in 2015-16 for the Moresby estuary is ‘good’.

Water quality grades are based on aquatic ecosystem guidelines for protection of estuarine waters, and are not based on load reduction targets for the marine environment. The results are derived from four monitoring sites in the Moresby River.

The physical and chemical score of 69.3 (‘good’) is comprised of a dissolved oxygen (DO) score of 48.5 (‘poor’) meaning that the annual median of DO concentrations did not comply with guideline values, and a turbidity score of 90 (‘very good’) meaning that the annual median and at least 80% of monthly medians of turbidity comply with the guideline values.

Nutrients scored 75.7 (‘good’) in the Johnstone estuary, comprising of a DIN (dissolved inorganic nitrogen) score of 61.42 (‘good’) meaning that the annual median of DIN concentrations complies with guideline values, and FRP (filterable reactive phosphorus) score of 90.0 (‘very good’) meaning that the annual median and at least 80% of monthly medians of FRP concentrations comply with guideline values.

The chlorophyll a score in the Moresby estuary is 90 (‘very good’) meaning that the annual median and at least 80 per cent of the monthly medians of chlorophyll a concentrations comply with guideline values.

Pesticides are not monitored in the Moresby estuary therefore a score and grade cannot be provided

Habitat and hydrology

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The overall habitat and hydrology grade for Moresby estuary is ‘Moderate’.

The mangrove and saltmarsh extent scored 79.2 (‘good’) with 5.9% loss from pre-clear to 2013. The riparian extent scored 64.6 (‘good’) with 13.2% loss from pre-clear to 2013.

The seagrass condition score is 18.4 (‘very poor). The low seagrass score is due to the large scale declines in seagrass meadow condition recorded in the 2010-2014 periods across the Wet Tropics, predominantly resulting from extreme weather events including storms and tropical cyclones. Since 2014-5 seagrass condition has remained ‘very poor’ in Moresby estuary.

Estuary fish barriers for the Moresby estuary are scored 61 (‘good’) and are graded 'poor’ for barrier density, ‘good’ for percentage of stream length to the first barrier, and there is an absence of low passability barriers (graded ‘very good’).

Estuary riparian extent, mangrove and saltmarsh extent and estuary fish barriers are updated every four years. The data for riparian extent, mangrove and saltmarsh extent is to be updated in 2018.

The method for the flow indicator is currently under development and will be available for future report cards.

Fish

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.

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