ENVIRONMENTAL
RESULTS
AREA: 39.19 km2
ABOUT THE ZONE
The Western Basin is located near the north-western end of Gladstone Harbour. Three large-scale Liquid Natural Gas (LNG) plants have been constructed on the south-western shore of Curtis Island. The first of these commenced operation in late 2014. Large industrial plants located on the western shore of this zone include Queensland Energy Resources, Rio Tinto Yarwun, Orica, Transpacific Waste and Cement Australia. Areas of mangroves and mudflats remain between Fisherman’s Landing and the Wiggins Island Coal Export Terminal (WICET) and on the southern tip of Curtis Island.
This zone has six water and sediment monitoring sites, six monitored seagrass meadows, one fish monitoring site, and two mangrove monitoring sub-zones.
WATER & SEDIMENT
WATER
SEDIMENT
Western Basin received an overall water quality score of 0.77 (B). This score was based on the scores for physicochemical (0.77), nutrients (0.56) and dissolved metals (0.99).
Sediment quality of Western Basin was very good with an overall score of 0.98 (A).
MEASURES RESULTS
WATER
SEDIMENT
pH = acidity TN = Total nitrogen TP = Total phosphorus Chl-a = Chlorophyll-a Al = Aluminum Cu = Copper Pb = Lead Mn = Magnesium Ni = Nickel Zn = Zinc
As = Arsenic Cd = Cadmium Cu = Copper Hg = Mercury Pb = Lead Ni = Nickel Zn = Zinc
Very good (0.85-1.00)
Poor (0.25-0.49)
Good (0.65-0.84)
Satisfactory (0.5-0.64)
Very Poor (0.00-0.24)
No data available
Western Basin received a very good score of 1.00 for pH indicating that the average pH was well within the guideline value range. This zone received a satisfactory score for turbidity (0.53) indicating that average turbidity was below the guideline value.
All six dissolved metals received very good scores (0.94-1.00) indicating that average concentrations were well below the water quality guideline values.
​
Western Basin received a satisfactory overall score for nutrients (0.56). Total phosphorus had a good score (0.68) while chlorophyll-a (0.50) and total nitrogen (0.50) had satisfactory scores, indicating that average concentrations for these measures were below the guideline values for this zone.
HABITATS
SEAGRASS RESULTS
The Western Basin includes six monitored seagrass meadows, five of which are intertidal and one subtidal (Meadow 7).
In 2022 this zone was in good condition (0.82, B) for the fourth consecutive year. All seagrass meadows were in satisfactory or better condition—with one meadow scored as satisfactory, two meadows scored as good, and three meadows scored as very good. This resulted in the highest overall zone score since GHHP monitoring began.
Sub-indicator scores at the six meadows were mostly very good. Biomass scores were very good (0.87–1.00, A) at five of the meadows, with Meadow 7 receiving a satisfactory score (0.61, C). Both area and species composition sub-indicators also received good or better scores. For the area sub-indicator, four meadows received very good scores (0.93–1.00, A) and two meadows received good scores (0.73–0.77, B). Similarly for the species composition sub-indicator, four meadows received very good scores (0.86–1.00, A) and two meadows received good scores (0.74–0.77, B).
MANGROVE RESULTS
Very good (0.85-1.00)
Good (0.65-0.84)
Satisfactory (0.5-0.64)
Poor (0.25-0.49)
Very Poor (0.00-0.24)
No data available
The overall zone score for the Western Basin was 0.51 (C) indicating a satisfactory condition. While mangrove extent (0.76) received a good score, both canopy condition (0.39) and shoreline condition (0.37) had poor scores.
​
The overall score for Western Basin fell from 0.57 in 2018 to 0.51 in 2019. This was largely a result of changes in canopy condition where the score declined from 0.60 in 2018 to 0.39 in 2020. This may reflect the impacts off decreased rainfall over the reporting year.
FISH & CRABS
FISH HEALTH RESULTS
HARBOUR SCORE
OVERALL VISUAL FISH CONDITION: HARBOUR SCORE
VISUAL FISH CONDITION: HARBOUR SCORE
FISH HEALTH ASSESSMENT INDEX: HARBOUR SCORE
Very good (0.85-1.00)
Good (0.65-0.84)
Satisfactory (0.5-0.64)
Poor (0.25-0.49)
Very Poor (0.00-0.24)
No data available
Fish Health (Overall)
The overall score calculated for fish health in 2022 was 0.80 (B), which is an average of the scores for Fish Condition 0.72 (B) and the Health Assessment Index 0.90 (A).
​
Visual Fish Condition:
The overall score for Fish Condition (0.72) is an average of 0.97 (A) for Fish Visual Condition (FVC) and 0.47 (D) for Fish Body Condition (FBC).
The high scores for FVC are a result of a low incidence of poor visual health. All fish species assessed for this metric received very good scores ranging from 0.90 (A) to 0.98 (A). This result was similar to the HAI scores for external measures where a very low number of external health issues were recorded.
The poor score for FBC in 2022 was a result of poor scores for yellow-finned bream (0.43), pikey bream (0.46) dusky flathead (0.43), and barred javelin (0.44). Almost all species assessed had a mean body condition below the long-term average (2003 – 2021). However, the remaining species assessed, mangrove jack, had a satisfactory score of 0.50.
​
Fish Health Assessment Index (HAI):
The overall HAI score for Gladstone Harbour was 0.90 (A), as data from the 2021 Gladstone Harbour Report Card was reused.
This was comprised of scores from five fish species, barramundi 0.98 (A), barred javelin 0.90 (A) and blue catfish 0.81 (B), bream 0.98 (A) and mullet 0.81 (B).
In general, the surveyed fish species showed very few signs of external health issues, a similar result to the Fish Visual Condition sub-indicator. Scores for internal organs were also low indicating good to very good fish health.
FISH RECRUITMENT RESULTS
Fish recruitment was assessed for two species: yellow-finned bream Acanthopagrus australis and pikey bream Acanthopagrus pacificus. The overall score for 2022 was 0.57 (C) similar to the 2020 score of 0.62. The final scores were measured against a 2012 to 2021 baseline. The 2022 score for fish recruitment indicates a season with higher recruitment rate (increased catch rate) relative to the mean reference level determined over the baseline period. The total number of bream caught in the 2022 reporting year was 764, 316 yellow-finned bream and 448 pikey bream.