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 ENVIRONMENTAL 
RESULTS 

6 Calliope Estuary'.png

AREA: 7.71 km2

 ABOUT THE ZONE 

The Calliope River is fed by Gladstone Harbour’s largest freshwater catchment. The river’s main tributaries include Oakey, Paddock, Double and Larcom creeks. The Calliope River flows into the Western Basin and is a source of turbid freshwater during floods or other high flow events. The WICET and RG Tanna’s coal terminal are located at the mouth of the Calliope Estuary. Queensland’s largest coal-fired power station is located alongside the Calliope Estuary, approximately 4km upstream from the river mouth and has been operating since 1976.

This zone has three water and sediment monitoring sites, two fish monitoring sites, one mud crab monitoring site and one mangrove monitoring sub-zone.

Gladstone Healthy Harbour Partnership GHHP report card

 WATER & SEDIMENT 

Calliope Estuary received an overall water quality score of 0.81 (B). 

Sediment quality of Calliope Estuary was very good with an overall score of 0.97 (A).

The following graphs compare the Water and Sediment scores reported for 2023 (top line) to those from the previous year.

WATER

SEDIMENT

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 Grade.png

No data available

Overall, Water quality in Calliope Estuary scored 0.81 and received a good grade (B), identical to the 2022 report card. This score was calculated by aggregating the three sub-indicator and associated measure scores (Physiochemical – pH and turbidity, Nutrients – total nitrogen, total phosphorus and dissolved metals, and dissolved metals – aluminum, copper, lead, manganese, nickel and zinc).


Within the Physiochemical sub-indicator, Calliope Estuary received a score of 1.00 and a very good grade (A) for pH indicating that the average pH was well above the guideline value. This zone received a score of 0.55 and satisfactory grade (C) for turbidity indicating that average turbidity was within the guideline value. 


Within the Nutrient sub-indicator group, total nitrogen (0.57) received a satisfactory grade (C) indicating concentrations for this measure were within guideline values. In contrast, total phosphorus (0.70) and chlorophyll-a (0.68) received good grades (B), indicating that average concentrations for these measures were below the guideline values.


All six Dissolved metals received high scores (1.00) and very good grades (A) indicating that average concentrations were well below the water quality guideline values.


For Sediment quality, Calliope Estuary received an overall score of 0.97 and a very good grade (A), also a similar result to the previous year. This score was calculated by aggregating one sub-indicator and associated measure scores (Metal and metalloids – arsenic, cadmium, copper, lead, mercury, nickel and zinc).


In 2023, six of the seven Metal and metalloid sub-indicator measures received very high scores (1.00) and very good grades (A) and reflect all concentrations were well below guideline values. One measure – nickel – received a score of 0.80 and a good grade (B), indicating that concentrations of nickel in the Inner Harbour are within guideline value.

Gladstone Healthy Harbour Partnership GHHP report card

 HABITATS 

MANGROVE RESULTS

No mangrove assessment was conducted in 2023, results are from monitoring conducted in 2019. The overall score for Calliope Estuary was 0.58 (C) indicating mangroves were in satisfactory condition in this zone. Mangrove extent (0.80) received a good score and canopy condition (0.48) and shoreline condition (0.47) were poor.

 

The overall score for Calliope Estuary fell from 0.67 in 2018 to 0.58 in 2019. This was largely a result of changes in canopy condition where the score declined from 0.61 in 2018 to 0.48 and a decline in shoreline condition from 0.56 to 0.47 in 2019. This may reflect the impacts off decreased rainfall over the reporting year and increased shoreline erosion.

C Score Card.png

 FISH & CRABS 

 FISH RECRUITMENT RESULTS 

Fish recruitment was assessed for two species: Yellowfin bream Acanthopagrus australis and Pikey bream Acanthopagrus pacificus. The overall score for 2023 was lower than the previous year (2022: 0.47, 2023: 0.28) and retained poor (D) grade. The number of bream caught during the 2022–23 reporting period were as follows: 2022 report card: 35 fish, 2023 report card: 21 fish.

Fish health is assessed though two sub-indicators, Fish condition and Fish Health Assessment Index (HAI). 
The overall score for Fish health in 2023 was 0.81 and received a good grade (B). The 2023 results were calculated by the average of the Fish HAI score (0.90; results carried over from 2021) and new assessment of Fish condition which scored similar to the previous year (2022: 0.74, 2023: 0.73).  
 

 MUD CRAB RESULTS 

Calliope Estuary is fed by Gladstone Harbour’s largest freshwater catchment. Main tributaries of the Calliope River include Oakey, Paddock, Double and Larcom creeks.

 

The overall zone score for Calliope Estuary was 0.54 and satisfactory grade (C) is an improvement from the previous year. As with other zones, this improvement was due to a large increase in sex ratio scores reflecting a rebalance of male to female crabs caught. The scores for abundance and prevalence of rust lesions remained consistent and indicate low catch rates and low prevalence of rust lesions. 

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