ENVIRONMENTAL
RESULTS
ABOUT THE ZONE
South Trees Inlet is a mangrove and salt pan-lined tidal inlet that flows into the Mid Harbour Zone.
WATER & SEDIMENT
South Trees Inlet received an overall water quality score of 0.84 (B).
Sediment quality of South Trees Inlet was very good with an overall score of 0.97 (A).
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The following graphs compare the Water and Sediment scores reported for 2024 (top line) to those from 2023.
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 data available
Overall, Water quality in South Trees Inlet scored 0.84 and received a good grade (B), a similar score but decline in grade from the 2023 report card. This score was calculated by aggregating the three sub-indicator and associated measure scores (Physicochemical – pH and turbidity, Nutrients – total nitrogen, total phosphorus and dissolved metals, and dissolved metals – aluminium, copper, lead, manganese, nickel and zinc).
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Within the Physicochemical sub-indicator, South Trees Inlet received a score of 1.00 and a very good grade (A) for pH, indicating that the average pH was within the guideline value range. This zone received a score of 0.75 and a good grade (B) for turbidity, indicating that turbidity was below the guideline value range.
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Within the Nutrient sub-indicator group, total nitrogen (0.55) and chlorophyll-a (0.54) received satisfactory grades (C), indicating these measures were below guideline values. Total phosphorus (0.84) received a good grade (B), indicating that total phosphorus was below the guideline value.
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All six Dissolved metals received high scores (1.00) and very good grades (A) indicating that they were well below the water quality guideline values.
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For Sediment quality, South Trees Inlet received an overall score of 0.97 and a very good grade (A), a similar result to the previous year. This score was calculated by aggregating measure scores (Metal and metalloids – arsenic, cadmium, copper, lead, mercury, nickel and zinc).
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In 2024, all seven Metal and metalloid sub-indicator measures received very high scores (0.87–1.00) and very good grades (A), indicating that metals concentrations were well below the guideline values.
HABITATS
SEAGRASS (MEADOW 60)
South Trees Inlet has one monitored meadow which sits off the northern tip of South Trees Island. Meadow 60 is an intertidal meadow and the second smallest of the monitored meadows.
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South Trees Inlet received the same overall score (0.81) in 2024 and remained a good grade (B). Area and species composition scores also remained very similar.
MANGROVE RESULTS
South Trees Inlet has one Mangrove monitoring zone. Overall, in 2024, South Trees Inlet maintained a satisfactory grade (C). In 2024, mangrove extent remained good (B) at South Trees Inlet. The grade for canopy condition at South Trees Inlet improved from a satisfactory (C) in 2019 to a good grade (B) in 2024. Shoreline condition of mangroves at South Trees Inlet declined from a satisfactory (C) in 2019 to a poor (D) grade in 2024.
FISH & CRABS
FISH RECRUITMENT RESULTS
Fish recruitment was assessed for two species: Yellowfin bream Acanthopagrus australis and Pikey bream Acanthopagrus pacificus. Fish recruitment improved in score (2023: 0.31; 2024: 0.39) but remained a poor grade (D) at South Trees Inlet in 2024.