ENVIRONMENTAL
RESULTS
ABOUT THE ZONE
Auckland Inlet is a tidal inlet that connects to the Inner Harbour through a complex network of small streams meandering through mangrove-lined mudflats that are often inundated at high tide.
WATER & SEDIMENT
Auckland Inlet received an overall water quality score of 0.84 (B).
Sediment quality of Auckland Inlet was very good with an overall score of 0.95 (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 at Auckland Inlet scored 0.84, a slight improvement from 2023 and again received a good grade (B). 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 – aluminium, copper, lead, manganese, nickel and zinc).
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Within the Physicochemical sub-indicator, Auckland 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 0.58 and satisfactory grade (C) for turbidity, indicating that average turbidity was within the guideline value range.
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Within the Nutrient sub-indicator group, total nitrogen (0.48) remained a poor grade (D) in 2024, indicating total nitrogen was above the guideline value. Total phosphorus (0.70) received a good grade (B) (an improvement from satisfactory (C) in 2023). Chlorophyll-a (0.76) also received a good grade (B), indicating that average concentrations for these measures were below the guideline values.
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Five out of six Dissolved metals received high scores (1.00) and very good grades (A). Copper received a score of 0.83 and a good (B) grade in this zone. These results indicate that metal concentrations were all below the guideline values.
For Sediment quality, Auckland Inlet received an overall score of 0.95 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, six of the seven Metal and metalloid sub-indicator measures received very high scores (0.88–1.00) and very good grades (A), and one sub-indicator – nickel – received a high score (0.79) and a good (B) grade, indicating that metals were well below the guideline values for this zone.
HABITATS
MANGROVE RESULTS
In 2024, the overall grade for Mangroves at Auckland Inlet declined from a good (B) in 2019 to a poor grade (D). The very poor shoreline condition sub-indicator score (0.03) contributed to this decline. Both human activities and natural climatic events have impacted developed shoreline areas near mangroves in this zone. Mangrove extent remained a good grade (B) at Auckland Inlet in 2024. The grade for canopy condition at Auckland Inlet improved from a satisfactory (C) in 2019 to a good (B) in 2024. Shoreline condition of mangroves at Auckland Inlet declined in grade from satisfactory (C) in 2019 to very poor (E) in 2024.
FISH & CRABS
FISH RECRUITMENT RESULTS
Fish recruitment was assessed for two species: Yellowfin bream Acanthopagrus australis and Pikey bream Acanthopagrus pacificus. The Fish recruitment score for Auckland Inlet remained the same in 2024.
MUD CRAB RESULTS
Overall, Mud crabs at Auckland Inlet received a score of 0.35 and a poor grade (D). Abundance and sex ratio scores were both very poor (0.00 and 0.05, E) at Auckland Inlet, similar to the results from the 2023 Report Card. There was no prevalence of rust legions, resulting in a high score and a very good grade (1.00, A), also similar to 2023 results.