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Macroinvertebrates Report Card

Aquatic Plants

B

Aquatic Plants

Macroinvertebrates

C

Black Bream

D

Waterbirds

D

Fish Kills

A

Water Quality

B

Macroinvertebrate are an important food source for fish and waterbirds and provide critical ecological functions including decomposition of organic matter and recycling of nutrients.  Benthic macroinvertebrate including worms, shrimps, and snails were monitored in spring across four regions in the wetlands.  Seven metrics including community dominance and diversity were used to calculate macroinvertebrate indicators for each region following methodology developed by Murdoch University.

2023 Macroinvertebrates Grades and Species Abundance Across Regions

Upper Vasse

B

 

Lower Vasse

B

 

Lower Wonnerup

C

 

Upper Wonnerup

C

 

ANNELIDA

HEXAPODA (CLASS INSECTA)

MOLLUSCA(CLASS GASTROPODA)

CRUSTACEA

Density (per phyla)

1 invertebrate = 10-50 per 225m²

2 invertebrates = 50-100 per 225m²

3 invertebrates = 100-200 per 225m²

4 invertebrates = 200+ per 225m²

Densities of under 10 were excluded

Key Findings

  • In spring 2023, the ecological health of macroinvertebrate communities in the Vasse-Wonnerup was ‘Fair’ with an overall grade of 63 out of 100, down from ‘Very Good’ and a grade of 72 in spring 2022.
  • From spring 2022 to spring 2023, macroinvertebrate health remained stable in the Vasse estuary, with a slight decline in the Wonnerup Estuary.
  • Macroinvertebrate health was worse in January 2023, with the estuary having an average grade D, ‘Poor’.
  • The decline in macroinvertebrate health in summer is typical and is due to challenging conditions that include high temperatures and high salinities.
  • A preliminary analysis of spring grades indicates that the macroinvertebrate health scores are higher in years with higher rainfall.

Macroinvertebrates Grades Over Time

YearUpper VasseLower VasseLower WonnerupUpper WonnerupDownload Reports
2023BBCCDownload Report
2022BBBBDownload Report
2021BBAADownload Report
2020BBCB
2019DCBB
2018BBAB
2017BBAA

Grades

A

Excellent

B

Very Good

C

Fair

D

Poor

E

Very Poor

View other report cards

Aquatic Vegetation

B

Aquatic Plants

Black Bream

D

Waterbirds

D

Fish Kills

A

Water Quality

B