Westport has partnered with the Western Australian Marine Science Institution (WAMSI) to deliver the $13.5 million WAMSI-Westport Marine Science Program. This 3-year program is developing the latest data, information and modelling on the complex environmental systems and community values associated with Cockburn Sound.
Project 2.4.2 Benthic communities in soft-sediment and on hard substrates: baseline data, pressure response relationships of key biota for EIA, and mitigation strategies for artificial reefs
Research theme: Benthic habitat and communities
Researchers: S. Cronin-O’Reilly, G. Hyndes, Z. Richards, H. Carrick, A. Hosie, L. Kirkendale, A. Hara, O. Gomez, C. Whisson, B. Roots, D. Johnston, J. Tweedley. (2025)
Recording the benthic invertebrates in soft sediment and on natural hard habitats to understand their contribution to the Cockburn Sound ecological system.
Benthic invertebrates are small animals that live on the seabed in the sediment and include everything from worms, crustaceans, urchins, bivalves and clams.
They are a critical part of the ecosystem, acting as a food source for pink snapper and other marine life and supporting the ecosystem through grazing and oxygen, detrital and nutrient cycling.
Some are commercially valuable, including the blue swimmer crab and the western rock octopus.
This research project provides up to date data on the abundance, diversity and assemblage structure of benthic invertebrate communities across Cockburn Sound and Owen Anchorage, on both soft sediment and hard substrate.
What the report found
- Species diversity was high in Cockburn Sound, with 193 and 248 megabenthic invertebrate species spanning eight phyla collected across large and small trawls.
- Between 37% and 54% of species were considered “rare”, i.e. limited to a single sample.
- The composition of fauna on Kwinana Shelf differed from other regions, likely due to the shelf being shallower than the basin of Cockburn Sound and Owen Anchorage, and comprised of low-relief limestone reefs, rubble and patches of seagrass.
- Historical data shows fauna had changed over time. For example, a marked shift in the 2000’s saw a decline in the western king prawn and an increase in the blue swimmer crab.
- The size, structure and organic content of sediment appeared to influence the composition soft-sediment invertebrate communities.
How Westport will use the report
Westport will use this research to inform our environmental impact assessment and related environmental management program to reduce impacts of dredging on the Cockburn Sound ecosystem and support the long-term health of Cockburn Sound.
