03/11/2026
As a freediving community, our wellbeing and connection relies on high quality experiences in accessible blue spaces. Blueback Freediving & Yoga has decided to oppose Westport and the AUKAUS proposal whose cumulative impacts will change the wellbeing of Derbal Nara - Cockburn Sound forever unless we, as a community, do something to keep our home waters wild. 🌱🌊🐬
Imagine a calm Makuru-June morning in Derbal Nara - Cockburn Sound.
Resident Indo-Pacific bottlenose dolphins swim from deeper water toward the Kwinana Shelf and Garden Island seagrass beds, hunting fish in small groups while calves stay close to adults. Little penguins leave their Garden Island burrows before dawn and forage across the Sound for scaly mackerel, anchovies and pilchards; this is also within their breeding and pre-moult period, which runs from about April to January.
Australian sea lions haul out on Garden Island after feeding, while migratory shorebirds use undisturbed shoreline and island habitats.
Offshore, southern right whales and humpback whales are moving along the Perth coast, and a loggerhead or green turtle occasionally drifts into the Sound after being carried south by the Leeuwin Current.
By afternoon, snorkeling the Sound, we might see and FEEL the peace and awe of floating over the Posidonia seagrass meadow nursery and feeding area for fish, seagrass-associated invertebrates, dolphins and penguins.
🩵🐬Treasured time for our nervous systems to restore and for nearshore ecosystems in Cockburn Sound to go enjoy a life of critically interconnected relationships.
Occasional shark and turtle species presence is why Cockburn Sound’s habitat quality, prey availability and water clarity matter beyond the resident dolphins and penguins.
Please don’t take this precious place for granted. Nature has not been given a priority in these industrial plans for our home waters.
We must act, together, to protect the sound.
https://recfishwest.org.au/news/cockburn-sounds-future-on-the-line/
🏗️🏭🚢🛳️⛴️📦WHAT WESTPORT & AUKUS WORKS WOULD MEAN?
Westport would require a new shipping channel, breakwater, berth areas and a large MULTI YEAR DREDGING CAMPAIGN to accommodate larger container ships.
The dredging would create sediment plumes and turbidity, reducing light for seagrass, smothering benthic habitat and reducing the visibility and availability of prey for visual hunters such as little penguins and dolphins.
To put this in perspective Recfishwest has noted it is “one of the largest dredging projects in Australian history”
🚜 Total Dredge Volume: Up to 35 million cubic metres of seabed and marine material will be removed - for a relative scale - that is roughly 14 full-to-the-brim Optus Stadiums!
🚜 Second Main Channel (Indian Ocean to Cockburn Sound):
-Approximately 21 km long.
-Between 250 m and 470 m wide.
-Minimum design depth of 18m with deeper sections up to 20m.
• Indicative Footprint: 626 hectares.
🐬🤦🏻♀️For scale - this will feel like to marine life is your new next door neighbour decides to dig a hole roughly equal to 1.5 times the size of Kings Park, or about three times the size of the entire Perth C*D grid, for the next decade or more!
🌱Key Environmental Areas Affected: The dredging cuts across recovering seagrass meadows and banks including Parmelia Bank and Success Bank.
‼️🚨⏰🔔Timeline: Capital dredging is planned to start around November 2027, subject to ongoing state and federal Environmental Protection Authority (EPA) assessments.
🐧For little penguins, the key risk is that dredging makes foraging harder, reduce fish availability and lower breeding success.
🐬🦭For dolphins and sea lions, the main concerns are underwater construction noise, disruption to hunting, loss or degradation of seagrass foraging habitat, and a higher collision risk as vessel traffic increases.
🐋🐢🦈For whales, turtles and sharks, impacts would include vessel strikes, noise, altered access to the Sound’s single navigable entrance, and disturbance during construction or transit.
AUKUS-related works at HMAS Stirling would add dredging near Diamantina Pier to provide under-keel clearance for nuclear-powered submarines, plus berthing upgrades, piling and dredge disposal.
These proposed works would be referred under the EPBC Act because of potential impacts from intrusive marine activities; Defence has stated that the adjacent little penguin colony would not be directly affected, but noise, turbidity, seagrass and marine fauna would need monitoring and management. How do they know that? What scientific evidence proves we have another species on the brink of extinction and they won’t alter the little penguins decline until it’s 11th hour?
The cumulative effect would be tremendous. A busier, noisier and more turbid Cockburn Sound: more commercial ships and submarines sharing a constrained entrance and internal channel, more dredging-related sediment, and greater pressure on the same seagrass and fish habitats that support dolphins, penguins, sea lions and visiting threatened species.
Below is the EPBC-listed species in Cockburn Sound
🐬Indo-Pacific bottlenose dolphin (Tursiops aduncus) — (Listed cetacean/marine species), resident dolphin population using seagrass beds and shallow areas for feeding, nursing and socialising.
🐧Little penguin (Eudyptula minor) — (Listed marine species), nests on Garden Island/Penguin Island and forages within Cockburn Sound on small schooling fish.
🦭Australian sea lion (Neophoca cinerea) — (Vulnerable; listed marine species), males feed in the Sound and haul out on nearby islands.
🐢Loggerhead turtle (Caretta caretta) — (Endangered; migratory), occasional foraging visitor.
🐢Green turtle (Chelonia mydas) — (Vulnerable; migratory), occasional visitor to the Sound, foraging or passing through.
🐢Leatherback turtle (Dermochelys coriacea) — (Endangered; migratory), occasional visitor.
🐢Flatback turtle (Natator depressus) — (Vulnerable; migratory), occasional foraging visitor.
🐋Southern right whale (Eubalaena australis) — (Listed threatened/migratory cetacean), regularly seen in Perth coastal waters during winter–spring migration, including Cockburn Sound sightings.
🐋Humpback whale (Megaptera novaeangliae) — (Vulnerable; migratory), passes through Perth coastal waters during its annual north–south migration.
🦈Grey nurse shark, west coast population (Carcharias ta**us) — (Vulnerable), likely to occur in the Cockburn Sound.
🦈White shark (Carcharodon carcharias) — (Vulnerable; migratory), likely to occur in the wider assessment area and reported in Cockburn Sound.
🐦⬛Migratory shorebirds and seabirds — (Listed migratory species), including species such as the common sandpiper, fork-tailed swift, white-bellied sea-eagle and roseate tern, use coastal islands, shallows and foreshores seasonally.
Do your home waters, blue spaces and coastal communities mean something to you? Enough to do something to protect them now - while it matters most?
If so, drop Tania Douthwaite a line. 0439770038.
Of course, it involves getting in the water - the source of so much wellbeing.
🩵✌🏽🌊🐟🌱💧
