This winter has brought a run of unusual marine moments along the Mandurah coast. A southern right whale spent days inside the estuary, dolphins shifted their usual patterns, a white pointer moved through the Dawesville Channel, and further offshore Antarctic orcas travelled north into Western Australian waters. None of these events sit alone. They are part of a wider seasonal shift happening along the south west coast and the Southern Ocean beyond.

Connecting Corridors tracks how wildlife moves through our region and how those movements reflect deeper ecological change. Winter 2026 is one of those seasons where the patterns are clear enough to see.

Whale Migration Numbers Are Dropping

Across Western Australia, humpback migration numbers have fallen sharply. Operators along the coast are reporting one of the quietest seasons in more than a decade. This drop is well outside normal year to year variation and points to changes in the wider system. When a migratory species reduces its numbers this noticeably, it usually means something has shifted in feeding grounds, ocean conditions or the cues whales use to time their movements.

The Southern Ocean has been under pressure this year. Food availability has changed in several regions and researchers are watching how this affects the long migration north.

Super El Niño Effects Reaching WA

The current Super El Niño has reshaped ocean conditions across the Pacific and Indian Oceans. Warmer surface waters disrupted currents and changes in upwelling zones have affected prey distribution from the tropics down to the Antarctic fringe. These changes flow into Western Australian waters through altered current strength, shifts in water temperature and changes in the timing of seasonal pulses.

For Mandurah, this has meant cooler mixed winter water, strong winds and late autumn & early winter heavy rainfall feeding freshwater into the estuary. These conditions influence where fish move and how dolphins, sharks and whales respond.

A Whale Inside the Estuary

A southern right whale entered the estuary and Dawesville Cut this winter and stayed far longer than expected. Whales rarely enter sheltered waterways and when they do it is often a sign they are seeking calmer conditions or responding to stress offshore. Dolphins accompanied the whale as it moved through the system which could tell us they were reacting to the same change.

Dolphins Adjusting Their Movements

Mandurah’s dolphins form a small resident community that is sensitive to environmental change. Heavy late autumn & early winter rainfall, strong winds and freshwater pulses through the Peel Harvey alter salinity, turbidity and where fish choose to feed. The dolphins follow those shifts. When their patterns change it is usually because the underlying conditions have changed first.

A White Pointer in the Dawesville Channel

A white pointer was seen in the Dawesville Channel this winter. While not an everyday sight it fits the ecological context. Cooler mixed winter water brings prey closer to shore and large predators follow. Recent whale activity in the system would also have drawn attention from apex species.

Orcas Travelling Further North

Antarctic orcas have been documented travelling north into Western Australian waters this year. These orcas normally inhabit cold Southern Ocean waters but are known to move into warmer areas to clean their skin and occasionally to feed. Their appearance off WA is rare and significant and aligns with broader Southern Ocean disruption including marine heatwaves and shifting prey fields.

A Coastline in Transition

When we join the dots this winter we see a clear pattern. Fewer humpbacks on migration, a whale inside the estuary, dolphins adjusting their movements, a white pointer in the Channel, Antarctic orcas travelling further north and unusual orca behaviour reported overseas. These events point to a coastline responding to a shifting ocean.

None of this is cause for alarm. It is a reminder that our marine corridor is dynamic and that wildlife responds quickly to changes we do not always see. For Connecting Corridors this is a seasonal pulse worth noting.