As seas warm, some shark species are spending longer in southern waters — and a few are pushing into places they rarely appeared before.
By Swikriti | Updated: January 18, 2026
If it feels like sharks are showing up in places you don’t remember seeing them — you’re not imagining the broader pattern. Marine scientists say warming ocean temperatures are reshaping where many shark species spend their time, how long they stay, and which stretches of coastline remain “comfortable” as seasons shift. The ABC recently pulled together the latest research and tracking data on how this is playing out around Australia, particularly along the east coast, where waters have been warming quickly. ABC Science reports that multiple species are responding in different ways — and the changes have real implications for how we manage ocean life and coastal safety.
The core idea is simple: many sharks are ectothermic (“cold-blooded”), meaning the temperature of the surrounding water strongly influences their metabolism, movement, and behaviour. As the ocean warms, animals that prefer certain temperature bands often shift to stay within those bands — sometimes moving south toward cooler water, sometimes staying longer where conditions used to be seasonal.
A “grey nomad” migration — but in the sea
Scientists often describe a seasonal north-south rhythm in Australian waters: in cooler months, some sharks move north to avoid colder temperatures, then drift south again as summer heats up. With climate change raising baseline temperatures, that rhythm can stretch and bend. One big outcome: sharks that used to pass through southern areas for a short summer window may now linger longer, because the water stays within their preferred temperature range for more of the year.
That doesn’t automatically mean “more sharks” in the sense of a sudden population boom. In many cases it means the same visiting sharks are simply spending more time in the area — which increases the chance of sightings and detections.
Bull sharks: longer summers near Sydney
Bull sharks are a standout example because they typically prefer warmer waters (often cited as above roughly 22°C). On Australia’s east coast, they’re generally more common north of Sydney, but some individuals travel into southern waters in summer — including urban waterways in the Greater Sydney region.
Tracking work highlighted in the ABC report suggests migrating bull sharks have been adding time to their summer stays around Sydney over the years. That’s a subtle change, but it adds up: a few extra days, repeated annually, can become weeks over a decade-plus timeframe. Researchers also note reports of very young bull sharks (pups) being spotted farther south than historic “nursery” limits, which may signal shifting nursery habitat.
For everyday readers, the takeaway isn’t panic — it’s context. Warmer summers can mean a longer period each year when bull sharks may be present in southern NSW waters. That can affect how local authorities time monitoring, and how communities think about risk during peak swimming months.
Tiger sharks: detections pushing into Tasmania
Tiger sharks are wide-ranging and adaptable, but their movement patterns can still be shaped by temperature, age, and sex. The ABC story points to research tracking tiger sharks over many years, noting differences in how juveniles and adults use the east coast.
Here’s the headline detail: tagged tiger sharks have been detected as far south as Tasmania — including around Maria Island — a notable signal in a long-running monitoring program. Modelling cited in the report suggests Tasmania’s east coast could become increasingly suitable for tiger sharks by around 2030, particularly as warm conditions become more common.
One reason this matters is that sharks don’t move in isolation. Their prey shifts too. If sea turtles and other prey species extend farther south, predators may follow. It’s an evolving system — temperature, prey distribution, and habitat all interact.
Young white sharks: habitat could get squeezed
White sharks are a little different. They’re regionally endothermic, meaning they can generate and retain heat in parts of their bodies — which helps them operate in cooler waters better than many strictly ectothermic species. Even so, young white sharks still show clear preferences for certain temperature ranges and coastal habitats.
The ABC report highlights a concern from researchers studying juvenile and sub-adult white sharks on the east coast: if northern waters warm beyond what’s optimal during winter, suitable wintering habitat may shrink. At the same time, there may not be an equal “bonus” of brand-new habitat opening in the far south. The result can be a compression effect — fewer areas that are “just right” across the seasons.
Regions such as the Twofold Shelf (near the NSW–Victoria border) may become increasingly important as a key habitat zone. From a management perspective, that raises questions about how monitoring, protection, and public safety messaging should evolve in the coming decades.
Not every species can simply move south
The southward shift is not a universal escape hatch. Some warm-water species can expand poleward, but cold-adapted species along Victoria and other temperate regions may face a different problem: there’s only so far south you can go. Research discussed in the ABC story suggests some smaller sharks and rays in Victorian waters could lose suitable habitat under moderate warming scenarios by later in the century, though outcomes may vary by species. In some cases, marine protected areas could function as refuge sites.
(If you want a deeper look at the science of large-scale ocean monitoring and animal movement tracking, the Integrated Marine Observing System (IMOS) provides useful background on how Australia collects and shares ocean data.)
What this means for beachgoers — without the hype
A warmer ocean does not automatically translate into more shark attacks. But shifting distributions can change where and when people are more likely to see sharks, and where authorities may focus surveillance and public alerts. The practical approach is to treat this as an evolving environmental pattern — and keep basic safety habits consistent.
- Swim between the flags and follow lifeguard advice.
- Avoid murky water, river mouths, and areas with baitfish activity.
- Don’t swim at dawn/dusk when visibility is lower and some species feed.
- Pay attention to local shark alerts, drone patrol updates, and signage.
The bigger picture is that sharks are responding to the same environmental pressures reshaping many marine ecosystems. Tracking data, modelling, and on-the-water observations are converging on a consistent message: Australia’s ocean life is shifting with the temperature. The smart response isn’t fear — it’s better monitoring, clearer public information, and management that adapts as conditions change.
Related reading on Swikblog: explore more environment and science explainers on Swikblog and browse our latest updates in News.
Sources referenced in reporting include ABC Science coverage and linked peer-reviewed research and tracking programs (for example, IMOS and published studies on shark habitat and movement).
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