Paramount Importance Podcast

Tunas are not just swimming past sharks, they may actually be using them.

In this strange behaviour, tunas have been filmed rubbing against sharks, likely using their rough skin to help remove parasites. It is one of those moments that shows how much is still hidden in the open ocean, and how technology like midwater BRUVS is revealing behaviours we would almost never see otherwise.

This behaviour was studied by Dr Chris Thompson and discussed with Professor Jessica Meeuwig AM from The University of Western Australia and the Marine Futures Lab.
Host: Kurt Krispyn
Guest: Professor Jessica Meeuwig AM
Podcast: Paramount Importance

That strange hammer-shaped head is not just for looks.

The hammerhead’s head, known as the cephalofoil, spreads its sensory organs across a much wider surface. This includes the ampullae of Lorenzini, specialised receptors sharks use to detect tiny electrical signals produced by other animals.

That wider head may also help with navigation and manoeuvrability through the water, giving hammerheads a very different body design to most other sharks.

It is one of the most distinctive shapes in the ocean — and a perfect example of how unusual anatomy can evolve for multiple functions.

Host: Kurt Krispyn
Guest: Dr Naima Andrea López | The University of Western Australia, Marine Futures Lab
Drone: Seen by Lexo (Lexo Aveleyra)
Podcast: Paramount Importance

Scalloped hammerhead sharks are listed as critically endangered globally — yet in Western Australia they can still legally be caught recreationally.

That becomes even more significant when you consider their biology. Scalloped hammerheads produce relatively few young and can take around 13 years to reach sexual maturity, meaning populations can be slow to recover when numbers decline.

Andrea explains why these life-history traits make hammerheads particularly vulnerable to fishing pressure, and why accurate species-specific catch data is so important for understanding what is actually happening to their populations.

Host: Kurt Krispyn
Guest: Dr Naima Andrea López | The University of Western Australia, Marine Futures Lab
Drone: Seen by Lexo (Lexo Aveleyra)
Podcast: Paramount Importance

These hammerhead sharks may be using Perth’s shallow coastal waters as a place to rest.

After potentially feeding farther offshore, juvenile scalloped hammerheads return to warm, shallow embayments where Andrea has recorded hundreds of hours of drone footage showing them moving slowly, with little obvious direction and no clear signs of feeding.

For a shark that needs to keep swimming to move water across its gills, “sleeping” looks very different to how it does for us.

Scientists are still working to understand exactly why these aggregations form, but the behaviour suggests these areas could be important resting habitat for the sharks.

Host: Kurt Krispyn
Guest: Dr Naima Andrea López | The University of Western Australia, Marine Futures Lab
Drone: Seen by Lexo (Lexo Aveleyra)
Podcast: Paramount Importance

Scalloped hammerhead sharks are usually associated with tropical waters — which makes what is happening off Perth so unusual.

Large, recurrent aggregations of juvenile scalloped hammerheads are now appearing along the metropolitan coastline each summer, far farther south than scientists would traditionally expect to see them.
Historical records suggest these aggregations were not being observed around Perth before the early 2000s, raising an important question: are these sharks shifting their range south as ocean conditions change?

For researchers, Perth may be providing a rare glimpse into how a highly mobile shark species responds to a changing ocean.

Host: Kurt Krispyn
Guest: Dr Naima Andrea López | The University of Western Australia, Marine Futures Lab
Drone: Seen by Lexo (Lexo Aveleyra)
Podcast: Paramount Importance

Some hammerhead sharks can dive beyond 1,000 metres deep — but getting there creates a major problem.

The deeper they go, the colder the water becomes. Unlike us, sharks don’t regulate their body temperature in the same way, so passing freezing water continuously across their gills can rapidly cool them down.

Research suggests scalloped hammerheads may solve this by effectively “free diving” — reducing water flow across their gills during these deep dives to limit heat loss before returning to warmer surface waters.
It is one of the most extraordinary adaptations we are only beginning to understand in these sharks.

Host: Kurt Krispyn
Guest: Dr Naima Andrea López | The University of Western Australia, Marine Futures Lab
Drone: Seen by Lexo (Lexo Aveleyra)
Podcast: Paramount Importance

Moving animals to save them from extinction is not a new idea.

Conservationists have been relocating species for more than a century, often moving them away from predators, disease or habitat destruction. What is changing is the reason we may need to move them.

Professor Nicki Mitchell explains how climate change is forcing scientists to consider relocating threatened species into places they have never historically lived, raising difficult questions about risk, responsibility and how far conservation should intervene.

Host: Kurt Krispyn
Guest: Professor Nicki Mitchell
University: The University of Western Australia

This tiny Tasmanian frog skips the free-swimming tadpole stage entirely.

Its eggs are laid within damp moss, where the embryos can spend up to 14 months developing before emerging as fully formed froglets.

Professor Nicki Mitchell explains the extraordinary biology of the Tasmanian moss frog and how studying this newly discovered species helped launch her scientific career.

Host: Kurt Krispyn
Guest: Professor Nicki Mitchell
University: The University of Western Australia

How does a species officially become threatened?

A species can be declining towards extinction without receiving formal protection. Before it can be listed, scientists must gather enough evidence to assess factors such as its population decline, geographic range and the threats it faces.

Professor Nicki Mitchell explains how Australia’s threatened species assessment process works and why a lack of research can leave vulnerable species unlisted and potentially without the protection they need.

Host: Kurt Krispyn
Guest: Professor Nicki Mitchell
University: The University of Western Australia

What happens when an animal’s natural habitat is no longer the safest place for it?

The Critically Endangered Western Swamp Turtle depends on seasonal wetlands, but climate change is making its remaining habitat warmer and drier.

Professor Nicki Mitchell explains how scientists are trialling assisted colonisation by moving turtles into cooler areas outside their known historical range. It is a groundbreaking attempt to answer one of conservation’s most difficult questions: should we move a species to save it from extinction?

Host: Kurt Krispyn
Guest: Professor Nicki Mitchell
University: The University of Western Australia