Mystery Bay

Key takeaways

Alison Kock's accidental discovery of flying sharks changed her life and sparked her career in marine biology.
Seal Island is a battleground for seals and sharks, where predation events reveal nature's brutal realities.
The arrival of orcas has disrupted the food chain, challenging the notion of sharks as top predators.
Fear among sharks is a contagion that influences their behavior and movements, showcasing the complex dynamics of marine ecosystems.

Summary

The Discovery of Flying Sharks

In this episode, Alison Kock recounts her extraordinary discovery while working at a car wash in Cape Town, where she stumbled upon a trunk containing photos of great white sharks appearing to fly above the waves. Skeptical at first, Alison was introduced to Chris Fellows, the photographer behind these stunning images, leading her to a profound fascination with these apex predators. This chance encounter not only influenced her career path but also inspired her to pursue marine biology, eventually leading her to Seal Island, a hotspot for these majestic creatures.

Life and Death on Seal Island

As Alison Kock continued her research, she discovered the harsh realities of life on Seal Island for seals and sharks alike. Witnessing a series of predation events, she saw sharks leaping from the water to catch seals, revealing the brutal dynamic of predator and prey. Marine ecologist Dr. Neil Hammerschlag highlights that the stress levels among seals on the island are significantly higher, demonstrating how the presence of sharks influences their behavior and survival.

The Unseen Threat: Orcas Invade Seal Island

A shocking turn of events occurs when local great white shark populations begin to decline, sparking investigations into the cause. Researcher Alison Kock is alerted to a series of incidents where sharks wash ashore with surgical-like wounds and missing livers. The mystery unfolds further when drone footage reveals orcas attacking and preying on great white sharks, showcasing a predator-prey dynamic that alters the landscape of Seal Island. This revelation challenges the long-held perception of great whites as the apex predators.

Fear: A Contagious Force Among Sharks

The episode delves into the behavioral responses of sharks to threats, highlighting how fear can spread through chemical signals in the water. This fear response, dubbed 'tresskoff,' can ripple through shark populations, influencing their behavior and movement patterns. The research presents a fascinating new perspective on how marine animals interact and respond to the dangers within their environment.

Show notes

This is episode four of Swimming with Shadows: A Radiolab Week of Sharks.

Alison Kock was working at a car wash in Cape Town when she made a discovery that completely changed the course of her life. Inside a customer’s trunk, she found photographs of white sharks flying so high above the water they looked like airplanes. She followed those photographs to False Bay, “the Great White Capital of the World.” These sharks, in this place, are the apex of apex predators. Or they were. Until they mysteriously began to disappear.

Special thanks to Kathryn Ayres.

EPISODE CREDITS:
Reported by - Rachael Cusick
Produced by - Simon Adler and Maria Paz Gutierrez
with help from - Rebecca Laks
Original music from - Simon Adler and Maria Paz Gutierrez
Sound design contributed by - Jeremy Bloom
with mixing help from - Jeremy Bloom
Fact-checking by - Diane A. Kelly
and Edited by - Pat Walters

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