Marine Conservation and Volunteering - Encountering the Marbled Electric Ray in Mozambique
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- Jul 8
- 3 min read
Some marine encounters demand awe. Others demand caution. This week, on a dive at a dive site we call Lighthouse, our marine conservation volunteers hovered silently over the sand and I locked eyes with a creature that embodies both: the Marbled Electric Ray (Torpedo marmorata).
Perfectly camouflaged and barely moving, it looked like a lazy ripple of blotched brown silk lying on the seafloor. Upon closer inspection, I recognised the telltale round body and thick tail. However, this was no ordinary ray. It was one capable of delivering a nasty electric shock.
Ghosts of the Sand
Marbled electric rays are ambush predators, burying themselves in sandy bottoms, waiting for unsuspecting fish or crustaceans to pass by. When the moment comes, they lunge forward and release a jolt of electricity that stuns their prey, allowing for an easy capture. Unlike pursuit predators like most stingrays, electric rays rely on stealth and shock rather than speed and strength.
Deep Dive: How the Marbled Electric Ray Shocks
Electric rays like Torpedo marmorata are capable of electrogenesis. That is, the ability to generate electricity using specialised electric organs. The marbled electric ray has a pair of these organs situated on either side of its head, which are derived from modified muscle tissue called electrocytes. These cells don’t contract like normal muscles; instead, they function like stacked batteries.
🔋 How It Works
When stimulated by the ray’s nervous system, thousands of electrocytes activate simultaneously.
Each cell generates a small electric potential.
The cells are arranged in series (like batteries), so the voltages add up.
A coordinated discharge sends an electric current through the water, enough to stun prey—or ward off predators.
⚡ How Much Voltage Can It Produce?
The marbled electric ray can produce between 70-80 volts.
That’s more than enough to stun small fish, confuse predators, and deter divers from getting too close.
How Does It Compare to Other Electric Species
Species | Maximum Voltage | Use |
Marbled Electric Ray (Torpedo marmorata) | 80 V | Defence, stunning prey |
Electric Catfish (Malapterurus electricus) | 350 V | Defence, stunning prey |
Electric Eel (Electrophorus electricus) | 600 - 860 V | Defence, hunting, navigation |
Lesser Electric Ray (Narcine bancroftii) | 37 V | Defence |
Atlantic Torpedo Ray (Tetronarce nobiliana) | 220 V | Defence, stunning prey |
More Than a Shock Factor
Encounters like these remind us why the underwater ecosystems off Southern Mozambique deserve global attention and protection. The marbled electric ray, like many of the region’s marine species, is both biologically fascinating and ecologically vital. It plays a key role in controlling prey populations and maintaining healthy and balanced benthic (bottom-dwelling) habitats.
Yet many rays—electric or otherwise—face threats from bycatch, habitat degradation and climate change. Understanding how they live, hunt and use their habitat is crucial to preserving their populations and the ecosystems they inhabit.
Join us
At Underwater Africa, we are committed to shining a spotlight on the region’s underwater wonders. Want to join a dive, support research, or learn more about our conservation efforts? We’d love to help you experience these encounters for yourself—no electricity required.
Until next week, stay curious, and stay respectful of the power of the ocean’s quietest hunters!
By Jake Ballin, Underwater Africa Research Assistant & Volunteer Coordinator
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