Application Note

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Application Note

From the Fluke Digital Library @ www.fluke.com/library

On the rivers of

Suriname, electric eels

reveal their secrets

Into the wild

So Nat Geo contacted Will

Crampton, assistant professor

in the biology department at

the University of Central Florida

in Orlando. Crampton is one of

the world’s experts on electric

fishes. In the 1990s he earned

his PhD through a four-year

project studying Gymnotiformes

in the Brazilian city of Tefé, high

up on the Amazon in the state

of Amazonas. Crampton knows

the tropics and the fish that

swim those waters. In 2009, he

worked with Nat Geo on an ear-

lier project to investigate electric

eels.

It wasn’t his quarry’s good looks that drew

Will Crampton to the wilds of Suriname.

It was the animal’s technical skills.

With his Fluke ScopeMeter

portable oscilloscope in hand,

Professor Crampton and a National Geographic video crew

flew into Suriname’s 1.3-million-acre Raleigh Vallen nature

preserve in July 2011. Their goal: capture the world’s most

powerful electric fish—Electrophorus electricus, the electric

eel—and measure its punch.

Lanky and mud-colored, the beady-eyed electric eel

can grow up to six feet in length and 45 pounds. It’s not a

true eel, but one of the neo-tropical knifefishes in the order

Gymnotiformes, more closely related to catfish.

Like other knifefishes, the electric eel can generate low-

level electrical fields that it uses for navigating through its

sometimes turbid environment and for identifying others of

its species. But Electrophorus electricus can also crank out

a dc current powerful enough to stun its prey and to shock

potential predators into choosing something else for dinner.

It was this unique capabil-

ity that attracted producers

for the National Geographic’s

Nat Geo WILD channel as they

planned a series on “Animal

Superpowers.” The eel, which

carries on shockingly well in

water nearly devoid of oxygen,

would fit perfectly in the “Survi-

vors” segment.

Professor Will Crampton (with ScopeMeter Test Tool)

and the Suriname expedition crew. Left to right:

Sonny, who caught the eel; videographer Roeland

Doust of Windfall Films; field station manager;

Crampton and Benito, aka “Doctor Five.” Crew member

at right not identified. Courtesy of Windfall Films, Ltd.

Summary of content (4 pages)

PAGE 1
On the rivers of Suriname, electric eels reveal their secrets Application Note It wasn’t his quarry’s good looks that drew Will Crampton to the wilds of Suriname. It was the animal’s technical skills. With his Fluke ScopeMeter® portable oscilloscope in hand, Professor Crampton and a National Geographic video crew flew into Suriname’s 1.3-million-acre Raleigh Vallen nature preserve in July 2011.
PAGE 2
So in July 2011, Crampton and Roeland Doust, producer/ director for London’s Windfall Films, flew into the Suriname capital of Paramaribo. There they chartered a light plane for the 50-minute flight southwest to Raleigh Vallen and the dirt strip on Foengoe Island, in the midst of the Coppename River not far from Suriname’s highest waterfall. “They wanted a relatively short sequence that just described what the electric eel is, how it generates its electric field, and what it uses it for,” Crampton said.
PAGE 3
While the Electric Eel relaxes in its wading pool, Prof. Will Crampton prepares the Fluke ScopeMeter to test the most powerful electric fish. Courtesy of Windfall Films, Ltd. How the eel measures up With the eel safely corralled in an inflatable holding pool, Crampton and the crew deployed their ScopeMeter 190-202 to measure the animal’s output. Thought it wasn’t designed for biometrics in the rain and humidity of the Suriname jungle, the instrument’s durability and compact design proved ideal.
PAGE 4
Something in the Water . . . Unlike sound, which can travel tremendous distances in water, electrical signals decay rapidly as distance increases, Crampton said. The nature of water in the Amazon basin also affects the signals. Much of the water is low in mineral salts, and electrical conductivity can range from three to four micro Siemens per centimeter (µS/cm) to 20 or 30 µS/cm, Crampton said—not far from the 10 µS/cm of distilled water. That inhibits electrical signals from traveling far.