Tag Archives: ocellated wrasse

Nonprofit’s scientific news is a salve for a gloomy world

Published August 27, 2016 in the “Ocean Watch” column, Honolulu Star-Advertiser ©2016 Susan Scott

The Society for Science and the Public, a nonprofit organization dedicated to sharing scientific news, emails me with weekly updates. As I scroll through the headlines, I’m amazed at the scope of human curiosity and people’s creativity in gaining knowledge, from finding exoplanets to editing genes.

I can spend hours at this well-written site, but before I lose myself in the DNA of Darwin’s dogs or how neuroscientists view “Donkey Kong,” I check out the latest in the marine world. One study that caught my attention was about the Taser-packing fish, the electric eel.

Before I even read the study, I wondered how this eel, scientific name Electrophorus electricus, is related to the moray eels we know so well here in Hawaii.

They’re not. The electric eel isn’t an eel at all. It’s a member of a fish family called knifefish, native to South American lakes and rivers.

The 6-foot-long electric eel delivers up to 600 volts to kill its prey. For those of us who’ve been accidentally shocked by a 110-volt household outlet — or worse, the 220 volts used in other countries — 600 volts is a mind-blowing jolt. Evolution made sure that the eel got its meal.

In waters where electric eels go hunting, other fish lie low, staying motionless behind rocks and among plants. Given such hiding, plus the fact that the electric eel’s vision is poor and the rivers are murky, a biologist at Nashville’s Vanderbilt University wondered how the eel finds its prey.

The researcher discovered that as the eel swims it shoots out tiny electric currents that cause a hiding fish’s muscles to twitch. And that’s all it takes. The eel heads toward the twitcher, shocks and eats.

Another fishy headline read, “Female fish have a fail-safe for surprise sperm attacks.” After a female ocellated wrasse (a Mediterranean species) chooses a mate, the couple make their nest. But bachelor wrasses lurk nearby, waiting for the female to lay her eggs. The rascal then dashes in and floods them with sperm. A Yale biologist discovered, however, that the female wrasse’s ovaries coat the eggs with a fluid that favors fast-swimming sperm. Because mated males have speedier sperm, the female’s chosen mate wins the race to the egg.

Sometimes I get so discouraged by the stream of terrible news throughout the world that I wonder whether our species is doomed. But then I get these science emails and life looks much better. T.H. White explained my feeling in a favorite book, “The Once and Future King”:

“‘The best thing for being sad,’ replied Merlin … ‘is to learn something. … Learn why the world wags and what wags it. That is the only thing which the mind can never exhaust, never alienate, never be tortured by, never fear or distrust, and never dream of regretting.’”

For a learning lift, visit www.societyforscience.org.