UNC's Institute of Marine Sciences

vibracore
Dave DeWitt

For a coastal geologist, a vibracore is like a time machine. As a generator vibrates a long aluminum tube, Professor Antonio Rodriguez and his two graduate students force it deep into the Onslow Beach sand.

When they pull it up a few minutes later, it reveals several thousand years of history.

A champion tiger shark at a fish rodeo in 1988
Joel Fodrie / UNC IMS

Over the past 30 years, the size of sharks in the Gulf of Mexico has been shrinking. Drastically. Some sharks are 70 percent smaller.

The findings come from the University of Alabama and the University of North Carolina's Institute of Marine Sciences.

Researchers came up with a novel way of gathering the historical data. While there wasn't any academic database that collected such information, local newspapers in the Gulf region have been publishing the results of fishing competitions for years.