Great white sharks around Mexico's Guadalupe Island sometimes hang out with each other — and while it's not a popularity contest, some might just be a little more social than others.
FIU marine scientist Yannis Papastamatiou, Ph.D. candidate Sarah Luongo and a collaborative team of researchers, wanted to uncover some of the mysteries of the white sharks that gather seasonally around Guadalupe Island. With an innovative combination of tracking tools, they found sharks tend to stick together when patrolling, like stopping by to check out the seal colonies around the island. Some were together for more than an hour.
"Most associations were short, but there were sharks where we found considerably longer associations, much more likely to be social associations," said Papastamatiou, lead author of the study. "Seventy minutes is a long time to be swimming around with another white shark."
Guadalupe Island is brimming with tuna and seals making it a hotspot for white sharks. But, it's unlike other places white sharks spend time, like South Africa or Australia, where waters are murkier and white sharks leap out of the water to launch sneak attacks and ambush prey. Guadalupe Island's waters are very blue and very clear. Prey is easily seen. But, prey, can also see the predators. That's why the research team wanted to see if the sharks were adjusting their hunting strategies and doing something differently.
Normally, studying such cryptic animals involves some form of tracking device. To study these white sharks, though, the researchers knew they were going to need a much bigger, better tag.
So, they combined different commercially available technology into a "super social tag" that collected data for up to five days before popping off the shark's dorsal fin and floating to the surface. It was equipped with a video camera and an array of sensors tracking acceleration, depth, direction and how rapidly the shark turned while swimming. What put the "social" in this specific tag was special receivers that could detect other tagged sharks nearby.
The findings were published in and featured on the cover of Biology Letters.
Part of this research was also featured in Discovery's Shark Week show "Great White Kill Zone: Guadalupe."
