Kim Segal and John Zarrella
CNN
[cnn-photo-caption image=http://www.cnn.com/video/us/2010/06/28/zarrrella.oil.shark.tagging.cnn.640×360.jpg caption="It's still unclear if the sharks are avoiding the oil spill" width=300 height=169]
They're at the top of the ocean's food chain - but it is still a mystery how the oil disaster is affecting the shark population in the Gulf of Mexico.
Even if sharks never touch the oil slick, their sources of oxygen and food are at risk. And a reduced shark population could impact the entire Gulf ecosystem, according to Neil Hammerschlag, a researcher at the University of Miami, who has been studying sharks for a decade - tagging them to determine their migratory patterns and other behaviors.
Today, his research focus has changed.
"The oil spill opens up a whole new avenue for critical research," says Hammerschlag.