Saturday, August 31, 2013

GPS Tracking Suggests How Sharks Really Behave During Storms

I’ll give you a big hint: Sharknado will never be anything more than a beloved SyFy channel B-movie. Research shows that sharks can actually sense upcoming storms and typically flee the area until the storm passes. Sharks have a canal filled with fluid running along each side of their bodies, with a row of small pores connecting the canals the skin’s surface. This is known as the lateral line and allows sharks to detect changes in pressure in the water around them.


Flatnose SharkTypically, sharks use these senses while hunting to detect injured or weak prey. Research suggests that with the lateral line, sharks can predict storms due to the sudden drop of barometric pressure leading up to hurricanes. “I paid particular attention to the inner ear of the shark. A deflection of hair cells in the inner ear occurs when exposed to changes in barometric pressure,” Dr. Lauren Smith said, shark expert. “This then relays impulses to the brain which may result in the subsequent behavior changes.” Dr. Smith studied lemon sharks at Alberdeen University, particularly their responses to pressure changes.


Baby sharks usually stay in shallow waters where they are safe from predators and have access to smaller prey. However, when a hurricane approaches, even juvenile sharks risk deeper waters to avoid the wrath of the storm. “The juveniles inhabit super shallow nursery environments,” Dr. Smith explained. “If a storm was hitting, this creates considerable surface chop and tidal surges so they would be really flailing around in there, hence its possible that they are effectively deciding that to be trapped in a shallow area in a storm is worse than risking the deeper potentially predator patrolled water.”


The OCEARCH Global Shark Tracker is a team of researchers studying deep sea sharks with GPS tracking devices. The GPS data shows that even great white sharks tend to flee approaching hurricanes. “Hurricane Sandy passed just to the east of this area on October 27th, 2012 as a Category One storm, and this did coincide with a rare 6-day gap in detections – from October 25-31st – from Mary Lee’s SPOT tag,” explained Dr. Nick Whitney. “This may indicate that she stayed deep to avoid the storm, but could also be a result of weather and waves inhibiting tag transmission to the satellites. It’s hard to say.”



GPS Tracking Suggests How Sharks Really Behave During Storms

No comments: