Sharks off the US East Coast may soon be doing more than hunting: scientists are testing whether the ocean's top predators can moonlight as mobile weather monitors. Researchers at the University of Delaware are attaching CTD tags — small devices that measure electrical conductivity, a proxy for salinity, along with temperature and depth — to sharks that surface often enough to beam their readings to passing satellites.
The prize measurement is the heat content of the ocean's mixed layer, the sun-warmed surface water that feeds hurricanes. 'Warmer mixed layer equals stronger hurricane,' said Aaron Carlisle, a professor in the university's School of Marine Science and Policy and principal investigator of the project. Shortfin mako sharks, blue sharks, smooth hammerheads and juvenile great white sharks are the favored candidates because they are abundant, widely distributed and far easier to reach than many protected marine mammals.
Tagging is run 'like a pit crew' and takes under five minutes, Carlisle said. The work is done under institutional animal-care oversight: tags are made of materials designed to corrode and fall off over time, and every shark gets a health check before release so a stressed animal does not bias the data. The tags transmit each time a shark swims at the surface, giving scientists near-real-time profiles of the ocean from waters where instruments are scarce.
If the approach works, shark-gathered data could sharpen forecasts of how intense hurricanes will be as they near the US East Coast, giving communities from North Carolina to Massachusetts more reliable warning. 'If we can show that sharks can help people, it's a win-win situation,' Carlisle said.
