Scientists use sharks to improve hurricane forecasts

Scientists at the University of Delaware in the United States are investigating whether sharks can be used to improve predictions of hurricane intensity and serve as ocean-observing systems for collecting marine data.

Researchers at the University of Delaware are attaching sensors to sharks that measure ocean temperature, electrical conductivity and depth. Electrical conductivity is related to the amount of salt in the water.

According to Aaron Carlisle, a professor at the university’s School of Marine Science and Policy and the lead researcher of the study, animal-mounted sensors have been successfully used in marine research for several years particularly in areas where scientific observations are limited.

Researchers say sharks are suitable for this research because they are abundant, inhabit vast areas of the ocean and are relatively easier to access than many protected marine mammals.

So far, shark tagging has mainly been used to study their movements and habitats. However, in this new research, scientists are selecting sharks that can collect useful data for hurricane forecasting and swim close enough to the ocean surface for their tags to transmit information via satellites.

Preliminary analyses in the North Atlantic have identified shortfin mako sharks, blue sharks, smooth hammerhead sharks and juvenile great white sharks as suitable species for the research.

According to Aaron Carlisle, scientists are paying particular attention to the heat in the upper layer of the ocean known as the “mixed layer.” This layer of water plays an important role in the intensity of hurricanes because a warmer mixed layer can contribute to the formation of stronger hurricanes.

Caroline Wiernicki, a doctoral student at the University of Delaware said the shark-tagging process begins in early May, when several migratory shark species come closer to the coast after spending the winter in remote areas of the Atlantic Ocean.

Researchers travel 50 to 65 kilometres offshore in a research vessel where they deploy baited lines and typically wait two to three hours for sharks to approach. A tag is attached to the shark’s dorsal fin. When the shark swims near the surface, the tag connects with a network of satellite receivers and transmits data.

Carlisle said the tagging process is completed rapidly similar to a “pit crew” during a motor race and usually takes less than five minutes. Shark tagging is carried out under institutional animal-care oversight to minimize its impact on the animals.

The tags are attached using materials that gradually dissolve and eventually detach on their own. Before each shark is released back into the ocean, its health is examined because stress or injury could affect its natural behaviour and consequently, the reliability of the data collected.

Caroline Wiernicki said sharks are portrayed as extremely frightening animals in movies whereas in reality they are relatively calm creatures.

According to the researchers, if the project proves successful, data collected from sharks could help improve forecasts of the intensity of hurricanes approaching the US East Coast. This information could provide more reliable forecasts to coastal communities from North Carolina to Massachusetts helping them prepare for storms and improve coastal protection.

Aaron Carlisle said sharks are remarkable animals that are exceptionally well adapted to life in the ocean and there is much that humans can learn from them. If it is proven that sharks can also benefit humans, it would be a win-win situation for both.