Sharks Fitted With Sensors to Improve Hurricane Intensity Predictions

University of Delaware researchers are testing whether sharks fitted with sensors can serve as mobile ocean-data observers to improve hurricane intensity predictions. The tags measure temperature, depth and conductivity as the sharks swim and dive, feeding data into oceanographic, atmospheric and climate models. By focusing on the heat content of the ocean's upper layer, which drives hurricane strength, the research aims to gather scarce data that could help forecasters assess a storm's potential intensity before it makes landfall.

 

The Research Concept

 

Researchers are exploring an unconventional source of ocean data. A University of Delaware team is testing whether sharks can serve as data observers. The sharks would act as mobile, near-real-time collectors of ocean conditions. They carry sensors measuring conditions as they move through the water. This data would inform oceanographic, atmospheric and climate models.

The approach builds on established scientific practice. Animal-borne sensors have been used by oceanographers for years. They have proven successful on elephant seals in polar regions. Such regions are areas where scientific observations remain scarce. This precedent provides a foundation for the shark-based research.

 

Why Sharks Were Chosen

 

Sharks offer distinct advantages for this kind of research. They are abundant across the waters being studied. They are also widely distributed geographically. This makes them easier to access than many protected marine mammals. These practical factors make sharks attractive research subjects.

The research also represents a new use for shark tagging. Until now, shark tagging typically tracked only where the fish travel. It also recorded the habitats these sharks use. The new approach extends tagging to environmental data collection. This adds a scientific dimension beyond simple movement tracking.

 

The Sensor Technology

 

The research relies on specialised electronic tags. These are known as CTD tags, small electronic devices. They measure ocean electrical conductivity, which relates closely to salinity. They also record temperature and depth. These measurements are taken as the tagged creatures swim and dive.

The tags are designed to transmit their data efficiently. They are attached to the shark's dorsal fin. Every time the shark surfaces, the tag can communicate. It transmits data to a network of orbiting satellite receivers. This allows the information to reach researchers in near-real time.

 

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Selecting the Right Species

 

Researchers carefully choose which sharks to tag. They select species that can collect the most useful measurements. They favour sharks that surface often enough to transmit data. Frequent surfacing is essential for reliable satellite communication. This selection process maximises the value of the collected data.

Previous analyses identified several strong candidate species. These include shortfin mako sharks and blue sharks. Smooth hammerheads were also identified as suitable. Juvenile great white sharks completed the list of candidates. All are considered strong prospects for research in the North Atlantic.

 

The Science of Hurricane Intensity

 

The research targets a specific ocean characteristic. Researchers are most interested in the heat content of the ocean's top layer. This layer is known as the mixed layer. It is the part of the water column that drives hurricane intensity. Understanding it is central to predicting storm strength.

The relationship between ocean heat and hurricanes is direct. A warmer mixed layer equals a stronger hurricane. This layer holds the heat that feeds hurricanes. Measuring its heat content therefore helps assess a storm's potential. This makes the data valuable for improving intensity forecasts.

 

The Tagging Process

 

The tagging follows a seasonal schedule. It begins in early May each year. This timing coincides with highly migratory species moving closer to the coast. These sharks move in from their winter habitats further out in the Atlantic. This seasonal movement makes them accessible to researchers.

The fieldwork involves dedicated offshore expeditions. Researchers travel 30 to 40 miles offshore aboard a research vessel. They deploy baited lines and wait for a shark to take the bait. This typically takes two to three hours. Once caught, the shark is fitted with a tag before release.