If the prospect of sharks and inclement weather has you reaching for your skewering flag, we’ve got some reassuring research detailing what really goes on when sharks and hurricanes collide. Published in the journal Estuarine, Coastal and Shelf Science, the study investigated the behavior of large sharks in Miami and the Bahamas and how it changed leading up to serious storms. The researchers used tagged animals for the data, revealing the locations of tiger sharks (Galeocerdo cuvier), bull sharks (Carcharhinus leucas), nurse sharks (Ginglymostoma cirratum), and great hammerheads (Sphyrna mokarran) before, during, and after Hurricane Matthew in 2016 and Hurricane Irma in 2017.
Fortunately (or unfortunately, depending on your feelings towards low-budget sci-fi movies), sharks encountering severe weather do not band together to form a Sharknado. What actually happens when you combine sharks and storms is dependent on the species and location you are investigating. Bull sharks, great hammerheads, and the majority of tagged nurse sharks demonstrated that they weren’t so keen on Hurricane Irma, fleeing the shallow waters of Biscayne Bay as she made ground. The move is perhaps a logical one, considering deeper waters will be less disturbed by all the drama, and potentially helped along by their ability to orientate themselves with the geomagnetic field.
Tiger sharks, it seems, don’t give a crap. These large predators appeared to welcome the category 5 Hurricane Matthew as they remained in shallow inshore waters even when the eye of the storm was directly on them. Their numbers also doubled just after the storm had passed.
"I was amazed to see that big tiger sharks didn't evacuate even as the eye of the hurricane was bearing down on them, it was as if they didn't even flinch," said Neil Hammerschlag, a research associate professor at the UM Rosenstiel School and the Abess Center for Ecosystem Science and Policy in a statement. "Their numbers even increased after the storm passed. We suspect tiger sharks were probably taking advantage of all the new scavenging opportunities from dead animals that were churned up in the storm."
Beyond being an excuse to ask your art director to insert some spinning sharks into a stock photo of a tornado [thanks Chris], the research’s findings are a valuable tool in better understanding the fate of these apex predators in the ongoing climate crisis. With inclement weather becoming increasingly common on a warming planet, understanding the impact of storms could inform predictions as to how these marine species may respond to future changes.
"Major storms, like hurricanes, are predicted to increase in frequency and strength with climate change," continued Hammerschlag, who is also the director of the University's Shark and Research Conservation Program. "How these storms impact the environment, including large sharks, is of interest and conservation concern to many."