Consistent with the 2018 data, the number of unprovoked shark attacks remained remarkably low in 2019. However, one elusive shark species has become more aggressive toward humans.
New data from the University of Florida’s International Shark Attack File (ISAF) — the world’s “comprehensive database of all known shark attacks” — show that unprovoked shark attacks remained infrequent in 2019.
Scientists in charge of ISAF define “unprovoked shark attacks” as attacks that take place in the shark’s natural territory and do not involve the human trying to initiate interaction.
ISAF data indicate that over the past decade, there have been 799 unprovoked shark attacks worldwide. Yet in 2018, and again in 2019, the numbers were remarkably low.
Last year, there were 64 unprovoked shark attacks in total, with only two more cases than in 2018, when scientists registered a total of 62 such attacks worldwide.
The number of registered attacks in 2019 is also 22% lower than the average of 82 cases per year over the 2014–2018 period.
Two of the shark attacks last year proved fatal, but this number, once more, is lower than the average of four shark attack-related deaths per year. Researchers are not quite sure what could explain this change.
“We’ve had back-to-back years with unusual decreases in shark attacks, and we know that people aren’t spending less time in the water,” says Gavin Naylor, director of the Florida Museum of Natural History’s shark research program.
“This suggests sharks aren’t frequenting the same places they have in the past. But it’s too early to say this is the new normal,” Naylor cautions.
The ISAF report shows that one trend has remained consistent, however: Once again, most of the unprovoked shark attacks occurred in the United States, which registered as many as 41 such cases last year.
This number was, in fact, higher than the 32 unprovoked attacks that people reported in the U.S. in 2018 but lower than the 5 year average of 61 attacks per year.
Among the U.S. states, Florida led with 21 unprovoked shark attacks, and Hawaii followed with nine cases.
Other than the U.S., only Australia reported a relatively high number of unprovoked shark attacks last year: 11 cases. This country, too, however, saw a decrease from its recent 5 year average of 16 attacks per year.
The Bahama Islands followed, with two cases of unprovoked shark attacks in 2019.
The Canary Islands, Caribbean Islands, Cuba, French Polynesia, Guam, Israel, Mexico, New Caledonia, South Africa, and Réunion Island reported one case each.
South Africa has notoriously been the home of many different shark species, but new reports suggest a decrease in the shark populations in that area.
“The news coming out of South Africa is that they’re not seeing as many sharks,” says ISAF manager Tyler Bowling.
“White sharks have been moving out of some areas as pods of orcas move in, and there are reports that sharks are disappearing along the whole Cape,” he adds.
ISAF scientists also note that although the number of unprovoked shark attacks has declined overall, one typically elusive shark species appears to have become more aggressive toward humans.
The so-called cookiecutter shark (Isistius brasiliensis) — which reaches no more than 56 centimeters (22 inches) in length — has bitten three long-distance swimmers who were training in the Kaiwi Channel in Hawaii at night.
ISAF researchers say that they only have two previous reports of cookiecutter shark bites: one in 2009 in Hawaii, and one in 2017 in Australia.
It appears that this is the first time that this shark species has struck three times in the same year, unprovoked.
Naylor explains that researchers still do not know much about cookiecutter sharks except that, although they look unimpressive, their bite can be very dangerous.
“They’re quite mysterious animals. While they’re found all over the world, we don’t know how many of them there are, or how exactly they create this seemingly perfect circle [when they bite their prey],” says Naylor.
“They can look pretty pathetic, like a lazy sausage, but they can do a lot of damage,” he goes on to note.
The ISAF also report some marked changes in shark behavior. Most notably, they say that anglers fishing on the U.S. East Coast have been alarmed to see an increase in large numbers of sharks following fishing boats and eating captured fish on the line.
These sightings could be an indication that shark populations, in general, may be increasing, although Naylor and Bowling advise against jumping to any such conclusions just yet.
“Shark aggregations are highly localized. We haven’t yet seen census data that show shark numbers are bouncing back,” says Naylor.
The scientists also say that anglers have reported finding fewer available fish, which could mean that sharks have started following fishing boats to get an easy meal.
“If [the sharks’] resources are thin, they’re going to go to places that are more reliable, and if that means fishing boats, that’s where they’re going to go. That exacerbates problems for fishermen.”
– Gavin Naylor
Bowling also notes that the sheer proximity of sharks to humans as they approach fishing boats may lead to incidents.
“[Sharks] associate [boat engine] noise with food,” notes Bowling.
Despite the lower number of reported unprovoked shark attacks last year, ISAF specialists still urge people who fear coming into contact with sharks to follow ISAF guidelines on minimizing the risk of getting bitten.