After three consecutive years of worldwide declines, the number of shark bites increased in 2021, with a total of 73 unprovoked incidents.
The data, released this week by the Florida Museum of Natural History’s International Shark Attack File (ISAF), also included 39 provoked shark bites and nine deaths that occurred throughout the year.
The number of unprovoked bites in 2021 aligns with the five-year global average of 72 a year, but contrasts sharply with the 52 confirmed bites recorded in 2020, which was the lowest documented in more than a decade. While the exact cause of the reversal is unclear, ISAF Manager Tyler Bowling attributes some of the trend to beach closures associated with COVID-19 restrictions.
"Shark bites have dropped dramatically in 2020 due to the pandemic. Last year was much more typical, with an average of bites from a variety of species and deaths from white sharks, bull sharks and tiger sharks."Bowling said.
The number of fatal unprovoked shark encounters also remained high in 2021, with the majority taking place in the South Pacific. There were six confirmed deaths in Australia, New Caledonia and New Zealand, while single incidents occurred in South Africa, Brazil and the United States. Great white sharks (Carcharodon carcharias) were characteristically the main culprits in unprovoked deaths.
While IFAS investigates all reported shark bites, it emphasizes those that were unprovoked, which are defined as incidents that occurred in the shark’s natural habitat without human provocation. These help researchers understand the natural behavior of animals, which can help develop mitigation measures.
The United States continues to lead in the annual number of shark bites, totaling 47 in 2021, accounting for 64% of global cases. Of these, all but five took place along the Atlantic coast.
As in previous years, Australia had the second highest number of stings globally, with 12 in total, down from its five-year global average of 16 stings. Australia also had three deaths, which, while down from six last year, was still the highest tally of any country in 2021. Brazil and New Zealand each had three stings, while Canada, Ecuador and St. Kitts and Nevis followed with individual incidents.
Shark bites have resumed in South Africa in 2021 after zero reported incidents the previous year. Great white sharks are thought to be common off the coast of Cape Town, but after a pod of killer whales (Orcinus orca), which are known to feed on sharks, migrated to the region in 2017, shark sightings whites became rare.
"We don’t know how often killer whales kill white sharks, but when they do, they seem to have a preference for fatty liver and leave the rest behind. However, as of 2021, white sharks appear to have migrated east, with more now being seen along the wild coast of South Africa."Bowling said. As a result, three shark bites were reported for the country in 2021, one of which was fatal.
Despite the relaxation of COVID-19 travel and recreational restrictions, reports of shark bites remain spotty as first responders and medical examiners continue to deal with a high number of deaths due to the virus. As a result, the number of unconfirmed shark bites in 2021 was high for the second year in a row, with 14 putative incidents still under investigation and one occurrence where a designation could not be made.
While last year saw a dramatic increase in shark bites and a large number of deaths, both remain well within long-term averages. As more people flock to the warm beaches, shark encounters have become more common, especially in Florida, which has the second-highest rate of population growth in the United States. However, deaths, in the long run, are becoming less frequent.
Surfers and sharks share an ideal environment
"The overall decline in shark bite mortality is likely due to a combination of improved beach safety protocols around the world and a decline in the number of sharks of various species in coastal waters"said Gavin Naylor, director of research for the Florida Museum’s shark program. "The increase in 2020 and 2021 is almost certainly due to increasing numbers of white sharks, which have increased in several locations, likely in response to a boom in populations of the seals they feed on.".
The majority of people (51%) bitten by sharks were surfers or snowboarders, who spend a significant amount of time in the water in and around surf breaks. This thin strip of water, where incoming waves that may have traveled hundreds of miles eventually catch on the rising coastal seafloor and crash down, creates the perfect environment for surfers and sharks alike.
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