Biting on some morsels: shark bites on the rise
Shark bites increased in 2021, after three straight years of decline, according to the Florida Museum of Natural History’s International Shark Attack File (ISAF). Researchers counted 73 unprovoked attacks worldwide last year. Although this figure is slightly higher than the global five-year average of 72, it is significantly higher than the 52 confirmed bites in 2020 – the lowest in 10 years.
“Shark bites dropped drastically in 2020 due to the pandemic. Last year was much more typical, with an average number of bites from an assortment of species and fatalities from white sharks, bull sharks and tiger sharks,” said ISAF director Tyler Bowling. .
Fatal encounters have mostly occurred in the South Pacific, peaking in 2021. In Australia, New Caledonia and New Zealand there have been six confirmed fatalities, but similar attacks have occurred in Brazil, South Africa and the United States. In most cases, Carcharodon carcharias, or the great white shark, caused the carnage.
Vacationers should know that Florida has had the most bites of any region for several decades. Blacktip sharks (Carcharhinus limbatus) probably cause the most bites in the Sunshine State. Relatively small blacktip sharks swim close to shores and shallows to hunt, but also shun larger species, such as voracious hammerhead sharks (Sphyrna mokarran) and bull sharks (Carcharhinus leucas).
“About 60% of all stings we record occur in low-visibility waters,” close to shore, said ISAF’s Gavin Naylor.
Volusia County and Daytona Beach recorded the most shark bites (17), accounting for 63% of Florida’s total, an increase from the annual five-year average. Other bite incidents in Florida have occurred in Brevard (2), Miami-Dade (2), and St. Lucie (2) counties, with single incidents in Broward, Manatee, Martin, Palm Beach counties and St. Johns.
There were 47 recorded shark bites in 2021 for the United States, making it the world leader with 64% of cases worldwide. All but five of these attacks took place along the Atlantic coast.
Australia came second with 12 bites but was first in fatalities, with three recorded. Bites were down from the annual five-year average of 16 bites, as were deaths, which fell from the six recorded in 2020. Brazil and New Zealand were also in competition for bites with three each, while Canada, Ecuador and the St. Lawrence. The archipelago of Kitts and Nevis recorded one bite each.
As shark bites resumed in South Africa in 2021 after zero incidents in 2020, the arrival of a pod of killer whales (Orcinus orca), also called killer whales, just off the coast has given swimmers and surfers to breathe a little better. The number of great white sharks near Cape Town declined dramatically when killer whales migrated to the area in 2017.
“We don’t know how often killer whales kill white sharks, but when they do they seem to have a preference for foie gras and leave the rest. As of 2021, however, white sharks appear to have migrated east, and more are now being seen along the wild coast of South Africa,” Bowling said. In 2021, there was one death and three shark bites in total.
The sharp increase in shark bites and deaths in 2021 can be attributed to the growing number of people enjoying the beaches, especially in Florida, which has the second highest population growth rate in the country. However, deaths from shark attacks are becoming rarer.
“The overall decline in shark bite mortality is likely due to a combination of improved beach safety protocols around the world and a decrease in the number of sharks of various species in coastal waters,” Naylor said. He noted that the increase in the past two years is attributable to “increased numbers of white sharks, which have increased in various localities, likely in response to a boom in the seal populations on which they prey.”
Of those bitten by sharks, 51% were surfers or boarders. The narrow strip of water known as the surf zone is where the waves tumble and create an ideal environment for sharks and surfers. Shallow waters and choppy waves stir up sediment, obstructing sharks’ vision, prompting them to munch on anything. The study indicated that in 39% of bite cases, the victims were swimming or wading.
Surf areas are where a variety of fish forage for food, such as algae and invertebrates. This activity in the area attracts sharks.
“For blacktip sharks in Florida, it’s most often a matter of mistaken identity,” Bowling said, explaining how a shark might bite a human rather than its daily meal. The ISAF advises swimmers to avoid shiny jewelry that could attract sharks and not to swim at night or at dusk.
Edited by Siân Speakman and Kristen Butler