Shark attacks: After recent bites, your questions answered

Shark attacks have been rising steadily
for more than a century.

Over the past several summers, a number
of high-profile shark attacks have been seen in the U.S., from
North Carolina to Hawaii. Still, officials say beaches remain safe
to visit, since the incidents are statistically very rare. An ocean
swimmer has only a one in 11.5 million chance of being bitten by a
shark, according to the museum^[1].

In recent years, North Carolina’s beach
officials have said any shark “acting
aggressive^[2],” such as swimming
within 100 feet of the shore, could be euthanized. That order
prompted criticism from shark experts, who said the shark or sharks
involved in attacks would likely not be in the area
long.

Here are some more things you should know
about sharks and shark attacks:

What kinds of sharks attack
humans?

George Burgess^[3], who studies shark
attacks at the Florida Museum of Natural History, says coastal
incidents are often caused by tiger or bull sharks. Those two
species are often found right along the coast and are known to
occasionally bite people.

Great white sharks, immortalized by Jaws, are also
occasionally responsible for attacks on people. Other sharks
involved in incidents around the world in recent years occasionally
include mako, nurse, lemon, and spinner sharks.

Why do sharks attack people?

Burgess writes on his website in clear terms that “humans are
not on the menu of sharks. Sharks bite humans out of curiosity or
to defend themselves.”

As a result, the majority of incidents over time have tended to
be what’s called “provoked” attacks, in which someone is bitten
while spearfishing or while trying to catch a shark or release it
from a line or net. Among unprovoked attacks, the fish are most
often confusing people with their normal prey, often due to poor
visibility. Surfers are most often involved, most likely because
they spend long periods of time in the water and often splash
around like prey.

Why are shark attacks rising?

Although individual years have so few shark attacks that
statistical analysis in the short term is dicey, the long-term
trend shows an increase in incidents. Part of that is likely due to
better reporting, according to the Florida Museum of Natural
History.

But beyond that, the most likely explanation for rising numbers
of attacks is the “ever-increasing amount of time spent in the sea
by humans, which increases the opportunities for interaction
between the two affected parties,” according to the museum. A
steadily rising human population is also a big factor.

What should I do if a shark starts attacking me?

Hit it in the nose, which is often enough to end the attack,
says the museum. Then head for shore.

If that doesn’t work, claw at its eyes and gill openings, two
sensitive areas. “One should not act passively if under attack,”
the museum says, because “sharks respect size and power.”

How do I reduce the odds of an attack?

People should remember that swimming in the ocean is always “a
wildlife experience,” says Burgess. There are some ways to better
your already very low odds of getting attacked. For one thing, it’s
a good idea to avoid known shark nursery grounds, as
tourists recently discovered in Recife, Brazil^[4].

Shark safety researcher Christopher Neff^[5]
suggests avoiding
swimming during or after storms^[6], which can make the
water cloudy and churn up the bait fish that lead to shark feeding
frenzies. Neff also suggests avoiding swimming at dawn and dusk,
for the same reasons, as well as swimming near the presence of
seals or other prey species or where fishermen have dumped
guts.

It’s also a bad idea to feed sharks, which can confuse them or
teach them to associate people with food.

Are there other shark safety tips?

Sharks can be attracted to blood, so people should avoid
swimming with open wounds. Shiny objects can also attract sharks,
who are naturally curious.

Neff suggests avoiding swimming alone or going too far away from
shore. He also says people should avoid splashing around too
much.

“There are a number of stories about the way playing ‘shark
attack’ in the water attracted a shark to the area,” he
says^[7].

Do anti-shark wetsuits or repellents work?

“I seriously doubt that will work,” shark ecologist Bradley
M. Wetherbee^[8] of the University of
Rhode Island told National Geographic.

Other research has investigated the efficacy of chemical^[9]
and even electrical^[10] repellents, though more
work needs to be done.

Is euthanizing sharks off beaches effective?

No, says Burgess. Sharks are highly migratory fish that can swim
thousands of miles in a season, so targeting them in one place
doesn’t make sense. Recent attempts to cull
great white sharks^[11] to reduce attacks on
people in Western Australia have met with sharp criticism from
scientists.

Shark culls performed in Hawaii in the 1950s showed “no
measurable effect on the rate of shark attacks on people,” said
Chris Lowe^[12], professor of marine
biology at California State University, Long Beach, who analyzed the
data^[13] taken during those
culls.

Does the economy affect shark attacks?

Aren’t more sharks killed by humans than the other way
around?

Yes, by a huge multiple. Experts estimate that around 100
million sharks are killed by people every year^[14], in a haul that many
consider unsustainable and which threatens many species. Sharks
reproduce slowly so they are particularly vulnerable to
overfishing.

Sharks are harvested for their fins, considered a delicacy in
some Asian countries, and are collected for their meat and skins.
They are also frequently ensnared in fishing gear as unwanted
“bycatch.”

If many sharks are in trouble, how could attacks
increase?

A rising number of countries, from the U.S. to the South
Pacific, are passing and enforcing bans on shark fishing, and the
fish are showing some localized signs of recovery as a result.
However, the overall conservation picture remains dim, especially
with illegal fishing^[15].