UNCW marine biology professor shares what people need to know about shark bites, beach safety

University of North Carolina Wilmington marine biology professor Lawrence Cahoon explains why shark attacks are rare.
Posted 6/25/2024, 7:16:00 PM Updated 6/26/2024, 12:58:04 AM

OK

What what people need to know and I think they

probably heard it a lot is that shark attacks are

rare

Uh But I wanna give some background about why they're

rare and explain what it is that's really going on

Sharks have different sensory systems that they use to detect

prey

And we humans rely on vision and hearing uh to

find our way through the air

Sharks rely far more on their sense of hearing than

we realize

Um They're capable of hearing very very low frequency sounds

They have a sound detection system that's called the lateral

line and it's a series of pressure sensors along the

the sides of their bodies and they can hear very

low frequency sounds like the sounds made by humans swimming

or even walking in the water we can't hear those

sounds but they can low frequency sound is transmitted very

well in seawater this is how submarines use sonar for

example

And the sharks can actually hear you swimming or walking

in the water as far as a kilometer away

And so they are aware that we are in the

water

And the fact is if you go to the beach

there will be 100 or more people in the water

for each kilometer of beach and there's probably 10 sharks

in the water and they can hear each of us

The fact is they don't bother us by and large

Um about half of all shark attacks in in beach

areas are actually mistaken identities

Uh sharks are you know not intellectual giants and they

tend to explore possible new food sources and that leads

to about half of all the shark attacks that we

know about

They'll take a bite of something they think is interesting

and realize oh no that's not food and it's not

normal and they they leave

Um and so you'll get one bite and that's bad

enough

They have very sharp teeth then they leave you alone

Um There are however situations where shark attacks are much

more serious

There are a few species of sharks that are very

aggressive once they take a bite and they think ok

I'm gonna eat this

They keep coming at you

Um we had eight shark attacks in North Carolina waters

back in 2015 in a stretch of about eight weeks

or excuse me three weeks and about half of those

were single bites mistaken identity

The others were much more deliberate attacks and we suspect

that the culprits might have been bull sharks

Bull sharks are cousins of great whites

They don't get as big they're very aggressive animals

So um shark attacks again are very rare

Um the the one species that we probably need to

be most aware of in our water

If if that's possible is the bull shark

They're common in North Carolina coastal waters but most of

them most of the sharks in general will not bother

humans

They hear us they know what we are they won't

attack us and the fact is they're well aware that

we're in the water and they leave us alone

Right

Um you need to be much more concerned about rip

currents and you want to pay attention to the instructions

about that when the lifeguards whistle you to come in

when they're flying a red flag to warn about rip

currents that's really important

We have more people die from rip current accidents where

they get caught and carried out beyond their depth of

comfort than we ever will have from shark attacks

I understand there were dozens of rip current rescues just

this past weekend

That's far more dangerous to people

You gotta pay attention to the conditions on the beach

and if you don't know what a rip current is

ask a lifeguard we quite often have uh posted warnings

that explain what a rip current is

That to me is a much much greater concern than

shark attacks

Well not really

We get a few every summer

Um it's surprising that most shark attacks are in fairly

shallow water

Uh it's rare that you get a shark attack with

someone's whole body is in the water because they can

hear that you are big when you're all in the

water when you're only standing waist deep they only hear

the part of you that's in the water and they

don't realize how big you are

Um so uh I'm not surprised these things do happen

if you do the math on the number of encounters

there are you know probably thousands of sharks along the

North Carolina Beach and tens of thousands of people swimming

and you multiply that times the amount of time that

the sharks are aware of people

Uh if they really wanted to attack us there'd be

a lot more attacks and the fact is there are

very very few

So when I go to the beach I don't worry

about sharks

I'm more concerned about how rough it is and whether

or not there are rip currents that's what you really

want to pay attention to