Today’s society is more educated about sharks and shark behavior than our forefathers. In the 18th, 19th, and much of the 20th century we thought of sharks as mindless eating machines – consuming anything available. Whalers would witness sharks consuming carcasses, as did many other fishermen. Sailors noted sharks following the smaller boats across the ocean, always present when bad situations occurred.
During World War II the U.S. Navy was moving across the Pacific and a deeper understanding of sharks was needed to keep servicemen safe. The sinking of the USS Indianapolis pushed the Navy into a larger research program to determine how to repel sharks and better understand what made them tick. After the war funding for such research continued. One of the leading researchers was Dr. Eugene Clark, who eventually founded the Mote Marine Laboratory in Sarasota with the intention of developing a better understanding of shark behavior. Dr. Clark frequently appeared on the Undersea World of Jacques Cousteau educating the public about how sharks function and respond to their environment. All with the idea of how to better reduce negative shark encounters.
In the 1970s Peter Benchley wrote Jaws but included a marine biologist as one of the key characters who would provide science insight into how sharks work. The film was a cultural phenomenon. I remember standing in a line that wrapped the cinema twice to get in. This was followed by more funding for shark research and a better understanding of how they work. This was then followed by a popular summer series known as “Shark Week”, which remains popular to this day. Many of the old tales of shark behavior were disproved or explained. The idea of a mindless eating machine was replaced with a fish that actually thinks and responds to certain cues. People began to realize that shark attacks are quite rare and could be explained if we understood what happened leading up to the attack.
We now understand that sharks are fish, in a class where the members have cartilaginous skeletons (they lack true bone). They are one of the most perceptive creatures in the ocean, using their senses to detect potential prey and that there are signals that can “turn them on”. On the side of their bodies there is a line of small gelatinous cells that can detect slight vibrations in the ocean – from up to a mile away. The ocean is a noisy place, and it appears that sharks respond to different frequencies. I like to use the analogy of yourself being in a large student cafeteria. Everyone is talking and it is very noisy. Then someone calls your name. Somehow, amongst all the background clatter, you hear this and respond to it. Studies suggest that sharks do the same. With all of the noise moving though the ocean, sharks hear things that catch their attention and then move towards the source.
Blacktip sharks are one of the smaller sharks in our area reaching a length of 59 inches. They are known to leap from the water. Photo: Florida Sea Grant
As they get closer their sense of smell kicks in. Everyone has heard that sharks can detect small amounts of blood in large amounts of seawater – remember “Bruce” from Finding Nemo? It is true, but they do have to be down current to pick up the scent and they will now focus their search to find the source. Some studies suggest other “odors”, such as the urine of seals, might produce the same reaction that blood does. All may lead to shark to think a possible meal is nearby.
Eyesight is not great with any creature in the sea. Light does not travel well in water – but sharks do have eyes and they do see well (one of the old tales science disproved – that sharks are basically “blind”). However, because of the low light, they do have to be close to the target to get a visual. Some studies suggest that sharks are detecting shadows or shapes they may confuse as a potential prey, bite it, and then release when they discover it was not what they thought it was. This idea is supported by the fact that many who are bitten experience what is called “bite and release” – and they turn and swim away. It is also known that sharks have structures in the back of their retinas that act as mirrors, collecting what light is available, reflecting it within the eye, and illuminating their world. They believe they see pretty well at night – better than us for sure. The image they see may appear to be a prey item and may be what is producing the vibrations and odors that they detected.
The Scalloped Hammerhead is one of five species of hammerheads in the Gulf. It is commonly found in the bays. Photo: Florida Sea Grant
And they have one more “sixth sense” – the ability to detect weak electric fields. The shark’s mouth is not in position to attack prey as they move forward. It is on the bottom of their head and, one of the old tales, was that sharks must swim over their prey to bite it. Video taken during the filming for Jaws showed that the shape of the shark’s head changes at the last moment of an attack. The entire head becomes distorted to get the mouth in the correct position for the bite. The “eyes roll back” – as the old fishermen used to say – and the jaws move up and forward. At this point the shark can no longer use its eyes to zero in on the target. However, they have small cells around their snout called the Ampullae of Lorenzini that can detect the small electric fields produced by muscle movement – even the prey’s heartbeat – and know where they are. But – they must be very close to the prey to detect this.
Understanding all of this gives scientists, and the public, a better idea of how sharks work. What “turns them on” and how/when they will select prey. One thing that has come from all of this is that we do not seem to be high on their target list.
The Great White shark. Photo: UF IFAS
The International Shark Attack File is kept at the Florida Museum of Natural History in Gainesville. It has cataloged shark attacks from around the world dating back to 1580. The File only catalogs UNPROVOKED attacks. With provoked attacks – those occurring while people are grabbing them, or fishing for them, or in some way provoked an attack – we understand why the shark bit the human. It is the unprovoked attacks that are of more interest. Those where the person was not doing anything intentionally to invite a shark bite, but it happened.
One thing we can tell from this data is that unprovoked attacks are not common. Since 1580, they have logged 3,403 unprovoked shark attacks worldwide. Considering how many people have swum in the ocean since 1580, this is a very small number. Note, the File is only as good as the reports it gets. In the past, many unprovoked attacks were not reported. But in our modern age of communication, it is rare that such an attack does not make the headlines today.
The Bull Shark is considered one of the more dangerous sharks in the Gulf. This fish can enter freshwater but rarely swims far upstream. Photo: Florida Sea Grant
Of these attacks 1,640 (48%) have occurred in the United States, followed by 706 in Australia. Many have explained this by the large levels of water activities people in both countries participate in. In the US Florida leads the way with 928 unprovoked attacks (57%), most of these (351 – 34%) are from Volusia County. This may be due to breakthrough emergency communications with Volusia County and thus more reports. Many of the reports are minor, small bites from small sharks such as blacktips, but unprovoked none the less. There are 26 unprovoked attacks logged from the Florida panhandle – 3% of the state total – and most of these (n=9) were from Bay County.
When looking at what people were doing when attacked, most were at the surface and participating in some surface water activity such as surfing, skiing, boogie boarding, etc. This is followed by surface swimming or snorkeling.
This brings us to the attacks this summer in the panhandle. There have been a lot of questions as to what may have caused them. They are still assessing the situation before and during these attacks to try and determine why they happened. As we have mentioned, we have learned a lot about sharks and shark behaviors over the last 50 years and several hypotheses are open for discussion. We will see what the investigators learn. Until then, the International Shark Attack File does offer a page on how you can reduce your risk. There is “Advice to Swimmers”, “Advice to Divers”, “Color of Apparel”, “Menstruation and Sharks”, “Quick Tips”, “Advice to Spearfishers”, and “How to Avoid a Shark Attack”. Read more on these tips at https://www.floridamuseum.ufl.edu/shark-attacks/reduce-risk/.
This is not a word that most visitors to the beach want to hear. However, shark attacks are actually not that common and the risk is very low. People hear this every year on shark programs, but it does not seem to make them feel any better. Here is what the International Shark Attack File says (as of 2020)…
–Since the year 1580 there have been 3164 unprovoked shark attacks around the world.
Let that sink in for a moment… 3000 unprovoked attacks on humans in the last 440 years.
Now consider the number of car accident victims that have occurred in the last month within the United States. See what they are getting at? Let’s look at more…
–Of the 3164 reported unprovoked attacks (yes… these data only include what was reported) 1483 were from the United States… 47% of them. This may be due to the fact we are “water people”. The other top countries are Australia, South Africa, and Brazil, all “water people” as well.
–Of the 3164 reports 851 were from Florida (27%). This is the number of reported shark attacks in our state since the Spanish settled it. This comes out to 2 each year – though the data shows a sharp increase in attacks starting in the 1970s (most have occurred since then).
–Of the 3164 reports 25 were from the panhandle region (0.8%) and 7 from the Pensacola Bay area (0.2%).
Let that sink in for a moment. Seven reported attacks from the Pensacola Beach area since the time DeLuna landed here in 1559… 7.
And lets once again consider the number of vehicle accidents that will occur in the bay area today.
These numbers have been posted before. Yet people are still very worried when the hear sharks are in the Pensacola Beach region. When attacks occur, they are big news. The International Shark Attack File does give trends and suggestions on what to do. But as many say, sharks are the least of your worries when you are planning a day at the beach.
Now that we have said all of that, they are truly amazing animals.
They are fish but differ in that their skeletons lack hard calcified bone – they are cartilaginous. There are 25 species in 9 different families in the Gulf of Mexico. Many are completely harmless – 13 of the 25 have been reported to have had unprovoked attacks somewhere around the world – the white, tiger, and bull sharks leading the way. Several rarely come close to shore.
Sharks lack a swim bladder and thus cannot “float” in the water column the way your aquarium fish do. Some, like the nurse and angel sharks, rest on the bottom. Others, like the white and blue sharks, swim constantly to get water flowing over their gills.
Because of this, they are very streamlined with reduce scales. They actually have modified teeth for scales – called placoid scales. Their fins are angular and rigid (as are other open water fish) and some can swim quite fast – makos have been clocked at over 30 mph for short distances. Many have seen video of large white sharks exploding with a burst of speed on a sea lion and actually leaping out of the water with it.
Many species do lay eggs, but others keep the eggs within and give live birth after they hatch. One species, the sand tiger, produce four embryos within the mother. The first to hatch consumes the other three!
The teeth of sharks are famous. Rows of them, some pointed, some are serrated, all are designed to cut and swallow. The tiger shark has a serrated tooth that is angled like a can opener. They can use this to “open” sea turtle shells – adding them to their rather large menu. They “shed” these frequently – placing a new sharp tooth where the dull old one was – and will go through tens of thousands of teeth in a lifetime.
The sensory system is one of the most amazing in the world. Tiny gelatinous cells along their sides, called the lateral line, detect pressure waves from great distances. Splashing, thrashing movements made by fish can be detected a mile away – and get their attention. As they approach the sound their sense of smell kicks in. It has been said that a shark can detect one drop of blood in thousands of gallons of water – and it is true. However, the sharks must be down current of the victim to detect it. Their eyes are much better than most think. They have “crystals” within their retina that act as mirrors reflecting light that enters. Imagine turning on a flashlight in a dark room. Now imagine doing this if the walls and ceiling were mirrors – you kind of understand how they can actually see pretty well even in the low light. That said, light does not travel well under water, so they rely on their other senses more. And as if that were not enough. They have small gelatinous cells around the head region that can detect small electric fields. When a shark bites, it must close its eyes and – as the fishermen say – “roll back” out of the head. At this point the shark is basically blind and cannot see the target it is trying to bite. However, if you move out of the way, the weak electric fields produced by your muscles in doing so can be detected by these cells and the shark knows where you are.
Cool – and scary at the same time. Let’s meet a few of these amazing fish in our area.
The nurse shark. Notice the barbels (whiskers) on its head. Photo: NOAA
NurseShark
This is one of the bottom dwelling sharks that appear harmless – and they are – but if provoked, they will bite. They have less angular fins, or a brownish-bronze color, and really like structure – they are found on our reefs. They posses a “whisker-like” structure called a barbel. These are common on other bottom fish, like catfish, and possess chemo-sensory cells to detect prey buried in the sand. They are not as common here as they are in the Keys, but they have been seen. They can reach lengths of 14 feet.
Blacktip sharks are one of the smaller sharks in our area reaching a length of 59 inches. They are known to leap from the water. Photo: Florida Sea Grant
Blacktip – Spinner
These are grouped together because (a) they resemble each other, and (b) they are both common here.
They are both stream-lined in shape and have blacktips on their fins. Actually, spinner sharks have more fins tipped-black than the blacktip. The anal fin of the spinner is tipped black, but this is not the case for the blacktip. The spinner gets its name from the habit of leaping from the water and spinning very fast as it does so. Both are quite common in the Gulf and the bay. They reach about eight feet in length and unprovoked attacks are very rare.
The Scalloped Hammerhead is one of five species of hammerheads in the Gulf. It is commonly found in the bays. Photo: Florida Sea Grant
Hammerheads
This is a creepy group – check out the head. It is one that many people fear, and unprovoked attacks have occurred. The reader may not know that there are more than one kind – five species actually. They have a tall dorsal fin which sometimes extends above the water when swimming near the surface – the classic “shark is coming” look. Their heads are aerofoil shaped and there are several possible explanations for this. 1) It is more aerodynamic, making it easier for this ram-jetter to swim, using less energy to do so. 2) It is a battery of sensory cells. By swinging the head back and forth, as they do, it is an advanced radar searching for prey, possibly finding it before other sharks do. There are stories of hammerheads arriving first. 3) It is also believed they use their electric sense to detect buried prey – the shape making this easier to find and expose them. It could very well be that all of these could explain the shape.
This pregnant bull shark has an impressive girth.
Bull Shark
Since the film Jaws the world has turned its attention from solely the white shark – to the bull shark. As you can imagine, it is hard for a shark attack victim to tell you which species bit them – “I don’t know… it was a big gray thing chomping on my leg!” or “It was a great white!” because that is the only one many know. But studies sine the 1970s suggest that the bull shark is an aggressive species and may be responsible for a lot of attacks. Particularly in the estuaries and upper estuaries. Bull sharks are what we call euryhaline – they have tolerance for a wide range of salinities. This shark has been reported in low salinities of the upper estuaries and even into freshwater rivers. One report had them over 100 miles from the coast – they are certainly where the people are.
The extremely long upper lobe of the thresher shark. Image: NOAA
ThresherSharks
These are bizarre looking sharks. Most sharks have what we call a heterocercal tail – different – different meaning the upper lobe of the forked tail is longer than the lower. But the threshers take this to the extreme – the tail can make up almost half of their body length, which can be 20 feet. It is believed that use this extremely long tail to herd and stun baitfish – their favorite prey. They prefer colder waters and records in the Gulf are not common. Those that exist suggest they live offshore and are rarely encountered near beaches. There are no unprovoked attacks reported from this shark.
The massive whale shark. Photo: Florida Museum of Natural History.
WhaleShark
Amazing… heart stopping… what else can you say. Encounters with the largest fish on our planet are rare – but when they do happen you will never forget it – it will be one of the highlights of your life. As the name suggest – these are large sharks, with a mean length of 45 feet but some reporting in at 60 feet. They are easily recognized first by their size, but also their coloration. They are brownish color with beige or white spots in nice rows running across the dorsal side. They swim slowly filtering plankton from the sea – though will occasionally take in a fish. Some reports show them vertical in the water column moving up and down filtering from a school of plankton or tiny fish. They are rarely seen because they tend to dive deeper during the day with the plankton layer – then surfacing at night following the same plankton. They are, unfortunately, sometimes struck by boats while at the surface.
The recent attacks on swimmers in North Carolina have once again brought up the topic of sharks. And of course, “Shark Week” is coming up. It is understandable why people are concerned about swimming in waters were animals weighing several hundred pounds with rows of sharp, sometimes serrated, teeth are lurking. It is also understandable that local tourism groups are concerned that visitors are concerned. Sounds like the movie Jaws all over again.
The Bull Shark is considered one of the more dangerous sharks in the Gulf. This fish can enter freshwater but rarely swims far upstream. Photo: Florida Sea Grant
So, what is the risk?
It is good question to ask for anything we feel uncomfortable with. Hiking in Rockies where bears might roam. Hiking in wetlands of Florida or deserts of the American southwest where venomous snakes may lurk. Paddling the creeks and rivers of the American southeast where alligators could be basking. All are concerns.
According to G. Tyler Miller and Scott E. Spoolman, a risk is the probability of suffering harm from a hazard that can cause injury, disease, death, economic loss, or damage. There is a difference between possibility and probability. There is always the possibility of a shark attack, but what is the probability it will happen? Unfortunately, media blast can create a scare over a highly unlikely possibility without discussing the data driven probability of it happening. We all take risk every day – riding in a car, smoking, drinking alcohol, eating bad food – which can lead to heart issues and the number one killer of humans worldwide, and more. Many of these we do not consider risky. We feel we are in control, understand the risk, and are managing from them. Those risk we have little control over – shark attacks – seem more of a risk than they really are. The car is far more dangerous, yet we do not hesitate to get in one at zoom onto the interstate.
Let’s conduct a simple risk assessment of shark attacks…
What is the hazard of concern?
Being attacked by a shark
Dying from the shark attack
How likely is the event?
The International Shark Attack File was first developed after World War II to address the issue of shark attacks on US Navy personnel, but expended to everyone. It was originally housed at the Smithsonian Institute but is currently housed at the Florida Museum of Natural History in Gainesville. Based on their records of unprovoked shark attacks (the ones we are truly interested in) there have been 3103 attacks on humans since 1580. 46% of those were in the United States, ranking us #1. Number two and three are Australia and South Africa. So as far as nations go, we are number one for attacks. However, this equates to 7 attacks / year – worldwide. And not all of those died. Most did not.
Which state?
Since 1837, 828 attacks (57%) occurred in Florida. This equates to 4.5 attacks / year. Florida is number one, followed by Hawaii and California.
What about counties in Florida?
Since 1882 there have been 303 attacks (36%) in Volusia County. This equates to 2.2 attacks/year. The total number of attacks in Florida panhandle counties since 1882 have been 25 – this is 0.2 attacks/year for the entire panhandle.
What were these Floridians and visitors doing when they were attacked?
Surface recreation (surfing, boogie boarding), swimming, and wading top the list, the other activities were logged.
So, there have between 8-10 shark attacks each year, and two fatalities, worldwide.
The white shark is responsible for more attacks on humans than any other species. It is found in the Gulf of Mexico in the winter months but there are no reports of attacks in Florida. Photo courtesy of UF IFAS
The Risk Assessment is used to develop a Risk Management Plan
First, How do these shark attack data compare with other risks?
I wondered how many car accidents occur each year worldwide?
According to USA Insurance Coverage, who got their data from the National Highway Traffic Administration – 5,250,000 each year in the United States alone. About one every 60 seconds.
Situations that cause human deaths annually in the United States
Heart disease 652,486 1 in 5 people
Cancer 553,888 1 in 7
Stroke 150,074 1 in 24
Shark attack1 1 in 3,748,067
Between 1992-2000 there were 2 shark attacks in Florida. In that same time period, there were 135 drownings.
Between 2004 and 2013, 361 people drowned in rip currents. During that same period, 8 people were attacked by sharks.
Between 1990 and 2009, in Florida, 112,581 people were involved in bicycle accidents; 2272 died. In that same period, there were 435 shark attacks in Florida; 4 died.
And my favorite…
Between 1984 and 1987, 6339 people had to visit a hospital in New York City because they were bitten by a human. This was 1585 / year. In that same period there were 45 shark attacks in the entire United States. This was 11 / year.
Second, How should we reduce the risk of shark attack?
Well… as you can see from the assessment and comparative risk analysis, many would say you did not need to develop a plan to reduce risk because the risk is too low to fool with. You should spend time on hazards that are of a more real concern. That said, there are some things you can do.
– Avoid excessive splashing; it is known that sharks are attracted to this. It is also known that more often than not, they move away when they detect the source of the splashing.
– Avoid swimming when bleeding or in water with strong smells (like fish bait); this too will attract them.
– Most unprovoked attacks occur between 11:00 AM and 3:00 PM. But honestly, that is when most people are in the water. This could be different if most of us swim after sunset. That said, we recommend that you reduce swimming at dawn and dusk.
I hope this clear up some of the concerns about shark attacks. Yes, they do happen – but infrequently. There are some things you can do to reduce your risk, but these should not keep you from enjoying water related activities. Enjoy your time here on the Gulf coast. Be careful driving and try to eat healthier.
In recent weeks, the country has heard about shark attacks off the Carolina coast and great whites off the northern coast of the Gulf of Mexico – then of course, we just completed “Shark Week”. This sometimes makes visitors to our beaches a bit unnerved about swimming. Each year we hear about how other activities we engage in are much more dangerous than swimming in the Gulf where there are sharks – and this is true – but we may still have a concern in the back of our minds. So – we will give you some information that will hopefully enlighten you on the issue of sharks.
First, what kind of sharks are in the Gulf and how common are they?
According to Dr. Hoese and Dr. Moore from Texas A&M, there are 30 species of sharks who have been found in the Gulf of Mexico – and this includes the great white. They range in size from the Cuban Dogfish (3 ft.) to the whale shark (60 ft. in length). Each has their own niche. Some, like the large whale sharks, are plankton feeders. Others, like the blue and mako, are open ocean travelers covering large stretches of water hunting prey. Others, like the blacktip and spinner, are more common near shore – close to estuary outfalls where food is plentiful. And others still, like nurses sharks, are bottom dwellers feeding on slow fish and crustaceans.
The Bull Shark is considered one of the more dangerous sharks in the Gulf. This fish can enter freshwater but rarely swims far upstream. Photo: Florida Sea Grant
As far as how common they are – I was involved in shark tagging in the early 1980’s and we tagged several species. Blacktips and spinner sharks were very common. We also tagged a lot of bull and dusky sharks – though dusky sharks are declining. Tiger sharks were not as common at the time. It was believed this was due to an increase in shark rodeos in the 1970’s – which were popular during the “Jaws” films. However, those events stopped for several years and recent shark events have once again captured tigers. There are five species of hammerheads that were tagged – the scalloped and bonnethead were the most common. White sharks and makos are in the Gulf but were never tagged. It was believed they spent more time offshore (where we were not sampling). Both species have been seen closer to shore in recent years, but there are no reports of any problems from this. It is possible they have been doing this all along and were just undetected. Blacknose, finetooth, and silky sharks were also frequently tagged.
People are probably not surprised to hear that sharks frequent the bays. Many of the species mentioned above do so. The small (3 ft.) Atlantic sharpnose shark is one of the most common. Sawfish were once common in the estuaries but have declined significantly across the region to do over harvesting in the early 20th century. They are currently protected.
You have probably also read that bull sharks have been found in freshwater rivers – and this is the case. Some have been found several miles up river systems.
What type of prey do sharks prefer and how to do they select and hunt for them?
This, of course, varies from species to species. Plankton feeding whale sharks generally cruise slowly through the water column filtering small fish and crustaceans – the same as the great whales. They do tend to feeding in deeper water during the day and closer to the surface at night. They are following what is known as the Deep Scattering Layer. This is a large layer of zooplankton (animal plankton) that migrates each day – deeper (600 feet or so) during the daylight hours and closer to the surface in the evenings.
Bottom dwelling sharks feed on benthic creatures like flounder and crabs. Many have the ability to detect their prey buried beneath the sand using electric perception they have.
Many species of sharks are what we call “ram-jetters”. This means they do not have a pump system to pump water over their gills. So, in order to breath, they must swim forward. Swimming continuously requires a lot of energy. Most of them are what we call opportunistic feeders – meaning they will grab what they can. Stomach analysis of such sharks find primarily fish and squid, but other creatures have been found – such as birds and even other sharks. The general rule here is seek prey that is “easy”. If your objective in feeding were to obtain energy – it would not make since to chase prey that would require a lot of energy to catch. Simple first, and take opportunities when you can. It is the ram-jetter species that people are most concerned. Swimming and taking opportunities. However, evidence suggest that we are not a prey of choice, not good opportunities. More on this in a minute.
Tiger sharks are interesting. It is in their stomachs we find such things as hubcaps, metal, and other sorts of garbage. Because of their tooth design, they are also capable of eating sea turtles.
How often do shark attacks on humans actually occur and what were the people doing that may have enticed it to happen?
Records on human shark attacks are kept at the International Shark Attack File at the Florida Museum of Natural History in Gainesville, FL. This data set only logs unprovoked attacks – those where the people were doing their thing and all of a sudden… Not those where humans were pulling them into their boats after fishing or grabbing their tails while diving.
Blacktip sharks are one of the smaller sharks in our area reaching a length of 59 inches. They are known to leap from the water. Photo: Florida Sea Grant
Based on this data – there have been 3031 unprovoked shark attacks reported worldwide since 1580 A.D. This equates to seven attacks / year. Granted… not all attacks are reported, particularly from the undeveloped regions of the world – and from early history, but it does give us something to look at.
Currently, we are averaging between 70 and 100 shark attacks worldwide and between 5-15 of these are fatal. Honestly, this is very low when compared to other activities in which humans participate.
Year
Deaths from Other
Deaths from Shark Attacks
1959 – 2010
Lightning strikes – 1970
26
2004 – 2013
Rip Currents – 361
8
2001 – 2013
Dog bites – 364
11
2000 – 2007
Hunting accidents – 441
7
2002 – 2013 (Florida only)
Boating accidents – 782
2
As you can see… the risk is much lower.
It is true that most of the shark attacks worldwide are in the United States (46%) and that most in the U.S. are in Florida (56%). However, it is believed that this is due to the number of Americans (and Floridians) who enjoy water activities. In Florida, most of the encounters have been on the east coast – 89% of them! There have only been 65 attacks reported from the west coast – only 37 from the Florida panhandle – since 1580 A.D. There have only been six reported from Escambia County and one from Santa Rosa in that time.
As far as what people were doing when a shark attack occurred – most were surfing, but swimming has increased in recent years. This is believed to be connected to the increase in the number of humans swimming. The human population visiting beaches, particularly in the U.S., has increased significantly. Most shark attacks occur in near shore waters – which would make sense… that is where we are. Most are the “hit & run” version – meaning the shark hits the person and runs… not returning. Based on Florida reports, it is believed most of these are blacktips, spinners, and blacknose sharks. These rarely end in a fatality. “Bump & Bite” – meaning the shark circles, bumps the person, and then bites, are not as common. It is believed most of these are from great whites, tigers, and bull sharks. The few fatalities that happen are usually from this form of encounter.
Summary
When assessing “risk” in an activity you have to consider “control”. This means that the more you are in control of the situation, the less risky the activity seems to be. Most feel that in the water, the shark is in control – this increases our fear and risk concern. However, as mentioned in this article, many of the other activities we are involved – where we think we are in control – are far more risker than swimming on the open Gulf of Mexico.
However, shark attacks do occur and there are a few things swimmers can do to reduce their risk.
Do not swim alone – all predators will try and isolate an individual from a group before they attack – much easier to attack an individual than a group
Do not swim near dusk or after dark – to increase their chance of hunting success, sharks are more actively hunting in low light conditions
Remove shiny objectives like jewelry – sunlight hitting metal objectives can appear to be baitfish to a shark
Avoid blood in the water – it is true they have an excellent sense of smell – small amounts of blood in the water can be detected as far away as 100 feet suggesting easy prey nearby. Avoid swimming near fishing activity where bait and fish blood may be discharged into the water
I have been swimming in the Gulf all of my life. It is too much fun to worry about a low risk encounter with a shark. Follow the simple rules suggested by the ISAF and you should not have any problems.
You might get that impression from the movies but if you look at the data you will see quite a different story. With nearly fifty species identified in the Gulf of Mexico, an encounter with a shark is eminent if you spend much time in our coastal waters. So, let’s get the “scary” stuff out of the way first and finish with the more interesting facts for our much-maligned “toothy” friends.
The Bull Shark is considered one of the more dangerous sharks in the Gulf. This fish can enter freshwater but rarely swims far upstream. Photo: Florida Sea Grant
The most recent data from the University of Florida’s International Shark Attack File shows that unprovoked attacks have occurred in 26 of Florida’s 35 coastal counties, from 1882 to present. Florida is the hotspot in the U.S. which makes sense with our 1,300-plus miles of coastline. Volusia County has recorded the most incidents at 299. Brevard County is second (144) and Palm Beach County third (75). Do you have any idea how many people have been in the water in these three counties since 1882? Let’s just say, a lot; if sharks were hunting for people, they would have found more of us by now.
In the coastal counties of the Florida Panhandle, numbers are much lower with Bay County having the most incidents at 9. Numbers drop from there with Escambia at 6, Okaloosa at 4, Gulf and Franklin at 2, Santa Rosa and Walton at 1 and none from Wakulla down through Pasco; remember, since 1882. Species most often involved have been bull or blacktip sharks (20% each), spinner at 16% and hammerhead at 13%. Believe it or not, the next highest is nurse sharks at 7%. Compared to drowning fatalities from 1992-2000, sharks loose, 2 to 135.
Okay, now for some more interesting facts about our Gulf of Mexico sharks. Some of you have heard about the encounter that Grayson Shepard (of Apalachicola) had with a great white back in 2015. If you want to see his amazing video visit this link. Even though great whites are considered a cold-water species, scientists have known for a long time that they do visit the Gulf of Mexico. Their incredible migratory nature has been studied in greater detail of-late. An 8.5 foot juvenile female that was radio-tagged off Hilton Head South Carolina travelled to Nova Scotia Canada before turning around and going south all the way around the tip of Florida and into the Gulf of Mexico. The most northerly “ping” picked up by the satellite receiver was north of Tampa on January 31, 2018. Savannah (her given name) is currently back on the east coast near where she was tagged by researchers. Vist this website to follow Savannah’s incredible journey.
The Great White shark. Photo: UF IFAS
Another impressive shark species that occurs in our Gulf waters holds the title of “world’s largest fish!” Whale sharks can reach lengths of fifty feet and weigh around 20 metric tons. Most of the sightings in the Gulf have proven to be juveniles but occasional aggregations happen around abundant plankton resources. One chance encounter by scientists from the Mississippi-based Gulf Coast Research Laboratory, documented a large number of whale sharks feeding near the surface. Plankton samples revealed a rich concentration of fish eggs from recent spawning activity of little tunny and crevalle jack. Aggregations numbering near 150 individuals, feeding on abundant plankton, have been reported in the nutrient-rich waters near the Mississippi River drainage.
Sharks in the Northern Gulf of Mexico, just as alligators in our lakes and rivers, deserve our respect and a balanced conservation-minded attitude. They are an incredible resource that have vital connections to many other species in our marine environment. They are also one of the most thrilling creatures on the planet when you get to meet one up close. Just please use some good sense and mind those pearly-white teeth if you catch one on a line. Even a cute little wild mouse will bite you when handled but the outcome is slightly more concerning with sharks and alligators.
White Shark (Carcharhinus carcharias). Credit: Florida Sea Grant Stock Photo
From Fear to Fascination: White Sharks in the Florida Panhandle
UF/IFAS Extension – Florida Sea Grant
By Rick O’Connor (Escambia County) and L. Scott Jackson (Bay County)
Recently, I was walking on our local Gulf fishing pier checking fishing line recycle bins. You can’t walk on a Gulf pier without looking over to possibly catch a glimpse of a sea turtle or a shark, and I was not disappointed. It was hard to tell which species of shark but it was about 6 feet in length. It swam south along the edge of the pier and then east to make a large arching circle through the emerald water, past bathers at the surf break, and back to the pier only to swim the pattern again. Onlookers from out-of-town were giggling with delight to see the animal while a couple of local fishermen tried tossing bait at it, but most ignored it and went on with their fishing.
Bob Shipp’s book, Fishes of the Gulf of Mexico, lists 29 species of shark found locally. Most are members of the requiem shark family, such as blacktips and bulls, and hammerheads. Though these sharks are certainly capable of attacking humans, their presence usually does not interrupt water activities. Divers who encounter sharks may be startled at first but rarely do they end their dive or have problems with them. Even in 2005, remembered as the “summer of the shark attack”, few people stopped diving or surfing. Individuals have become educated regarding shark behavior and are not as startled when they see one. However, in 2015 there were several encounters with White Sharks.
Sightings in the Gulf of Mexico are rare but usually occur in the cooler months. Is the increased interaction with White Sharks unusual or something to worry about?
Burgess assured me that White Sharks do occur in the Gulf of Mexico usually during cooler months and are transients, as opposed to residents. Their movement in and out of the Gulf is temperature driven. As late spring Gulf waters continue to warm into early summer, sighting a White Shark is less likely to occur. According to Burgess, White Sharks use deep water when traveling but prefer shallow water when hunting fish, turtles, and marine mammals. So, inshore encounters especially in cooler months would not be unusual.
Why is there a sudden increase in the numbers of encounters?
One part of the answer lies with the increased number of White Sharks. Conservation of sharks has been effective. Additionally, with the passing of the Marine Mammal Protection Act, there are more marine mammals, thus an increase in their predators, White Sharks. The other part is the number of humans visiting the northern Gulf has increased. There are more more visitors to marine waters, especially since the Deepwater Horizon oil spill. Everyone has a camera. Beachgoers, Swimmers, Divers, and Anglers all have improved technology to record their adventures.
Is Northwest Florida a “hot spot” for White Sharks? Burgess indicated that the northern Gulf of Mexico is more productive than the peninsular Florida due to the number of nutrient rich rivers in the region. Seeing more White Sharks here would not be any more unusual than finding more snapper, lionfish, or other species of shark. As far as worrying, there have been no records of White Shark attacks in the northern Gulf of Mexico since they began keeping records in 1872.
Finally, what does one do if they encounter a White Shark?
The quick answer is nothing different than with any other shark. It is true that most White Shark attacks occur at the surface but there are no records of any attacks in Florida. Burgess indicated that the Bull Shark is probably a bigger threat than the White Shark. For more information about Bull Sharks and general tips to avoid a negative shark encounter read this articlehttps://nwdistrict.ifas.ufl.edu/nat/sharktips
In a recent video, recorded near Apalachicola, a diver was on an anchor line on a decompression stop when he saw a White Shark approaching from depth. What should a diver do in this situation? Should they swim for the surface and risk decompression sickness, remain still, or return to the bottom?
The answer has a lot to do with what the shark is actually doing. Is the shark interested in the diver or acting aggressively? Burgess suggests, you assess the situation and the shark’s behavior. All options are on the table and have to be weighed against the consequences given in this scenario. As a last resort, a diver may need to make a quick but graceful exit out of the water, past the shark, and depend on their diving partners to render aid as needed. The lesson is for divers to be prepared for a variety of potential issues on every dive.
