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?
To answer this question I turned to George Burgess, a shark expert who manages the International Shark Attack File housed at the UF Florida Museum of Natural History.
Is this unusual?
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 article https://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.
For more information on sharks and shark attacks in Florida visit the International Shark Attack File at http://www.flmnh.ufl.edu/fish/Sharks/ISAF/ISAF.htm
Note: White Sharks are a protected and prohibited species. It’s illegal to beach or land them. See guidance on shark fishing regulations, gear requirements, Including catch and release methods from the Florida Fish and Wildlife Conservation Commission at http://myfwc.com/fishing/saltwater/recreational/sharks
This is a question I have been asked several times in the last week. As most of you know the red tide that has been occurring off the panhandle the last few months is still around. Dead fish were reported on Pensacola Beach again the weekend of Dec 12-13 and a few people said they were having eye and throat problems. This weekend I received a call of dead fish inside the bay but the caller was not suffering from eye and throat issues. Its December… what’s going on?
The dinoflagellate Karenia brevis.
Photo: Smithsonian Marine Station-Ft. Pierce FL
Well let’s look again at what red tide is and what facilitates the bloom. Red tide is caused by small microscopic plants called dinoflagellates. Dinoflagellates, like all plants, develop defense against herbivores that may try and feed on them. A few of these dinoflagellates release toxins when disturbed as a defense. They are in the Gulf all of the time but usually in low numbers, maybe 300 cells per liter of water, and cause no problems. But when conditions favor growth and reproduction they do just that – grow and reproduce – in great numbers, maybe 3000 cells per liter. When this happens the water actually darkens with their presence and the amount of toxin they release increases due to the increase number of cells – now marine creatures other than those that feed on them are impacted by the toxin – this is a red tide.
So, what are these conditions?
Well, like all plants dinoflagellates like sunlight, warm temperatures, and nutrients (fertilizers). So you would think that these blooms would occur when most plants grow – summer… and you would be right. There is another condition that contributes and those are currents. If currents are strong it will spread the bloom and the concentrations are spread as well, lowering the concentration per liter of water and thus reducing or diminishing the red tide.
We generally have plenty of sunshine here in the panhandle – temperatures are relatively warm, though they are warmer in south Florida – and there are nutrients. Nutrients are available naturally in the Gulf but are increased when we have a lot of rain as the runoff brings nutrients from land. But remember red tides are not always the result of human pollution – they occur naturally but can be increased or extended with excess nutrients from human runoff. The currents here along the panhandle tend to keep red tides at bay most of the time – we do not see them often here, but that is not the case with southwest Florida. In the Port Charlotte area red tides are more common part of life. It is warmer, there is more agriculture and municipal nutrients entering the Gulf, and the currents there are slower/weaker than we have here.
So what is up in the panhandle this year?
Well the sun is still shining! Feels great out there actually. The water temperatures were in the upper 60’s inside Pensacola Bay this week and that is typical, but the Gulf is still in the 70’s, and that is typical as well. What is not typical is the warmer air temperatures. This will slow the temperature drop of the Gulf and allow plants to extend their non-dormant season. H2O is a polar molecule (has an electric charge) and so the molecules are bonded together like two magnets. Because of this it takes more heat (energy) to warm the water and so area waters warm at a slower rate than the air. If the air temperatures remain warm it will be longer before the Gulf cools down. These warmer temperatures may extend the red tide a bit longer. As far as nutrients, heavy rains in October and November probably supplied more food for the plants and contributed to the beginning of the tide. Currents pushed the red tide inshore where we began to experience the eye problems and fish kills. The north winds from the recent fronts passing through may generate upwellings in the Gulf. Upwellings are currents that bring water from the ocean floor to the surface, this would bring nutrients with it. So we still have sun, warm temperatures, and nutrients – and the bloom is still with us. What will reduce the problem will be wind and currents to drive it offshore… and time – the Gulf will eventually cool and the tide will be reduced. How long is anyone’s guess.
So why is it 70 degrees in December?
That is a question for another article…
You can track red tides in the panhandle by visiting http://myfwc.com/REDTIDESTATUS
Yep, but do not get to alarmed just yet… it is not the same species as the famous one from Australia. That said… who is this new invader to our waters and is it of concern?
This Four-handed box jelly was found near NAS Pensacola in 2015.
Photo: Courtesy of Robert Turpin
According to NOAA and the University of California at Berkeley there are between 20-50 species of box jellies from around the world. Their distinct shape, often called “cubomedua”, places them in their own family. Most of the “medusa” jellyfish we know are in a group called “scyphozoans” but box jellies differ in several ways.
- Their shape – the “box” shaped and their tentacles are clustered into four groups on the corners of the “box”.
- They are very good swimmers – most medusa can undulate their “bells” and move but they are planktonic (drifters) in the ocean currents. Box jellies are very strong swimmers. They can move against currents, tend to swim below the surface more (often collected in shrimp trawls), and have been clocked at top speeds of 4 knots! (This is very fast for a jellyfish).
- They do have eyes. They know where they want to go, can avoid colliding with piers, and have been known to even swim away from collectors trying to catch them. Not typical of our locals jellyfish. Lacking a central nervous system like ours, science is not sure how they see, or what they see, but they do.
Box jellies are found in all tropical seas, including the south Atlantic and Gulf of Mexico. They range in size from less than an inch to about 8 inches, with tentacles extending as far as 10 feet behind. Breeding in this group is interesting. Males will place their tentacles inside the bell of the female and deposit sperm. The female will then fertilize her eggs and release planktonic larva called planula. These planula will drift in the currents for a short period before metamorphosing into a flower-like creature called a polyp. Polyps are sessile (non-swimming) and attach to hard structures on the ocean floor. Here they can move and adjust to feed with their extended tentacles and can actually produce more polyps by budding. After a period of time each polyp will metamorphose into a swimming medusa, the box jelly we know and love. As already mentioned, they swim with purpose hunting small fish and invertebrates. They do have their predators. Certain fish and sea turtles are known to consume with no ill effects.
They all possess a very strong toxin which is quite painful. The most toxic of the group is Chironex fleckeri, the famous one from Australia. This jellyfish has been listed by many, including NOAA, as the most venomous marine animal in our oceans. It has certainly caused death in their waters. The majority of the lethal box jellies live in the Indo-Pacific. So what about Florida?
I am aware of two species that have been found here. The “Four-handed Box Jelly” (Chiropsalmus quadrumanus) and the “Mangrove Box Jelly” (Tripedalia cystophora). The Four-handed box jelly is the larger of the two, and the one pictured here. The Mangrove Box Jelly typically lives in the Caribbean. The first reported in south Florida was in 2009 near Boca Raton but they have since been reported in the Keys and along the Southwest coast of Florida. This is a small box jelly (about 0.25” in diameter) and seems to prefer the prop roots of mangrove trees.
The Four-handed box jelly can reach almost 5” in length with up to 10’ of tentacles attached. It is more widespread in Florida, though more common on the Atlantic coast then our own. One was brought to me about 6 years ago. The person found it next to pier at Quietwater Boardwalk, in the evening, swimming around the lights shining in the water, it was near Thanksgiving also. The one pictured here was seen by a local surfer and by Robert Turpin (Escambia County Division of Marine Resources) last week. Both sightings were near NAS Pensacola and may have been the same animal. This box jelly has the same characteristics as others – box shape, clustered tentacles, and very painful sting. The surfer who brought me the one from 6 years ago was stung by it. He said the pain brought him to his knees… so do not handle this animal if you see one. There was a report of a small child who died after being stung by one in 1991. However there are reports of young kids dying from the Portuguese man-of-war as well. Lesson here… treat it with caution.
These box jellyfish are not the deadly ones known from Australia, and it is certainly not common here – preferring to stay in the open ocean more than nearshore, but it is an animal all should know about and avoid handling if encountered.
More resources on this animal:
After the recent report of a fatality due to the Vibrio bacteria near Tampa many locals have become concerned about their safety when entering the Gulf of Mexico this time of year. So what are the risks and how do you protect yourself?
The rod-shaped bacterium known as Vibrio. Courtesy: Florida International University
What is the Flesh Eating Disease Vibrio?
Vibrio vulnificus is a salt-loving rod-shaped bacteria that is common in brackish waters. As with many bacteria, their numbers increase with increasing temperatures. Though the organism can be found year round they tend peak in July and August and remain elevated until temperature decline.
How do people contract Vibrio?
The most common methods of contact with Vibrio are entrance through open wounds exposed to seawater or marine animals and by consuming raw or undercooked shellfish, primarily oysters. The bacterium can also be contracted by eating food that is either served, and has made contact with, raw or undercooked shellfish or the juice of raw or undercooked shellfish.
What is the risk of serious health problems after contracting Vibrio?
Cases of Vibrio infection are rare and the risk of serious health problems is much higher for humans who are have a suppressed or compromised immune system, liver disease or blood disorders such as iron overload (hemochromatosis). Examples include HIV positive, in the process of cancer treatment, and studies show a particularly high risk for those with a chronic liver disease. The Center for Disease Control indicates that humans who are immunocompromised have an 80 times higher chance of serious health issues from Vibrio than healthy people. He also found that most cases involve males over the age of 40. According to the Center for Disease Control there were about 900 cases reported between 1988 and 2006; averaging around 50 cases each year. The Florida Department of Health reported 32 cases of Vibrio infections within Florida in 2014 with 7 of these begin fatal. Five of the cases were in the Florida panhandle but none were fatal. So far this year in Florida there have been 11 cases statewide, 5 of those fatal. Only 1 case was in the panhandle and it was nonfatal. Though 43 cases and 12 fatalities over the last two years in Florida are reasons for concern, when compared to the number of humans who enter marine and brackish water systems every day across the state, the numbers are quite low.
What are the symptoms of Vibrio infection?
For healthy people who consume Vibrio containing shellfish symptoms could include vomiting, diarrhea, and abdominal pain. Wounds exposed to seawater that become infected will show redness and swelling. For the at-risk populations described above the bacteria will enter the bloodstream and rapidly cause fever and chills, decreased blood pressure, and blistering skin lesions. For these at-risk population 50% of the cases are fatal and death generally occurs within 48 hours.
It is important that anyone who believes they are at high risk and have the above symptoms that they seek medical attention as quickly as possible.
How can I protect myself from Vibrio infection?
We recommend anyone who has a chronic liver condition, hemochromatosis, or any other immune suppressing medical condition, not consume raw or undercooked filter-feeding shellfish and not enter the water if they have an open wound.
The Center of Disease Control recommends
- If harvesting or purchasing uncooked shellfish do not consume any whose shells are already open
- Keep all shellfish on ice and drain melted ice
- If steaming, do so until the shell opens and then for 9 more minutes
- If frying, do so for 10 minutes at 375°F
- Avoid foods served, and has had contact with, raw or poorly cooked shellfish or that has had contact with raw shellfish juice
- If shucking oysters at a fish house or restaurant, wear protective gloves
It is also important to know that the bacteria does NOT change the appearance or odor of the shellfish product, so you cannot tell by looking at them whether they are good or bad.
For more information on this bacteria visit:
Pregnant Bull Shark (Carcharhinus leucas) cruses the sandy seafloor. Credit Florida Sea Grant Stock Photo
Shark Safety Tips
UF/IFAS Extension – Florida Sea Grant
By L. Scott Jackson (Bay County) and Rick O’Connor (Escambia County)
Recently, two teens were victims of unusual shark attacks in North Carolina. The two attacks occurred within minutes and miles of each other. A similar incident happened in the Florida Panhandle in 2005. One teen lost her life and one lost his leg. The attacks were within days of each other and the distance between the two attacks was less than 100 miles. Experts identified Bull Sharks as being responsible for both Panhandle shark encounters.
Bull Sharks migrate north as ocean waters of the Gulf and Atlantic warm. As the nearshore environment cools in the late fall and winter, Bull Sharks follow the receding warm water and eventually move out of the local area. Bull Sharks are an aggressive shark responsible for a reported 100 attacks on humans resulting in 21 fatalities. (Reported from 1580 to 2014 Source: International Shark Attack Files).
Experts suggest Bull Sharks may be responsible for many shark attacks where the species is unknown or not identified.
Overall, the number of shark encounters is slowly trending higher as more people swim and participate in other water related activities. However, negative encounters with sharks remain a rare occurrence. In 2014, Florida reported 28 shark bites with no fatalities. On average, only one shark attack fatality is reported every other year in the United States. The risk of shark attack is very low compared to other potential recreational hazards. For example, in 2014, 26 people died as a result of lightning strikes in the United States, with six of those being in Florida.
George Burgess with the International Shark Attack File has compiled a list of action strategies you can use to reduce the chances of a negative encounter with a shark:
Keep these tips in mind the next time you hit the beach!
- Avoid being in the water from sunset to sunrise. This is when sharks are most active and have a competitive sensory advantage.
- Stay in a group, and do not wander too far from shore. Isolated individuals are more likely to be attacked than large groups; in addition, the farther you are from shore, the farther you are from help.
- Consider your clothing: avoid wearing shiny jewelry, because the reflected light resembles the sheen of fish scales.
- Avoid brightly colored or patterned clothing, because sharks see contrast particularly well.
- Do not enter waters being used by sport or commercial fisherman – sharks can sense the smells emitted from bait at incredible distances.
- Avoid entering waters with sewage output and/or entering the water if you are bleeding. Such additions to the water can act as strong olfactory attractants to sharks.
- Know your facts! Porpoise sightings do not indicate the absence of sharks. In fact, the opposite is often true. Also be on the lookout for signs of baitfish or feeding activity – diving seabirds are good indicators of such action. Animals that eat the same food items are often found in close proximity. Remember, a predator is never too far from its prey.
- Refrain from excess splashing while in the water, and do not allow pets in the water because of their erratic movements.
- Exercise caution when occupying the area between sandbars or near steep drop-offs, as these are favorite hangouts for sharks.
- Do not enter the water if sharks are known to be present, and evacuate the water if sharks are seen while there. And, of course, do not harass a shark if you see one!
- Stay calm if you do see a shark, and maintain your position in as quiet a manner as possible. Most sharks merely are curious and will leave on their own.
- Relax! You are more likely to be injured by lightning than attacked by a shark. To learn more about your relative risks, see: The Relative Risk of Shark Attacks to Humans
Our beautiful Emerald Coast is an alluring wild habitat. Simply put – Swimming at the beach is not the same as swimming in a backyard pool. Have fun at the beach but be mindful and respectful of potential hazards. Knowing what to do to be safe will actually help you enjoy time at the beach while keeping worry and concern at a minimum.
Follow these beach safety tips for helping your family enjoy the beach while protecting coastal wildlife.