Friends, meet your local sharks!
Most people probably grew up with some amount of fascination regarding sharks coupled with fear, of course, and both of these likely stemmed from seeing movies like “Jaws” or “Deep Blue Sea”. Until recently, what the general public knew about sharks was very limited and perceptions were more negative. Instead of thinking about their importance and how to preserve them, more focus was on the dangers and inconveniences they cause us as humans.
With shows like “Shark Week” though, a boom in the amount of televised material on shark behavior and biology has transpired, and I believe the public interest has increased while attitudes have grown more curious and sympathetic.
Don’t get me wrong, sharks are dangerous, and you won’t see me giving any of them a Jimmy Houston signature kiss on the mouth, but it is important to understand them and their natural role in the oceans, and I’m glad to see this newly kindled public love affair with those snaggle-toofed gill-breathers.
So, we all see them on t.v., and a lot of us have probably been in or near the ocean this year and thought, “I wonder if there’s anything like that around me?”, “How many?”, “How big?”, “Surely there’s nothing like that one we saw on shark week.... right?”, “Shit, something touched my leg!”. “Cohen, PICK ME UP! PICK ME UP! SOMETHING TOUCHED MY LEG!” OK, that last one was my fiancé Lexi.
Anyways, if you're reading this you are probably a friend or family member and thus in or around the Southeast. So, this one’s for you and your interest in what’s likely out there next time you are at Folly Beach, Hilton Head, Tybee, St. Simons, Jekyll, Cumberland, Jax Beach, or St. Augustine, among others including those in the Gulf of Mexico. It might even put you a little at ease on your next plunge into the big blue if you are currently a little skeptical about your safety considering... the unknown, because the unknown will be a little smaller after reading this (I hope). Now, sharks obviously don’t heed state lines, and many of the species found here in Georgia are also common in neighboring states, however, these are a few of the most commonly found species inhabiting Georgia waters at some point during a given year.
I’ll list them by relative abundance from most common to least, based on survey data and personal observations, and give a little description. Some information is given about diet, but most sharks tend to be “generalists” and opportunistic feeders, meaning that they often cruise around and feed if an opportunity presents itself, not always being picky about the type of prey. This convenience factor is one of the advantages of being an apex predator and has aided in their success over the last 400 million years... give or take a few million.
*The exact order of relative abundance may differ at times during the year or between years based on movement patterns and fluctuations in population levels.
Atlantic Sharpnose (Rhizoprionodon terraenovae)
*Photo: This is a pretty typical adult Atlantic Sharpnose. Yep, that’s about as big as they come. First year on the water for me as a shark researcher (2013).
This little dude or dudette is likely your most common shark in coastal Georgia waters, swimming around the beaches and inshore waters. I would not consider them to be a threat to humans, as you could probably deduce from this picture... Phew! They just aren’t very big, but they can put up a nice fight if you want to throw out a bottom rig baited with shrimp or mullet (or likely any local marine critter) off the beaches or piers. They are easily identified by the white splotches along their sides. As neonates (newborns) they have some black markings along their fins, not to be confused with the Blacktip though, as the Atlantic Sharpnose pups are significantly smaller (9-14 inches) than even the smallest Blacktip. As adults, they reach about 3-3.5 feet in length, and they feed on teleosts (bony fishes), crustaceans, like shrimp, and mollusks, like squid.
Bonnethead (Sphyrna tiburo)
*Photos: (Top) - adult, female Bonnethead with numbered tag in dorsal fin prior to release by my good buddy and fellow UNF graduate student, John Whelan. (Bottom) - adult, female Bonnethead upon release.
Running a close second in relative abundance behind the Atlantic Sharpnose is the Bonnethead, a smaller member of the Hammerhead family of sharks. These sharks are very common to the inshore waters and tidal creeks behind our barrier islands and are fairly docile. They exhibit a pretty rare feature regarding shark reproduction: sperm storage! Wait, what? Yep, after mating in September females store sperm until the Spring, then fertilize their eggs (internally), and carry developing embryos for the next 4-6 months until giving birth in September. This results in one of the shortest gestation periods (time of pregnancy) known among sharks and rays.
The flattened head shape of Hammerheads and Bonnetheads is thought to increase the surface area for a wider distribution of electroreceptors called Ampullae of Lorenzini, which are common to all sharks. These small holes are filled with a jelly-like substance that conducts electric fields which aid in detecting potential prey items in the water. Their head shape also increases their range of vision and is used to pin prey down against the bottom. Their favorite meal is the blue crab, but they also feed on shrimp and fish. Adults are typically 3-3.5 ft. By the way, these length estimates are describing the “fork length”, which is from the tip of the snout to the inside of the “V” created by the two lobes of the tail. Total length is a less consistent measurement, as the upper tail lobe is included and tends to vary from species to species.
Finetooth (Carcharhinus isodon)
*Photo: Adult male Finetooth shark with numbered tag in dorsal fin. On the underside, about 2/3 of the way back on his body you can see his claspers, or male sex organs. (Yes, they have two.)
The finetooth shark is another small coastal shark species common to the southeast and Gulf of Mexico, and is one of my personal favorites. They have a beautiful greenish-blue and grey mixture of coloring and similarly greenish eyes. Their top and bottom rows of teeth are nearly identically shaped teeth, which are slender and straight, hence their common name. They also have relatively long gill-slits compared to other coastal sharks. My favortism for this species largely stems from my research using gill nets, which has provided information on nursery habitat use by these sharks in areas where little information on them has previously been published. So, I am excited to present some new findings for the species and contribute to conservation efforts in that way. They grow to about 5.5 to 6 ft. and feed mainly on fish and shrimp.
Blacknose (Carcharhinus acrontus)
*Photo: Mature male (notice the claspers) Blacknose shark
These sharks are common to the coast in nearshore waters, rather than inshore and grow to be about 4 - 4.5 ft. They are very strong, so if you catch one be ready for a good fight on the line and probably an even bigger one if you pull him or her onboard. They have an olive-brown and bronze tint to them and somewhat olive colored eyes and, of course, a black smudge on the tip of their snout. They feed mainly on smaller fish and sharks (ie. Atlantic Sharpnose and Bonnetheads).
At this point, we’ve covered the grouping known as the “small coastal sharks” complex, and combined with the sandbar shark, listed below, members of these species will most likely make up the overwhelming majority of individuals inhabiting Georgia’s coastal waters at any given time. I would venture to estimate at least 95%. Oh, and have you noticed? They aren’t very big! So, you shouldn’t be too concerned about swimming in the ocean around here, but it is always healthy to remind ourselves that when we do, we are in their world and thus, shouldn’t take a little nibble here or there so personally. Kidding, but I do think it’s important not to vilify them, and increasing our understanding is one of the best ways to avoid that. Plus, to my knowledge, there have been zero shark attacks recorded in Georgia. Getting pretty comfortable now, huh? Don't worry, we will get to a few of larger species as we continue! (evil laugh)
Sandbar (Carcharhinus plumbeus)
*Photo: Neonate sandbar shark being measured. Working on getting a better photo for this species! You can still get an idea of their distinct coloration from this shot, though.
The sandbar shark is another beautiful coastal shark and is a member of the ridge-back group of sharks. This means that they have a raised ridge of skin between their first and second dorsal fin, a trait that is also shared by sharks such as the Tiger and Oceanic Whitetip. They are grey and have a bronze/golden tint, and when the sun hits their side it gives them an awesome glow. Their jaws and teeth seem like a miniature version of “Jaws” and are what I would describe as the typical, voracious-looking mouth we all expect to find on a shark. Not to worry though, they are relatively small and not thought of as likely to attack a human. Plus, it seems that juvenile Sandbars, like the one pictured, are more likely than adults to be in inshore or nearshore waters.
Sandbars are prohibited species for harvest in state and federal waters (3 miles offshore) because of their high susceptibility to overfishing and current attempts to rebuild population levels. Sandbar sharks often take about 13 years to become reproductively mature, reproduce every two or three years, and have small litters when they do. These characteristics combine for slow turnover rates, which are very concerning when attempting to rebuild any fish population. Like plenty of species, they were overfished for many years, and are now at a point where no harvest can be allowed and continued monitoring is necessary to successfully manage them. Luckily, fisheries managers know this and are acting with the best data and tools available to turn this story around and are making progress. They grow to about 6-8 ft. and feed on fish and smaller sharks.
Blacktip (Carcharhinus limbatus)
*Photo: Neonate Blacktip shark with numbered tag in dorsal. Notice the coloration and black marking on the pectoral, dorsal, and lower caudal (tail) lobe.
Blacktips can be found in inshore waters mainly as neonates and juveniles, and they spend more time as adults outside in nearshore waters. As their name implies, they can be identified by the dark black tips on several of their fins, most prominently of their pectoral, both dorsals, and lower caudal lobe. However, Blacktips do not typically have a black-tipped anal fin, whereas an almost identical species, the Spinner shark (Carcharhinus brevipinna), does often have this feature. It’s easy to confuse the two, but Blacktips are more common in coastal Georgia it seems.
Here is a useful diagram for learning the shark fins and other anotomical features
Ironically, the Spinner shark shares the trait for which the Blacktip is named (black tips), and the Blacktip shares the trait for which the Spinner is named... (spinning)! Both of these sharks can be seen leaping vertically out of the water, rotating rapidly, nose to the sky, only to return in an often awkward side-flop. These aerials are executed when Blacktips or Spinners launch an ambush from below while chasing smaller, schooling fish. Both sharks can also be identified by the distinct “z-line” along their sides, a Zorro-esque marking behind their pectoral fins toward the tail. They are typically grey with some dark-blue to bronze tinting. Blacktips like to feed on small, schooling fish, other sharks and rays, and even crustaceans and squid. Adults average about 5.5 to 6.5 feet.
Scalloped Hammerhead (Sphyrna lewini)
*Photos: Neonate scalloped hammerhead. Looking at the profile of the cephalofoil or “hammer”, notice the scalloped portion in the middle of the curved edge of the hammer. These two characteristics are useful in distinguishing between the different hammerheads. The Floridagofishing website has a nice diagram comparing a few members of the Hammerhead family, along with some good information on various other sharks!
Like many of the other larger sharks, adults are more common offshore while the pups will often spend some time in inshore and nearshore waters around the beaches. Here they get some easier meals and don’t have to worry so much about larger predators (the main benefits provided by nursery habitat). Pups like this one can grow to be 12 ft. as adults, and consume a variety of prey including but not limited to bony fish, other sharks, stingrays, crabs, and squid. As mentioned earlier, they will use their hammers to pin down prey, particularly stingrays, who are often found skimming the sea floor. If you happen to catch one and don’t plan to harvest it (one per boat is allowed if it’s >78 inches at the fork), try to get it back in the water quickly as this species doesn’t handle the stress of being captured very well.
Lemon (Negaprion brevirostris)
*Photo: What is going on here? This photo is of a juvenile female lemon shark who was caught in our longline survey by eating a bonnethead who was also, already caught on a longline hook. This girl was roughly 5 ft. and was tagged in this position along side our vessel before she was released in great condition. This was just after we had caught and tagged another female lemon of the same size. A few months later, an angler near Jekyll Island called in and had caught two lemon sharks with tags. When we asked, he read off the tag numbers from the notes he had taken. A quick look in the database revealed that it was those same two gals! They have been known, along with many other sharks, to form loose aggregations or small schools for feeding and protection from larger predators, and it seems that they were doing just that!
While they are present in the area, they are not very common compared to other species and are more abundant in warmer, more tropical areas such as the Bahamas. An easy way to identify a lemon shark is the relatively large 2nd dorsal fin, which is of a similar size to the first. If you look at all of the other sharks in this article you’ll notice that a smaller 2nd dorsal is more common. They also have a golden-yellow tint, hence the name. Lemon sharks will grow to roughly 7.5-10 ft. as adults, and often feed on bony fish, crustaceans, and even sharks, rays, and seabirds. One of the most well-studied nurseries for this species in located in Bimini, Bahamas, where the pups thrive amongst mangroves and seagrass beds.
Ok, information overload! I’ll stop now and say thanks for reading, and I hope that you enjoyed it and are able to take something away from it. Maybe you even feel a little better about that next swim, or not. Or better yet, you’ve gained a greater understanding and appreciation even. That was really the point to this post... and the blog in general, to give myself a reason to consistently get immersed in the natural world and share with all of you who crave the same information and experiences.
So, now you know major players and can use this list to help guide you as you continue to feed your curiosity about our local sharks!
I’ll be continuing to photograph to hopefully provide you with some examples of adults for those species with only pups pictured above and vice versa.
Feel free to reach out if you have any questions or would like a particular topic to be covered, and I’ll see what I can do.
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