Sharks in the Gulf of Mexico

Ever wonder what top predators share the water when you go down for a weekend at the coast? 

Sharks are apex and meso predators, meaning they occupy the highest as well as mid-level parts of the food chain to keep other species’ populations in check. While some find them frightening, shark attacks are uncommon and sharks work hard to maintain ecosystem balance and health that keep our oceans thriving. Given their important role, it’s not uncommon to find sharks along the Texas coast and in the Gulf of Mexico in general. 

Certain shark species are seen more often than others though. 

A 14-foot great white shark was found swimming along the Texas coast in late February. The satellite pinged off the tagged female, “LeeBeth”, when she surfaced at the southern tip of the Padre Island National Seashore and again near South Padre Island. She has since made her way down to Mexico. 

You might be thinking “Great… another shark and another reason not to go in the water. But why should I care?” LeeBeth made shark history by being the first great white to ever travel that far west into the Gulf. She also surfaced more often than other sharks, helping make her presence known as the tag sends a signal to a satellite when it senses air instead of water.  

Here is a guide to shark species commonly found in the Gulf of Mexico:

Atlantic sharpnose shark

The Atlantic Sharpnose shark is one of the most commonly found sharks in the Gulf of Mexico. It can be identified by its slender body and gray-brownish color that is sprinkled with white dots. It also has a particularly long upper labial furrow, which is a groove on the sides of the shark’s lips, and distinctive pointed snouts (hence its name). This species is found at many depths. They come closer to shore (bays, estuaries, river mouths) for mating in late spring/early summer and birthing live young the following summer. These sharks are viviparous, meaning they give birth to live young and mothers nourish the growing embryos internally through a placental sac. They feed on multiple prey items including bony fishes, shrimp, and mollusks, and are preyed upon themselves by large carnivorous predators including other sharks. 

Due to their small size ranging between 2.5-3 feet in length and the minor effects seen from human bites, they do not pose a serious danger to people. The Atlantic sharpnose shark is heavily fished commercially for its meat and also faces the threat of bycatch (caught accidentally when a different species is the target) from shrimp fisheries. 

Atlantic blacktip shark

Another shark found around beaches, bays, estuaries, and river mouths is the Atlantic blacktip shark. They are also viviparous, giving live birth to “pups” (term for baby sharks) in shallow-water nurseries after an 11-12 month gestation period. Unlike the sharpnose shark though, this species is bigger and can grow up to 6 feet long. They are gray or gray-brown colored and have a wedge-shaped band that is obvious against its white lower side. While their pectoral (side fins), dorsal (top fin), and tail fins all have black tips, it is a more inconspicuous fin that helps people identify an Atlantic blacktip shark. Its anal fin is white, and this feature distinguishes it from the commonly confused Spinner shark whose anal fin has a black tip. It’s also confused with the Spinner shark because of its similar behavior to leap out of the water when hunting schools of fish, although not to the extent of the Spinner shark. Interestingly, Atlantic blacktip sharks are known to aggregate into groups of males and groups of females in the mating offseason, before they come together in the early summer to breed. 

According to the National Oceanic and Atmospheric Administration (NOAA), the Atlantic blacktip shark is “a management success story.” Back in 1998, this species was overfished so NOAA implemented restrictions on commercial fisheries and eventually separated the species into the Gulf of Mexico stock and Atlanitc stock for their assessments. Now, neither stock is overfished and their rebound has been “enough to support four times the original harvest.” 

Spinner shark

The most notable characteristic of the spinner shark is the way it swims rapidly upward through a school of fish, snapping its body at them before leaping and spinning up to three times out of the water when it attacks! They showcase this unique skill when feasting on swarm fish, tuna, mollusks and other fish with narrow teeth better for small prey. Spinner sharks have similar coloration to the previous two sharks on our list with a white band along their sides and black-tipped fins. They average about 6 feet in length and grow roughly two inches per year – a faster growth rate than many other sharks. Spinner sharks usually bear between 7-11 live young every two years and after an 11-15 month gestation period. They often form groups and are highly migratory among warm-water regions. 

Spinner sharks are typically caught on longlines both purposefully and as bycatch. Longlines use a long main line with hundreds of other baited hook lines attached throughout the length of it that can be set up at different ocean depths. Their meat and fins are sold for human food and their skin for leather. They rank “Near Threatened” on the IUCN Red List because their populations aren’t concerningly low yet, but they face significant fishing pressure as well as habitat loss in shallow waters used for nurseries. 

Hammerhead sharks 

There are multiple species of hammerhead sharks that can be found in the Gulf of Mexico, including the Great hammerhead, Scalloped hammerhead, and Bonnethead. 

The Great hammerhead is the largest of these, reaching lengths up to 15-20 feet! They are also the longest living with a lifespan up to 40 years. They have a very large dorsal fin (top) and both their eyes and nostrils are located on either side of their hammer-shaped head (called a cephalofoil). They like to feed along the seafloor on prey like stingrays, groupers, and catfishes. Great hammerheads have even been observed to pin stingrays down to the seafloor using their head while they spin around to bite the wings. They travel alone and are highly migratory. Because of their large size, prized fins, and long reproductive time, the great hammerhead is heavily fished and critically endangered. 

The Scalloped hammerhead is smaller than the great hammerhead (about 12 feet long) and has notches/indentations along its cephalofoil that mimic a scallop. Like all hammerheads, scalloped hammerheads are viviparous, meaning they bear live young and nourish embryos using a yolk sac. They are also found in groups with seasonal aggregations seen off the Gulf of Mexico sometimes including hundreds of sharks! They prey on stingrays, smaller sharks, grunts, and invertebrates. Scalloped hammerheads are critically endangered on IUCN Red List due to threats including overfishing for the shark meat/fin trade, caught as bycatch, low reproductive rates, and lacking regulation. 

The Bonnethead, also nicknamed “shovel-heads,” is the smallest of the hammerheads, reaching only about 4 feet in length, although they grow at a faster rate. They eat small invertebrates and fishes, having a particular taste for blue crabs. Uniquely, bonnetheads are the only species of sharks to exhibit sexual dimorphism! This means that there is a difference in characteristic(s) between males and females of the same species; for bonnetheads, it’s the shape of the head. They also have among the shortest gestation periods known of all sharks at around 5 months. Typically, Bonnetheads are found in groups of around 15 individuals, but these groups can be bigger during migration and divided by sex during spawning. They are considered quite shy and harmless to humans. 

Tiger shark

We’ve all heard of these! And we know them well by the dark vertical stripes that appear on young tiger shark’s bodies. They grow over 18 feet in length  They are known to be curious creatures and are some of the least picky eaters around. While they feed mainly on marine critters like fish, stingrays, and turtles, they have also been known to eat license plates, tires, and cans!  Uniquely, tiger sharks are the only sharks of the family Carcharhinidae family that are ovoviviparous! This means that rather than developing a live embryo through a yolk-placenta like viviparous sharks, they lay eggs. However, these eggs hatch internally and the pups retain their yolk sac after the live birth until they can digest food on their own. 

Tiger sharks are near threatened due to similar threats we have seen before: overfishing for their fins and liver oil along with a low reproduction rate. They are also on many beach protection lists as a species to kill/control given their higher numbers of attacks on humans (though still very rare), second to great white sharks. 

Some other species found in the Gulf include:

• Blacknose shark
• Blue shark
• Thresher shark 
• Finetooth shark 
• Lemon shark
• Atlantic nurse shark

Sharks are misunderstood

Sharks are unfairly viewed as hungry-for-human killers in part due to how they’re portrayed in movies. In reality, there are many other things more likely to kill you than a shark such as lighting, a car accident, a dog attack, heart disease, and the list goes on. On top of that, humans kill about 80 million sharks per year, while only about 10 people die from shark attacks each year (10 recorded deaths globally in 2023). While people should be mindful of sharks when entering the water, given it is their home after all, one should not let the fear of them influence their feelings about the ocean or sharks themselves. 

With this in mind, here are some tips for reducing your risk of a shark attack:

• Don’t swim alone
• Avoid excessive splashing
• Avoid wearing jewelry in the water
• Don’t swim at dawn or dusk
• Don’t swim near areas where there’s lot of fish or where people are fishing

Protecting Sharks

Texas has taken a few steps to protect our misunderstood neighbors. In 2015, Texas joined nine other states in banning the sale, purchase, transports, and possession of shark fins with intent to sell. Later, in 2022, the shark fin trade was officially banned in the United States.  Despite the ban, shark finning and shark fin possession still occurred often in Texas, leading to Texas Senate Bill 1839 passed late last year, which strengthened and clarified restrictions on shark finning. Commercial fishing management continues today with regulations such as which species are allowed to be caught, size limitations for catch and gear, regional boundaries, and more. However, it is difficult to enforce these regulations and humans still widely fear sharks. This sentiment is backwards when you think about how many sharks humans kill every year, and it interferes with creating widespread conservation support many shark species need to save their populations. We applaud the work of conservation groups such as Shark Stewards, Oceana, Ocean Foundation, Humane Society International, Saving the Blue, and MANY more!

We hope that next time you visit our Gulf shores, you remember these respectable creatures whose home you’re entering and actively reflect on how much more useful and majestic they are contrary to common human perceptions.