Blacktip Shark (Carcharhinus limbatus)

The blacktip shark (Carcharhinus limbatus) is one of the most common large sharks found in tropical and subtropical coastal waters around the world. Blacktip sharks are not open-ocean dwellers preferring instead coastal waters less than 100 feet deep, although individuals sometimes venture some distance offshore. Favorite blacktip shark habitats include muddy bays, lagoons, and coral reefs; however, they are also found in brackish habitats, such as estuaries and mangrove swamps.

The blacktip shark is a species of requiem shark in the family Carcharhinidae. The blacktip shark has a pointed snout and a fusiform body with long gill slits. As its name would suggest, the blacktip shark has black tips on its pectoral, dorsal, pelvic, and caudal fins.

The blacktip shark is an extremely fast, energetic predator hunting mainly at dawn and dusk. Fish, including rays, skates, and smaller sharks, make up nearly 90% of the blacktip shark’s diet. Crustaceans and cephalopods are also occasionally eaten. In the Gulf of Mexico, the Gulf menhaden (Brevoortia patronus) and the Atlantic croaker (Micropogonias undulatus) are the most important prey items in the blacktip shark’s diet; while off South Africa, jacks and herring are the most common prey fish eaten.
The blacktip shark has a timid disposition as compared to other shark species of equal size, such as the Galapagos shark (C. galapagensis) and silvertip shark (C. albimarginatus). When competing for food with these other species the blacktip will usually loses out.

The blacktip shark is a very social species of shark, commonly found in groups, segregated by sex and age. Pregnant females aggregate in groups, while other adults aggregate together. Juvenile blacktips aggregate in shallow coastal nurseries seeking refuge from predators (mainly larger sharks). The mortality rate of juvenile blacktips during their first 15 months ranges from 60 to 90 percent.

Adult blacktip sharks are highly mobile and can disperse over long distances. Seasonal migration has been documented in some populations of blacktip sharks. However, blacktip sharks are philopatric and return to their original nursery location to give birth. Mating occurs from spring to early summer. Like other requiem sharks, the blacktip shark is viviparous, with young being born fully developed. The blacktip shark has a gestation period of ten to twelve months with young born in the spring and early summer. Females give birth to up to ten pups every other year. Baby blacktip sharks are about two feet long at birth. Male blacktips mature in four to five years, and female blacktips mature in seven to eight years. Mature blacktip sharks are usually four to five feet in length. The blacktip shark has an average lifespan of about 12 years.

Parthenogenesis, a form of asexual reproduction, has been observed in some sharks, including the blacktip shark.

The blacktip shark poses little danger to humans. However, these sharks can become aggressive in the presence of food. The excitability and sociability of blacktip sharks makes them prone to feeding frenzies when large quantities of food are suddenly available. Blacktip sharks are responsible for a small percentage of the shark attacks around Florida, most of which resulted in only minor wounds. This timid shark is not regarded as highly dangerous to humans.

The blacktip shark is caught in large numbers by commercial fisheries throughout the world. Its high quality meat is marketed fresh, frozen, or dried and salted. Its fins are used for shark fin soup, the skin for leather, the liver oil for vitamins, and carcasses for fishmeal. The blacktip shark is also a popular game fish with recreational fishermen. In the United States, the number of blacktip sharks taken for recreation now surpasses the number taken by commercial fishermen.

Black Tip Shark Falls Prey to Massive Goliath Grouper

Off the coast of Bonita Springs Florida in August 2014 a sports fisherman catches a four foot blacktip shark (Carcharhinus limbatus). However, before the shark is landed by the fisherman it is swallowed in one bite by a huge Goliath grouper (Epinephelus itajara) that comes to the surface to feed on the blacktip shark.

 

The blacktip shark is a member of the Carcharhinidae family and is a species of requiem shark common to coastal tropical and subtropical waters throughout the world. The blacktip shark’s diet is primarily other fish and this predator grows to nine feet in length, although five feet is a more normal size.

 

The Atlantic goliath grouper is an endangered species that can grow over eight feet in length and weigh nearly 800 pounds. The Atlantic goliath grouper is found in shallow tropical waters throughout the Atlantic Ocean. This fish lives primarily among coral and artificial reefs at depths from ranging from 20 to 160 feet. Goliath grouper commonly eat crustaceans, cephalopods, young sea turtles, and other fish, including sharks, rays and barracudas. These groupers have also been known to stalk and attempt to eat scuba divers.

 

Goliath groupers are believed to be born female and then later in life change sex and become male, since most groupers are protogynous hermaphrodites; however, this has not been verified for certain in this species. Protogyny is also the most common form of sequential hermaphroditism found in nature among species of fishes. Goliath groupers are aggregate spawners, often in groups of 100 individuals or more, and return to the same spawning sites time after time.

 

Atlantic Goliath Grouper (Epinephelus itajara)

Atlantic Goliath Grouper (Epinephelus itajara) at Dry Tortugas National Park

Enormous Great White Shark Filmed Near Guadalupe Island in Mexico.

Perhaps best known as the villain in the movie, “Jaws”, the great white shark (Carcharodon carcharias), is one of the world’s most feared animals. The sheer size and strength of a fully grown great white shark is quite remarkable.  A gigantic great white shark measuring more than 20 feet long was filmed near Mexico’s Guadalupe Island.  Mexico’s Guadalupe Island, also known as “The White Shark Cafe”, is located 165 miles west of Ensenada, and is one of the best spots in the world to see a great white shark . Scuba divers, fishermen and shark enthusiasts travel from all over the world to find the great white sharks which are attracted to Guadalupe Island’s colony of northern elephant seals (Mirounga angustirostris). The fall is the best time of the year for sighting the great white shark in the clear water around the Guadalupe Island.

 

The large, pregnant female shark shown in the video is nicknamed “Deep Blue”.  She is one of the largest great white sharks ever videotaped underwater. This massive fish, with a girth the size of a fat hippopotamus and measuring over 20 feet long, is believed to be around 50 years old.  Deep Blue was featured on the Discovery network last year in a piece about local shark researcher Mauricio Hoyos Padilla.  The footage, shot in in the fall of 2013, shows how huge this great white shark is in comparison to the scuba divers.

 

While little is known about great white sharks, they have been known to leap out of the water to capture seals; however, seals aren’t the only item on the menu.  Great white sharks may eat different prey depending upon their age, size, and location.  For example, great white sharks under 10 feet in length generally have a diet comprised predominantly of fish, including smaller sharks.  More mature individuals often exhibit a dietary shift to larger prey, including marine mammals.

Not much is known about great white shark’s  social behavior.  However, a dominance hierarchy dictated by size and sex has been observed at some locations. In this dominance hierarchy, females were dominant over males, larger sharks were dominant over smaller sharks and residents were dominant over newcomers.  Individual great white sharks have been observed with shark bite marks, suggesting that when these sharks get too close, they may give out warning bites to exert dominance.

Great whites are found off the coasts of South Africa, Australia, New Zealand, and Hawaii, as well as, the west coast and the Gulf coast of North America.

Great whites can reach speeds of 35 mph and tagged individuals have been known to undertake long distance migrations.

The great white shark is the closest living relative of the Megalodon, a giant prehistoric shark and the biggest shark to have ever lived. The two species of shark share many similarities, however, their hunting patterns are quite different. While the great white shark tends to attack the soft under belly of their prey for a quick kill; the Megalodon attacks its prey by biting off their fins before going for the final kill.

 

Greenland Shark (Somniosus microcephalus)

The Greenland shark is a large, sluggish shark that is grey or brown in color. The Greenland shark reaches over 20 feet in length and can weigh over a ton, although the Greenland shark is more commonly smaller than this. The Greenland shark has a heavy and cylindrical body and a short, round snout. Interestingly, the Greenland Shark has different shaped teeth. While the teeth in the upper jaw are spear-shaped, the teeth in the Greenland Shark’s lower jaw are short, smooth cusps that bend outward. The teeth in the upper jaw anchor the shark’s bite while the teeth in the lower jaw do most of the cutting.

The Greenland shark is a sub-Arctic shark living farther north than any other known shark species. Native to the waters of the North Atlantic Ocean, the Green shark is more usually found around Canada, Greenland, and Iceland, but has been known to travel down to the waters off the coast of the southern United States.

The Greenland shark feeds on a variety of prey including various marine invertebrates, fish, seabirds, and seals. However, scientists have also found parts of reindeer, dogs, cats and even a polar bears in the stomach of the Greenland shark. Although the Greenland shark is clearly a predator, it is one of the slowest-swimming species of shark and surprisingly its maximum swimming speed is only about half the maximum swimming speed of a healthy seal. There is some evidence suggesting the Greenland shark may ambush seals while they are sleeping. This shark is also known to be attracted by the smell of rotting meat in the water, so the Greenland shark can also be a scavenger.

Baby Greenland sharks are born and the mother shark can carry litters of up to 10 shark pups. The Greenland shark is a slow-growing shark and it appears to be extremely long-lived, possibly more than 100 years, although no specific age range has been determined.

Historically, the Greenland shark had been targeted by shark liver fisheries of several Scandinavian countries during the first half of the 20th century; however commercial fishing for Greenland shark as a source of shark liver oil stopped in the 1960s. Currently, the Greenland shark’s main threat is the Greenland halibut and shrimp trawl fisheries where it is often caught accidentally.

Inuit people used the dried meat of the Greenland shark for both human and sled-dog food, and the shark’s leathery skin to make boots. The meat of the Greenland shark can be toxic if not prepared properly due to the presence of high levels of trimethylamine oxide, which, upon digestion, breaks down into trimethylamine. Trimethylamine oxide is a protein stabilizer often found in sharks, skates and rays, but found in much higher concentrations in deep-water fishes, where it counteracts the protein-destabilizing effects of additional ocean pressure.

Bigeye Thresher Shark (Alopias superciliosus)

Bigeye Thresher Shark (Alopias superciliosus)

The bigeye thresher shark is one of three species of thresher shark and is recognized by its enormous eyes.

Pelagic Thresher Shark (Alopias pelagicus)

Pelagic Thresher Shark (Alopias pelagicus)

The Common Thresher Shark (Alopias vulpinus)

The Common Thresher Shark(Alopias vulpinus)

The common thresher shark(Alopias vulpinus) is the largest species of thresher shark reaching nearly 20 feet in length.

Megamouth Shark (Megachasma pelagios)

The megamouth shark is an extremely rare species of deep-water shark. The megamouth shark is the smallest of the three plankton-eating sharks.

Basking Shark (Cetorhinus maximus)

The basking shark is the second largest living fish, after the whale shark. The basking shark one of three known plankton-eating sharks, the other two are the whale shark and megamouth shark.

Whale shark (Rhincodon typus)