Oceanic Whitetip Shark

an oceanic whitetip in the Bahamas

The Oceanic Whitetip Shark
           Carcharhinus longimanus


The oceanic whitetip shark is a majestic shark that inhabits the open oceans of the world. One of their claims to fame is the tragedy of the USS Indianapolis. When the ship was sunk on a top-secret mission, less than of a third of the men survived and many deaths were attributed to oceanic whitetip attacks. However, most of the men died from exposure to the elements rather from shark bites.



Identification:
The oceanic whitetip is a grey to brown shark, known for their long, wide pectoral fins with mottled white tips. They have wide, rounded dorsal fins that are also white tipped. Oceanic whitetips have blunt, rounded snouts and small eyes.

Classification:
Kingdom : Animalia
Phylum : Chordata
Subphylum : Vertebrata
Class : Chondrichthyes
Subclass :  Elasmobranchii
Superorder : Selachimorpha
Order : Carcharhiniformes
Family : Carcharhinidae
Genus : Carcharhinus
Species : longimanus


Similar Species and Other Family Members:
One species similar to the oceanic whitetip is the whitetip reef shark - although it is similar in name and coloration only. The whitetip reef shark (Triaenodon obesus) is a much smaller shark that lives on coral reefs and has a slender body with a very short snout. They are typically dark brown in color with bright white tipped dorsal and caudal fins.

Triaenodon obesus

Reproduction:
The oceanic whitetip is a viviparous shark, meaning it gives placental live birth, just like humans. They tend to have a small amount of pups, around 5 or so per brood.


Size:
Female oceanic whitetips tend to reach about 200 cm (6.5 ft) in length, while males tend to be slightly smaller, reaching around 190 cm (6.2 ft). It is possible that oceanic whitetips could reach up to 350 cm (11.4 ft).


Diet: 
Oceanic whitetips feed mainly on pelagic bony fish, such as tuna and dolphin fish. They also eat cephalopods and have been known to eat marine mammals - normally in the form of carrion.


Teeth & Jaws:

The upper teeth of the oceanic whitetip are broad, triangular, and serrated. The lower teeth are more narrow and pointed. 

Upper tooth

Habitat and Distribution:
Oceanic whitetips are found all over the world in warm temperate and tropical waters. They live almost exclusively in pelagic waters, far off-shore.


Conservation Status:
The oceanic whitetip used to be the most abundant pelagic shark in the world; they are now listed as vulnerable on the IUCN Red List. The sharp decline in their population is due mainly to bycatch in pelagic fishing. They also suffer from heavy overfishing and are prized by shark finners for their large fins.



sources:
The Sharks of North America, Jose I. Castro
http://www.iucnredlist.org/details/39374/0
Sharks of the World, David A. Ebert, Sarah Fowler and Leonard Compagno 
note: none of the images are mine

Shark Poster

Created by Finformation

The Scalloped Hammerhead Shark

photo credit : Rafael Pesantes



The Scalloped Hammerhead
Sphyrna lewini 


The scalloped hammerhead is a very interesting species, as are the rest of the hammerheads. It is also occasionally known as the bronze hammerhead, or the kidney-headed shark. Hammerhead sharks are not normally considered a threat to humans. According to the International Shark Attack Files, from 1580 - 2011, approximately only 15 non-fatal attacks have been recorded, and no fatal attacks have been recorded.

The famous hammer shaped head.

Identification:
The scalloped hammerhead has the infamous hammer shaped head that all hammerheads have. It can be distinguished from other hammerheads by the "scalloped" edge of their head. They have a large, triangular first dorsal fin and a smaller second dorsal fin that is close to the caudal fin. Their coloring ranges from dark olive to brownish gray with a whitish ventral side. The ventral side of the pectoral fins darken with age, sometimes even darkening to black in larger sharks.

Classification:

Kingdom : Animalia
Phylum : Chordata
Subphylum : Vertebrata
Class : Chondrichthyes
Subclass :  Elasmobranchii
Order : Carcharhiniformes
Family : Sphyrnidae
Genus : Sphyrna
Species : lewini

Similar Species and Other Family Members:
The family Sphyrnidae has eight described species, all with unique"hammer" shaped heads. Scalloped hammerheads are most commonly mistaken for the Great Hammerhead (Sphyrna mokarran). However, the great hammerhead is larger and has a shorter head with more square ends.

Reproduction:
Scalloped hammerheads are viviparous, meaning they give placental live birth, like humans do. They tend to have 12-38 pups and typically have a 9-10 month gestation period.

Size:
Scalloped hammerhead are typically between 160-200 cm (5.2-6.5 ft) with the males being smaller than females at maturity. Females can occasionally reach up to 243-365 cm (8-12 ft).

Diet: 
The scalloped hammerhead tends to eat bony fish. They also eat invertebrates and other sharks. Hammerheads in general are known for their appetite for rays, including dangerous stingrays.

Schooling scalloped hammerheads

Habitat and Distribution:
Scalloped hammerheads are found worldwide in tropical and warm temperate seas. They are unique in that they migrate and school in large groups around sea mounts and islands, most famously around the Cocos Islands and the Galapagos Islands.

Life Span:
Scalloped hammerheads are believed to live up to 35 years.

The scalloped hammerhead's large fin puts it at
great risk from shark finners. 

Conservation Status:

On the IUCN Red List, the scalloped hammerhead is listed as endangered worldwide. They are heavily fished around the world, and are commonly hunted for the shark fin soup trade due to the large size of their fins.

sources:
The Shark Handbook, Dr. Greg Skomal
http://www.iucnredlist.org/details/39341/0
Sharks of the World, David A. Ebert, Sarah Fowler and Leonard Compagno 

note: none of the images are mine, however I did draw the illustrations

The Frilled Shark

The Frilled Shark  
      Chlamydoselachus anguineus

The frilled shark is a rare deep-water species. It poses no threat to humans due to the fact it lives where it is not likely to encounters people.


Identification:
The frilled shark's most identifiable feature is its long, eel-like body.

It is dark to light brown with darker fin edges. It has a long lower jaw and an enormous gape. It has six gill slits, the first of which goes continuously underneath the head.

Frilled sharks also only have one dorsal fin, located by the base of the caudal fin. Its caudal fin is almost completely an upper lobe.


Classification:
Kingdom : Animalia
Phylum : Chordata
Subphylum : Vertebrata
Class : Chondrichthyes
Subclass :  Elasmobranchii
Order : Hexanchiformes
Family : Chlamydoselachidae
Genus : Chlamydoselachus
Species : anguineus


Similar Species and Other Family Members:
There are speculations that the frilled sharks that live in South Africa are a different species, the South African frilled shark.


Reproduction:
Frilled sharks are ovoviviparous. We do not know their age of maturity. Frilled sharks are believed to give birth to 12 young. We do not know the frilled sharks' gestation period, however it has been estimated to a year or more due to the large size of the eggs.


Size:
 Male frilled sharks are believed to be sexually mature at 110 cm (3.6 feet), while females are sexually mature at about 135 cm (4.4 feet). The maximum reported length is 196 cm (6.4 feet).


Diet: 
Most of what the frilled shark feeds on is unknown. However, we do know that  it does eat squid and bony fish.


Teeth & Jaws:
Here is an image of frilled shark teeth. These teeth are perfect for snatching slippery prey, such as squid.

Habitat and Distribution:
Frilled sharks are found all over the world. They are most common at depths of 50-200 meters (160-660 ft), but they have been found as deep as 1,570 meters (5,150 ft).


Lifespan:
The lifespan is unknown. Since we cannot tag or track these sharks and they do not survive in captivity, we can't tell their life span.


Conservation Status:
According to the IUCN Red List of Threatened Species, the frilled shark is near threatened. They are generally a rare species. They are not actively fished, but a regular bycatch in many bottom trawl, midwater trawl, deep-set longline, and deep-set gillnet fisheries.



sources:
The Sharks of North America, Jose I. Castro
http://en.wikipedia.org/wiki/Frilled_shark
Sharkpedia, DK Publishing 
http://www.elasmo-research.org/education/ecology/deepsea-frilled_shark.htm
http://www.iucnredlist.org/details/41794/0
note: none of the images are mine

The Nurse Shark

The Nurse Shark
       Ginglymostoma cirratum


The nurse shark is a common shark species. It poses no threat to humans unless harassed or threatened.

Identification:
The nurse shark's most identifiable feature are it's conspicuous nasal barbels.

Color is variable, ranging from light yellowish to dark brown. The underside is a whitish-gray color. Neonatal nurse sharks have dark spots to aid camouflage.

 Another way to identify a nurse shark is by its caudal fin, which is almost completely an upper lobe.

Classification:

Kingdom : Animalia
Phylum : Chordata
Subphylum : Vertebrata
Class : Chondrichthyes
Subclass :  Elasmobranchii
Order : Orectolobiformes
Family : Orectolobidae
Genus : Ginglymostoma
Species : cirratum

Similar Species and Other Family Members:
There are no similar species or any other species in the family.

Reproduction:
Nurse sharks are an ovoviviparous. Male nurse sharks are sexually mature at 10 - 15 years, while females are sexually mature at 15 - 20 years. Nurse sharks give birth to 20 - 30 young about every other year. The gestation period is 5.5 months.

Size:
Males mature at 210 cm (7 feet), while females mature at 240 cm (8 feet). The maximum reported length is 430 cm (14 feet), but most experts agree that 430 cm is an exaggeration. A more realistic size estimate is 270 cm (9 feet).

Diet: 
The nurse shark feeds on crabs, lobsters, bivalves, squid, bottom-dwelling fish, octopus, shrimp, sea snails and sea urchins. They will also occasionally feed on stingrays. Most feeding is done at night, as nurse sharks often rest during the day.

Teeth & Jaws:
Here is an image of fossilized nurse shark teeth.

Habitat and Distribution:
Nurse sharks live on reefs and are found all throughout Atlantic reefs. They are found in tropical and sub-tropical waters of the east coast of the Americas and the west coast of Africa. This species is abundant all year long in Florida and the Caribbean.

Life Span:
The life span in the wild is unknown, but the oldest shark in captivity reached an age of 25 years.

Conservation Status:
According to the IUCN Red List of Threatened Species, the nurse shark is data deficient, meaning there is not enough data to determine a conservation status.

note: none of the images are mine

Shark Classification

Here is a quick thing on shark classification

Kingdom- Animalia

Phylum- Chordata

Subphylum- Vertebrata

Class- Chondrichtyes (cartilaginous fish)

Subclass- Elasmobranchii (upper jaw that is not fused to the braincase, no swim bladder, advanced electroreceptive system, a spiracle, skin with placoid scales, teeth modified placoid scales, and 5-7 separate slit-like gill openings on each side of the body: there are about 600 species of sharks, skates, and rays) 

Subclass- Plagiostomi (sharks and rays: upper jaw hung from skulls and different kind of blood)

Superorder- Selachimorpha (sharks: free upper eyelids, gill openings on the head, and pectoral fins separate from the side of the head)

Orders- Living sharks are split into 8 orders.

Shark Orders

Zebra Shark

The Zebra Shark
 Stegostoma  fasciatum




The zebra shark is know for its beautiful markings. There are no attacks on humans by a zebra shark on record.

Identification:
The easiest way to identify a zebra shark is by its unique markings. When it is young it has striped markings (hence the name zebra shark). As they get older, the stripes break into spots. Sometimes the spots will make the outline of the stripes, such as in the picture above. The coloration in juveniles is dark brown with tan or pale yellow stripes. Adult coloration is tan to pale yellow with black to dark brown spots. The zebra shark has 5 gills on each side. It has a broad elongated upper lobe of the caudal fin, and almost no lower lobe. It has small eyes and a small mouth with barbels on both sides of its mouth.

Classification:
Kingdom: Animalia
Phylum: Chordata
Subphylum: Vertebrata
Class: Chondrichtyes
Subclass: Elasmobranchii
Order: Orectolobiformes
Family: Stegostomatidae
Genus: Stegostoma
Species: fasciatum

Similar Species and Other Family Members:
The zebra shark is the sole member of the Stegostomatidae family. This shark is very distinctive, but as it is sometimes called a leopard shark, it is often confused with a cold water species which is also called the leopard shark (Triakis semifasciata).


Reproduction:
The zebra shark is oviparous (lays eggs). They will lay one to four eggs a brood. Their size at birth is around 25 centimeters (9.8 inches).

A young zebra shark

Size:
The maximum length of the zebra shark is 350 cm (11.5 feet).

Diet:
The zebra shark feeds on shellfish, crustaceans, and small fishes.

Teeth:

Zebra shark jaws

Habitat and Distribution:
The zebra shark lives in the warm waters of the tropical western Pacific and Indian Ocean.

Life Span:
The zebra shark's life span is believed to reach up to 30 years in the wild. The longest known life span in captivity is 25 years.

Conservation Status:
The zebra shark is listed as vulnerable.


A video of a zebra shark I took at
Discovery Cove.


Note: I do not own any of the still images. 

The Whale Shark

Whale shark (Rhincodon typus) with a diver

The Whale Shark is the worlds largest shark. It will occasionally hit a diver with its tail on accident, but other than that it is mostly harmless to humans.

Identification:
 The easiest way to identify a whale shark is by its massive size.  It is the largest fish in the ocean. It has dark greenish to brownish gray skin covered with white or yellowish spots and irregular dark and light bars. It has a huge mouth that can reach 4 feet (1.4 meters) wide.  The mouth is in front of the head, instead of below the head like it is in most sharks. It has 5 gills and small eyes.

Classification:
Kingdom: Animalia
Phylum: Chordata
Subphylum: Vertebrata
Class: Chondrichtyes
Subclass: Elasmobranchii
Order: Orectolobiformes
Family: Rhincodontidae
Genus: Rhincodon
Species: typus


Similar Species and Other Family Members:
The whale shark is the only member of the family Rhincodontidae.  Its massive size and  striking markings make it easy to distinguish from other sharks.

Reproduction:
The whale shark is ovoviviparous (the eggs are nourished by a yolk, but the mother keeps them inside her body until they run out of food from the yolk and then they are born live). Their size at birth is 21 to 25 inches (55 to 64 centimeters). Whale sharks are sexually mature at 30 years. It is thought that one brood can contain up to 300 young!

A man holding a young whale shark.

Size:
The whale shark can reach lengths of up to 45 feet ( 13.7 meters)! It can weigh up to 30 tons (33 metric tons).


Diet:
 The whale shark lives mainly on plankton, but will also eat small squids and bony fishes.


Teeth:
Here is a good image of  whale shark teeth. 

Habitat and Distribution:
Whale sharks are found in warm waters all around the world. They are not, however, found in the Mediterranean Sea. Large populations of whale sharks are often found near Ningaloo Reef, Australia.


Life Span:
The whale shark may live up to 150 years.


Conservation Status:
The whale shark is now listed as a threatened species.


note: I do not own any of these pictures

The Goblin Shark

Goblin shark with jaw protruding.

Goblin shark with jaw in normal position.

Common name:
 Goblin  Shark.
Scientific name:
 Mitsukurina owstoni





The goblin shark is a very rare, deep water specimen. It is not a threat to humans, since it lives at depths that humans can only visit via submarine.

Identification:
This unmistakable shark's most recognizable feature is its long, paddle-like snout. The snout's use is unknown, but some scientists believe it allows the shark to have more ampullae of Lorenzini, therefore making its sense of electroreception stronger. Goblin shark juveniles are white to pinkish light gray dorsally and white below.  Adults are pink to light tan, and preserved specimens are gray. The jaw is able to protrude very far. Their skin is soft and flabby. Goblin sharks have 5 gills on each side, two dorsal fins, no fin spines, no nictitating membranes, and their mouths are behind their eyes.

Classification:
Kingdom : Animalia
Phylum : Chordata
Subphylum : Vertebrata
Class : Chondrichthyes
Subclass :  Elasmobranchii
Order : Lamniformes
Family : Mitsukurinidae
Genus :  Mitsukurina
Species : owstoni


Similar Species and Other Family Members:
The goblin shark is the only member of the Misukurinina, and their are no other species similar to it.


Reproduction:
Very little is known about this subject when it comes to goblin sharks. They are believed to be ovoviviparous (the eggs are nourished by a yolk, but the mother keeps them in her body till they run out of food from the yolk and then they are born live).

Size:
Goblin sharks are thought to grow from 6 to 15 feet (180 to 450 cm) long. They may reach over 400 pounds (180 kilograms) in weight.

Diet:
Very little is known on this subject, but we do know they will eat bony fish, squid, and crustaceans. We do not yet know of anything else they will eat.

Teeth & Jaws:
Here is a good illustration of a goblin shark tooth.

When a goblin shark bites prey, it's jaw protrudes out. This gif shows this action excellently.

Habitat and Distribution:
The goblin shark is a deep water species, found at depths of up to 3,940 feet (1,200 meters). It is found in the western Pacific Ocean, the western Indian Ocean, and the western and eastern Atlantic Ocean.

Life Span:
No one knows the life span of the goblin shark.

Conservation Status:
Data deficient.

note: I do not own any of these pictures. 

Save the Sharks

Right now, you're probably thinking, "Why should we bother saving sharks? They are mindless killing machines, out to hunt us." That's not true. Sharks are dangerous, that is true. But so are big cats. They are both smart, deadly, and dangerous predators. Most often the cause of a shark bite is that they are trying to see if we are edible. When they realize we aren't dinner, they swim away to find something else. Sharks are naturally curious but they, unlike humans, don't have hands to feel so they use their mouth. Unfortunately a small bite from a big shark can be deadly. But don't let this keep you out of the water! In truth, you are more likely to die from food poisoning than from a shark attack!

Now let's talk about how sharks help us. Without sharks, the ocean would be a big mess. Sharks eating carcasses helps keep the oceans carrion free and their hunting helps prevent over population. If, for example, white sharks went extinct. The seal colonies wouldn't have as many predators, so they would start to grow. Interbreeding and cramped spaces would cause illness. The sharks would have normally picked of the sick ones. Slowly the seals would eat all the available food and the chain of events would cause the food web to fall apart.

Okay, now that we have established why we need to save sharks, what exactly do we need to save them from?  The simple answer to that is humans. While sharks kill at the most 100 people a year, we kill over 7 million sharks a year! Sharks are apex predators so their slow reproductive rates can't keep up with this massive slaughter. Some sharks are killed for their jaws, liver oil, skin, teeth, and meat, most are killed for shark fin soup. This delicacy is most popular in China and Japan. It can cost up to 100 dollars a bowl! This soup is viewed as a social status; if you can afford it you are upper class. I have heard it isn't even that good!

To get the fins, finning vessels go out to sea and capture any shark they can.  Then they cut the fins off of the shark, sometimes while it is still alive and then throw the shark back into the ocean to die. This is a truly barbaric practice.

Sharks have been around since before the dinosaurs. There is no need for them to disappear for soup!

note: I do not own any of these pictures.

Shark Basics

Shark. A name that sends most people running, or swimming, for cover. But, what exactly is a shark?
                                   
Are sharks fish? Do they have bones?
Sharks are fish and they are in the cartilaginous fish family, a.k.a the Chondrichtyes. This means that, instead of bones, sharks have cartilage for every "bone" in their body except their teeth and jaws. Other members of the class Chondrichthyes are the rays, skates, and chimaeras.

How many types of sharks are there?

There are eight orders of sharks. The Hexanchiformes, the Squaliformes, the Pristiophoriformes, the Squantiniformes, the Heterodontiformes, the Orectolobiformes, the Lamniformes, and the Carcharhiniformes. In total, there is believed to be over 400 shark species.

A chart of all shark orders.

How long have sharks been around?

Fossil records show that sharks have been swimming in the seas for over 400 million years. That's about 175 million years before the dinosaurs! Since then the basic shark design has barely changed.

How long do sharks live?

Some sharks are so rare or just cannot be kept in captivity long enough that their longevity is still unknown. Their longevity also depends on the species of shark. Some sharks such as the smooth dogfish (Mustelus canis)  may only live 16 years, where as the porbeagle shark (Lamna nasus) may live as long as 46 years. The whale shark (Rhincodon typus) is thought to live to 100 years.

What does shark skin feel like?

Shark skin feels exactly like sandpaper. It is made up of tiny teeth-like structures called placoid scales, also known as dermal denticles.

Do sharks sleep?

It was once believed that sharks had to keep swimming to breath and could not sleep for more than a few minutes at a time. While some sharks do need to keep swimming, some species, such as the nurse shark (Ginglymostoma cirratum) use spiracles to force water over their gills allowing for stationary rest. Sharks do not sleep like humans, instead they have active and restful periods.

Can sharks hear?

Sharks have an excellent sense of hearing, though you can't see their ears since they have inner ears instead of big, non-streamlined, outer ears like humans have.

How many teeth do sharks have? 

Sharks can have up to 7 rows of teeth in their mouth at any one time. This is so they can lose a tooth and one will be right there to take its place. This way the shark is always ready to attack.

What is "electroreception"?

Electroreception is the sharks sixth sense. It's also the rarest animal sense. Only sharks and the duck-billed platypus of Australia are thought to have this sense. Here's how it works: All organs emit electrical signals. Sharks have special organs called the ampullae of Lorenzini that can detect these electrical signals. This allows sharks to pinpoint and locate the electric field- even if it's coming from an animal buried motionless on the seabed. The ampullae are delicate, jelly-filled pores on the snout. They are so sensitive they can detect electrical fields of one hundred-millionth of a volt.

I hope that answered all your sharky questions!

                                                                                                                                        

note: I do not own any of these pictures.