Sharks

Great white shark breaching

• Sharks are amazing fish that have been around since long before the dinosaurs existed.

• They live in waters all over the world, in every ocean, and even in some rivers and lakes.

• Unlike bony fish, sharks have no bones; their

skeleton is made of cartilage, which is a tough, fibrous substance, not nearly as hard as bone. Sharks also have no swim bladder (like bony fish do).

General Shark

• Sharks may have up to 3,000 teeth at one time.

• The teeth are arranged in rows; when one tooth is damaged or lost, it is replaced by another.

• Most sharks have about 5 rows of teeth at any time. The front set is the largest and does most of the work

• Most sharks do not chew their food, but gulp it down whole it in large pieces.

Ampullae of Lorenzini

• The ampullae of lorenzini are small vesicles and pores that are part of the skin’s sensory network system.

• These pores detect weak magnetic fields produced by other fish and allow it to locate prey that are buried in the sand.

Do Sharks Sleep?• Fish don't sleep in the

same way that we do, but they have active and inactive periods.

• Some sharks (like the nurse shark) have been observed resting motionless on the sea floor, but others have to keep moving in order to breathe.

• The bull shark is the only shark that can live in both fresh and salt water.

Fun Facts:

• More people are killed by bee stings than by shark attacks.

• More than 90% of people who are attacked by sharks survive the attack.

• Sharks' bodies are heavier than the sea, so if they stop moving they sink. If they want to stay afloat, they must keep moving!

http://images.google.ca/imgres?imgurl=http://www.theage.com.au/ffximage/2004/03/08/09SHARK.jpg&imgrefurl=http://www.theage.com.au/articles/2004/03/08/1078594298166.html&h=239&w=200&sz=19&tbnid=b07AR-9f7UUJ:&tbnh=104&tbnw=87&hl=en&start=4&prev=/images%3Fq%3Dshark%2Battack%2Bsurfer%26hl%3Den%26lr%3D

No Cancer?

• It was thought that sharks never get cancer! It was the craze to take shark cartilage (powdered) because it had cancer fighting properties.

• However, in 2000, researchers at John’s Hopkins discovered several types of tumors and cancers in various sharks.

http://www.canoe.ca/Health0004/06_cancer.htmlhttp://www.seacure.com.au/Default.asp?c=5586

Shark skin

• Shark skin is covered with tiny tooth-like structures called denticles that protect them from abrasion, parasites, and helps them to swim efficiently by reducing drag

Unfortunately…

Sharks common to Nova Scotia

• These are the shark more commonly found in the Bay of Fundy

Have been seen….

Rare Species

• These are the sharks less common to the Bay of Fundy but are familar to the Atlantic Region.

The biggest shark is the whale shark (Rhincodon or Rhiniodon typus), which can be up to 50 feet (15 m) long. It is a filter feeder and sieves enormous amounts of plankton to eat through its gills as it swims

And still more:

More Shark Facts

• The biggest meat-eating shark is the Great white shark (Carcharodon carcharias) which grows to be up to 21 feet (6.4 m) long. Great whites up to 37 feet (11.3 m) long have been reported, but not verified.

MOST COMMON SHARK

• The piked dogfish shark (Squalus acanthias) is very abundant, especially in the North Atlantic Ocean. It is a small shark, about 63 inches (1.6 m) long.

DEEPEST DIVER

• The Portuguese shark dives down over 9,000 feet (2750 m). This is over 1.5 miles

Biggest shark ever!

• The largest shark known was the Megalodon (Carcharodon or Carcharocles megalodon); it is now extinct. It was an ancient, meat-eating shark that lived between 25 million and 1.6 million years ago. It was up to 40 feet (12 m) long and its teeth were each the size of a person's hand!

Smallest Shark

• The smallest sharks are: Dwarf Lanternfish (Etmopterus perryi), which is about 7 1/2 to 8 inches (19 - 20 cm) long for fully-grown females and 6 to 7 inches (16 - 17.5 cm) long for adult males

Fastest

• The fastest swimming sharks are the mako sharks and blue sharks, which can even leap out of the water. They are also probably the fastest fish. Estimates of their speed varies; some say that they can swim at about 60 miles per hour (97 kph), while more conservative estimates are about 22 mph

Longest Tail

• Thresher sharks -the upper lobe of their tails are about the same length as their bodies.

STRONGEST SHARK BITE

• The strongest shark bite belongs to the dusky shark (Carcharhinus obscurus); its jaws have been measured to exert 132 pounds (60 kg) of force per tooth!

Largest Litter

One Blue Shark was found with 135 pups in her uterus.

Other types:necklace carpet shark

goblin shark

great hammerhead shark

smooth hammerhead shark

megamouth shark

sand tiger or

gray nurse shark,

broadnose sevengill shark or cow shark

ornate wobbegong

Looking at Shark’s Relatives: Skates, Rays and Chimaeras

Chondrichthyes!!!

Rays

• The biggest ray is the Manta Ray which is over 22 feet (6.7 m) wide and weighs many tons (thousands of pounds).

• Remoras (another type of fish) are frequently seen with mantas, staying near the manta's mouth (even going inside the gill cavities). The remoras probably feed on parasites on the manta's body and eat bits of the manta's food.

•

• The smallest ray is the Short-nose electric ray, which is the size of a pancake; it is only 4 inches (10 cm) across and weighs about 1 pound (0.5 kg).

• Electric rays have specialized organs that can deliver a specific electric charge if provoked. This can stun an attacker, or prey!

PACIFIC ELECTRIC RAY

Skates

• Little Skate (Raja erinacea) - Bottom living, winter residents, they reach a max. length of 53 cm (or 21"). They eat bottom living invertebrates such as crustaceans. They are used for fish meal or as laboratory animals.

Common Skates and Rays in The Bay of Fundy

• Barndoor Skate (Raja laevis) - Bottom living, probably year-round, they reach a length of 127-142cm (or 50-56"). They eat bivalves, squid, rock crabs, lobsters, shrimp, marine worms, and a variety of fish. Of little value to the fishing industry, they are sometimes ground into fish meal.

• Winter Skate (Raja ocellata) - Bottom living, winter residents, they reach a length of 80cm (or 31"). They eat crustaceans, small fish, and bivalves. Of little value to the fishing industry, they are sometimes ground into fish meal. They are also used occasionally as laboratory animals.

• Thorny Skate(Raja radiata) - Bottom living, found year round, they reach max. lengths of 100 cm (or 39") although size varies with location. They eat polychaetes, crustaceans and fish. Of little value to the fishing industry, they are sometimes ground into fish meal. In Europe these skates are marketed for human consumption.

• Smooth Skate (Raja senta) - Bottom living, year round residents, they reach max. lengths of 60 cm (24"). They feed on crustaceans. Of little value to the fishing industry, they are sometimes ground into fish meal.

Chimaeras

Something Fun

• Video on Shark vs. Octopus

• Great White Shark Feeding Video

• Great White Shark Accident Video