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Common Sharks Caught off Ocean City
The Shortfin Mako Shark (Isurus oxyrinchus
"sharp nose"), commonly just called Mako Shark despite not being the only
species of mako, is a large shark of the Lamnidae family.
With a full-grown size of 9-13 feet (2.75–4
m). It has been reported to weigh up to 1750 pounds (800 kg) and has a
bluish top and a white underside. Although the sexes grow at about the
same rate, females are thought to have a longer life span. Females grow
larger and weigh more than the males. Shortfin Makos are renowned for
their speed and their ability to leap out of the water.
The shortfin mako is found in temperate and
tropical seas all around the world.
The sharks speed has been recorded at over
22 miles (35 kilometers) per hour, with perhaps a burst speed of up to 60
miles (100 kilometers) per hour.
This high leaping, boat attacking fish is sought as game worldwide. Some
of the largest makos in the world can be found in New England waters. The
closely related Longfin Mako Shark, Isurus paucus, is found in the Gulf
Stream or warmer offshore waters. Shortfin Makos were popularized in the
movie Deep Blue Sea.
The Shortfin Mako Shark is a yolk-sac
ovoviviparous shark, meaning it gives birth to live young who feed off of
a sac full of yolk in the womb. The gestation period for a Mako Shark is
15-18 months. Mako embryo in the female's body literally consume each
other to get nutrients. This is called intrauterine cannibalism. (From
Wikipedia, the free encyclopedia)
The Blue Shark (Prionace glauca) is a
carcharhinid shark. They are surface predators in the deep waters of the
world's temperate and tropical oceans. They prefer cooler waters and are
not found, for example, in the Gulf of Mexico, the Adriatic or Red Sea.
Blue Sharks are known to migrate long distances — from New England to
South America for example. Although generally lethargic, they are capable
of moving very quickly if the need arises. Blue Sharks are viviparous
(give live birth) and are noted for their large litters of 25 to over 100
pups. They feed primarily on small fish and squid although they are
perfectly capable of taking larger prey should the opportunity present
itself. They are often found in schools segregated by sex and size.
Blue Sharks are light bodied with long
pectoral fins. The top of the body is deep blue lightening on the sides.
The underside of the shark is white. The animals grows to lengths of 3.8
meters or more, but the usual size is 1.8 to 2.4 meters. Typical weight is
30 to 50 kg. Blue Sharks are not easily confused with any other species.
They are occasionally sought as game fish. The flesh is edible, but not
widely sought after. Blue Sharks are frequent accidental catches by
commercial fisherman seeking swordfish or tuna.
Blue Sharks are rarely or never found in shallow water and thus are not
included in lists of sharks endangering humans. However, they are believed
to attack victims of air and sea disasters. (From
Wikipedia, the free encyclopedia)
Thresher sharks are large lamniform sharks
of the family Alopiidae. Found in all temperate and tropical oceans of the
world, the family contains three species all within the genus Alopias.
Like all large sharks, threshers are slow growing and are therefore
threatened by commercial fisheries. Other than for its meat, the sharks
are hunted for their liver oil, skin (for leather), and their fins, for
use in shark-fin soup.
The genus and family name derive from the Greek word alopex, meaning fox.
Indeed the Long-tailed Thresher Shark (Alopias vulpinus) is named the Fox
Shark by some authorities.
Named for and easily recognized by their
exceptionally long, thresher-like tail or caudal fins (which account for
50 percent of their total body length), thresher sharks are active
predators; the tail is actually used as a weapon to stun prey. By far the
largest of the three species is the thintail thresher (Alopias vulpinus)
which may reach a length of 7.6 metres and a weight of 348 kilograms. The
bigeye thresher (Alopias superciliosus) is next in size, reaching a length
of 4.89 metres; at just 3 metres, the pelagic thresher (Alopias pelagicus)
is the smallest.
Thresher sharks are fairly slender, with small dorsal fins and large,
recurved pectoral fins. With the exception of the bigeye thresher, these
sharks have relatively small eyes. Coloration ranges from brownish, bluish
or purplish gray dorsally with lighter shades ventrally.
Although occasionally sighted in shallow, inshore waters, thresher sharks
are primarily pelagic; they prefer the open ocean, staying within the
first 500 metres of the water column. They are also found in coastal
waters over continental shelves.
Pelagic schooling fish (such as bluefish, juvenile tuna, and mackerel),
squid and cuttlefish are the primary food items of the thresher sharks.
They are known to follow large schools of fish into shallow waters.
Crustaceans and the odd seabird are also taken.
Thresher sharks are solitary creatures which keep to themselves. They do
not appear to be a threat to humans, although some divers have been
whacked with the upper tail lobe. It is known that thresher populations of
the Indian Ocean are separated by depth and space according to gender. All
species are noted for their highly migratory or oceanodromous habits.
No distinct breeding season is observed by thresher sharks. Fertilization
and embryonic development occur internally; this ovoviviparous or
live-bearing mode of reproduction results in a small litter (usually 2-4)
of large well-developed pups, up to 150 centimetres at birth in thintail
threshers. The young fish exhaust their yolk sacs while still inside the
mother, at which time they begin feeding on the mother's unfertilized
eggs; this is known as oophagy.
Thresher sharks are slow to mature, males reaching sexual maturity between
7-13 years of age and females between 8-14 years in bigeye threshers. They
may live for 20 years or more. (From
Wikipedia, the free encyclopedia)
The hammerhead shark (genus Sphyrna) is a
member of the family Sphyrnidae. The only other genus of Sphyrnidae,
Eusphyra, contains only one species, E. blochii, the winghead shark).
The eight species of hammerhead range from 2–6 m long, and all species
have projections on both sides of the head that give it a resemblance to a
flattened hammer. The shark's eyes and nostrils are at the tips of the
It is an aggressive predator that eats fish, rays, other sharks,
cephalopods, and crustaceans. It is found in warmer waters along
coastlines and continental shelves.
The shape of the head seems to act as a wing, aiding in close-quarters
maneuverability, allowing sharks to execute sharp turns without loss of
stability. It also seems to help in electrolocation by separating the
receptors, thus giving hammerheads a wider area of search. These sharks
have been able to detect an electronic signal of half a billionth of a
volt. The hammer shaped head also gives these sharks larger nasal tract,
increasing the chance of finding a particle in the water by at least 10
times as compared to other 'classical' sharks. Hammerheads have
proportionately small mouths and seem to do a lot of bottom-hunting. They
are also known to form schools during the day, sometimes in groups of over
100. In the evening, like other sharks, they become lonely hunters.
Reproduction in the hammerhead shark occurs once a year and each litter
contains 12–15 pups. Hammerhead shark mating courtship is a very violent
affair. The male will bite the female until she acquiesces, allowing
mating to occur. Unlike many other shark species, the hammerhead shark has
internal fertilization which creates a safe environment for the sperm to
unite with the egg. The embryo develops within the female inside a
placenta and is fed through an umbilical cord, much like in mammals. The
gestation period is 10–12 months. Once the pups are born the parents do
not stay with them and they are left to fend for themselves.
Of the eight species of hammerhead, three (3) can be dangerous to humans:
the scalloped, great, and smooth hammerheads.
Since sharks do not have mineralized bones and rarely fossilize, it is
their teeth alone that are commonly found as fossils. The hammerheads seem
closely related to the carcharhinid sharks that evolved during the
mid-Tertiary Period. Because the teeth of hammerheads resemble those of
some carcharhinids, it has been difficult to determine when hammerheads
first appeared. It is probable that the hammerheads evolved during the
late Eocene, Oligocene or early Miocene.
There are two schools of thought for the odd head shape of the
hammerheads. One states that it is because of the greater area for sensors
to scan the bottom of the seafloor for food and the other that it provides
lift (Hammerheads are one of the most negatively buoyant of sharks) and
added maneuverability. Both of the theories are probably correct. (From
Wikipedia, the free encyclopedia)
The name dogfish is applied to a number of
small sharks found in the northeast Atlantic, Pacific, and Mediterranean,
especially those in the three families Scyliorhinidae, Dalatiidae and
Squalidae. The name is applied only loosely and does not signify a close
taxonomic relationship. A number of other unrelated fish, notably the
bowfin,eelpout/burbot are also sometimes referred to as dogfish and
commonly sold as Rock Salmon (or Huss) as Fish and chips.
Two features distinguish the spiny dogfish from the smooth
variety. First, rows of small white dots run along its slate-grey sides,
and second, it has a sharp spine in front of each of its two dorsal fins.
The shark uses the spine defensively by curling around in a bow to strike
an enemy. The spines are also thought tobe slightly poisonous.
Spiny dogfish are common in the Mid-Atlantic
region and are considered pests by commerial and sportfishermen because it
has no great value on the local market and doesn't put up much of a fight
(Mustelus canis) -- Averaging 3
to 4 feet in length, the Smooth Dogfish Shark is one of the most abundant
sharks on the East Coast.
The smooth dogfish is found in great numbers
in summer in the Delaware Bay and more of them are caught here than all of
the other sharks combined.
They will leave the area in mid-October when the water starts to cool and
by early November most of them will have headed south. They won't return
until mid-April or when the water rises above 50 degrees.
Smooth dogfish have many low, flat, pavement-like teeth that crush and
grind more than they actually bite or tear. They feed mainly on lobster,
crabs, small fish, razor clams and small hard clams.
Common names include brown shark, queriman
shark, and thickskin shark.
Order - Carcharhiniformes
Family - Carcharhinidae
Genus - Carcharhinus
Species - plumbeus
The sandbar shark is a coastal-pelagic species that inhabits temperate and
tropical waters. It is the most abundant species of large shark in the
Western Atlantic. It can be found in mid-Atlantic waters from May to
September in the Delaware Bay area, which appears to be a mid-point in its
migration to southern wintering and northern summering grounds.
The Sandbar Shark has a massive set of teeth
that are triangular, serrated and razor sharp.
Because is it so scarce in this area, Sandbar shark meat isn't available
commercially, but the fish does yield delicious meat.
C. plumbeus is essentially a
bottom-dwelling, shallow coastal water species that is seldom seen at the
water's surface. It tends to prefer waters on continental shelves, oceanic
banks, and island terraces but is also commonly found in harbors,
estuaries, at the mouths of bays and rivers, and shallow turbid water. It
is believed that the sandbar shark favors a smooth substrate and will
avoid coral reefs and other rough-bottom areas. It spends most of the time
in water from 20-65 m (60-200 ft) deep but undoubtedly moves into deeper
water to undergo migration.
(Carcharias taurus) -- The Sand Shark likes
to spend time in the bays and the larger ones are usually caught in the
upper parts of our bays.
Most sand sharks are found from Cape Cod
south, but they aren't found in great numbers below the Delaware Bay.
The sand shark's mouthful of teeth can send chills through you. Still,
this is not a man-eater. Instead, it is somewhat sluggish and lives on the
bottom of the sea or close to it.
The sand shark appears in our waters mostly in summer when the surface
temperature reaches 60 to 70 degrees.
Most weigh less than 150 pounds but some have been caught weighing more
than 200 pounds. The average length is 4 to 6 feet with the largest
growing to 10 feet or more.
The blacknose shark Carcharhinus acronotus is a common shark in inshore
and moderately deep waters of the western Atlantic Ocean (North Carolina
to the Bahamas to southeastern Brazil). This requiem shark averages about
4 feet (1.2 m) long, but can grow to 6 1/2 feet (2 m) long. It has gray
skin above (and white skin below) and the snout is dark; some of these
sharks have spots that fade with age. The fins are darker at the edges.
When threatened, it exhibits a "hunch" display: this shark arches its
back, raises its head, and lowers its tail. The blacknose is harmless to
people - it is fished as game. The blacknose eats small fish; it is eaten
by larger sharks and people. It is viviparous (it has a yolk-sac placenta
to nourish the embryos). There are 3 to 6 pups in each litter; the
gestation period is 8 to 9 months long. Newborns are 10-19 inches (25.5 to
48.5 cm) long. Classification: Order Carcharhiniformes (ground sharks),
Family Carcharhinidae (requiem sharks), Genus Carcharhinus, Species C.
The angel shark is lives on the sandy
bottom of the ocean. It lives offshore, in bays, and along the fringe of
kelp forests. Its flat body is gray with olive blotches and it has large
pectoral fins that look like wings. Its shape and color help it to hide in
the sand on the ocean bottom.
The angel shark preys on other fish by burying itself in the sand and
ambushing them as they swim by. It likes to eat small fish and squid, and
though it's not very dangerous to people, it can inflict a painful bite if
surprised or harassed.
The female angel shark lays an egg case that looks like a little
drawstring purse and is sometimes called a mermaid's purse.
There are three types of embryonic
development, oviparous, ovoviviparous, and viviparous.
Did you know the largest shark known is
called the Whale Shark? Some grow to be almost 50 feet long! One of the
smallest sharks is the Midwater Shark which only grows to around 10 inches
Sharks have been known to shed as many as
30,000 teeth in a lifetime.
Certain shark species bite with the force of
42,000 pounds per square inch - compared to the adult male human's bite of
150 pounds per square inch.
At least eight known species of shark are
endothermic, or warm blooded - controlling their temperature much as
The largest organ in a shark is the liver.
The shark lacks flotation bladders and that is why most sharks will sink
if they stop moving. The liver contains an oil, called squaleen, which
helps to float sharks. The sharks stomach can be turned inside out if the
shark swallows something it cannot digest. Male sharks have a pair of
claspers that are formed from the inner pelvic fins. The shark's brain is
similar in weight to those of birds and mammals making the shark the most
intelligent of fish. Sharks can even be trained. The olfactory bulb is
close to the front part of the brain.
THE SHARK'S SIXTH SENSE: The shark has all
the senses that we humans do but they also have one we don't have. Tiny
pores on the snout leads to jelly-filled sacs known as ampullae of
Lorenzini. This sense can detect very weak electrical fields that can
detect electrical "vibes" as weak half a billionth of a volt. Struggling
or scared animal creates a strong electrical current, which flows through
the water, and even though it gets weaker as it travels away from the
animal sharks can pick it up. Every animal sends electrical "vibes". A
shark can find animals under the sand, and at night, and when at the last
moment of attack when the eyes are rolled back and it cannot see. In many
cases when doing shark research the shark would attack the boat and other
objects instead of the food offered. Humans used to
think that the shark was just a stupid, crazy eating machine that went
after anything. It turns out however that the shark when coming for the
prey would roll it's eyes back and have the ampullae of Loranzini direct
it to the prey. The boat gives out very strong electrical "vibes" which
confuse the shark and direct it to the boats direction, and since the
shark cannot see at the moment it would not know the boat is not the prey.
Hammerhead sharks have a large number of ampullae of Lorenzini on their
heads. Hammerheads use their heads like mine sweepers to find stingrays,
and other prey in the sand. Large number of hammerheads can be found near
underwater volcanoes which attract them from miles away with their
electrical fields. The rare and strange goblin shark has a strange snout
hanging over is head which may be used the same way as a hammerheads head
and help it hunt in the deep dark water it lives in. Goblin shark teeth
have been found in underwater electrical cables.
THE LATERAL LINE: The lateral line is another sense that we human do not
have. The lateral line is a fluid filled canal that is lined with tiny
hair like receptors that are attuned to vibrations made by prey. These
lateral lines are located just under the skin on the shark's snout and
along both sides of the body. These lines are also in bony fish. Fish
(sharks included) can also use these lines to sense water currents and
pressures and even sounds. Some say that the bumping behavior of sharks
allows external taste receptors to see if the organism is edible (this may
explain why sharks often bump objects).
SMELL: Unlike the nostrils of "higher" animals, sharks are not used for
repertory functions. The shark can sense one molecule of blood in a
million molecules of water. Each nostril is divided by a skin flap, which
separates the water flowing in and out. As the fish swims water enters the
nostrils and through the nasal capsule that contains lamellae. Lamellae
increase the shark's sensitivity to odors. The olfactory bulb is close to
the front of the brain.
HEARING: The shark has an excellent sense of hearing and can hear the low
pulsing sounds made by animals swimming, splashing, and struggling. These
sounds are too low for humans to hear, however sharks can hear them from a
thousand miles away. Sharks do not have external ear flaps, but instead
have ears inside their heads on both sides of the brain case. Each ear
leads to a small pore on the sharks head. A shark's inner ear can also
detect acceleration, and gravity.
SIGHT: It was once thought that sharks had very bad eyesight, and were
nearly blind. It is know known that sharks have very good eyesight, some
better then ours. Like cats, a shark's eye contracts or expands to alter
the size of the pupil, according to how much light there is. In the back
of the eye there is a layer of cells known as the tapetum lucidum. The
cells reflect light back onto the retina. This is where images are
focused, making good use of light. Due to this a sharks can see in dim
light, and the
eye "glows" like a cats when light is shined on them. With pigment layers
a shark can protect it's eyes on sunny days. The shark's eyes also have
cells called rods, and cones. The rods work in dim light and are sensitive
to changes in light. The cones may allow sharks to see color. We humans
have rods, and cones. Fish lack eyelids because they don't need to blink
and clean their eyes due to their watery environment. During attack some
sharks use their nictitating membranes (translucent eyelids) to protect
them from the thrashing animal. Sharks that have no nictitating membranes,
like the great white for example roll their eyes into the back to their
heads. The size, shape, and overall look of a shark's eye depends on their
environment. Deepwater sharks have large eyes to take in more light, while
smaller eyes are on sharks that live closer to the surface.