This page is dedicated to the shark species commonly found in the waters around North America! Swim with Caution the next time you decide to venture into the waves; You may not be as alone as you think!
This page is dedicated to the shark species commonly found in the waters around North America! Swim with Caution the next time you decide to venture into the waves; You may not be as alone as you think!
The lemon shark (Negaprion brevirostris) is a species of shark from the
family Carcharhinidae and is classified as a Vulnerable species by the
International Union for the Conservation of Nature. Lemon sharks can
grow to 3.4 metres (11 ft) in length. They are often found in shallow
subtropical waters and are known to inhabit and return to specific
nursery sites for breeding. Often feeding at night, these sharks use
electroreceptors to find their main source of prey: fish. Lemon sharks
enjoy the many benefits of group living such as enhanced communication,
courtship, predatory behavior, and protection. The shark's yellow
colouring serves as an excellent camouflage when swimming over the sandy
seafloor in its coastal habitat.The lemon shark commonly attains a
length of 2.4 to 3.1 m (7.9 to 10.2 ft) and a weight up to 90 kg (200
lb) by adulthood. The maximum recorded length and weight is 3.43 m (11.3
ft) and 183.7 kg (405 lb), respectively. It has a flattened head with a
short, broad snout, and the second dorsal fin is almost as large as the
first. Like all cartilaginous fish, lemon sharks have electroreceptors
concentrated in their heads, known as the ampullae of Lorenzini. These
receptors detect electrical pulses emitted by potential prey and allow
these nocturnal feeders to sense their prey in the dark. Note that Lemon
shark are often confused with Bull shark, Lemon sharks have roughly
equal first and second dorsal fins where Bull sharks have uneven sizes.
More About Lemon Sharks
The goblin shark (Mitsukurina owstoni) is a rare species of deep-sea
shark. Nicknamed the "Vampire Shark", due to its unusal look and love
for depths at which sunlight does not penetrate. This pink-skinned
animal has a distinctive profile with an elongated, flat snout, and
highly protrusible jaws containing prominent nail-like teeth. It is
usually between 3 and 4 m (10 and 13 ft) long when mature, though it can
grow considerably larger such as one captured in 2000 that is thought to
have measured 6 m (20 ft). Goblin sharks are benthopelagic creatures
that inhabit upper continental slopes, submarine canyons, and seamounts
throughout the world at depths greater than 100 m (330 ft), with adults
found deeper than juveniles. Some researchers believe that these sharks
could also dive to depths of up to 1,300 m (4,270 ft), for short periods
of time. Various anatomical features of the goblin shark, such as its
flabby body and small fins, suggest that it is sluggish in nature. This
species hunts for teleost fishes, cephalopods, and crustaceans both near
the sea floor and in the middle of the water column. Its long snout is
covered with ampullae of Lorenzini that enable it to sense minute
electric fields produced by nearby prey, which it can snatch up by
rapidly extending its jaws. The jaws are very protrusible and can be
extended almost to the end of the snout, though normally they are held
flush against the underside of the head.
The goblin shark has been caught in all three major oceans, indicating a
wide global distribution. In the Atlantic Ocean, it has been recorded
from the northern Gulf of Mexico, Suriname, French Guiana, and southern
Brazil in the west, and France, Portugal, Madeira, and Senegal in the
east. It has also been collected from seamounts along the Mid-Atlantic
Ridge. In the Indo-Pacific and Oceania, it has been found off South
Africa, Mozambique, Japan, Taiwan, Australia and New Zealand. This
species has been recorded from off East Cape to Kaikōura Canyon and from
the Challenger Plateau near New Zealand. A single eastern Pacific
specimen is known, collected off southern California. This species is
most often found over the upper continental slope at depths of 270–960 m
(890–3,150 ft). It has been caught as deep as 1,300 m (4,300 ft), and a
tooth has been found lodged in an undersea cable at a depth of 1,370 m
(4,490 ft). Adults inhabit greater depths than juveniles. Immature
goblin sharks frequent the submarine canyons off southern Japan at
depths of 100–350 m (330–1,150 ft), with individuals occasionally
wandering into inshore waters as shallow as 40 m (130 ft). On 19 April
2014, fishermen in Key West, Florida, while fishing in the Gulf of
Mexico, caught a goblin shark in their fishing net, only the second one
ever to be caught in the Gulf. The shark was photographed and released
back into the water. The first shark found in the Gulf was caught by
commercial fisherman on 25 July 2000 at a depth of approximately
919-1,099 m (3,016-3606 ft) and is thought to have been about 20 ft
long.
More About Goblin Sharks
The great white shark (Carcharodon carcharias), also known as the white
shark, white pointer, or simply great white, is a species of large
mackerel shark which can be found in the coastal surface waters of all the
major oceans. It is the only known surviving species of its genus
Carcharodon. The great white shark is notable for its size, with the
largest preserved female specimen measuring 5.83 m (19.1 ft) in length and
around 2,000 kg (4,410 lb) in weight at maturity. However, most are
smaller; males measure 3.4 to 4.0 m (11 to 13 ft), and females measure 4.6
to 4.9 m (15 to 16 ft) on average. According to a 2014 study, the lifespan
of great white sharks is estimated to be as long as 70 years or more, well
above previous estimates, making it one of the longest lived cartilaginous
fishes currently known. Great white sharks live in almost all coastal and
offshore waters which have water temperature between 12 and 24 °C (54 and
75 °F), with greater concentrations in the United States (Northeast and
California), South Africa, Japan, Oceania, Chile, and the Mediterranean
including the Sea of Marmara and Bosphorus. One of the densest-known
populations is found around Dyer Island, South Africa. Juvenile great
white sharks inhabit a more narrow band of temperatures, between 14 and 24
°C (57 and 75 °F), in shallow coastal nurseries. Increased observation of
young sharks in areas they were not previously common, such as Monterey
Bay on the Central California coast, suggest climate change may be
reducing the range of juvenile great white sharks and shifting it toward
the poles. The great white is an epipelagic fish, observed mostly in the
presence of rich game, such as fur seals (Arctocephalus ssp.), sea lions,
cetaceans, other sharks, and large bony fish species. In the open ocean,
it has been recorded at depths as great as 1,200 m (3,900 ft). These
findings challenge the traditional notion that the great white is a
coastal species. According to a recent study, California great whites have
migrated to an area between Baja California Peninsula and Hawaii known as
the White Shark Café to spend at least 100 days before migrating back to
Baja. On the journey out, they swim slowly and dive down to around 900 m
(3,000 ft). After they arrive, they change behaviour and do short dives to
about 300 m (980 ft) for up to ten minutes. Another white shark that was
tagged off the South African coast swam to the southern coast of Australia
and back within the year. A similar study tracked a different great white
shark from South Africa swimming to Australia's northwestern coast and
back, a journey of 20,000 km (12,000 mi; 11,000 nmi) in under nine months.
These observations argue against traditional theories that white sharks
are coastal territorial predators, and open up the possibility of
interaction between shark populations that were previously thought to have
been discrete. The reasons for their migration and what they do at their
destination is still unknown. Possibilities include seasonal feeding or
mating.
More About Great White Sharks
The tiger shark (Galeocerdo cuvier) is a species of ground shark, and the
only extant member of the genus Galeocerdo and family Galeocerdonidae. It
is a large macropredator, with females being capable of attaining a length
of over 5 m (16 ft 5 in). Populations are found in many tropical and
temperate waters, especially around central Pacific islands. Its name
derives from the dark stripes down its body, which resemble a tiger's
pattern, but fade as the shark matures. The tiger shark is a solitary,
mostly nocturnal hunter. It is notable for having the widest food spectrum
of all sharks, with a range of prey that includes crustaceans, fish,
seals, birds, squid, turtles, sea snakes, dolphins, and even other,
smaller sharks. It also has a reputation as a "garbage eater", consuming a
variety of inedible, man-made objects that linger in its stomach. Tiger
sharks have only one recorded natural predator, the orca. The tiger shark
is second only to the great white in recorded fatal attacks on humans.
Among the largest extant sharks, the tiger shark ranks in average size
only behind the whale shark (Rhincodon typus), the basking shark
(Cetorhinus maximus), and the great white shark (Carcharodon carcharias).
This makes it the second-largest predatory shark, after the great white.
The tiger shark is often found close to the coast, mainly in tropical and
subtropical waters throughout the world. Its behavior is primarily
nomadic, but is guided by warmer currents, and it stays closer to the
equator throughout the colder months. It tends to stay in deep waters that
line reefs, but it does move into channels to pursue prey in shallower
waters. Tiger sharks can be seen in the Gulf of Mexico, North American
beaches, and parts of South America. It is also commonly observed in the
Caribbean Sea. Other locations where tiger sharks are seen include off
Africa, China, India, Australia, and Indonesia. Certain tiger sharks have
been recorded at depths just shy of 900 m (3,000 ft).
More About Tiger Sharks
The bull shark (Carcharhinus leucas), also known as the Zambezi shark
(informally zambi) in Africa and Lake Nicaragua shark in Nicaragua, is a
species of requiem shark commonly found worldwide in warm, shallow waters
along coasts and in rivers. It is known for its aggressive nature, and
presence mainly in warm, shallow brackish and freshwater systems including
estuaries and (usually) lower reaches of rivers. This aggressive nature is
a reason for its population being listed as vulnerable on the IUCN Red
List. Shark-culling occurs near beaches to protect beach goers, which is
one of the causes of bull shark populations continuing to decrease. Bull
sharks are euryhaline and can thrive in both salt and fresh water. They
are known to travel far up rivers, and have been known to travel up the
Mississippi River as far as Alton, Illinois, about 1,100 kilometres (700
mi) from the ocean, but few freshwater interactions with humans have been
recorded. Larger-sized bull sharks are probably responsible for the
majority of nearshore shark attacks, including many incidents of shark
bites attributed to other species. Unlike the river sharks of the genus
Glyphis, bull sharks are not true freshwater sharks, despite their ability
to survive in freshwater habitats. Since bull sharks often dwell in very
shallow waters, are found in many types of habitats, are territorial by
nature, and have no tolerance for provocation, they may be more dangerous
to humans than any other species of shark. Bull sharks are one of the
three shark species (along with the tiger shark and great white shark)
most likely to bite humans. One or several bull sharks may have been
responsible for the Jersey Shore shark attacks of 1916, which were the
inspiration for Peter Benchley's novel Jaws. The speculation that bull
sharks may have been responsible is based on two fatal bites occurring in
brackish and fresh water. Bull sharks have attacked swimmers around the
Sydney Harbour inlets. In India, bull sharks swim up the Ganges,
Bramaputra, Mahanadi, and other Indian rivers and have bitten bathers.
Many of these bite incidents were attributed to the Ganges shark, Glyphis
gangeticus, a critically endangered river shark species, although the sand
tiger shark was also blamed during the 1960s and 1970s. Bull sharks have
also attacked humans off the coast of Florida.
More About Bull Sharks
The hammerhead sharks are a group of sharks that form the family
Sphyrnidae, commonly referred to as ‘hammerheads’ for the unusual and
distinctive form of their heads, which are flattened and laterally
extended into a "hammer" (or letter-“T”) shape called a cephalofoil. The
shark’s eyes are placed one on either end of this T-shaped structure, with
their small mouths directly centered and underneath. Most hammerhead
species are placed in the genus Sphyrna, while the winghead shark is
placed in its own genus, Eusphyra. Many different— but not necessarily
mutually exclusive—functions have been postulated for the cephalofoil,
including sensory reception, manoeuvering, and prey manipulation. The
cephalofoil gives the shark superior binocular vision and depth
perception. Hammerheads are found worldwide, preferring life in warmer
waters along coastlines and continental shelves. Unlike most sharks, some
hammerhead species will congregate and swim in large schools during the
day, becoming solitary hunters at night. The known species range from 0.9
to 6.0 m (2 ft 11 in to 19 ft 8 in) in length and weigh from 3 to 580 kg
(6.6 to 1,300 lb). One specimen caught off the Florida coast in 1906
weighed over 680 kg (1,500 lb). They are usually light gray and have a
greenish tint. Their bellies are white, which allows them to blend into
the background when viewed from below and sneak up to their prey. Their
heads have lateral projections that give them a hammer-like shape. While
overall similar, this shape differs somewhat between species; examples
are: a distinct T-shape in the great hammerhead, a rounded head with a
central notch in the scalloped hammerhead, and an unnotched rounded head
in the smooth hammerhead. Hammerheads have disproportionately small mouths
compared to other shark species. Some species are also known to form
schools. In the evening, like most other sharks, they become solitary
hunters. The great hammerhead, tending to be larger and more aggressive to
its own kind than other hammerheads, occasionally engages in cannibalism,
eating other hammerhead sharks, including mothers consuming their own
young. In addition to the typical animal prey, bonnetheads have been found
to feed on seagrass, which sometimes makes up as much as half their
stomach contents. They may swallow it unintentionally, but they are able
to partially digest it. At the time of discovery, this was the only known
case of a potentially omnivorous species of shark (since then, whale
sharks were also found to be omnivorous).
More About Hammerhead Sharks
The shortfin mako (Isurus oxyrinchus), also known as the shortfin mako
shark, blue pointer, or bonito shark, is a large mackerel shark. It is
commonly referred to as the mako shark, as is the longfin mako shark
(Isurus paucus). The shortfin mako can reach a size of 4 m (13 ft) in
length and weigh 570 kg (1,260 lb). Shortfin mako sharks travel long
distances to seek prey or mates. In December 1998, a female tagged off
California was captured in the central Pacific by a Japanese research
vessel, meaning this fish traveled over 2,776 km (1,725 mi). Another
specimen swam 2,128 km (1,322 mi) in 37 days, averaging 58 km (36 mi) a
day. Of all studied sharks, the shortfin mako has one of the largest
brain-to-body ratios.[citation needed] This large brain size prompted New
Zealand Sealife Australia and New Zealand senior curator Craig Thorburn of
Auckland, New Zealand, and film-maker Mike Bhana to investigate the
intelligence of the shortfin mako. From tests involving shape
differentiation to electroreception tests and individual recognition,
Isuru Somawardana and his team of shark experts discovered shortfin mako
are fast-learning sharks, able to determine whether or not the researchers
were threatening. The sharks involved in the study (while never the same
individuals) after initial caution showed unique and novel behaviors, such
as refusing to roll back their eyes during feeding and allowing themselves
to be briefly restrained and touched while being offered bait. Shortfin
mako also do not rely on electroreception when hunting, unlike the great
white shark, based on tests involving wired fiberglass fish designed to
emit weak electrical signals resembling real fish of similar size.
Instead, they rely on smell, hearing, and most prominently, vision. The
results of this research were featured on a documentary presented by Shark
Week in 1999 called Mako: Swift, Smart & Deadly.
More About Mako Sharks