Sea Creatures in Real Life

Marine biology is the scientific study of organisms in the sea. Given that in biology many phyla, families and genera have some species that live in the sea and others that live on land, marine biology classifies species based on the environment rather than on taxonomy.

A large proportion of all life on Earth lives in the ocean. The exact size of this large proportion is unknown, since many ocean species are still to be discovered. The ocean is a complex three-dimensional world covering approximately 71% of the Earth's surface. The habitats studied in marine biology include everything from the tiny layers of surface water in which organisms and abiotic items may be trapped in surface tension between the ocean and atmosphere, to the depths of the oceanic trenches, sometimes 10,000 meters or more beneath the surface of the ocean. Specific habitats include coral reefs, kelp forests, seagrass meadows, the surrounds of seamounts and thermal vents, tidepools, muddy, sandy and rocky bottoms, and the open ocean (pelagic) zone, where solid objects are rare and the surface of the water is the only visible boundary. The organisms studied range from microscopic phytoplankton and zooplankton to huge cetaceans (whales) 30 meters (98 feet) in length. Marine ecology is the study of how marine organisms interact with each other and the environment.

Marine life is a vast resource, providing food, medicine, and raw materials, in addition to helping to support recreation and tourism all over the world. At a fundamental level, marine life helps determine the very nature of our planet. Marine organisms contribute significantly to the oxygen cycle, and are involved in the regulation of the Earth's climate. Shorelines are in part shaped and protected by marine life, and some marine organisms even help create new land.

Many species are economically important to humans, including both finfish and shellfish. It is also becoming understood that the well-being of marine organisms and other organisms are linked in fundamental ways. The human body of knowledge regarding the relationship between life in the sea and important cycles is rapidly growing, with new discoveries being made nearly every day. These cycles include those of matter (such as the carbon cycle) and of air (such as Earth's respiration, and movement of energy through ecosystems including the ocean). Large areas beneath the ocean surface still remain effectively unexplored.

Sword Fish
Swordfish (Xiphias gladius), also known as broadbills in some countries, are large, highly migratory, predatory fishcharacterized by a long, flat bill. They are a popular sport fish of the billfish category, though elusive. Swordfish are elongated, round-bodied, and lose all teeth and scales by adulthood. These fish are found widely in tropical and temperate parts of the Atlantic, Pacific, and Indian Oceans, and can typically be found from near the surface to a depth of 550 m (1,800 ft). They commonly reach 3 m (9.8 ft) in length, and the maximum reported is 4.55 m (14.9 ft) in length and 650 kg (1,430 lb) in weight.

They are the sole member of their family, Xiphiidae.

Jelly Fish
Jellyfish or jellies are softbodied, free-swimming aquatic animals with a gelatinous umbrella-shaped bell and trailing tentacles. The bell can pulsate to acquire propulsion and locomotion. The tentacles may be utilized to capture prey or defend against predators by emitting toxins in a painful sting. Jellyfish species are classified in the subphylum Medusozoa which makes up a major part of the phylum Cnidaria, although not all Medusozoa species are considered to be jellyfish.

Jellyfish are found in every ocean, from the surface to the deep sea. Scyphozoans are exclusively marine, but some hydrozoans live in freshwater. Large, often colorful, jellyfish are common in coastal zones worldwide. Jellyfish have roamed the seas for at least 500 million years, and possibly 700 million years or more, making them the oldest multi-organ animal.

Squid
Squid are cephalopods of the order Teuthida, which comprises around 304 species. Like all other cephalopods, squid have a distinct head, bilateral symmetry, a mantle, and arms. Squid, like cuttlefish, have eight arms arranged in pairs and two, usually longer, tentacles. Squid are strong swimmers and certain species can "fly" for short distances out of the water.

Giant Puffer Fish
The Mbu puffer, giant puffer, or giant freshwater puffer (Tetraodon mbu) is a carnivorous freshwater pufferfishoriginating from the middle and lower sections of the Congo river in Africa, as well as the east coast of Lake Tanganyikanear the Malagarasi River mouth.

The species is commonly referred to as the giant freshwater pufferfish due to its massive size, growing to a length of 67 cm (26 inches). As such, these fish are difficult to adequately house in home aquaria since they require a very large tank and appropriately scaled water filtration.

Like all of its relatives, the Mbu puffer is capable of inflating itself with water or air when stressed or otherwise frightened. It feeds on smaller fish, mollusks and crustaceans. Species kept in captivity require a varied diet consisting of crunchy foods to help ensure good health and to prevent tooth overgrowth.

Hammerhead Shark
The hammerhead sharks are a group of sharks in the family Sphyrnidae, so named for the unusual and distinctive structure of their heads, which are flattened and laterally extended into a "hammer" shape called a cephalofoil. Most hammerhead species are placed in the genus Sphyrna, while the winghead shark is placed in its own genus, Eusphyra. Many not necessarily mutually exclusive functions have been proposed for the cephalofoil, including sensory reception, manoeuvering, and prey manipulation. Hammerheads are found worldwide in warmer waters along coastlines and continental shelves. Unlike most sharks, hammerheads usually swim in schools during the day, becoming solitary hunters at night. Some of these schools can be found near Malpelo Island in Colombia, Cocos Island off Costa Rica, and near Molokaiin Hawaii. Large schools are also seen in the waters off southern and eastern Africa.

White Shark
The great white shark (Carcharodon carcharias), also known as the great white, white pointer, white shark, or white death, is a species of large mackerel shark which can be found in the coastal surface waters of all the major oceans. The great white shark is notable for its size, with larger female individuals growing to 6.1 m (20 ft) in length and 1,950 kg (4,300 lb) in weight at maturity. However most are smaller, males measuring 3.4 to 4.0 m (11 to 13 ft) and females 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,[7] making it one of the longest lived cartilaginous fish currently known.According to the same study, male great white sharks take 26 years to reach sexual maturity, while the females take 33 years to be ready to produce offspring. Great white sharks can swim at speeds of over 56 km/h (35 mph), and can swim to depths of 1,200 m (3,900 ft).

The great white shark has no known natural predators other than, on very rare occasion, the killer whale. The great white shark is arguably the world's largest known extant macropredatory fish, and is one of the primary predators of marine mammals. It is also known to prey upon a variety of other marine animals, including fish and seabirds. It is the only known surviving species of its genus Carcharodon, and is ranked first in having the most recorded shark bite incidents on humans. The IUCN list the great white shark as a vulnerable species, while it is included in Appendix II of CITES.

The novel Jaws by Peter Benchley and the subsequent film by Steven Spielberg depicted the great white shark as a "ferocious man eater". Humans are not the preferred prey of the great white shark, but, nevertheless, the great white is responsible for the largest number of reported and identified fatal unprovoked shark attacks on humans.

Giant Jelly Fish
The lion's mane jellyfish (Cyanea capillata), also known as the giant jellyfish or the hair jelly, is the largest known species of jellyfish. Its range is confined to cold, boreal waters of the Arctic, northern Atlantic, and northern Pacific Oceans. It is common in the English Channel, Irish Sea, North Sea and in western Scandinavian waters south to Kattegat and Øresund. It may also drift in to the south-western part of the Baltic Sea (where it cannot breed due to the low salinity). Similar jellyfish, which may be the same species, are known to inhabit seas near Australia and New Zealand. The largest recorded specimen found, washed up on the shore of Massachusetts Bay in 1870, had a bell with a diameter of 2.3 metres (7 ft 6 in) and tentacles 37.0 m (121.4 ft) long. Lion's mane jellyfish have been observed below 42°N latitude for some time in the larger bays of the east coast of the United States.

The lion's mane jellyfish uses its stinging tentacles to capture, pull in and eat prey such as fish, sea creatures and smaller jellyfish.

Giant Squid
The giant squid (genus Architeuthis) is a deep-ocean dwelling squid in the family Architeuthidae. Giant squid can grow to a tremendous size due to deep-sea gigantism: recent estimates put the maximum size at 13 m (43 ft) for females and 10 m (33 ft) for males from the posterior fins to the tip of the two long tentacles (second only to the colossal squid at an estimated 14 m (46 ft), one of the largest living organisms). The mantle is about 2 m (6.6 ft) long (more for females, less for males), and the length of the squid excluding its tentacles (but including head and arms) rarely exceeds 5 m (16 ft). Claims of specimens measuring 20 m (66 ft) or more have not been scientifically documented.

The number of different giant squid species has been debated, but recent genetic research suggests that only one species exists.

In 2004, Japanese researchers took the first images of a live giant squid in its natural habitat, and in July 2012, a live adult was first filmed in its natural habitat off Chichi-jima.

Viper Fish
A viperfish is any species of marine fish in the genus Chauliodus. Viperfish are characterized by long, needle-like teeth and hinged lower jaws. A typical viperfish grows to lengths of 30 to 60 cm (12 to 23.5 in). Viperfish stay near lower depths (250–5,000 feet [80–1,520 m]) in the daytime and shallower depths at night, primarily in tropical and temperate waters. Viperfish are believed to attack prey after luring them within range with light-producing organs called photophores, which are located along the ventral sides of its body, and with a prominent photophore at the end of a long spine in the dorsal fin reminiscent of the illicium of the unrelated deepsea anglerfishes. The viperfish flashes this natural light on and off, at the same time moving its dorsal spine around like a fishing rod and hanging completely still in the water. It also uses the light producing organ to communicate to potential mates and rivals.

Viperfish vary in color from green, silver, to black. A viperfish uses its fang-like teeth to immobilize prey and would not be able to close its mouth because of their length, if it were not able to fold and curve them behind its head. The first vertebra behind the head of the viperfish absorbs the shock of biting prey. As with other deepsea fish, they are able to undergo long periods with scarcely any food.

Viperfish are believed to live from 30 to 40 years in the wild, but in captivity they rarely live more than a few hours. Some species of dolphins and sharks are known to prey upon viperfish. Scientists believe they can swim at a speed of two body lengths per second, but this is not yet an official speed.

Although it may look like it is covered in scales, it in fact is covered by a thick, transparent coating of unknown substance. Extremely large, fang-like teeth give the fish a slightly protruded lower jaw which makes catching prey easy for this deep-sea predator. The viperfish is lined with three different types of photophores which some speculate is used to lure in unsuspecting prey They have microscopic spheres without a pigment layer that are scattered over the dorsal side, large spheres with a pigment coat, reflectors, and lens, and finally, large, bell-shaped organs with a pigment coat, reflectors, and lens that are grouped together in rows along the dorsal surface. Photophores can also be seen along the ventral and lateral surface of the fish.

Anglerfish
Anglerfishes are fish of the teleost order Lophiiformes /ˌlɒfiːəˈfɔːrmiːz/. They are bony fish named for their characteristic mode of predation, in which a fleshy growth from the fish's head (the esca or illicium) acts as a lure.

Some anglerfish are also notable for extreme sexual dimorphism and sexual symbiosis of the small male with the much larger female, seen in the suborder Ceratioidei. In these species, males may be several orders of magnitude smaller than females.

Anglerfish occur worldwide. Some are pelagic (dwelling away from the sea floor), while others are benthic (dwelling close to the sea floor); some live in the deep sea (e.g., Ceratiidae), while others on the continental shelf (e.g., the frogfishes Antennariidae and the monkfish/goosefish Lophiidae). Pelagic forms are most laterally compressed, whereas the benthic forms are often extremely dorsoventrally compressed (depressed), often with large upward-pointing mouths.

Deep Squid/Firefly Squid
The  firefly squid, Watasenia scintillans, also known as the  sparkling enope squid, is a species of squid  in the family Enoploteuthidae . It is the sole species in the genus   Watasenia.

The firefly squid measures about 3 inches (7.6 cm) long at maturity and dies after one year of life. It has the standard eight arms and two tentacles, with one pair each having three, bright light-emitting organs at the tips.

Tuna
A tuna is a saltwater fish that belongs to the tribe Thunnini, a sub-grouping of the mackerel family (Scombridae) – which together with the tunas, also includes the bonitos, mackerels, and Spanish mackerels. Thunnini comprises fifteen speciesacross five genera, the sizes of which vary greatly, ranging from the bullet tuna (max. length: 50 cm (1.6 ft), weight: 1.8 kg (4 lb)) up to the Atlantic bluefin tuna (max. length: 4.6 m (15 ft), weight: 684 kg (1,508 lb)). The bluefin averages 2 m (6.6 ft), and is believed to live for up to 50 years.

Tuna and mackerel sharks are the only species of fish that can maintain a body temperature higher than that of the surrounding water. An active and agile predator, the tuna has a sleek, streamlined body, and is among the fastest-swimming pelagic fish – the yellowfin tuna, for example, is capable of speeds of up to 75 km/h (47 mph). Found in warm seas, it is extensively fished commercially, and is popular as a game fish. As a result of over-fishing, stocks of some tuna species such as the southern bluefin tuna have been reduced dangerously close to the point of extinction.

Lionfish
Pterois is a genus of venomous marine fish, commonly known as lionfish, native to the Indo-Pacific. Pterois, also called zebrafish, firefish, turkeyfish or butterfly-cod, is characterized by conspicuous warning coloration with red, white, creamy, or black bands, showy pectoral fins, and venomous spiky fin rays. Pterois radiata, Pterois volitans, and Pterois miles are the most commonly studied species in the genus. Pterois species are popular aquarium fish. P. volitans and P. miles are a recent and significant invasive species in the west Atlantic, Caribbean Sea and Mediterranean Sea.

Sea Turtle
Sea turtles (superfamily Chelonioidea), sometimes called marine turtles, are reptiles of the order Testudines. The seven extant species of sea turtles are: the green, loggerhead, Kemp's ridley, olive ridley, hawksbill, flatback, and leatherback.

Blobfish
The blobfish (Psychrolutes marcidus) is a deep sea fish of the family Psychrolutidae. It inhabits the deep waters off the coasts of mainland Australia and Tasmania, as well as the waters of New Zealand.

In an exhaustive 2015 feature story on blobfish, Smithsonian magazine essayist Franz Lidz wrote: "Unlike most fish, they have no swim bladder to help maintain buoyancy.... The blobfish’s blancmange of a body is less dense than water, allowing it to drift passively above the seabed. Having realized long ago that activity does them no good, they tend to remain almost, if not entirely, still. Like other lie-and-wait predators, blobfish stick around until anything remotely edible floats into their open jaws, then suck it in."

Blobfish are typically shorter than 30 cm (12 in). They live at depths between 600 and 1,200 m (2,000 and 3,900 ft) where the pressure is 60 to 120 times as great as at sea level, which would likely make gas bladders inefficient for maintaining buoyancy. Instead, the flesh of the blobfish is primarily a gelatinous mass with a density slightly less than water; this allows the fish to float above the sea floor without expending energy on swimming. Its relative lack of muscle is not a disadvantage as it primarily swallows edible matter that floats in front of it such as deep-ocean crustaceans.

Blobfish are often caught as bycatch in bottom trawling nets.

Stonefish
Synanceia is a genus of fish of the family Synanceiidae, the stonefishes, whose members are venomous, dangerous, and even fatal to humans. It is one of the most venomous fish known. They are found in the coastal regions of the Indo-Pacific.

Kraken
The kraken is a marine creature of Scandinavian mythology commonly described as a type of octopus or giant squid that, emerging from the depths, attacked ships and devoured the sailors. The legend may actually have originated from sightings of actual giant squids estimated to be 13 to 15 meters long, including tentacles.

Cthulhu
Cthulhu (/kəˈθuːluː/  kə-THOO-loo ; for variant pronunciations, see below) is a cosmic entity created by writer H. P. Lovecraftand first introduced in the short story "The Call of Cthulhu", published in the American pulp magazine Weird Tales in 1928. Considered a Great Old One within the pantheon of Lovecraftian cosmic entities, the creature has since been featured in numerous popular culture references. Lovecraft depicts Cthulhu as a gigantic entity worshipped by cultists. Cthulhu's appearance is described as looking like an octopus, a dragon and a caricature of human form. Its name was given to the Lovecraft-inspired universe where it and its fellow entities existed, the Cthulhu Mythos.