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1. Giant Oarfish
2. Mola Mola
3. Whale Shark
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Throughout history, stories of giant sea creatures rising from the great depths of the open ocean have haunted sailors and other would-be travelers. Incredible species both in size and unique appearance.
Myths of large, snake like, sea serpents appearing at the surface have given rise to many fictional accounts – however one particular deep sea creature may be the source of many of these tales.
Found throughout the tropic and subtropic regions of the Atlantic, Indian and Pacific Oceans, these strange deep water inhabitants possess a reflective silver, extremely long ribbon-like body with red dorsal fins running the length of its tapering tail. This bizarre animal is commonly known as the Giant Oarfish.
Giant oarfish are generally 10 to 15 feet in length when discovered however some have been reported with a length of more than 30 feet – making them the longest bony fish in the world.
The Giant Oarfish is a open ocean deep water species commonly found more than 600 feet beneath the surface, though they have been known to swim as deep as 3200 feet.
Oarfish have a long tapering body with a blunt, slightly concave head and a small protrusible mouth containing no visible teeth. They are a scaleless fish species. The dorsal fin starts just above their eyes, running the entire length of the fish. It is distinctly colored, ranging from pinkish to dark red. Consisting of approximately 400 dorsal fin rays, the first 10-12 are elongated forming a hair-like looking crest with reddish spots and flaps of skin on the tip of each ray.
Another visible characteristic that gives the species its common name is the long, red pelvic fins that hang below the Giant Oarfish’s body ending in small paddle shapes. It was onces believed that this peculiar animal, since it lacks a swim bladder, moved through the water by “rowing” itself with these oar like appendages.
The giant oarfish, however, swims by undulating its long dorsal fin while its body remains straight – this type of movement is known as amiiform swimming. It has also been observed swimming in a vertical position with its head facing up toward the surface. Researchers believe this swimming position is the method that the oarfish uses to searches for prey.
Giant oarfish have no visible teeth but instead have internal gill rakes that they use to feed on plankton, crustaceans, krill and squid by straining them from the water.
Most of the animals internal organs are located in the front quarter of its thin, long body. This may help the oarfish avoid some fatal wounds when predators strike the longer back portions of their tail – many giant oarfish that have been studied show scars and wounds in this region of their body. Sharks are considered to be their primary natural predators.
Giant Oarfish are believed to live solitary lives with the exception of spawning activities.
Little is known about oarfish reproduction, spawning has been observed off of Mexico between July and December. After spawning is complete, the fertilized eggs drift, remaining at the surface of the ocean until hatching. It is believed that the eggs take up to three weeks to incubate. Upon hatching, the larvae appear similar to adults but in miniature and feed primarily on plankton.
Despite its tendency to live in deep water, oarfish have sometimes been caught by fishing vessels. Giant Oarfish is not of commercial value due to the poor quality of meat which is gelatinous in nature and generally considered inedible.
Sometimes known in history as ribbon-fish, streamer fish, king of the herring and even sea serpents – the Giant Oarfish was first described in 1772.
This species is rarely observed by humans and even when it is swimming at the surface, encounters with live oarfish are very rare. Giant oarfish have been found cast upon beaches after storms or near the surface when injured or dying, but it wasn’t until 2001 that a live giant oarfish was captured on film by the US Navy.
While tales of sea serpents have long been a part of human history, the amazing giant oarfish continues to be a signature species of the many unique animals found in the mysterious depths of the world’s oceans.
Mola Mola (Ocean Sunfish)
Found in temperate and tropical waters all around the world, is a large behemoth. A fish with a rather odd bullet-like shape, very short tail fin and a relatively smaller round mouth.
With a flat, silvery gray body, these animals can grow to be 14 feet tall and over 10 feet long – they are the heaviest bony fish in the world – sometimes weighing as much as 5000 pounds. They are the Mola Mola.
One of 3 known species of Mola, the Mola Mola are open ocean – or pelagic – animals and they are the largest of their species. Mola Mola are also known as Ocean Sunfish.
The Mola Mola’s primary diet consists of various gelatinous organisms like the many jellyfish species, including the Portugese Man-O-War – but they will also feed on squid, fish and crab.
Inside a mola’s tiny mouth are two pairs of hard teeth plates shaped with a slightly curved ridge that look kind of like a bird’s beak. Mola Mola don’t actually chew their food but instead suck their prey in and out of their mouth until it is ground into almost jelly like chunks.
A mucuslike lining in the digestive tract is believed to help keep the Mola Mola from getting stung by the jellies it consumes.
Usually spotted at the surface during feeding times, Mola Mola will also dive into deeper, colder waters to feed and will even sometimes feed at the ocean floor – scooping up fish and invertebrates found there.
It is believed that the Mola Mola will return to the surface following these deeper dives and in an effort to warm they bodies they will often lay on their sides like a sunbather – this is where their common name Ocean Sunfish comes from.
Mola Mola have smaller rear fins, known as the clavus – this fin acts more like a rudder while it uses its dorsal and anal fins for propulsion and movement – this type of swimming is also seen among triggerfish, boxfish and their closest relatives – the pufferfish.
While it is often believed that Mola Mola are rather slow and clumsy swimmers, they are actually quite strong and capable of fast speeds, using their pectoral flippers for steering they are also rather nimble and the Mola Mola will sometimes even leap out of the water – jumping as high as 10 feet above the surface.
Mola Mola have also been observed schooling together at times, though many sightings are of a single fish moving slowly at the surface.
The biggest predators of the Mola Mola include the Killer Whale, White Sharks and California Sea Lions.
The Mola is related to pufferfish, and a just-hatched mola is puffy, round and covered with spines like its relatives. Despite the eventual size of the Mola Mola – newly hatched fry are only about 2 millimeters in diamter but grown extremely fast -increasing it’s weight 60 million times. According to the Monterey Bay Aquarium, this growth would be equivalent to a 1-gram tadpole growing into a 60 ton frog!
Mola Mola may have up to 40 different types parasites living on, inside or beneath their skin. While at the surface, birds and cleaner fish species may approach the giant Ocean Sunfish as it lays on its side – the animals come to feed on these parasites which otherwise may compromise the Mola’s health. This essential cleaning may be another reason researchers believe they lay on their sides at the surface.
Many other species of fish and aquatic animals are also seen drifting along with them as they travel – making the open water Mola Mola its own habitat.
Though it’s closest relative species – the Pufferfish – are extremely poisonous in specific parts of their bodies, scientific studies have found no trace of the toxin in the mola mola.
Due to their slow moving, surface feeding behaviors, mola mola are vulnerable to fishing boats that use drift gill nets. Gill nets usually don’t kill molas immediately, but they cut into their skin and scrape off their protective mucus leading to infection and eventually death.
Also, like sea turtles who also feed on jellyfish at the surface, mola mola are in danger of consuming plastic bags floating on the water’s surface. Often mistaken as jellyfish – the bags can choke the fish as it sucks it in or it can cause a blockage in the animal’s stomach causing it to slowly starve to death.
Today, the Mola Mola is listed as threatened on the IUCN Red List.
The Monterey Bay Aquarium is a leading accredited facility in Ocean Sunfish research and conservation – smaller adolescent Mola Mola can often be seen on exhibit (as well as their live webcam feeds) while the larger fish are released into the open ocean equipped with tracking tags to help scientist learn more about these strange giants of the sea.
Often traveling great distances across the worlds oceans is a large and impressive animal.With a a unique “checkerboard” color pattern of light spots and stripes on a dark background, its streamlined body is gray, brown or bluish in color with a wide mouth placed at the tip of its snout.
It may average between 18 and 32 feet long while the largest on record was nearly 62 feet long. It may alarm some to know this huge animal is a shark. It is not only the largest shark but is the largest known fish to have lived on the planet.
This giant of the deep is the Whale Shark!
Whale sharks are found worldwide in the tropical Atlantic, Pacific, and Indian Oceans.
Like all sharks and rays, the whale shark’s skeleton is made of cartilage. The have 3 very noticeable prominent ridge that run along the sides of their body, and 2 dorsal fins – the first fin is much larger than the second.
Whale sharks have a two-tone coloration with the darker shades on top and a lighter, white underside. Each whale shark has its own individual spot pattern on its skin. Like human fingerprints, no two are exactly alike.
The skin of an adult whale shark can be as thick as 4 inches and has the consistency of strong rubber, which may help protect it from possible predators like killer whales and large toothed shark species.
Whale sharks have uniquely shaped dermal denticles (tooth like scales found on sharks) – some researchers believe these may provide some hydrodynamic properties to aid them in their deep water, open ocean habitats.
Whale sharks swim at an average speed between 2 and 3 mph, when alarmed they are able to make short burst of speed – up to a full body length per second – but they cannot maintain this speed for long.
Despite their enormous size, a broad 4 foot wide mouth, and a jaw lined with up to 300 rows of tiny teeth, whale sharks are filter-feeders. They possess 20 filter pads inside the back their mouth.
Their diet consists primarily of zooplankton, specifically krill, shrimps, fish eggs as well as jellies, coral spawn, and small fishes like sardines and anchovies. Whale sharks can only swallow small prey because its throat is very narrow, about the size of a quarter.
Unlike most plankton feeders, Whale sharks do not depend on slow forward motion to filter, rather, they use a versatile suction filter-feeding method, which enables them to draw water into the mouth at higher velocities than other filter-feeders.
After drawing water into its mouth, the shark then filters food from the water by a process known as “cross-flow filtration,” which means the particles do not catch on the filter. Instead, water is directed away through the gills while food and other particles carry on towards the back of the mouth. As feeding continues, a spinning ball of food grows in diameter at the back of the throat until it triggers a swallowing reflex.
Whale sharks possess specialized flaps inside their mouth that stop the backflow of water as it closes its mouth, preventing the loss of food.
Though they are related to nurse sharks and other carpet shark species who often spend most of their time on the bottom. Whale sharks are considered a pelagic species typically found offshore in deep, open water. They are known to come close to shore, sometimes entering lagoons or coral atolls and even shallow water areas near bays during seasonal plankton blooms.
Whale sharks will often return to the same feeding site but are also highly migratory. Different geographic locations appear to be preferred at various times of the year and they may undertake large-scale migrations across the oceans. The coastal feeding sites consist of mainly juvenile male sharks, with the largest congregation containing hundreds to thousands of individual sharks. Each March and April, whale sharks are known aggregate on the continental shelf of the central western coast of Australia.
Very little is known about whale shark mating behavior as it has been rarely observed in its natural habitat.
As opposed to the other large sharks, which give birth to a small number of very large babies, whale sharks give live birth to hundreds of very small babies. After mating, the female whale shark produces hard, reinforced egg cases that remain inside her abdomen until they hatch, at which point she gives live birth.
The only litter size that has ever been documented was more than 300 pups. Newborns measure 21 to 25 inches long.
The average lifespan of the whale shark is estimated around 60 years though researchers do not know this for certain.
Whale sharks are considered harmless to humans and divers often encounter them in the wild. The Georgia Aquarium is currently home to 4 whale sharks which can also often be seen on the aquarium’s live webcam feeds – a unique opportunity to witness the largest fish in the world.
Special thanks to the following organizations for their education, research and conservation programs that provided information for this episode:
Monterey Bay Aquarium
Georgia Aquarium webcam
Monterey Bay Aquarium live feed cams
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