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1. Moray Eels
2. Portuguese Man O’ War
3. White Shark
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With scaleless skin that is covered in a slime coat and common behavior of lying inside rock crevices with their gaping mouth exposing razor sharp teeth it is no wonder that eels have long held a reputation as a sea creature to be feared.
Though these aquatic animals are sometimes mistaken as sea serpents, they are actually a type of bony fish. The most recognizable of these long, slender bodied fish with a menacing look are known as Moray Eels.
There are over 200 species of Moray Eels. They range in size from just 6 inches to over 10 feet depending on species – some like the Giant Moray, may even weigh more than 60 pounds.
Moray Eels are found in warm or temperate waters around the world and come in an amazing assortment of appearances. Various species have skin patterns that are often described as speckled, striped, freckled or tattooed, as well as a number of colors including brown, green, off white, yellow, black and blue.
This diverse coloration often lends to the name of many species including the Zebra, the Snowflake, the Honeycomb and the White Eyed Moray Eel.
A particular species of Moray is the Ribbon Eel, these unique species of Moray undergo an major transformation within their lifetime. At birth, they begin life as males and as they mature toward the end of their lifespan they make the switch and become females. With this change also comes different appearances. As juveniles they are all black, adult males are blue with a yellow coloration around their mouth and yellow dorsal fin while the maturing stage females will change to almost completely yellow.
Unlike most Moray Eels, that have sharp, pointed teeth that face backwards to grip slippery prey, the Zebra Moray has flat, plate-like teeth design for crushing crabs and other hard-shelled creatures.
One of the most familiar and feared of Moray species is known as the Green Moray Eel. Sometimes described as a beautiful green flowing ribbon when swimming out in the open waters beyond the reef, Green Moray Eels are sometimes known as Painted Eels.
Suprisingly, the Green Moray’s skin is actually blue, grey or brown but they are covered in a yellow-colored protective slime layer which when blended with their skin and filtered light give them a green appearance.
This slime coating, a common characteristics of all eels, helps protect the moray as it travels the jagged, rocky crevices where they’re often found during the day. Moray eels are primarily nocturnal, resting during the day and coming out to hunt at night.
Moray eels have a low dorsal fin that runs along the length of the body and lack pectoral and anal fins. Because of this, morays don’t have great lateral stability, so it isn’t unusual to see them resting on their sides.
Moray eels don’t have very good vision, but they do have a good sense of smell which they use to seek out prey. Depending on the species, common food items include fish, crustaceans and various cephalopods.
While many larger fish feed by opening their mouth wide which helps to create a suction that allows them to suck in and swallow many prey items, the Moray Eels take on a different, almost alien approach to feeding.
They are the only known creature to use pharyngeal jaws to grab and hold prey. In their throat lies a second set of jaws and teeth. When the front jaws bite prey, the pharyngeal jaws spring forward from the back of their throat to grab and pull their prey item down their throat. The biting attack of a Moray Eel is lightning fast as they strike from an almost motionless state to grab unsuspecting passerbys.
A common behavior seen in morays the often give them their menacing look is opening and closing their mouth as they lie resting among the rocks. While this display exposes their teeth and may seem threatening, this is simply how they breathe. Most fish breathe by opening and closing their gill covers to force water over their gills. Moray eels, however, lack gill covers and must open and close their mouth to force water over their gills.
Moray Eels have a reputation of being aggressive and dangerous towards humans. And while they are potentially dangerous, most Moray Eels are actually rather shy and tend to avoid humans. They usually only “attack” people when they feel threatened, such as when a diver mistakenly places their hands in a rock crevice or hole that is often home to these misunderstood and elusive sea creatures.
Portuguese Man O’ War
The Portuguese Man O’ War. The name alone demands attention. The sight of this aquatic lifeform floating in coastal waters or washed ashore on sandy beaches is cause for concern.
A relative of sea anemones and often mistaken by many to be a jellyfish – another relative species – this amazing specimen is actually classified as a siphonophore.
A siphonophore is comprised of a colony of specialized, genetically identical individuals called zooids, each unable to live on its own. These four specialized parts, or polyps, each part performing exclusive functions, such as capturing prey, reproduction, feeding and digestion and floating. And so, the Man O’ War is actually a group of several animals living together as one.
The most recognizable part of the Portuguese Man O’ War is the gas filled sac, or pneumatophore, which sits above the water and somewhat resembles an 18th century warship at full sail. A ridge along the top of the sac acts like a sail, its shape is said to resemble the helmets worn by Portuguese soldiers and so this dangerous and bizarre creature got it’s name.
This floating sac may rise as high as 6 inches and is what aids the Man O’ War in its travels across the oceans. Unlike jellyfish, which have the ability to contract and expand their bell and propel themselves through the water, the Man O’ War has no ability to propel or move itself and is totally dependent on ocean waves, wind and currents for movement. Sometimes as many as 1,000 or more may be carried along together by certain currents out at sea. Though incapable of propulsion, the creature can control the amount of gas within the sac, allowing it to submerge below the surface for periods of time – perhaps to avoid surface predators.
Below the floating sac and beneath the waters surface are the three remaining zooids that comprise the Man O’ War. The most prominent are the cluster of long, trailing tentacles that are used for capturing prey and defense. Averaging a length of 30 feet, these tentacles can grow more than 150 long. The tentacles are armed with stinging cells that contain nematocysts. Nematocysts inject a barbed thread and paralyzing toxin to capture and subdue prey like small fish, plankton and invertebrates.
The tentacle transfers prey to the mouths of vase-shaped individuals (gastrozooids) that perform digestion. Nutrients are shared through a common gut system that connects all members of the colony. Communication between individuals is maintained through a network of nerve fibers.
The final organism is the gonozooids which contain the reproductive organs. Each Man O’ War is either a male or female colony and they reproduce by a method known as broadcast spawning. Once fertilized, the egg develops by “budding” into the distinct structures and organisms that make up each Man O’ War.
Found in tropical and subtropical waters across all of the worlds oceans, the Portuguese Man O’ War is sometimes known as the Atlantic Portuguese Man O’ War. Another species – found exclusively in Indian and Pacific waters is sometime called a Bluebottle. It’s smaller than the Atlantic species and hunts with a single, elongated tentacle.
Though the Man O’ War slowly drifts along the surface of the ocean, its transparent float that is tinted blue, pink or violet helps it blend in with the waters reflective surface allowing it to go unnoticed by some predators. However the main predators of the Portuguese Man O’ War include the Loggerhead Sea Turtle and the Mola Mola – or Ocean Sunfish. Another predator includes the unassuming Sea Slug known as the Blue Dragon. The Blue Dragon has the ability to absorb the neurotoxins of the Man O’ War – storing it in its own skin – making it Man O’ War useful not only as a meal but also as a predator deterrent for the sea slug itself.
The stinging cells of the Man O’ War are capable of producing very painful injections of toxing into humans. Though the stings are rarely fatal, some deaths have been reported. Large welts on the skin as well as allergic type reactions such as elevated heart rate, muscle cramps and vomitiing.
The nematocysts have the ability to inject toxins even when separated from the rest of the organism and are still dangerous to touch for several days even if the Man O’ War is found dead on a beach.
A recent study has found that former supposed remedies for Man O’ War stings such as flushing the skin with sea water or urine, can actually cause additional venom to be released and spread across a larger affected region. It has been discovered that treatment with vinegar then soaking the affected area in hot water of 113 degrees Fahrenheit or more for 45 minutes may neutralize the toxins. But the best advice to avoid contact with the Portuguese Man O’ War is to stay away from them.
In the animal kingdom, few species are as infamous and feared as the shark. Most sharks species are considered the top predator in their respective ocean habitats. But one shark species is perhaps the most feared off all oceanic animals.
Its scientific name is Carcharodon carcharias and it is the largest predatory fish in the world. Throughout the ages, this large and dangerous creature has been commonly known as the great – white – shark.
The White Shark, as it is commonly referred to in the scientific community – is a large, bulky fish with a body shaped like a blunt torpedo. Though no maximum length has been confirmed many females may grow longer than 16 feet with some White Sharks reported to be nearly 20 feet long. They may weigh over 4,000 pounds with some reports of some reaching nearly 6,000 pounds.
The White Shark is classified as a mackerel sharks, a group that includes the Mako and Salmon sharks.
They have a sharply pointed conical snout, large pectoral and dorsal fins, and a powerful crescent-shaped tail. They are capable of swimming speeds of over 15 mph and burst speeds of up to 35 mph.
Despite its name, only the underside of the White Shark is white, with a contrast of grey or brown on the top and sides. This counter shading helps the White Shark blend in to its surroundings. When viewed from below the white belly blends with the back light of the sun and sky, and when seen from above the shark’s darker colored back allow it to disappear into the murky depths below.
Equipped with powerful muscles, good eyesight, and excellent sense of smell aided by the classic lateral line of that allows the animal to detect faint electrical fields from the bodies of potential prey – the White Shark is an efficient, aggressive and effective predator.
Perhaps one of the most stunning images in all of nature is the sight of the White Shark launching its entire body from the water in pursuit of its primary prey – seals and sea lions. White sharks are also known to feed on large fish, smaller sharks including other White sharks, and wounded dolphins and whale carcasses.
The most notable feature of these powerful hunters is their large and impressive jaws. Lined with several rows of nearly 300 large, sharply pointed, coarsely serrated teeth. Each tooth is designed to cut flesh and can easily puncture and shatter bone.
The White Shark has the ability to over extend its jaws beyond its mouth enabling them to take very large and deadly bites. A common tactic while feeding is to first bump the potential prey, then take a bite. To protect their eyes while feeding, they will roll their pupils back in their heads while they bite since White Sharks lack the protective membrane found in some shark species.
Unlike most fish – White Sharks, similar to the Mako Sharks, are considered warm-blooded. An adult White Shark can maintain a body temperature up to 27 degrees Fahrenheit warmer than the surrounding water. This is due to its large mass and a highly developed heat exchange function in their circulatory system that prevents heat from escaping as blood circulates through its gills and near the body surface.
Although capable of swimming across ocean basins, White Sharks, like salmon, return to their native waters to give live birth. Where some of these birthing areas exists across the globe remains a mystery.
Though White Sharks are typically solitary hunters they are also a highly migratory animal who often come together in large groups, sometimes for feeding and often for breeding.
In the eastern Pacific Ocean, they regularly migrate to a location between Mexico and Hawaii. This vast and somewhat empty ocean expanse located halfway between California and Hawaii is known to researchers as “the White Shark Cafe.”
Sharks normally found off the western North American coast may take nearly a month to swim to this location where they appear to remain for a couple of months before returning – studies are ongoing to learn more about this behavior and why the sharks return here each year.
In other parts of the world, White Sharks may migrate even longer distances. Some South African White Sharks have been tracked to southern Australia and back.
Modern tracking equipment and research from organizations like the Monterey Bay Aquarium, Ocearch and the Guy Harvey Ocean Foundation have allowed scientists to study these migration patterns in various locations more accurately but there is still much that is unknown about the amazing White Shark.
One thing has been discovered, many White Sharks frequent coastal waters and beaches (especially in the Southern US waters) for more often and much closer to shore than was once known.
Another means of identifying White Sharks is by photographing their iconic dorsal fin – each shark has a uniquely shaped fin that can aid researchers in observing the repeated habits of these incredible animals.
Though attacks on humans are not common and are rarely fatal, depictions of the White Shark in books, movies, and sensationalized news accounts have given the species a terrifying reputation. Up close studies with these animals in their native habitats however, have revealed they are not the indiscriminate man-eaters they were once believed to be.
While White Sharks are one of the top predators of their domain, there is an animal they seem to fear. The apex predator of the ocean – the Killer Whale. In a feeding ground off the Farallon Islands, near San Francisco – where White Sharks are known to gather to feed on elephant seals, researchers have noted that with the arrival of Killer Whales in the same waters, the White Sharks will flee and not return for several months.
There are also documented populations of some Killer Whales who are known to hunt and feed on White Sharks, though oddly they only consume the shark’s liver, leaving the rest of the carcass behind for other sharks and aquatic animals to feed on.
White Shark are currently listed as Vulnerable on the IUCN Red List. In the past century, White Shark populations worldwide have sharply declined. Despite their reputation as infamous killers, the White Shark plays a vital role in the ocean to help maintain a balanced and healthy ecosystem. Their removal from the top of the food chain can have long lasting adverse effects on the world’s oceans.
Special thanks to the following organizations for their education, research and conservation programs that provided information for this episode:
Guy Harvey Ocean Foundation
Monterey Bay Aquarium
National Ocean Service
NOAA Ocean Explorer
Sea World’s Animal Guide
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