...Are sharks perfectly adapted predators? This essay will discuss how sharks are thought to be one of the most perfectly adapted predators in the ocean food chain due to their physiology and interactions with their environment. However we must not disregard the fact that there are many species of sharks which may possess different features meaning that only certain species may be considered ‘perfectly adapted’. It is thought that sharks have been around for around 400 million years, in which they quickly evolved to the environment they live in. The sharks we see today are believed to be the result of evolution that took place 100 million years ago, making them largely unchanged over this time period. The most recently evolved sharks are the sphyrnids (hammerhead sharks) and the carcharhinids (requiem sharks). Although the reason behind why these sharks have survived could be due to early adaptation to their ecological role, we must consider those species of sharks that are now extinct and understand why certain species adapted quicker than others. Sharks main defining feature is their cartilaginous skeleton, placing them in the class Chondrichthyes, which is thought to make up only 1% of living fishes. By having cartilage as opposed to a bony skeleton they are lighter and more flexible in the water, as well as the cartilage strengthening the body frame of the shark. This class of fish are commonly known for their paired fins, paired nostrils and jaws and can then be further...
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...in so many shapes and kinds as the shark. The earliest evidences of sharks are isolated spines, teeth and scales that appeared about 430 million years ago in the Silurian Period, known as the "Age of Fishes". Sharks have a sleek, streamlined design which helps them swim without using up a lot of energy.They certainly need to conserve their energy because they never really sleep and most of them never stop swimming. Some sharks are fierce predators, and would be happy to eat you if they encountered you. Almost any shark six feet or longer is a potential danger, but three species have been identified repeatedly in attacks: the Great White Shark, the Tiger Shark and the Bull Shark . All three live world wide, reach large sizes and eat large prey such as marine mammals or sea turtles. But most sharks never grow longer than five feet and never even see anyone with legs and arms anyway. People kill thousands more sharks every year than sharks kill people. Sharks take about as long to mature as we do. Some of them become adults in their teens. A mother shark carries her babies inside her body while they develop, sometimes for more than a year. Even so, some sharks are born inside an egg which they have to crack open. They spend early portions of their lives in nursery grounds. Some of the advantages sharks have over people is that they keep growing new teeth, they don't have breakable bones, and they are not prone to get cancer. Sometimes sharks are referred to as swimming computers...
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...Shark Killing and the Ecosystem Introduction Sharks are fascinating creatures that come in all sizes and live in water all over the world. Arguably, these creatures play a very imperative responsibility in the ocean that a fish cannot. Apparently, sharks are the top food providers in the ocean almost in every part of the world. In this case, they assist in keeping the inhabitants of other fish species healthy and in suitable proportion for their ecosystem. However, shark population faces the threat of extinction in almost all parts of the world due to overfishing. Fishers us a technique called Bycatch, a process in which marine mammals or species of fish are unintentionally, caught while fishing for a specific target. Irrespective of the initiatives and laws put in place for overfishing, fishers have continued to hunt sharks for the fin soup, which is in high demand than their meat. On the other hand shark cartilage and shark liver oil are sold as cures for the hosts of aliments. Due to this disparity between meat and fins, it has led to a horrific practice of shark fining. As a result, there is need to create awareness on the importance of sharks in all parts of the world in order to save ocean ecosystem from extinction. Catching Techniques Many fishing techniques and gear are no selective and result in catching and discarding millions of marine life that is not always the target species. Most of the fishing methods like the long line typically are used to catch tuna. However...
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...Running head: Sharks Sharks T Tolerico Marine Biology Doctor Cameron Guenther Sharks What do you think of when you hear the word “Shark”? Do you think of the lion of the ocean or perhaps God’s perfect predator/scavenger? Perhaps you think of the movie “JAWS”? Most people will think of the movie “JAWS” and think killer, attacker, and predator. However, are sharks really preying on humans? I view sharks as God’s perfect predator and scavenger. Sharks, like lions, weed out the sick and slow fish to keep the population strong. They also scavenge on the bottom of the ocean any carcasses that settle there. The attacks on humans are more likely the shark “tasting” to see if the movement is a fish. When the shark realizes that the human is not its prey, they move away. Sharks can be found all over the world’s seas, from the equator to polar regions. We are currently aware of about 480 species and there are still species to discover. Some species, known as benthic, dwell mainly on the ocean floor. An example of a benthic is the nurse shark or ray shark. They scour the ocean floor for food. Other species are known as pelagic, meaning they spend much of their time navigating the open seas. Most of the species that we are familiar with are pelagic. Some species even inhabit rivers and lakes. The Bull shark can migrate into rivers and lakes. One important feature of sharks is that they are made up of cartilage not bone. There has been research done on shark cartilage...
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...Sharks One of the most feared predators of the ocean are the sharks, with more than 465 known species of sharks living in our ocean today. They are very popular animals with movies such as Jaws and Deep Blue Sea, these animals are also dedicated a whole week on animal planet they are often categorized as monstrous savages who just attack any and everything. In fact that isn’t a true reputation of them. These animals are survivors and have been around for a long time. These fascinating creatures have caught the eye and imagination of so many people as well as me. There are many things I want to cover over today just to give a better understanding and idea of sharks. Sharks are very smart creatures so its no surprise to learn they have plenty of ways in effective forms of communication. Eventhough sharks are generally loners, so they aren’t in groups. This makes it harder for scientist to observe how they actually communicate with each other than with other animals that live in the water. They have an amazing sense of hearing which is believed most likely to be how they communicate majority of the time. They can hear sounds at very low frequencies so a great part of it won’t even be picked up during the test observations. Sharks also use their hearing to allow them to pick up vibrations and electrical currents from other sharks in the water with them. Most of the communication among sharks involves aggression. They will fight each other not for territory but for food. For...
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...Shark Finning Shark finning is the practice of slicing off the shark's fins while the shark is still alive and throwing the rest of its body back into the ocean where it can take days to die what must be an agonising death. Some sharks starve to death, others are slowly eaten by other fish, and some drown, because sharks need to keep moving to force water through their gills for oxygen. Shark fins are used as the principal ingredient of shark fin soup, an Asian "delicacy". Demand for shark fin soup has rocketed in recent years due to the increased prosperity of China and other countries in the Far East. Shark fin soup, which can easily cost $100 a bowl, is often served at wedding celebrations so that the hosts can impress their guests with their affluence. Because there is such a high demand for shark fins, traders can make a lot of money from shark fin, but it is the restaurant owners who really "make a killing" in this foul trade. Fishermen are only interested in the fins because shark meat is of low economical value and takes up too much space in the hold. It also contains urea, which turns to ammonia once the shark has died and contaminates other fish. Shark fin itself is tasteless; it just provides a gelatinous bulk for the soup which is flavoured with chicken or other stock. Many people, especially the consumers, are unaware of the suffering that finning causes. To put it bluntly, shark populations have been decimated. Globally, tens of millions of sharks are slaughtered...
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...Basking Shark In the midst of all the masters of the sea, comes an enormous atrocious sea creature. It is known for being the second largest species of sharks in the world and also a fascinating monstrosity. Cetorhinus Maximus, also known as Basking sharks are fierce yet bizarre lethargic sharks. They are known for their gigantic mouths and unique appearance, which sets them apart, and additionally are quite impressive. According to “The Shark side of Life” it states that, “These sharks can grow to lengths of over 35 feet (10 meters), thus making them the second largest fish in the ocean ("The Shark side of the World ").” Due to their colossal appearance, this particular shark has few enemies. Basking sharks are very independent and known to depart from their mothers once born. They are ovoviviparous which is a form of reproduction where the eggs are internally fertilized as well as hatched within the female bearer which she gives birthed to fully young sharks. In addition to their eccentric process of reproduction, Basking sharks are oophagous, which means that the mother produces infertile eggs to nurture the fertile eggs, as a source of food. According to Sharks Trust, it states “Gestation periods of 1–3.5 years have been proposed though this figure has recently been revised to around 14 months. Estimates of the size at birth range from 1–1.7m, making Basking Shark pups larger at birth than the majority of other sharks are when fully grown ("Shark Trust ").” This shows...
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...Bloodthirsty, ruthless, killer: shark. For years people have feared and slaughtered sharks because of the bad rap they have received from Hollywood, but these beliefs are not justified. Sharks are not vicious and are actually quite gentle. Of the more than 388 species of sharks only two (the Great White and the Tiger) have been known to attack man and then only because of mistaken identity. Wetsuits and surfboards used by surfers are mistaken by sharks as the thick, rubbery, skin of seals, which are their main diet. Once the shark bites the surfer, it almost immediately lets go because it does not taste like its favorite meal. Not all big sharks have huge jaws full of teeth, as many people believe. Whale sharks, the largest fish in the world, are the most affable creatures you will encounter in our world's oceans. These sharks (that can weigh over three thousand pounds and grow up to five stories in length) have no teeth at all. Instead they have a mouth full of baleen that they use to filter plankton and tiny fish out the hundreds of gallons of sea water that passes through their monstrous mouths at one time. These peaceful giants have been known to let divers ride on their backs and don't show any aggression when approached. People should treat sharks with respect, as they should all earth's creatures. The only way for future generations to learn to appreciate these magnificent creatures (instead of fear them) is through education. This can be accomplished through...
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...Over the past million of years the shark species have evolved dramatically from their ancestors. Sharks were and still are the main predator of the sea, which have helped them thrive in waters where they live. Sharks are a diverse group of animals with over 440 known species roaming the oceans all over the world today. From the Whale Shark, to the Cookie Cutter Shark, to the Goblin Shark, this group of animals are an incredible species that are like no other. The Evolutionary Origin of Sharks: Sharks have been around for over 420 million years, that was 200 million years before dinosaurs became into existence, (Shark Evolution, 2016). From the very first known kind of shark to the present days modern shark, they have survived the five major...
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...Who is involved in shark finning, and where? Finning occurs worldwide and is most common in high seas fisheries, hundreds of miles out to sea. Oceanic fishing fleets target valuable fish such as tuna, using thousands of baited hooks on miles of long-line, and freezing their catch onboard. Unfortunately, long-liners often catch several times as many sharks than they do tuna. Until relatively recently, this shark 'bycatch' was considered a nuisance, and sharks were cut loose and allowed to swim away. However, as shark fins have become increasingly valuable, fewer sharks are being released. Bycatch is often not officially landed at ports, therefore data on the extent of the trade are limited. Traditionally Hong Kong was the centre for shark fin imports, however the economic rise of China has seen an increase in imports through mainland routes making accurate tracking of trade in shark fins more difficult. (We can mention Taiwan too) In small inshore fisheries in tropical countries, sun-drying of fins requires minimal technology and artisanal fishermen are encouraged by shark fin-traders to target local populations of sharks. As a result, even coastal shark populations in the remotest parts of the world are now vulnerable to over-exploitation, and rapid depletion of local shark populations often results from such trading activity. * Finning occurs worldwide and is most common in high seas fisheries * Bycatch is often not officially landed at ports * Traditionally...
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...White Shark Great White sharks are being killed to the point of extinction. Overfishing, finning, and the fear of humanity are going to be the death of these majestic creatures if we do not do something about it soon. Great White sharks have been called “the barometer of our oceans”. If they are no longer around, our whole ecosystem will go into a terrible tail-spin that we will be helpless to stop. Solutions to these issues can be found by making some big changes, but mostly a lot of people making small ones. Great White sharks are in danger, and if little things are changed in people’s daily lives, we may be able to reverse, or at least halt, the threat. One major problem Great White sharks face is finning. Finning is defined as the catching of a shark, pulling it aboard a boat, cutting off all of the shark’s fins, then throwing it back into the ocean to either be eaten alive or drown. Author Rebecca Tatum states in her academic journal “The Ecology and Controversy of Shark-Fin Soup” that “Shark-finning is increasingly illegal on a global basis; since 2004, at least sixty nations have banned the practice” (Tatum 6). Many specials have been aired (on Animal Planet) about the shark fin trade. One could see fins drying on rooftops for miles. Tatum also states “The extraordinary value of the fins, up to $2,000 per pound, incentivizes this wasteful practice” (Tatum 2). The price paid for these fins also encourages the practice to continue, despite it being illegal. Shark fin soup...
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...Shark fining is directly correlated with the ecosystem goods and services (EGS) framework. As sharks offer tourists an opportunity for leisure, and are able to advance scientific research on an educational standpoint, they directly correspond with the cultural services aspect of the EGS framework. Provisionally, sharks determine our accessibility to certain ocean food sources such as shrimp, crab and lobster. Thus, sharks also regulate the oceans by purifying the water and regulating trophic levels. In return, this corresponds with provisional services as sharks must regulate the trophic levels to ensure trophic cascades do not occur. Cultural Services On a cultural EGS standpoint, sharks provide ecotourism activities and educational opportunities which both correspond with this framework. Both ecotourism and education would be...
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...Name Course Instructor Course Date of submission Status of Shark Stocks Protection of all species in the ecosystem, especially the imperiled species, for reasons fundamental among them socioeconomic and environmental is crucial. Debate centering on whether the shark species is imperiled or not, has effects on allocation of funds meant for conservancy efforts. However, the agreement from both sides is on sharks importance and their sustainability as crucial. This expose elucidate positions informing both sides. Further, the expose will identify the most strongly supported side and identify probable lobbies that support either side. Baum and Myers used data on the number of catches to compare the amount of shark species captured in the 1950s and 1990s in addressing their decline in the Gulf of Mexico. They noted that, catches on the Whitetip shark, the most prevalent of the sharks in the 1950s, declined by 99%. Additionally, catches of the Silky and Dusty shark declined by 91% and 79% respectively (142). Thus, this decline historically reflects on the level of humanity’s exploitation, for instance, the disappearance of the Whitetip in the Gulf of Mexico. Effectively, the near disappearance of the species underlines an ecological shift on the pelagic baseline. In another study in the Northwest Atlantic, Baum et al. concluded that there was a 50% decline of all the recorded but one species of shark. This study focused a short period of 15 years between 1986 and 2000 (391)...
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...you know about our “living fossils?” Sharks have hardly evolved over time. In reality, the change has been very little in 425-450 million years. There are as many as 400 known shark species. Classifying sharks can be tricky. There are eight orders of sharks based on evolution; Squatiniformes, Pristiophoriformes, Squaliformes, Hexanchiformes, Carcharhiniformes, Lamniformes, Orectolobiformes, and Heterodontiformes. Below is a dichotomous key showing how taxonomists categorized sharks. Image belongs to: SharkSidercom Sharks are part of the chondrichthyes family, and the subclass of elasmobranchii and euselachii. They are classed based on whether their body is flattened, snout size, number of gill slits, has a dorsal fin, mouth placement, eye placement, and if their eyelids are nictitating. It can be difficult to identify sharks from fossils. Sharks are made out of cartilage which...
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..."We basically kidnapped these sharks from their home and confused them for an hour on the way out," said study lead researcher Andrew Nosal, a postdoctoral researcher at the Scripps Institution of Oceanography and the Birch Aquarium in California. "Yet, within 30 minutes of being released in the middle of the ocean a place that they had probably never been — they knew exactly where shore was, which was really neat. It's common knowledge that sharks are excellent navigators, often swimming along straight paths toward a target, but it's unclear what senses — such as sight, smell, or even electric or magnetic senses — help the animals plot a course, Nosal said. However, there are clues that sharks rely heavily on smell. For instance, the olfactory...
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