What's the first thing that comes to your mind when you think about a shark? 'Fearsome', 'predator', 'sharp teeth', 'strong sense of smell' and 'killer' are most likely to be what's commonly listed. I'd say they are beautiful. Maybe not so much when their mouths are open and their teeth exposed, but there's a certain draw that sharks have. It is quite a pity that sharks are misunderstood by many and seen as vicious human-hunters that should be terminated at first sight.
Shark History
Sharks have existed for hundreds of millions of years, much longer than us humans. From Elegestolepis, one of the world's earliest sharks, to Megalodon to the modern Great White, sharks have been the top predator in the ocean since they appeared. Back then, those ancient sharks had a range of anatomical oddities: Echinochimaera had a snout like that of a rabbit's and had spikes on its back while Scapanorhynchus had a snout that protruded from the top of its head. The Scapanorhynchus bears great similarities to the goblin shark in its appearance. Come to think of it, the modern goblin sharks are a teaser of what prehistoric marine life probably looks like.
Sharks today
There are over 400 species of sharks in the world today. While Megalodon isn't around to terrorise the sea and provide vicious-shark-behaviour fodder to the media, modern sharks are just as dangerous - only to fishes and the occasional human though. Today, sharks can be said to have lost their top position in the marine food chain. Humans are hunting millions of sharks each year to cater to the demand for shark's fin, which is used as a key ingredient in shark's fin soup. The soup, a thick flavourful broth, is considered a delicacy in Chinese cuisine and often served in restaurants and banquets.
While it may seem that shark's fin adds flavours to the soup, it is actually the various other ingredients and condiments used that gives the soup its rich flavour. Perhaps with sustainable shark farming and hunting practices, the world can continue to enjoy this delicacy (without guilt). Meanwhile, I shall live off shark's fin-less soup a.k.a. thick seafood broth.
Some Brief Shark Physiology
Some of you might be thinking now, 'shark physiology? It's so boring. Can we skip to the interesting parts?' Well, I'll pick out the interesting facts about sharks. Besides, they have intriguing body systems - more so than many other animals on Earth, and it's going to be tough to choose and pick out the facts.
For one, many species of sharks have to keep swimming in order to obtain oxygen from the water. You know how fishes can stay stationary for a period of time and still appear to be happy and survive? Most sharks can't do that, as when they swim, the forward movement pushes water through their gills, providing them with oxygen. This process is called ram ventilation. While some shark species can pump water through their gills using their cheeks (buccal breathing), most sharks aren't able to do that. So if you are planning to get a shark aquarium, do remember to buy a big tank for them to swim around in.
Because sharks have to swim constantly to obtain oxygen, it is likely that sharks don't fall asleep. Experts have theorized that sharks 'sleep' or rest in areas with strong currents, while remaining conscious of their surroundings. Sharks that are able to pump water through the gills using their cheeks don't need currents - they can literally rest wherever they want to.
Sharks have great immune systems - they rarely get diseases. This could be due to absence of bone marrows, reducing the time needed for the shark's antibodies to fight off the disease and nip the problem in the bud. And if this isn't enough to make others jealous of their disease-fighting capabilities, sharks have lower rates of cancer than people and animals. One theory is that compounds in shark cartilage can stop angiogenesis by the cancer tumour. Angiogenesis is the formation of new blood vessels which, when formed, brings nutrients to the cancer cells in the tumour, allowing the cancer cells to divide and grow. Whatever the cancer-killer is, sharks have it pretty good, in my opinion.
Read more about shark physiology here.
Threats to Sharks and the Need for Conservation
The over-hunting of sharks for their fins have led to a drop in shark populations worldwide. Often, the sharks caught are finned and thrown back into the sea while they are still alive. So, what's the problem of this practice?
To understand the severity of this, we have to know which fins are being cut off. In shark finning, all the shark's fins except the upper caudal fin, which is the upper part of the shark's tail, are cut by the fishermen. This leaves the finned sharks unable to swim. Since sharks need constant movement to breathe, and being unable to swim, a finned shark drowns, starve to death, or gets eaten by other fishes. Kind of ironic for a fish and top predator, don't you think?
Other times when sharks are not being finned, they are getting caught in fishing nets that were meant for other species of fishes. The sharks caught by the nets are often finned instead of being let go unharmed. The value of shark's fin give fishermen little incentives to release shark bycatch, and to change their fishing nets to reduce bycatch.
With the decreasing shark population, it is important that conservation efforts are pushed out aggressively. Sharks are at the top of the food chain, and as such often provide a top-down control on the populations of smaller fish in the ecosystem. If the population of sharks drop significantly, the ecosystem's balance would be tipped and fish populations would change - fishermen could be adversely affected by this. In addition, the threat of extinction looms large on sharks, and the extinction of another species of animal on Earth is not something that anybody wants.
The fate of the sharks lie in our hands, and whether we are able to stop our craving for shark's fin - something which studies have shown to contain no nutrition value. Conservation of sharks happen not just because people are doing so for the sake of it, but because there is genuine cause for concern in what's happening in the world today. Swap out your bowl of shark's fin soup for something else, save some sharks today.
--------------------------------------------------------------------------------------------------------------------------
Information obtained from:
Prehistoric Sharks, Shark Week in Discovery Channel
Sharkopedia, Discovery Website
Sharks, World Wildlife Fund
Sharks have existed for hundreds of millions of years, much longer than us humans. From Elegestolepis, one of the world's earliest sharks, to Megalodon to the modern Great White, sharks have been the top predator in the ocean since they appeared. Back then, those ancient sharks had a range of anatomical oddities: Echinochimaera had a snout like that of a rabbit's and had spikes on its back while Scapanorhynchus had a snout that protruded from the top of its head. The Scapanorhynchus bears great similarities to the goblin shark in its appearance. Come to think of it, the modern goblin sharks are a teaser of what prehistoric marine life probably looks like.
 |
| Goblin shark image by Dianne Bray / Museum Victoria via Fishes of Australia |
Sharks today
There are over 400 species of sharks in the world today. While Megalodon isn't around to terrorise the sea and provide vicious-shark-behaviour fodder to the media, modern sharks are just as dangerous - only to fishes and the occasional human though. Today, sharks can be said to have lost their top position in the marine food chain. Humans are hunting millions of sharks each year to cater to the demand for shark's fin, which is used as a key ingredient in shark's fin soup. The soup, a thick flavourful broth, is considered a delicacy in Chinese cuisine and often served in restaurants and banquets.
 |
| Shark's fin soup, mmm or hmm? |
Some Brief Shark Physiology
Some of you might be thinking now, 'shark physiology? It's so boring. Can we skip to the interesting parts?' Well, I'll pick out the interesting facts about sharks. Besides, they have intriguing body systems - more so than many other animals on Earth, and it's going to be tough to choose and pick out the facts.
For one, many species of sharks have to keep swimming in order to obtain oxygen from the water. You know how fishes can stay stationary for a period of time and still appear to be happy and survive? Most sharks can't do that, as when they swim, the forward movement pushes water through their gills, providing them with oxygen. This process is called ram ventilation. While some shark species can pump water through their gills using their cheeks (buccal breathing), most sharks aren't able to do that. So if you are planning to get a shark aquarium, do remember to buy a big tank for them to swim around in.
Because sharks have to swim constantly to obtain oxygen, it is likely that sharks don't fall asleep. Experts have theorized that sharks 'sleep' or rest in areas with strong currents, while remaining conscious of their surroundings. Sharks that are able to pump water through the gills using their cheeks don't need currents - they can literally rest wherever they want to.
Sharks have great immune systems - they rarely get diseases. This could be due to absence of bone marrows, reducing the time needed for the shark's antibodies to fight off the disease and nip the problem in the bud. And if this isn't enough to make others jealous of their disease-fighting capabilities, sharks have lower rates of cancer than people and animals. One theory is that compounds in shark cartilage can stop angiogenesis by the cancer tumour. Angiogenesis is the formation of new blood vessels which, when formed, brings nutrients to the cancer cells in the tumour, allowing the cancer cells to divide and grow. Whatever the cancer-killer is, sharks have it pretty good, in my opinion.
Read more about shark physiology here.
Threats to Sharks and the Need for Conservation
The over-hunting of sharks for their fins have led to a drop in shark populations worldwide. Often, the sharks caught are finned and thrown back into the sea while they are still alive. So, what's the problem of this practice?
To understand the severity of this, we have to know which fins are being cut off. In shark finning, all the shark's fins except the upper caudal fin, which is the upper part of the shark's tail, are cut by the fishermen. This leaves the finned sharks unable to swim. Since sharks need constant movement to breathe, and being unable to swim, a finned shark drowns, starve to death, or gets eaten by other fishes. Kind of ironic for a fish and top predator, don't you think?
 |
| Finned sharks that have been discarded. Image by Sebastian Losada, taken from Wikimedia Commons |
Other times when sharks are not being finned, they are getting caught in fishing nets that were meant for other species of fishes. The sharks caught by the nets are often finned instead of being let go unharmed. The value of shark's fin give fishermen little incentives to release shark bycatch, and to change their fishing nets to reduce bycatch.
With the decreasing shark population, it is important that conservation efforts are pushed out aggressively. Sharks are at the top of the food chain, and as such often provide a top-down control on the populations of smaller fish in the ecosystem. If the population of sharks drop significantly, the ecosystem's balance would be tipped and fish populations would change - fishermen could be adversely affected by this. In addition, the threat of extinction looms large on sharks, and the extinction of another species of animal on Earth is not something that anybody wants.
The fate of the sharks lie in our hands, and whether we are able to stop our craving for shark's fin - something which studies have shown to contain no nutrition value. Conservation of sharks happen not just because people are doing so for the sake of it, but because there is genuine cause for concern in what's happening in the world today. Swap out your bowl of shark's fin soup for something else, save some sharks today.
--------------------------------------------------------------------------------------------------------------------------
Information obtained from:
Prehistoric Sharks, Shark Week in Discovery Channel
Sharkopedia, Discovery Website
Sharks, World Wildlife Fund
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