- Sharks and rays have a very varied diet. They are carnivores which means that they eat animals rather than plants and algae. Some sharks commonly eat bony fishes, crustaceans (crabs, lobsters, and other animals with an external skeleton), mollusks(snails, sea slugs, octopus and squids), and different types of worms.
- A shark’s diet is often determined by its habitat. For example, sharks that live out at sea (pelagic sharks) are more likely to eatfish and squid because that is all that is available.
- Sometimes sharks change their diet as they get older. The Great White Shark mainly eats fish when it is young but once it reaches maturity it consumes more marine mammals like seals and sea lions.
- Most sharks prefer live food but they will also consume carrion (dead fish and other animals) that they find on the sea floor.
- Just like filter feeding whales, there are a few sharks that live by filtering plankton from the water. The filter feeding sharks may consume phytoplankton (microscopic plants and algae) while hunting for more nourishing zooplankton (tiny animals and larvae that drifts around on the currents). Ironically, the Whale Shark which is the largest fish in the sea, lives on plankton which is one of the smallest animals. So does the second largest fish; the Basking Shark. Although these sharks have huge mouths, their throats are tiny and they are unable to eat anything larger than a grapefruit. Their teeth which are no longer needed for feeding, have become very small.
- The largest ray (the Manta Ray) is also a plankton feeder. It has a flexible projection on each side of its mouth called cephalic lobes that it uses to funnel plankton towards its mouth.
- Most rays eat small fishes and benthic invertebrates; crabs, snails, and worms etc. that live on or under the sand.
- Sometimes its possible to tell what type of food a shark eats by the shape of its teeth. Sharks that catch fast swimming fishes tend to have very pointed teeth that help them grasp the fish. Sharks that eat hard shelled animals have flattened teeth that form a plate to help them crush the creature’s shell like a nutcracker.
- Tiger Sharks have a reputation for eating anything. They have been found with all sorts of strange things in their stomachs from clothes to license plates. Tiger Sharks have very sharp serrated teeth that are strong enough to bite through the shells of marineturtles.
Filed under Sharks Knowledges · Tagged with algae, amp, animal, anything, Basking, basking shark, benthic, bite, bony, bony fish, bony fishes, car, carnivores, carrion, catch, Co, Crab, creature, crush, Determined, diet, drift, eatfish, EST, example, feed, feeder, feeding, filter, fin, fish, fish in the sea, floor, food, form, grapefruit, Great, great white shark, habitat, hunting, largest fish, larvae, license, lobster, lot, Mammals, Manta, manta ray, Marine, marine mammals, maturity, mean, microscopic plants, mollusks, mouth, need, nutcracker, pelagic sharks, phytoplankton, plankton, plankton feeder, plate, point, project, projection, range, rat, rate, ray, reach, reputation, round, sand, sea, sea floor, sea lions, sea slugs, seal, seals and sea lions, shape, shark, Sharks, shell, side, skeleton, skin, small fishes, squid, swimming, term, They are carnivores, thing, tiger, tiger shark, Tiger Sharks, time, tiny animals, turtle, type, US, use, vertebrate, water, Whale, whale shark, what are sharks eat, White, white shark, With, zooplankton
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Sharks and rays do not have true bones like other fishes. They have cartilage instead which is lighter and much more elastic and allows them to bend in very tight circles.
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Sharks do not have swim bladders. A swim bladder is a gas filled sack inside the body of bony fishes that allows them to stay still without sinking. Sharks compensate by having a very big liver that is filled with oil. Even so, sharks sink unless they keep swimming forward. The exception is the Sandtiger Shark which swallows air to make itself more buoyant.
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A shark’s upper jaw is not fused to its skull like most animals. When a shark bites a large object, it is able to move its upper and lower jaw forward in order to take a bigger bite.
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Unlike other fishes, sharks are able to replace their teeth constantly. New teeth grow from the inner surface of the jaw and rotate forward when the old teeth get worn out or lost during feeding.
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Sharks and rays do not reproduce like other fishes. Most fish release clouds of sperm and eggs into the water column where they mix together. The fertilized eggs then float around until the fish larvae hatch and form schools of tiny fish. Male sharks have two organs called claspers attached to their anal fins. They insert one of these into the female shark’s cloaca (the entrance to the uterus) to transfer sperm (just like in mammals). Some sharks and rays incubate the eggs in their uteruses until the baby sharks are ready to be born. Other sharks and rays (i.e. skates) lay eggs and attach them to the reef.
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Sharks have between 5 and 7 gill slits on each side of their body in front of their pectoral fins. Bony fishes only have one pair. Having many exposed gill slits probably helps transfer more oxygen into their blood faster which allows them to swim very fast when they need to.
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Most shark’s skin is covered in small denticles instead of scales. Denticles are a lot like teeth. They have dentine in the centre and enamel on the surface. This makes shark’s skin very tough and abrasive like sandpaper. The shape and position of some shark’s denticles also helps reduce friction so that they can slip through the water easier.
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Sharks have an extra sense that is able to detect tiny electric fields. They can use this to find food that is buried or to search for animals to eat in the dark or in turbid water.
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Sharks and rays make up the sub-class of fishes called elasmobranches. This sub-class is part of a class of cartilaginous fishes called Chondrichthyes which also includes chimaeras (ratfishes).
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Filed under Sharks Knowledges · Tagged with advance, age, air, anal, anal fins, animal, baby, baby sharks, bite, bladder, blood, body, bone, bony, bony fish, bony fishes, car, cartilage, cent, centre, Chondrichthyes, Class, cloaca, Co, column, day, Denticles, dentine, ear, elasmobranch, ename, enamel, entrance, exception, face, feed, feeding, field, fin, fins, fish, fish larvae, fish release, food, form, friction, front, gas, gill, gill slits, incubate, inner surface, jaw, larvae, liver, loan, lot, lower jaw, Male, Mammals, mix, need, object, oil, old teeth, order, organs, oxygen, pair, paper, part, payday, pectoral, pectoral fins, place, position, rat, ray, Red, reef, reef sharks, release, round, row, sack, sand, sandpaper, Sandtiger, sandtiger shark, sea, sense, serv, service, shape, shark, Sharks, side, skate, skates, skin, skull, sperm, surface, swim bladder, swimming, tiger, tiger shark, tight circles, tiny fish, turbid, upper jaw, US, use, uterus, uteruses, water, water column, With
Following its acceptance of membership to the recently formed Shark Alliance, Save Our Sharks (SOS) attended the first anniversary and inaugural meeting of the Shark Alliance member groups in Brussels.
Around 35 delegates from 6 countries, U.K, France, Italy, Germany, Switzerland and Holland attended plus the directors and staff from the Pew Charitable Trusts, who financed the meeting.
Save Our Sharks were represented by Nigel Proctor (on behalf of the SOS committee) who met up at Brussels airport with the Sea Anglers Conservation Network (Scotland) representative, and SOS liaison officer Denis Kelly.
“Fins On”
One of the principal proposals that came out the conference is to be headed “Fins On” where the aim is to have sharks landed whole. There will be a drive to raise public awareness of the issue, and we will try to capitalise on the IUCN red listing, and create further publicity.
“Shark Week”
Another proposal is to hold a “Shark Week” in each member country, where each country’s members create a project to involve the community, schools, museums, aquariums and the like to raise awareness of shark issues.
There will be more to follow on the above shortly
There were many other issues and points made, however, these are the principal ones
• Strive to raise public awareness of shark related issues,
• Create adequate publicity and maintain the pressure,
• Educate journalists away from ‘sensationalism’ without portraying sharks as an animal they clearly are not, they are apex predators, not cuddly, loveable ‘toys’,
• Pre-influence the journalist way of thinking prior to ‘shark week’ and Ocean Day,
• Feed the media with facts and data to ‘force’ the attention on sharks prior to EU discussions on shark management,
• Similarly with CITES,
• Important to maintain ‘shark friendly’ states and get them to lobby less friendly countries,
• Lobby the UK to dispense with its ‘special permits’,
• Ensure that the Shark Alliance has a high profile at the release and showing of the new shark film,
• Don’t alienate the fishing industry,
• Work with fishermen, more is likely to be achieved at a faster rate,
Denis and Nigel were made extremely welcome and clearly treated as being amongst equals, if but a little less experienced in the ways of policy and lobbying. Nigel stated after the meeting that, “We have made significant moves along the pathway of shark conservation and have little to fear in the future, in terms of acceptability, we have a lot to offer and should not be afraid to push forward with our objectives, we can gain a great deal from liaison with the other member groups of the Shark Alliance, however, we also have a great deal to offer as well”.
At the conference Nigel reiterated the high level of importance UK anglers attached to sharks, skates and rays, making the point that the bad old days of trophy fish were long gone. He finished off by indicating our commitment and referencing the prohibition on the landing of tope along the English east coast (c 200 miles of coastline) which to the best of our knowledge is the first full protection, and or prohibition on the landing of any shark species in European waters. This brought about a warm and consensual round of applause, which probably indicates that we are not outcasts any more, but highly regarded and welcome members of an important Shark Alliance.
Well done to Nigel and Denis for helping to put recreational shark fishing on the front-line of European shark conservation
The next few months
We are in for a quiet time in Scotland until after the elections but there is much to do, in England and Europe. We will be writing to our members shortly with more details, please get involved.
• Liaise with the Shark Trust to organise a “Shark Week” to raise public awareness with the overall goal of banning the removing of fins at sea.
• Lobby Defra to stop handing out special permits which allows finning on Porbeagles. Both of the above are part of the “Fins On” campaign.
• Keep pressure on Defra to announce the results of the tope consultation.
• Build up a case to take to the EU to implement tope management across Europe.
• Remind Defra of their intention to implement a maximum landing size on rays, skate and spurdog.
• Keep pressure on the Scottish Exec. to have the Firth of Lorne, Sound of Mull and surrounding lochs and waters designated as a Spurdog nursery area.
• Lobby the EU to have the 25 per cent by catch on rays implemented in all UK waters.
• Continue with the red tape to get SOS listed for charitable status. Once achieved we can apply for grants to help with the campaigning and administrative costs.
Filed under Save Sharks · Tagged with ability, acceptability, acceptance, age, aim, air, airport, Alliance, alliance member, amp, Anglers, animal, anniversary, apex, apex predators, applause, aquariums, area, attention, awareness, ban, behalf, Brussels, brussels airport, Build, campaign, campaigning, capitalise, case, catch, cent, CITES, Co, coast, coastline, commitment, committee, community, conference, conference in Brussels, consensual, conservation, conservation network, consultation, Continue, country, Data, day, deal, Defra, Denis, Denis Kelly, Director, dog, Don, drive, ear, Educate, England, English, Ensure, EST, Europe, European, european waters, Exec, experience, fact, fear, feed, film, fin, Finning, fins, Firth, fish, fishermen, fishing, force, form, France, front, future, gel, Germany, germany switzerland, Gland, goal, Great, group, half, hand, head, hold, Holland, importance, Important, inaugural meeting, industry, influence, intention, International, issue, Italy, IUCN, iucn red list, journal, journalist, knowledge, land, landing, leg, level, Liaise, liaison, liaison officer, line, List, listing, Lobby, Lorne, lot, management, maximum, meeting, member, member country, member groups, membership, mind, Mull, Network, network scotland, Nigel, Nigel Proctor, nursery, object, ocean, offer, officer, organise, part, pathway, Pew, pew charitable trusts, point, policy, porbeagle, Porbeagles, Pre-influence, predators, pressure, Principal, principal proposals, proctor, profile, prohibition, project, proposal, protect, protection, public, public awareness, publicity, rat, rate, ray, recreation, Red, release, Remind, representative, round, Save, Scotland, Scottish, sea, sea anglers, sensationalism, serv, shark, Shark Alliance, shark conservation, shark fish, shark fishing, shark species, shark trust, shark week, Sharks, ship, showing, size, skate, skates, SOS, Sound, Species, spurdog, staff, status, Strive, Switzerland, tape, term, The Shark Trust, time, tope, trophy, Trust, Trusts, U.K, UK, uk waters, US, use, water, way, Week, With, work
Sharks have a great deal to fear from humans. Compared to the 10-15 people killed by sharks each year; over 100 million sharks perish at the hands of humans annually and many populations may face extinction. Sharks are killed for many reasons, including fear; food, sport, and ‘machismo’, but the great majority perish due to simple greed. Many shark products have commercial value, including: the flesh; the skin for high-quality leather; teeth and jaws for ornaments; liver oil for cosmetics, medicines, vitamin A, and skin-care products; and cartilage for false cancer ‘cures’. However; the product that drives the market are the fins. After drying, collagen fibers are extracted from them, cleaned, and processed to make ‘shark fin soup’. In spite of the fact that these fibers have little flavor or nutritional value, the soup is considered a delicacy, and may sell in the Orient for more than $100 ( £65) a bowl.
Over the years, shark fisheries have come and gone. In the early part of the century, sponge fishermen in Florida killed sharks to boil them down for their oil. The oil was then thrown on the ocean to smooth the surface of the water and make it easier to see the sponges from the boat. That ended when a plague killed off the sponges. In the 19405 to .19505 a number of shark fisheries sprang up to supply the market for vitamin A. That ended with the discovery of a method for its synthetic production. However; most shark fisheries, such as the one for dogfish sharks to supply the ‘fish and chips’ market in the UK, have ended only when the number of sharks dropped too low for the fishery to be sustained.
The explosive growth of the Chinese economy and rapid expansion of trade with the outside world during the 1985 and 1995 created an unprecedented situation. Suddenly there was an insatiable demand for shark fins of almost any size or type. Improvements in shipbuilding and navigational electronics meant that shark fishing boats could now go anywhere in the world, moving from one place to another as local shark populations were destroyed. The fins are now so much more valuable than the rest of the shark that the carcass is often discarded after the fins are removed, to save storage space on the boat. Often the fins are sliced off when the shark is still alive and the mutilated shark is dumped back into the water to die a slow and agonizing death.
Why should we be concerned about this situation? After all, wouldn’t the ocean be much safer without sharks? The answer is no. The chance of being attacked by a shark is already less than the chance of being struck by lightning. The real dangers for people in the water are drowning, exposure, and being struck by a boat. In the USA, for example, drowning incidents outnumber shark attacks by 1,000 to I. Without sharks, the whole experience of being in a natural ocean wilderness would be immeasurably reduced. It would be like being on the Serengeti with no lions or cheetahs. In losing the opportunity to view these magnificent and superbly-adapted predators in the wild, we are also losing part of our spiritual connection with nature.
But something else would be changed as well -the whole ecology of the ocean. Predators control the populations of their prey species in a beneficial way. They eliminate diseased and genetically defective individuals, and they stabilize population fluctuations. On land, when we have removed the natural predators of deer; for example, their populations have exploded until they overgrazed their food supply and died of starvation and disease. In the ocean we are not sure what all the consequences of removing the apex predators from the food pyramid might be. We do have one example, though. A shark fishery in Tasmania collapsed after two years of over fishing. Shortly afterwards, the fishery for spiny lobsters also collapsed and fishermen observed a lot of octopus in the area. Octopuses are both major predators of spiny lobster and an important food item for sharks. It seems that once the numbers of octopus were no longer controlled by the sharks, they became too numerous and decimated the lobsters. Economically, for those other than shark fishermen, it doesn’t make sense to allow sharks to be fished out, not only because of the possible damage to sustainable fisheries, but also because of the loss of earnings from divers coming to see sharks. Worldwide, shark-watching has become a multi-million dollar business.
Why do shark populations collapse so quickly when people begin fishing them? The answer lies in the life history of these animals. In many aspects, sharks are more similar to mammals such as whales, dolphins, or ourselves, than to other fish. Whereas most fish reach maturity in only a few years and produce thousands or millions of eggs per year; sharks take many years to reach maturity. Some species may not begin to reproduce until they are over 15 years old. Some species produce as few as two pups biannually, averaging only one offspring per year: So when a population is over fished, it may take many years to recover; or it may never recover: Some scientists believe that sharks should never be fished at all, that their biology is too fragile to withstand any exploitation. Perhaps sharks should have the total protection given to marine mammals in many countries. Unfortunately, sharks do not have big ‘fan clubs’ as dolphins do.
Although both are large predators with slow reproductive rates, sharks are handicapped, from a.: public relations perspective, by the fact that their mouths appear to be frowning, and that they must open their mouths to pass water over their gills, exposing their teeth. Dolphins, on the other hand, always appear to be smiling, because of the shape of their mouths. Since they breathe through the blowholes on top of their heads, they do not have to open their mouths and expose their formidable teeth in order to get oxygen. But even the dolphin’s smile may not protect it from the greed inspired by the high prices being offered by international buyers of shark fins. In a number of countries, fishermen are slaughtering dolphins to chop up for shark bait.
We should create save our sharks and dolphins lanyards to create awareness
Filed under Save Sharks · Tagged with A. That, age, amp, animal, answer, apex, apex predators, area, awareness, biology, boat, bowl, BSE, Build, business, Cancer, cancer cures, car, carcass, care, cartilage, cent, century, chance, chinese economy, Co, collagen, collagen fibers, collapse, Concern, connection, control, damage, deal, death, delicacy, demand, discovery, disease, diver, dog, Dogfish, dogfish sharks, Dollar, drive, ear, ecology, Economically, economy, EST, example, expansion, experience, exposure, Extinct, extinction, face, fact, fear, fin, fin soup, fins, fish, fish and chips, fisheries, fishermen, fishery, fishing, fishing boats, flavor, flesh, Florida, food, form, gene, gill, Great, greed, growth, hand, head, history, I. Without, Important, Improvements, insatiable demand, International, item, jaw, jaws, Killing Sharks, land, laugh, leather, life, lightning, liver, liver oil, lobster, loss, lot, machismo, majority, Mammals, Marine, marine mammals, market, maturity, mean, method, mid, mouth, Nature, navigation, navigational, navigational electronics, number, ocean, Octopuses, offer, offspring, oil, opportunity, order, Orient, outnumber, oxygen, part, perish, place, population, predators, prey, process, product, production, protect, protection, public, pyramid, quality leather, rapid expansion, rat, rate, reach, real victims, reason, Red, rest, row, Safe, sand, Save, sea, sense, Serengeti, serv, shape, shark, shark fin soup, shark fins, shark fish, shark fisheries, shark fishing, shark populations, Shark Products, Sharks, ship, shipbuilding, side, situation, size, skin, skin care products, skin-care, slaughter, slice, something, soup, space, Species, spiny, spiritual, spite, sponge, sport, stand, starvation, storage, story, supply, surface, synthetic production, Tasmania, thing, trade, tuna, type, UK, unprecedented situation, US, USA, use, value, vitamin, water, way, Whale, Wide, wilderness, With, world, worldwide, year
