Species culture book assignment pdf

Louise Young 17 March 2014

Bull Shark, Charcharhinuss leucas

David, 2011

Wet Set, 2012

Skerry, B.J., 2014

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Contents Page Chapter 1: Taxonomy !

Page 4 Chapter 2: Internal and External Anatomy!

Page 5 Chapter 3: Identifying Features!

Page 37 Chapter 4: National Geographic Distribution!

Page 39 Chapter 5: Life Cycle and Reproduction!

Page 41 Chapter 6: Biotic and Abiotic Requirements!

Page 42 Chapter 7: Nutritional Requirements!

Page 44 Chapter 8: Key Pathogen!

Page 46 Chapter 9: Conservation Issues!

Page 50 Chapter 10: Legislative Requirements!

Page 55

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Chapter 11: Extraordinary Issues!

Page 79

Chapter 12: Maintenance Programme!

86 Glossary!

Page 94

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Bull Shark;

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Chapter 1: Taxonomy

Phylum: Chordata!

Class: Chondrichthyes!

Subclass: Elasmobranchii!

Order: Carcharhiniformes!

Family: Charcharhinidae!

Genus and Species: Carcharhinuss leucas Taxonomy is the action of grouping living things in to closely related groups, also knows as Taxa [1]. By using systematics we are able to group organisms with the help of different qualities [10]. The first person to provide written definitions of classification was Plato (429-347 BC). Following him was his student, Aristotle, whose concepts of classification were used for over 2,000 years.

After many scientists contributed to these systematics, it was Carl Von LinnĂŠ who created what we use today, the Linnaean System. The Linnaean System contains the following groups of taxa (although not all species will have a complex taxonomy and so may have a smaller number of taxa): Kingdom, Phylum, Superclass, Class,

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Subclass, Superorder, Order, Suborder, Family, Genus, Species [10].

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Bull Shark; Chapter 2: External and Internal Anatomy External: E a r s [14] Eyes [13]

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1st Dorsal Fin [1]!

Colouration [16]

Dermal Denticles [15]

Lateral Line [17]

Caudal Fin [3]

2nd Dorsal fin [2]

Ampullae of !

Lorenzini [12]

Pelvic fin [6]

Nares [11]

Teeth ! and jaws [9] Mouth [10]

Gill Slits [8]

Anal Fin [5]

Pectoral Fin [7]

Fig. 1 Image: White, J, (2012)

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Caudal!

Peduncle [4]

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For almost 450 million years sharks have ruled the oceans [20] and up until now, have evolved very little and for good reason. Sharks are apex predators, remaining at the top of the food chain [20] for many biological reasons (Fig. 1)‌!

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1st Dorsal Fin [1]! !

All fins on sharks are used for stabilising, steering, lift and propulsion, with each fin being used for each different purpose [27]. The sharks first dorsal fin (fig. 2) is an Fig. 2 Dorsal Fin extremely important functional appendage which helps towards stability and manoeuvrability [5]. Beneath the sharks fin, at the core, lay soft cartilaginous radials and ceratorichia [5].

Although the shark’s dorsal fin cannot be moved flat against it’s body in order to reduce drag, the shark is able to use the drag created by this, in order to push themselves through the water [7]. This swirling gyre created by the sharks first dorsal fin is then used by its second dorsal fin, as the shark moves forwards, to push against [7].

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2nd Dorsal Fin [2]! !

Although not all sharks have a second dorsal fin (fig. 3), those that do, as mentioned above, use it for thrust against the gyre Fig. 3 Second created by it’s first dorsal fin. The Dorsal Fin shark’s second dorsal fin also helps to stabilise it, keeping the shark from rocking side to side as it swims [32].

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Caudal Fin [3]! !

The sharks body plan has been evolutionarily adapted in a way to suit its swimming style, whether that is anguilliform (eel-like), carangiform (mackerel-like) or thunniform (stiffer, tuna-like) [5].

The sharks caudal fin (fig. 4) is two lobed , where in most sharks the upper lobe is larger than the lower, and (According to Parker, Fig. 4. Caudal Fin S. 2008) “is supported by cartilaginous rods within and by dermal filaments”. Contained within the upper lobe of its tail is Bull Shark, Page !7

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the spinal column and because of this, the sharks tail has a heterocercal design. The caudal fin is used for thrust with the upper lobe of the caudal fin providing the most thrust, which can force the shark downwards. In conjunction of the use of the sharks pectoral fins and the shape of its body, the shark is able to counteract this [27].

The sharks caudal fin can vary in shapes and size, depending on its lifestyle. Some may have a lunate shape (e.g. makos, Isurus oxyrinchus and porbeagles, Lamna nasus -fast swimming sharks) used for thrust whilst others such as nurse sharks, Ginglymostoma cirratum and zebra sharks, Stegostoma fasciatum have non-lunate caudal fins in order to help undisturbed swimming close to the benthos [27].

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Caudal Peduncle [4]! !

Ahead of the caudal fin is the caudal peduncle (fig. 5). The caudal peduncle may have pre caudal pits (notches) and helps to provide a stiffness to the caudal tail when in motion. This is particularly Fig. 5 Caudal Peduncle useful for thunniform swimmers, remaining stable at high speeds for a

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long period of time. With thunniform swimmers, undulation is confined to the front part of the sharks body and so this stiffness provided by the caudal peduncle is extremely useful [5]. !

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Anal Fin [5]! !

Not all sharks have anal fins. The sharks anal fin (fig. 6) can be found between the pelvic fins and the caudal fin [27] Fig. 6 Anal Fin and is an unpaired fin that is used for stability as the shark swims [32].

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Pelvic Fin [6]! !

Pelvic fins (fig. 7) are paired (consist of two fins, either side of the sharks body and are mirror images of each other) Fig. 7 Pelvic Fin [39] and can be located between the pectoral fins and the anal fin. The pelvic fins can be subtly controlled, allowing for excellent hydrodynamic movement within the hinder part of the body [39]. !

In some species, females have been observed to be Bull Shark, Page !9

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‘cupping’ their pelvic fins. This is believed to be an acceptance towards the males sexual advances [39]. !

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Pectoral Fin [7]!

In some sharks species, the pectoral fins (fig. 8) are shown to be facing upwards. Along with this, the surface area and the foil action of the pectoral fins [5] help to lift the front end of the shark as it swims Fig. 8 Pectoral Fin forwards [7]. As well as helping the shark to aim up the pectoral fins also help, amongst other manoeuvres, to control rising and descending. Pectoral fins can also be used as a brake, but cannot be folded inwards unlike bony fish [4]. !

For ram ventilating sharks (whom must move in order to pump water through their gills) lift is especially important [5].

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Gill Slits [8]!

Sharks use their gills (fig. 9) to withdraw oxygen from the surrounding water. In order to do so, sharks take in water Fig. 9 Gill Slits

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through their mouth. The water then moves over their gills and out through their gill slits [7]. Each gill slit has lamellae which contain capillaries. As blood flows through these capillaries oxygen diffuses from its high concentration in the water to a lower concentration in the blood [31]. The number of gill openings can range from between 5-7 throughout shark species. Bull sharks are able to survive in both salt water and fresh water (See chapter 3).

Teeth and Jaws [9]! !

The sharks teeth (fig. 10) are one of its most vital body parts when it comes to survival. They are constantly renewing themselves using a fresh row of teeth resting Fig. 10 Teeth and Jaws behind [7]. Each one of the sharks teeth is made up of dentine, which is slightly pliable and shock absorbing and is covered in enamel [7]. The base of the sharks teeth are not stabilised within the jaw cartilages but sit in the tooth bed which then sits on the jaw cartilage, held in place by fleshy gum [7]. This allows the tooth to be slightly flexible, helping when it comes to attacking prey. If and when a

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tooth falls out, there is a new one moved in place from the row behind. Depending on the shark species and its lifestyle this mechanism can occur every few weeks or months [7]. Again, depending on the shark species and its lifestyle, the shape and size of the tooth can vary. Sharks with teeth that are long, thin and pointy tend to be employed for catching fast, slippery fish and squid whilst teeth that are serrated triangular blades are used for cutting through flesh [7]. Bull sharks have ‘steakknife’ teeth that have serrated edges, useful for catching almost any type of prey.!

The sharks upper jaw is not fused to its cranium and so can protrude slightly outwards helping to point the teeth out which in turn maximises their chance of catching prey [29].!

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Mouth [10]!

Ampullae of Lorenzini [12] are found along the mouth (fig. 11) and are electrical sensors that, at close range, can detect weak electrical fields given off by other Fig. 11 Mouth animals movements. Sharks use their mouth and snout to test certain objects/prey in order to decipher the situation. Sharks are able to open their

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mouths by up to 180 degrees in order to catch their prey [29]. When a shark bites into an object/prey chemicals are sent to gustatory sensory cells present in the sharks mouth and throat [31] helping the shark to decide whether or not it wants what it has bitten in to.

Nares [11]! !

Sharks nares (nostrils) (fig. 12) are located beneath their snout. The sharks nares are not part of breathing and so are Fig. 12 Nares separate from the mouth and throat but are used completely for olfactory [31]. The nares are extremely sensitive to odours within the water, with sharks being able to detach a single drop of blood in 25 gallons of sea water [32]. Each nare is separated in to two parts, incurrent aperture and the excurrent aperture.

Water is passed through the intercurrent aperture and passed over the olfactory lamellae, containing neurosensory cells which send information via the olfactory bulb to the large olfactory bulb located in the sharks forebrain [31]. Finally, once this action has been completed, the water is then channelled out through the excurrent aperture [31]. If, by this operation, the shark

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detects scent within the water column it will follow it, whilst moving its head back and forth [31].

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Ampullae of Lorenzini [12] Ampullae of Lorenzini (fig. 13) are small jelly filled pores contained along the mouth and are electrical sensors that, at close range, can detect weak electrical fields given off by other animals Fig. 13 Ampullae of Lorenzini movements. Water is 10 million times more conductive to the flow of electricity than air [5] so this adaptation is extremely valuable in regards to predator and prey.

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Eyes [13]

Fig. 14 Eyes

Sharks eyes (fig. 14) are able to function throughout a large range of light levels, depending on the species [5] and are able to control the amount of light entered in to the eye by using their cone cells to dilate or contort the pupil [31]. !

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Within many shark’s eyes are retinas containing millions of microscopic rod cells [7]. These retinas are extremely sensitive to light levels, sending nerve signal patterns to the optic lobe of the brain [7]. Laying behind this retina is the tapetum. The tapetum is a layer of cells with a silvery colour. Any light that passes through the retina is reflected off this ‘mirror’ helping create a greater amount of light sensitivity [7]. Sharks possess an upper and lower eyelid which usually don't meet and so when met with a prey encounter they roll their eyelids back in order to protect them. Along with this, some sharks also have a third eyelid, known as the nictating membrane, which rolls up from the base of the eyeball in order to cover and protect the sharks eye during a prey attack [31].!

Most sharks eyes are on the side of the head, meaning that their vision does not overlap. Without this ability of overlapping eyesight, sharks are unable to judge distance very well through sight alone [7].

Ears [14] Sharks ears are layered in millions of hair cells [cilia][5], this helps them to detect sounds of up to 400m away.

Sharks are able to tune in to low frequency sounds and so are able to detect irregularly pulsing frequencies below 80 Hz, helping them to detect struggling prey [5].

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Also within the sharks ear are tubes and chambers which are filled with gelatinous fluid but are still connected to the surrounding water [5]. Sounds moving through the water activate the cilia within the ear, signalling the shark to a sound.

Dermal Denticles [15]!

Sharks skin, when felt, often feels like sand paper. This is because of dermal denticles, teeth like scales, that make up the surface of the skin. Dermal denticles are attached to a basal plate [7]. Within the denticle is a pulp cavity, where a vessel of nerve and blood lie. Just like the sharks teeth, the denticles are layered in enamel and are moved and replaced often [7]. The denticles are situated in a particular way so as to create a swirling motion next to its skin. This helps to created a slippery feel, helping to make the shark more hydrodynamic [5].

Colouration [16]!

According to Jorgensen, S (2008) “The functionality of sharks colouration (Fig. 15) is generally more geared toward stealth than to mate attraction�. Generally the back and upper parts of the sharks body are darker than the bottom which tends to be Fig. 15 Colouration light in colour. This helps to Bull Shark, Page !16

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camouflage the shark from above and from below. Along with this, colour patterns may well help sharks to recognise other members of its species, help towards social interactions and mating [5].

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Lateral Line [17] Lateral lines are located on the upper side of the sharks body (although not completely visible to us). Sharks are able to use their lateral line, in oder to pick up any variations in the surrounding currents and pressure waves from underwater sounds [7]. Signals are sent from inside their canals, picked up by tiny cilia, to the brain.

Lining the canal are hundreds of neuromasts (cilia) [7], with openings from the sharks skin to its surroundings.

Sound waves moving through the tunnel hit cupula neuromasts and stimulate them, helping the shark with detection.

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Internal: Basihyal Gill Arch

Gallbladder

Skeleton Made of Cartilage

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Basihyal!

The sharks basihyal (tongue) is made up of cartilage, running through the sharks chest supporting the lower

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gill-related bones [25]. In most sharks the basihyal is useless and, unlike humans, does not contain taste buds (taste buds are located on the papillae lining the sharks mouth and throat) [25]. !

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Rostrum!

A sharks rostrum may also be called its snout and is located on the anterior. The rostrum holds the ampullae of Lorenzini (See Ampullae of Lorenzini [12]). The shape of the rostrum, depending on the sharks lifestyle, can often be shaped to help with the hydrodynamics (especially in the case of the Bull Shark).

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Brain and Nervous System!

Fig. 17 Image of ‘A Shark’s Brain (side view)’ taken from Parker, S. (2008)!

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The peripheral nervous system of a shark is responsible for sending nerve carrying information to the central nervous system, the muscles and the organs [7]. Nerve signals are the coded patterns of electrical pulses which ultimately carry this information [7]. Nerves are made up of nerve fibres (or axons). The nerves that carry sensory information from sense organs, around the sharks body and to the spinal column and brain are called sensory neurons. Following this, the information is processed in the brain. Motor neurons then send out signals to the sharks muscles and organs to make the shark react [7]. !

Most sharks brains are hollow, made up of ventricles (fluid filled chambers) and is made up of three main Bull Shark, Page !20

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sections, the forebrain (1), the midbrain (2) and the hindbrain (3) [7]:!

Forebrain (1):!

The forebrain (also known as cerebrum) is partly made up of olfactory lobes (Fig. 17) which control information gained about sense and smell. The cerebrum is mainly used to control information gained from olfactory sense and perception [7]. ! !

Midbrain (2):!

Within the midbrain are the optic lobes, taking in information collecting by the eyes [13] (Fig. 14). As well as this, most of the sensory information is coordinated here [7]. ! !

Hindbrain (3):!

The sharks hindbrain is fairly large with the cerebellum synchronising muscle movements [7]. The amygdaloid centre deals with the rapid, intuitive reactions from the shark. The sharks heartbeat, blood pressure, digestion and excretion is controlled by the brainstem. !

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Efferent Branchial Artery!

Efferent branchial arteries help to return oxygen gained

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from the gills with many branches helping to distribute oxygenated blood to anterior parts of the sharks body [26].!

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Gill Arch!

The amount of gill slits can vary from between 5-7 depending on the species of shark. Gill arches are supported by a cartilage branchial bar, curving around the tide of the throat cavity [7]. On this arch are gill filaments which are made up of lamellae helping to absorb as much oxygen as possible [7]. !

Within these lamellae lie capillaries. The capillaries are thin walled and so when blood flows through them, they are essentially very close the the water outside, this helps to collect the high concentration of oxygen from the water to the low concentration of oxygen to the blood [7].

Passing in the opposite direction to this flow is carbon dioxide, the body’s waste product, expelling from the blood to the water [7]. In order to have the highest chances possible of gaining enough oxygen from the water the sharks system is enhanced by the countercurrent principle, where blood and water flow in the opposite direction of one another [7]. The sharks gills need a constant supply of oxygen, thus a constant supply

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of water flowing over them. In order to do this, some sharks use muscular action to draw water through the mouth and squeezes it out over the gills. In order to do this, most sharks swim forward with pelagic sharks using ‘ram ventilation’. Benthic sharks are often still and so aren't moving forward, moving water over their gills.

According to Parker, S. 2008 “By doing this they risk blocking their gills with debris stirred up from the seabed”. In order to overcome this, they breath through an extra hole behind each eye known as the spiracle [7]. !

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Dorsal Aorta!

The dorsal aorta is composed of capillaries leading away from the heart, joined and having grown in size.

Following this, the dorsal aorta branches off in to smaller arteries which carry blood to all parts of the sharks body [7]. !

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Stomach!

The sharks stomach is split up in to two parts: the first part is the cardiac limb whilst the second part is the pyloric limb. The stomach is located within the middle of the shark body and is attached to the short oesophagus [31]. The stomach walls are made of muscle which helps Bull Shark, Page !23

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with the rhythmic squeezing [31]. Hydrochloric acid and mucus are produced by secretory cells, enabling the breakdown of food [31]. According to Smith, L (n.d.) “In addition the pancreas duct delivers protein-splitting enzymes into the stomach. Sharks have the ability to “evert” (push out) their stomachs in order to get rid of unwanted/indigestible items”. The acid in the stomach is extremely strong, helping to digest food extremely quickly.!

If there is something within the stomach that is unwanted, the shark has the ability to almost completely push it inside out, regurgitating any unwanted food. !

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Kidneys!

Sharks have two long narrow kidneys that lie on either side of the vertebral column. The kidneys are made up of many renal tubules that are closely intertwined with capillaries. These walls of renal tubules and capillaries work together to regulate the passing of salts and water [7]. !

Renal tubules are used to process water and dissolved substances from the blood in order to keep the wanted substances. Any unwanted waste remains in the tubules, joining together in to urinary ducts, carrying urine into

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the urinary sinus (bladder) which is joined to the cloaca, from where urine is excreted [7]. !

Sea water has a relatively high concentration of salt.

Sharks body fluids also contain salt concentrations. Due to osmosis, the balance of salts between the shark and its surrounding water can cause a problem. Osmoregulation can vary between species. According to Parker, S (2008) “Most marine fish have fluids and tissues that lower salt concentrations than the salty water around them, meaning they must drink large amounts of seawater”. In opposition to this, sharks keep the salts in their body fluids and tissues to the same levels as the surrounding seawater. They do this by containing high concentrations of waste products in the blood. In order to stop any ill affects from too much urea they may have, sharks have TMAO (trimethylamine oxide) [7]. !

According to Parker, S (2008) sharks have other waste disposal systems including:!

“-some unwanted salts and minerals, along with carbon dioxide, pass through the thin delicate gills in to the water;!

-the liver breaks down old blood cells and other things and mixes their remains with digestive juices to form a yellow fluid, called bile. This is stored in the gall bladder; squeezed in to the gut to help with digestion and Bull Shark, Page !25

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eventually voided with the faeces;!

-undigested waste from the gut form the faeces;!

-the rectal gland concentrates and secretes excess salts�. !

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Tissue sites - Immune cell production!

Spleen!

The spleen is located along the stomach and is rich dark red and purple in colour [31]. The sharks spleen also produces red blood cells [4].

Thymus!

The Thymus is a paired organ and is located towards the back of both sets of gills. It is ordered into small lobes, changing in size and location depending on growth and sexual maturation [31].

Epigonal!

Epigonal and leydigs are unique to elasmobranchs. They are found caudally from the back of the gonads with the size and shape of the epigonal varying drastically between species [31].

Leydig!

Leydigs are seen beneath the epithelium, on each side of the oesophagus, dorsally and ventrally and are white in colour [31].

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Reproductive Organs!

Testes and claspers!

According to Smith, L, n.d. “The male reproductive !

Fig. 18 A Female Shark’s Reproductive Organs. Taken from Parker, S (2008)

system consists of the testes, the genital ducts, the urogenital papilla, the siphon sacs and the claspers”. The Bull Shark, Page !27

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testes are paired and dorsal to the liver, suspended from the mid dorsal body wall [31]. The testes are used for discharging hormones and creating sperm. These are moved through a tube, of which the first part is called the vas efferentia and the second part being the vas deferens [31]. Spermataphores are bundles of sperm created due to the mucus like substance lining the tube. The spermataphores are then moved to a bag called the seminal vesicle. The sharks claspers are used to direct sperm when they are inserted in to the female. Attached to the clasper is a spur, which ! is used to help anchor on to the females reproductive tract [31]. In immature males the clasper is usually fairly small and flexible but when reaching maturity, the claspers begin to calcify and harden [31].

Ovaries and Oviducts Just like the testes, the ovaries (Fig. 18) are part of the endocrine system [7]. Most sharks only have one functioning ovary but this is enough as the sharks low reproductive rate means that the shark, relatively, only needs a few eggs throughout her life [7]. Often, female sharks are larger than male sharks with their skin also being thicker, this is believed to protect them from mating which can be extremely aggressive. !

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In breeding season the sharks ovaries become ripe and release eggs with cilia helping to move them in to the oviducts [7]. Following this, the eggs are passed through a gland which coats the egg and is also a reserve of food.

After this, comes the shell gland through which the eggs are passed and are wrapped in a soft, filmy case which is also known as a candle [7]. During mating, if successful, the eggs meet sperm when passing along the oviduct and are then fertilised [7]. Female sharks are able to store any sperm for up to one year [7]. !

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Rectal Gland!

The rectal gland is a small organ that opens by a duct in to the rectum [27]. The rectal gland removes excess sodium chloride from the blood. This secretion is twice the concentration as that found within the blood plasma and higher than the surrounding seawater [27]. !

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Intestine!

After many hours and/or days of food being in the stomach, it is then moved in to the intestine, with more digestive juices being added by the liver and the pancreas gland [7]. Within the shark’s intestines are intestinal valves which help to increase the surface area Bull Shark, Page !29

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of the intestine, solving the issue of the intestine being quite small in size [31].

Spiral Valve!

The spiral valve is helix shaped and is twisted as many as 40 times. Due to this the surface area is increased and so better absorption of digested nutrients [7]. The appearance of the spiral valve varies between species [7]. !

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Pancreas!

According to Smith, L (n.d.) “the pancreas duct delivers protein-splitting enzymes into the stomach”.!

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Liver!

The liver helps digestion by producing bile which is stored in the gall bladder. The liver is split in to two large lobes and one smaller central lobe. The sharks liver is usually 15-35% of the sharks weight [31] as well as storing 30-80% of the sharks energy. According to Smith, L (n.d.) “Some of the functions carried out by the liver include: storage and release of vitamins, manufactures a starch-like compound used as a fuel supply for white muscle, stabilises the blood sugar level, detoxifies poisons, builds enzymes, manufactures

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cholesterol and constitutes a major source of metabolic heat�. Circulating the liver is low density oils and hydrocarbons, including squalene which is less dense than seawater [31]. Because of this, the shark is able to maintain buoyancy/lift and thus does not have or need a swim bladder. This function helps to maintain a lot of the shark’s energy, leaving enough energy for propulsion.

Females will stop eating while going through late stages of gestation and transfer their energy from their liver to their pups. !

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Skeleton Made of Cartilage!

Cartilage is made of chondrocytes. It is flexible, lighter than bone and is able to grow as the shark grows [31].

Where a part of the skeleton touches another, the cartilage is extremely smooth. This helps to reduce any chance of wear and tear [7]. Between these pieces of cartilage are shock absorbing bags of fluids known as the synovial capsule [7]. Joints are held steady by strong, elastic ligaments. !

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Gallbladder!

The gallbladder is attached to the median lobe of the liver. The gallbladder stores bile which is used to bind Bull Shark, Page !31

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fats and during digestion [31].!

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Heart!

The sharks heart lies just behind the gills. The walls of sharks hearts are composed of strong muscle, contracting rhythmically, pumping blood around its body [7]. The sharks heart is separated into four sections: 1. Sinus Venosus which is round and thin walled that decides the hearts contraction rates; 2. Auricle which is also rounded with a thin wall that acts as a blood chamber; 3. Ventricle which is oval shaped, thick walled and muscular. It pushes blood through the heart and to the rest of the circulatory system; 4. Conus Arteriosus which is cone shaped, inflexible and has 3 rows of one way valves.

Although the exact function of the Conus Arteriosus is still unclear, it is believed to uniform blood pressure [31].

The sharks heart beats 19-78 times per minute, varying greatly with species.!

Following the heart is the Dorsal Aorta (see dorsal aorta). After this, the arteries are split up in to smaller parts, forming capillaries. The capillaries walls are extremely thin and so oxygen, nutrients and other substances pass in to the tissues [7]. These capillaries form and become larger tubes, veins and larger sinuses

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[7].

These veins and sinuses unload into the sinus venosus (the first chamber of the heart) [7]. Following this the blood moves in to the auricle or the atrium (the second chamber of the heart) and then is drawn in to the thick walled ventricle (the third chamber of the heart) [7].

Once blood has moved to the thick walled ventricle, it is moved in to the conus arteriosus (the fourth chamber of the heart). From here the blood is then moved to the ventral aorta (see ventral aorta) [7]. !

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Afferent Branchial Artery !

Blood is pumped by the heart through the afferent branchial artery to capillaries in the gills. !

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Blood Circulation!

Sharks blood is composed of 55% plasma which, according to Smith, L (n.d.) “contains: water (90%), dissolved proteins, glucose, minerals, hormones, gases, platelets and blood cells (erythrocytes – red blood cells, leukocytes – white blood cells and thrombocytes). Red blood cells contain haemoglobin; this binds to oxygen and gets transported around the shark’s body”. White blood cells include lymphocytes, granulocytes and monocytes and are responsible for immune functions Bull Shark, Page !33

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[31].

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The haemoglobin within the blood strongly connects with oxygen, aiding in the absorption of oxygen in the gills, releasing it to the body tissues. !

There are two types of immunity that sharks possess, natural or innate immunity which provides the first line of defence and specific or adaptive immunity which is immunological memory is generated. !

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Osmoregulation !

Osmoregulation regulates solute concentrations and balances the gain and loss of water. Relative concentrations of the surrounding seawater and solutes must be maintained within fairly narrow limits. !

Osmoregulation balances the uptake and loss of water and solutes. Osmoregulation is based largely on controlled movement of solutes between internal fluids and the external environment. If two solutions are isoosmotic, the movement of water is equal in both directions. If two solutions differ in osmolarity, the net flow of water is from the hypo-osmotic to the hyperosmotic solution (Pers. Comms. Baldwin, C. 2013). !

Osmoconformers, consisting only of some marine animals, are iso-osmotic with their surroundings and do

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not regulate their osmolarity. Osmoregulators, expand energy to control water uptake and loss in a hyperosmotic or hypo-osmotic environment. !

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Muscles!

Sharks have 3 main types of muscle; Cardiac muscle, Visceral muscle and Skeletal muscle [7]:!

Cardiac muscle!

Cardiac muscle is specialised for continuous use [7].!

Visceral muscle!

Visceral muscle is found in layers in the internal parts of the shark. These include, guts, arteries, excretory and reproductive organs. By the use of these muscles, contents is able to pass through these internal organs [31]. !

Skeletal muscle !

Skeletal muscles moves the shark’s skeleton [7]. The main pairs of the sharks muscle can be found on either side of its spinal column [7]. !

Sharks have myomeres. These are muscles that help the shark undulate it’s body in order to swim forward [7].

According to Parker, S. 2008 “The ends of each muscle fibres in each myomere attach to a tendon called a myosepta which then connects to the cartilage of the skeleton”. !

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Sharks also have red and white muscles. Red muscles are shown in thin layers underneath the sharks skin [31]. The sharks red muscle helps to break down fats in the sharks body. It also has a good blood supply which helps the shark to swim over a long distance, slowly, preserving its energy [31]. White muscle is used for short bursts of high speed, often used when having to catch prey or avoid danger. The white muscles works by using the energy created by breaking down sugars [31].

!

Body Temperature!

The majority of fish are poikilothermic or ectothermic (cold blooded) and so their body is the same as that of the surrounding water temperature. This is not always the case for all sharks though where some (Lamnidae family including the white shark, short fin mako, porbeagle, salmon shark and thresher shark) are endothermic (warm blooded) and are able to regulate their own body temperature [7]. This heat is produced by muscle activity and biochemical reactions in the tissues through rete mirabile [7].

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Bull Shark;

!

Chapter 3: Identifying Features

The Bull Shark (Carcharhinuss leucus) is known for its stocky, beefy shape. It’s body is usually grey on top and white on their ventral (under) side, with dark tips on the shark’s fins. Bull Sharks also have long pectoral fins [24]. The shark’s first dorsal fin is just under 3.2 time the size of the second dorsal fin [34]. They also have small eyes, saw edged upper teeth and 5 gill slits. ! !

Carcharhinuss leucus can grow up to 340cm and weighing up to 317kg. Their size at birth is 60-80cm in length and upon reaching maturity males can reach up to between 1.6-2.3m whilst females have been known to reach up to between 1.8-3.5m [34].! !

Unlike most sharks, bull sharks are able to live in both fresh water and salt water. This is due to adaptations of osmoregulation. According to Tennesen, M (2012) “Most ocean sharks need salt in their bodies to prevent their cells from expanding and rupturing. But bull sharks have a special gland near their tails that helps retain salt

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and they have kidneys that recycle the substance when they enter freshwater�. If there is ever an unequal balance between salts in the shark’s cell membranes from the internal and external environments any water will move from the area of highest concentration to the area of lowest concentration, helping to make the concentrations equal again. The problem with this is that the creature can then procure either too much or too little water [28]. Due to the environment marine animals live in being highly saline they must refrain from any dehydration occurring whereas freshwater animals need to obtain the salts in their body-this is where osmoregulation comes in.

!

In order for sharks to stop high levels of salt in their bloodstream, they remove the high concentration of salt through their urine [28]. The high concentration of urea and other biological solvents help to conserve their salts whilst urinating helps to expel any excess. These processes are performed by the kidneys [28].

!

Unlike most sharks, Bull Sharks, are able to adapt to what other sharks would die from the likely absorption of too much water relative to the body solvent concentration [28]. In order to do this, Bull Sharks have adapted to fresh water by adapting their processes by osmoregulation [28]. Their kidneys adjust to the fresh

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water salinity. They essentially reverse the normal process of osmoregulation in sharks by their kidneys removing less salt and having more urea in the blood stream [28].

The Bull Sharks are one of the top 4 most aggressive sharks known in the ocean. They also have a short, blunt snout and are known to ‘head-butt’ their prey before attacking prey [24]. !

!

Bull Shark; Chapter 4: National Geographic Distribution

Fig. 19 Global Distribution of Bull Shark. Map taken from Vector Templates (2014) whilst red information has been taken from Parker, S (2008).

- Global distribution of Bull Sharks, Carcharhinuss leucas

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! !

According to Parker, S (2008) Bull Sharks are commonly found “just off the Pacific and Atlantic coasts of North and South America (Fig. 19); around much of the coast of sub-saharan Africa; far along the Amazon and Mississippi river systems; along the shores of india, southeast Asia and Australia”!

Unless following a particular food source, most Bull Sharks will stay in a particular area [21]. Most sharks don't use a particular area as their ‘home’ but with Bull Sharks being an extremely territorial animal, they tend to stay in the same area (unless having reason to move).

Along with ensuing prey, pregnant female Bull Sharks have been known to migrate to estuarine areas in order to give birth [41]. According to Simpfendorfer, C. & Burgess, G.H. (2009) “The juveniles remain in these areas until temperatures drop below optimum levels and then migrate to warmer offshore waters. A general migration along the United States east coast is also observed, with movement northwards during the summer as water temperatures rise and southwards again as temperatures cool in the north (Castro 1983)”.

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Bull Shark;

!

Chapter 5: Life Cycle and Reproduction

Generally Bull Sharks have a very long life span and have been known to live up to 25 years in captivity, with examples including Shaka Marine World in South Africa and Sea World Florida, U.S [7]. !

Males sexual maturity is 1.6m whilst females are 2m (at about 10 years of age [21]), with the sexual maturity of Charcharhinuss leucas varying with the geographical location [37]. The Bull Shark mating season is during the summer and their reproduction is viviparous [7] which is where the shark gives birth to live young as opposed to laying eggs [6]. !

The Bull Shark’s gestation period is between 10-11 months with 1-13 pups per litter. The pups size at birth can range from between 55 and 80cm (Shark Foundation, 2005). According to Curtis, T (n.d.) “Growth rates calculated from captive bull sharks were estimated to be about 11 inches (28 cm) per year in the first years of life, slowing to half that rate after about 4

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years of age”. Once the female shark gives birth to its young, the young (who already have a full set of teeth) are immediately on their own; not only are they at risk of being eaten by their own siblings and other animals, but are at risk of being eaten by their own mother. Unlike many animals, they don’t bond with their mothers [21], with the ‘survival of the fittest’ taking place.

! !

Bull Shark;

!

Chapter 6: Biotic and Abiotic Requirements

Biotic requirements for the Bull Shark, Charcharhinuss leucas include food availability, predation, prey distribution and availability and reproduction activity.

The sharks life cycles are often ruled by their high priorities which include the needs to feed, avoid predation and the need to reproduce. Often, the amount of food availability will determine the location of the shark, although in Bull Sharks they are fairly stable in

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one location, unless the need to move for prey is quite high. Sharks are apex predators, meaning that they have few or no predators of their own. Although this is the case for sharks, they themselves can be their own predators. Many sharks are known to eat other sharks and so the avoidance of this occurrence is highly imperative. Bull sharks are known to migrate to rivers in other to give birth, with the young continue to grow their for approximately 4 months.!

Abiotic requirements for the Bull Shark, Charcharhinuss leucas include habitat, water temperature, salinity levels, depths, shelter and pollution. Bull Sharks are known for their ability to migrate far (up to 2,500 miles [7]) into low saline rivers/fresh water with the ability of their osmosis regulation. Bull sharks have a special gland near their tails that helps retain salt and they have kidneys that recycle the substance when they enter freshwater [44].

Although the main reason for Bull Sharks entering freshwater is not completely known, Heithaus, of Florida International University has stated “probably the biggest reason is that [freshwater tolerance] allows the juveniles, the little guys, to be in a place that's relatively safe from being eaten by other sharks�. Along with this, other theories have been placed such as the competition of salt water food sources meaning they have more chance at Bull Shark, Page !43

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locating prey as well as disease susceptibility [38]. Bull sharks are known to cruise shallow waters and are capable of great bursts of speed once spotting prey [7].

They are also found around continental shelves, at depths of up to 152m (500ft) but usually no deeper than 31m (100ft) [7]. Bull Sharks are found in tropical and subtropical regions as here the food is usually plentiful therefore little migration is needed [30].

!

Bull Shark;

!

Chapter 7: Nutritional Requirements

Bull sharks have been known to eat almost anything (fig.

20), including other sharks. The most common things on their diets include turtles, birds, dolphins, terrestrial mammals, crustaceans, echinoderms, teleost fishes and elasmobranchs [41]. According to Simpfendorfer, C. & Burgess, G.H. (2009) “The most commonly eaten prey items are teleost fishes and elasmobranchs. In the coastal lagoons of Florida, Snelson and Williams (1981)

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recorded a wide array of species in the diet including jacks, snook, tarpon, mullets, catfish, croaker, stingrays and sandbar sharks, but noted that saltwater catfish and stingrays (Dasyatis spp.) were most commonly eaten�.

Although humans aren't on their list of dietary requirements, they have been known to consume them, especially in estuarine environments, but more often than not, this is believed to be inadvertently or out of curiosity [24]. With this in mind the Bull Shark, along with the Tiger Shark, Galeocerdo cuvier and the Great White Shark, Carcharodon carcharias are responsible for the most amount of accidents involving people.

! ! ! ! ! ! !

Fig 20. Bull Shark feeding. Flammang, B. Taken from Curtis, T. (n.d.) [47]!

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Bull Shark;

!

Chapter 8: Key Pathogen

Common parasites that infest Bull Sharks include Pandarus sinuatus and Perissopus dentatus [37].!

There are many pests and parasites that commonly infect sharks and by sustaining a life in the ocean the chances of becoming infected are extremely high. These pests and parasites are able to infect the shark both internally and externally and can include barnacles, copepods and isopods, leeches, flatworms, tapeworms and ‘vampire snails’ [9]. !

There are many sharks that are able to carry lots of parasites and are still able to perform. Although this may well be the case, by having a parasite (and more!) the sharks health will undeniably become affected, leaving the shark to become vulnerable to become targets for predators. However, individuals that are able to get rid of any parasites do have a higher chances of survival than Bull Shark, Page !46

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those who don't [9]. !

Pests and parasites have been known to affect the eyes, gills, skin and the guts of sharks. Copepods are known to affect the eyes of sharks, severely damaging the corneas which can leave scars on the sharks eye [7] which is highly likely to have an effect on the sharks vision. This is likely to jeopardise any chances of catching prey and avoiding predators for those (especially the Bull Shark) who rely heavily on their eyesight for survival. Parker, S (2008) describes that there are many new parasites being discovered routinely, such as the sea louse Caligus oculicola which was discovered in 2004 attached to the eyes of Tiger Sharks, Galeocerdo cuvier [7]. !

According to Perrine, D (2005) “parasites are so ubiquitous that scientists have even been able to use them as biological ‘markers’ to study life history parameters, migration ranges and genetic characters of the host animals”.!

Along with these copepods, the monogenea worms are found on the skin of sharks and sometimes in their mouths and gills [7]. According to Parker, S (2008) “Like the copepods, they extract nourishment from the shark, and a heavy manifestation can cause severe malnutrition and increase susceptibility to disease”. !

Along with the eyes and gills, the sharks skin can Bull Shark, Page !47

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become infected with pathogens, these may include barnacles, lice and copepods [7]. Once barnacles have attached (usually on larger sharks) they are hard to remove. The barnacles don't take nourishment from the shark but they can cause the sharks swimming to slow and can be a route cause to infections [7]. !

Sharks guts are often affected by pathogens, including tapeworms in their digestive system. These worms are able to cling on to the thin, moist walls of the digestive tract by using their hooked heads and suck out any available nutrients [7]. !

With other marine animals having pathogens, this causes them to become preyed upon by predators-these predators usually being sharks. By sharks preying on any sick and weak prey, they are helping to prevent the spread of disease and prevent any further outbreaks [33].

According to Shark Savers (n.d.) “Preying on the weakest individuals also strengthens the gene pools of the prey species.

Since the largest, strongest, and healthiest fish generally reproduce in greater numbers, the outcome is larger numbers of healthier fish�. This rule also runs for the sharks themselves. A shark that may seem sick, weak or injured are more often than not preyed upon and eaten fairly quickly which is why the majority of cases recorded of parasite ridden sharks have Bull Shark, Page !48

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been when they are in captivity [9]. According to Perrine, D (2005) “This is because any that exhibit obvious signs of weakness disappear rather quickly - usually down the throat of a larger shark�. !

There are a large amount of fish that gain nutrients by picking off parasites, necrotic tissue and the mucus from the bodies of other fish [5]. The places in which these occurrences happen are known as cleaning stations, helping the shark to rid of any parasites and pests and helping the bony fish to gain any much needed nutrients.

Along with these cleaning stations, remora are commonly seen cruising along side the sharks in order to pick off any copepods that the shark may be burdened with [5]. Along with picking off any copepods, remoras also scavenge any scraps of food during the sharks feeding. The relationship between remora and shark is more than just a two way nutrient gain but the remora is also able to acquire protection from any predators, largely reducing their chances of being eaten [5]. !

As mentioned before, when exhibiting signs of illness sharks immediately make themselves vulnerable to attach from other sharks. This has caused sharks to evolve a powerful immune system, with their B cells (unlike humans) helping to provide immunity to a very large range of diseases [9] which has recently been Bull Shark, Page !49

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studied to reveal that sharks have a high resistance to tumour formation [9]. Tumours are large clusters of abnormal cells that grow very quickly which need blood vessels and are unable to form within cartilage. It is believed that because of this, sharks cartilage is in some way responsible for the repressing tumour growth [9].

Although this may be the case and some of the compounds that are isolated do seem to stop the growth of blood vessels, researchers believe that the elasmobranch’s resistance to tumour growth is more than likely down to their immune system [9].

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Bull Shark; Chapter 9: Conservation Issues!

!

For years sharks have faced many disturbing conservation issues, especially in recent years. The most widespread conservation issues sharks face include fishing (primarily for their fins, cartilage and the oil in

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their livers), pollution, angling, extinction and the hunting of newborn sharks [7][5].

Overfishing!

Sharks face the great threat of overfishing, this include the deliberate catch of sharks and by catch [7]. Sharks are more often than not fished for their oil, fins, meat and cartilage by use of curtain nets, trawls and hooked lines [7].

Pollution and angling !

Bull Sharks are known to be found around estuaries and shallow waters, which can cause a large amount of problems for them as these areas are the most commonly polluted areas with pollution build up of sewage, waste and agricultural and industrial chemicals washed into the sea from river mouths or inshore pipes [7]. Due to bioamplification which is where chemicals enter the food chain, climbing up it as smaller fish are eaten by the larger fish with the chemicals becoming more and more concentrated in the fish’s bodies until it eventually reaches the top of the food chain (in this case sharks), sharks often gather the highest levels of chemicals [7]. ! !

Finning!

Shark’s fins are a delicacy in parts of East and Southeast Bull Shark, Page !51

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Asia and so the demand for them in this area is very high, with the the sharks fins being very profitable (up to $100 per bowl of shark fin soup), fisherman may feel there is a lot to gain by catching and finning sharks and then selling them on. This practice is accountable for millions of deaths of sharks annually [7]. !

Often the sharks [pectoral and dorsal] fins are cut off whilst they are still alive and are thrown back in to the water, causing them to suffocate as they are unable to move. The shark will most likely either die from being unable obtain enough oxygen from the water or by being the subject of attack from [most likely] another shark.

Shark Liver Oil! Shark liver has been used for hundreds of years, initially for vitamin A that could be taken from the high-quality squalene oil that was within the sharks livers [5]. Beyond this and because of this, the price in shark liver shot up, resulting in a shortage [5]. Although the demand for shark liver oil has decreased over the years, sharks are still caught for their livers and their oil is still on the market, mainly in cosmetics and pharmaceuticals [5].

Hunting Newborns [5]!

Many shark species travel to shallow coastal areas in order to give birth to their pups which stay here in Bull Shark, Page !52

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schools until they are big enough to move on in to the open waters [5]. Fisherman are now homing in on these pups as the number of shark catches have fallen over the years. By doing this we are catching sharks before they are old enough to reproduce and so we are risking damaging the shark population. ! !

At the moment, according to the IUCN Red List [41], Bull Sharks are ‘Near Threatened’ meaning that they may be threatened with extinction in the near future. If these issues persist, the Bull Shark (as with many other shark species) may be a lot closer to extinction. In order to prevent this, there are many things we can do to help.

!

Improve the Shark’s Image!

In order to do so we need to educate the public and decimate the stereotype that sharks have. The ideal place to start would be to educate schools and colleges, especially in nature, biology and wildlife topics [7].

According to Parker, S (2008) “Television, books, magazines and websites can also inform about the shark’s fascinating behaviour and lifestyle”.

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Aquariums !

Aquariums and sea life centres are a massive help when educating the public about aquatic life. Things like walk through tunnels where the public are able to be close enough to sharks and yet feel safe are a great way to gain their attention [7] . Along with this, displays, commentaries and videotapes help to explain the sharks bodies and behaviours [7], as will the staff!

National and International Efforts!

According to Parker, S (2008) “National governments, regional organisations and international authorities can be persuaded to look after the welfare of marine life and develop strategies for conservation�. Along with this, more fishing quotas need to be put in to place as well as restrictions. These will help enormously towards the protection of sharks (and other marine life) [7]. This may be true but unfortunately there are many cultural differences between countries and not all will see eye to eye. For e.g. Shark Finning is extremely popular in East and Southeast Asia, helping them to gain large amount of profit and to stop this would mean a large decline in yield for them [7].

CITES! Convention on International Trade in Endangered Bull Shark, Page !54

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Species. Cites help to incorporate laws that “limit, license or ban trade in shark’s fins, bodies, remains, teeth, meat and other parts and products” [7]. By having a species listing in CITES Appendix I means that by having trade in any of these things would be illegal (except in [exceptional] licensed circumstances) [7].

Appendix II is where any species listed under this can be traded with permission and export permits. In 2008, the only three sharks listed under Appendix II were the Basking Shark, Cetorhinus maximus, Whale Shark, Rhincodon typus and the Great White Shark, Carcharodon carcharias [7].

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Bull Shark; Chapter 10: Legislative Requirements !

Up until recently there has been little interest and knowledge on sharks and so there hasn't been a massive Bull Shark, Page !55

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amount of legislation put in place to protect them. Along with this, sharks were believed to not be very ecologically important. As more and more data was collected, it became clear that shark populations were rapidly declining and so conservation measures were put in to place [45]. According to Shark Savers (2014) “Currently, there are several conservation and management initiatives and plans that operate on many levels from international conventions to local laws.�.

The following legislations have been taken from Shark Savers (2014) on 27th Feb 2014 and can be accessed via: <http://www.sharksavers.org/en/our-programs/sharksanctuaries/learn-more/laws-protecting-sharks/>

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Bans On Shark Fishing Ta b l e 1 : B a n s o n S h a r k F i s h i n g . S h a r k S a v e r s , 2 0 1 4 .

American Samoa

2012

Shark fishing and possession of sharks within three nautical miles of shoreline was banned in Nov 2012

Bahamas

2011

All shark fishing, sale and trade in shark products was banned in the Bahamas in July 2011

Cook Islands

2012

Shark fishing is banned in area of 1.9 million km

CongoBrazzaville

2001

All shark fishing is prohibited in Congo-Brazzaville (966 km

Egypt

2005

Shark fishing is prohibited throughout Egyptian Red Sea territorial waters to 12 miles from the shore as is the commercial sale of sharks.

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Fiji

2011

In July 2011, Fiji announced pending legislation to ban all shark fishing and sale in shark products.

French Polynesia

2006

In 2012, French Polynesia permanently banned shark fishing and trade in all sharks.

Moratorium on shark fishing while permanent shark protections are under review.

Affording sharks an area of 240,240 km of protection.

Honduras

Isreal

1980

All elasmobranchs are protected in Israeli waters (27,346 km

Maldives

2010

All shark fishing is prohibited in the Republic of the Maldives (916,189 km2

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Marshall Islands

2011

Commerical fishing of sharks is prohibited in all of the Marshall Islands (1,990,530 km2).

Any shark caught accidentally by fishing vessels must be set free.

Palau

2009

All shark fishing is prohibited in Palau (604,289 km

Raja Ampat, Indonesia

2010

All shark fishing is prohibited in the Regent of Raja Ampat (46,000 km2

Tokelau

2011

All shark fishing is prohibited in Tokelau (Area â&#x20AC;&#x201C; 319,031 km

! !

The following legislations have been taken from Shark Savers (2014) on 27th Feb 2014 and can be accessed via: <http://www.sharksavers.org/en/our-programs/sharksanctuaries/learn-more/laws-protecting-sharks/>

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Bans on the Sale of Shark Fins and Products Table 2: Bans on the Sale of Shark Fins and Products. Shark Savers, 2014. !

Bahamas

2011

All shark fishing, sale and trade in shark products was banned in the Bahamas in July 2011

Cook Islands

2012

Possesion and sale of shark productes banned in December 2012

Commonwealth of the Northern Mariana Islands (CNMI)

2011

Possession, sale and trade of shark fins was prohibited in January 2011 (with an exception for subsistence fishing).

Egypt

2005

Shark fishing is prohibited throughout Egyptian Red Sea territorial waters to 12 miles from the shore as is the commercial sale of sharks.

Fiji

2011

In July 2011, Fiji announced pending legislation to ban all shark fishing and sale in shark products.

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French Polynesia

2006

In 2012, French Polynesia banned shark fishing and trade in all sharks.

(Area â&#x20AC;&#x201C; 4,767,242 km2

Guam

2011

Possession, sale and trade of shark fins and ray parts was prohibited in March 2011 (with an exception for subsistence fishing).

Hawaii, USA

2010

Possession, sale and trade of shark fins is prohibited in the state as of July 1, 2010. (Area â&#x20AC;&#x201C; 2,474,884 km

Marshall Islands

2011

Possession and sale of any sharks or shark products.

Oregon, USA

2011

Possession, sale and trade of shark fins was prohibited (with an exception for dogfish)

Washington, USA

2011

Possession, sale and trade of shark fins was prohibited in May 2011.

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California, USA

2011

Possession, sale and trade of shark fins was prohibited in October 2011.

Illinois, USA

2012

Possession, sale and trade of shark fins was prohibited in July 2012.

Shark Savers, 2014.

The following regulations have been taken from Shark Savers (2014) on 27th Feb 2014 and can be accessed via: <http://www.sharksavers.org/en/our-programs/sharksanctuaries/learn-more/laws-protecting-sharks/>

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Domestic Regulations on Shark Finning Table 3: Domestic Regulations on Shark Finning. Shark Savers, 2014.

Argentina

2009

The practice of retaining fins and discarding carcasses is banned.

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Australia

Brazil

Various

States and Territories govern their own waters, which extend to three nautical miles offshore. Central government regulates â&#x20AC;&#x17E;Commonwealth" ( Federal) waters, from three to 200 nautical miles offshore. Most States and Territories ban finning, and some require that sharks be landed with their fins naturally attached.

1998

Prohibits landing of shark fins without the corresponding carcasses. The total weight of fins shall not exceed 5% of the total weight of carcasses, all carcasses and fins must be unloaded and weighed and the weights reported to the authorities.

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Canada

1994

Finning in Canadian waters and by any Canadian licensed vessel fishing outside Canadaâ&#x20AC;&#x2122;s Exclusive Economic Zone (EEZ) is prohibited. When landed, the fins must not weigh more than 5% of the dressed weight of the shark.

Cape Verde

2005

Shark finning is prohibited throughout the EEZ.

Chile

2011

Sharks must be landed with their fins naturally attached to their bodies.

Columbia

2007

All sharks must be landed with their fins naturally attached to their bodies.

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Costa Rica

Ecuador

2001-2006

Regulation AJDIP/ 47-2001 required fins to be landed attached to shark carcasses. This was replaced by AJDIP/ 415-2003, permitting fins to be landed separately from carcasses, but the “fins-attached” requirement was reinstated in 2006.

2004

Directed fishing for sharks is banned in all Ecuadorian waters, but sharks caught in “continental” (i.e. not Galapagos) fisheries may be landed if bycaught.

Sharks must be landed with fins attached in all fisheries. A previous ban on trade in shark fins was lifted in 2007.

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El Salvador

2006

Shark finning is prohibited. Sharks must be landed with at least 25% of each fin still attached in the natural way. The sale or export of fins is prohibited (be they fresh, frozen or dried) without the corresponding body.

England and Wales

2009

All sharks must be landed with their fins naturally attached.

European Union

2009

Prohibits finning in EU waters and by EU vessels worldwide. Requires sharks to be landed with fins naturally attached, unless a Special Permit has been issued to allow onboard removal of fins and landing in separate ports.

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Mexico

2007

Shark finning is prohibited. Shark fins must not be landed unless the bodies are on board the vessel. In 2011, Mexico banned shark fishing from May-August each year.

Namibia

2000

Namibia generally prohibits discards of harvested or bycaught marine resources. Namibia's National Shark Plan, adopted in 2003, recommends the formulation of legislation under the Marine Resources Act to prohibit finning of any shark species.

Nicaragua

2004

Prohibits vessels from having fins on board or from landing land fins that weigh more than 5% of the total weight of the sharks.

Those who wish to export fins must first prove that the meat has been sold.

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Oman

Panama

?

Sharks must be landed, transported, sold or disposed of whole. It is strictly forbidden to throw away any shark part or shark waste in the sea or the shores of the Sultanate of Oman. It is also prohibited to land shark fins separated from the body, unless otherwise authorized by competent authority.

2006

Shark finning is prohibited in all Panamanian waters.

Industrial fishers must land sharks with fins attached naturally. Artisanal fishers may land the fins separately but the weight ratio must be no more than 5% fins to whole weight of sharks.

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Seychelles

2006

Fins may not be removed onboard a vessel unless authorization is granted. Applicants are required to produce evidence that they have the capacity to utilize all parts of the shark.

Fins may not be transshipped. Fins landed separately from carcasses must weigh no more than 5% (after evisceration) or 7% (after evisceration and beheading).

South Africa

1998

Sharks caught in South African waters must be landed, transported, sold or disposed of whole (they can be headed and gutted).

However, fins from sharks caught in international waters may be landed in South Africa with fins detached from carcasses.

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Spain

2002

It is illegal to have shark fins onboard without the corresponding carcasses.

Compliance is verified through the use of a conversion system of fins to carcass weight.

Taiwan

2012

Bans shark finning for domestic fleets, but excludes "fishing vessels within the area of competence of international fisheries organizations and unloaded at foreign ports."

United States

2011

All sharks must be landed with their fins fully or partially attached in the natural way in all federal waters (with an exemption for smooth dogfish)

Shark Savers, 2014.

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The following regulations have been taken from Shark Savers (2014) on 27th Feb 2014 and can be accessed via: <http://www.sharksavers.org/en/our-programs/sharksanctuaries/learn-more/laws-protecting-sharks/>

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Regional Fisheries Shark Finning Regulations Table 4: Regional Fisheries Shark Finning Regulations. Shark Savers, 2014.

International Commission for the Conservation of Atlantic Tunas (ICCAT)

2004

The ICCAT finning ban requires full utilization (defined as retention by the fishing vessel of all parts of the shark excepting head, guts and skins, to the point of first landing) of entire shark catches. Fins should not total more than 5% of the weight of the sharks onboard. Does not specify if it is whole or dressed weight.

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General Fisheries Commission of the Mediterranean (GFCM)

2005

Same as ICCAT. Requires full utilization (defined as retention by the fishing vessel of all parts of the shark excepting head, guts and skins, to the point of first landing) of entire shark catches. Fins should not total more than 5% of the weight of the sharks onboard.

Inter-American Tropical Tuna Commission (IATTC)

2005

Same as ICCAT full utilization (defined as retention by the fishing vessel of all parts of the shark excepting head, guts and skins, to the point of first landing) of entire shark catches. Fins should not total more than 5% of the weight of sharks onboard.

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Indian Ocean Tuna Commission (IOTC)

2005

Same as ICCAT full utilization (defined as retention by the fishing vessel of all parts of the shark excepting head, guts and skins, to the point of first landing) of entire shark catches. Fins should not total more than 5% of the weight of sharks onboard.

Southeast Atlantic Fisheries Commission (SEAFO)

2006

Same as ICCAT full utilization (defined as retention by the fishing vessel of all parts of the shark excepting head, guts and skins, to the point of first landing) of entire shark catches. Fins should not total more than 5% of the weight of sharks onboard.

North Atlantic Fisheries Organisation (NAFO)

2005

Similar to ICCAT and IATTC.

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Western and Central Pacific Fisheries Commission (WCPFC)

2008

Full utilization (retention of all parts of the shark excepting head, guts, and skins), to the first point of landing or transshipment of retained sharks. Fins should make up no more than 5% of the weight of sharks onboard. Fins may be landed and transhipped separately.

Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR)

2006

Directed fishing on shark species in the Convention Area, for purposes other than scientific research, is prohibited.

Incidental catch of sharks taken in other fisheries should be released alive as far as possible.

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North East Atlantic Fisheries Commission (NEAFC)

2007

Full utilization (all parts of the sharks except head and guts to the point of first landing) of entire shark catches required. Shark fins should not total more than 5% of the weight of sharks.

Fins may be landed and transshipped separately from other shark parts.

Shark Savers, 2014.

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The following recommendations and resolutions have been taken from Shark Savers (2014) on 27th Feb 2014 and can be accessed via: <http://www.sharksavers.org/ en/our-programs/shark-sanctuaries/learn-more/lawsprotecting-sharks/>

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Recommendations and Resolutions on Shark Finning Table 5: Recommendations and Resolutions on Shark Finning Shark Savers, 2014.

United Nations Food and Agriculture Organisation (FAO)

1999

United Nations General Assembly (UNGA)

2007

The International Plan of Action for sharks calls on all States to minimize waste and discards, such as through requiring the retention of sharks from which fins are removed.

Calls on all States to consider requiring sharks to be landed with their fins naturally attached.

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IUCN - World Conservation Union

2008

United Nations Fish Stocks Agreement

2010

Calls on States with fisheries that capture sharks, whether in directed fishery activities or as accidental by-catch of other fisheries, to require at the point of first landing that sharks be landed only if their fins are naturally attached to their bodies, though allowing for partial detachment of fins to permit efficient storage and species identification.

Calls on all States to consider requiring sharks to be landed with their fins naturally attached.

Shark Savers, 2014.

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The following marine protected areas have been taken from Shark Savers (2014) on 27th Feb 2014 and can be accessed via: <http://www.sharksavers.org/en/ourprograms/shark-sanctuaries/learn-more/laws-protectingsharks/>

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Marine Protected Areas Table 6: Marine Protected Areas. Shark Savers, 2014.

The Cocos Marine Reserve The Galapagos Marine Reserve The British Chagos Archipelago in the Indian Ocean’s No Take Zone Sala y Gomez Island, Chile, No Take Zone The Great Barrier Reef Marine Protected Area (1/3

972 km 6,937 km 554,000 km

150,000 km 100,000 km

Shark Savers, 2014.

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As mentioned previously on page 54 CITES has also been put in to place in order to protect certain shark species from being over fished. Although this may well be the case, as of 2008 there are only 3 species put on their list and it is still only in Appendix II meaning any species listed under this can still be traded with permission and export permits. According to Shark Angels (n.d.) “There is also no international body to enforce this legislation”. Along with this, once Bull Shark, Page !78

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legislation has been put in to place that is only half of the issue ‘sorted’, there needs to be enforcement of the legislation and unfortunately this rarely ever happens [46].

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Chapter 11: Extraordinary Issues

Common Names Bull shark’s common names include River Shark, Freshwater Whaler, Estuary Whaler and Swan River Whaler [46].

According to Curtis, T (n.d.) “The bull shark was first described by Valenciennes in Muller & Henle (1839) as Carcharias (Prionodon) leucas, and later changed to the currently valid name Carcharhinus leucas. The genus name Carcharhinus is derived from the Greek "karcharos" = sharpen and "rhinos" = nose. It has also appeared in the literature as Carcharias (Prionodon) zambezensis, Carcharhinus zambezensis, Prionodon platyodon, Squalus platyodon, Squalus obtusus, Eulamia

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nicaraguensis, Carcharias azureus, Carcharias spenceri, Galeolamna (Bogimba) bogimba, Galeolamna greyi mckaili, and Carcharhinus vanrooyeni.â&#x20AC;? [37].

According to the Shark Attack File, 69 unprovoked attacks on humans around the world were caused by Bull Sharks, 17 of which were fatal [37]. Bull sharks are known to hunt where humans commonly assemble, around tropical coastal areas and in murky waters. Here, if splashing occurs, bull sharks can often mistake it for struggling prey and so may attack [46]. Although figures state the Bull Shark is responsible for only 69 attacks on humans, with the knowledge that their habitats include those commonly shared with us humans as well as their ability to survive in freshwater, the chances are that in reality the number of attacks are a lot higher than that with scientists believing that the Bull Shark may well be even more dangerous than the Tiger Shark and the Great White Shark [37]. !

During 1916 in New Jersey, USA there was 5 shark attacks on humans over a 12 day period, 4 of which were fatal. It is believed that the Bull Shark may well be the culprit for these [37]. 3 of these attacks happened â&#x20AC;&#x153;40 feet (12 m) across, 1.5 miles (2.4 km) from bay waters, and over 15 miles (24 km) from the open ocean; not a

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location where any other large shark species would likely occur” [37]. Following this a Great White Shark was captured around the area which allegedly had human remains in its stomach, after which a Bull Shark was also found in the area. Since then this has been a high topic of discussion. There is also evidence that both the Bull Shark and the Great White Shark are culprits [37].

Parker, S (2008) explains that relative risks include the following:!

“Data for Western industrialised nations such as the U.S. show that, overall, the relative risk of death is: • Heart disease: 1 in 5 • Influenza and complications: 1 in 70 • Road traffic accident: 1 in 100 • Train accident: 1 in 150,000 • Lightening: 1 in 80,000 • Shark attack: 1 in 3 million

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Shark attacks by species [7]: • Great White

33%

• Tiger

12%

• Bull

8%

• Sand Tiger

6%

• Unidentified requiem species

5%

• Nurse

4%

• Mako

4%

• Hammerhead

3%

• Blue

3%

• Blacktip

3%

By using information collected from observations on sharks attacking bait, as well as other species, and information used on captive sharks we are able to decipher how and when a shark attack will happen [7]. ! !

Countdown to the bite!

Upon approach to the sharks target, the first sense to come in to play for the shark is its smell. Sharks are able Bull Shark, Page !82

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to smell the scent of blood or body fluid from hundreds of meters away. They are also able to separate the smell of the substance from various bodily chemicals such as amino acids and fatty acids [7]. Once the sharkâ&#x20AC;&#x2122;s distance decreases, its hearing will then be the next sense to be used. Sharks are able to perceive different frequencies of sound vibrations [7] which travel faster and further in water than they do in air [7].

Closing in!

Upon approach to the sharks target its lateral line begins to detect any ripples and currents in the water produced by its prey [7]. If its fairly clear daylight water the sharks eyesight will also begin to decipher the shapes and movements of the target [7].

The Bull Sharks upper teeth (fig. 20) are broad, triangular, and heavily serrated (fig. 21) [37] whilst its lower teeth have a broad base, and are narrow and triangular with fine serrations [37]. The Bull Sharkâ&#x20AC;&#x2122;s anterior teeth are erect and nearly symmetrical, while posterior teeth become more oblique in shape (taken from Curtis, T. n.d. [37]).

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Fig. 20 The jaws of an 8-foot (245 cm) bull shark captured in the Gulf of Mexico. Taken from Curtis, T (n.d.). [48]

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Fig. 21 Bull Shark Teeth. (Ex Garrick (1982) NOAA Tech. Rep. NMFS Circ. 445) Taken from Curtis, T. (n.d.). [49]

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Bull sharks are extremely vulnerable to fishing due to them growing slowly, taking many years to mature (approx. 10 years), often only reproduce every other year, have very few young per litter, are quite specific about their nursery areas and are caught in many different types of fishing gear [50].

The bull shark is not legally protected around any parts of its habitat. More research will be needed for this special species of shark in order for its biological, ecological and fisheries consequence to be understood [37].

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Chapter 12: Maintenance Programme

Fig. 22. SzNews, 2009. Bull Shark in Captivity

Although the natural habitat of sharks is in the open ocean where they are free to hunt and migrate when ever they want and need, some scientists and conservationists choose to keep them in captivity for a number of reasons including to study their behaviour and to educate the public about them [7]. !

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With this being the case, sharks bring a number of challenges with them when being held in captivity with one of the main issues being the ability to actually keep them alive in an artificial environment in the first place [7]. This can cause the shark to refuse to eat as they have been taken away from their natural environment resulting in their stay in aquariums being cut short [7] which can mean that the knowledge we have of some shark species is very limited as it is restricted to having to study them in the open ocean [7]. We tend to be able to be more educated about the sharks that do respond well to being held in captivity [7]. !

In one circumstance a Great White was held at the Monterey Bay Aquarium in California in 2005 for 198 days, 182 days more than the previous record, before she had to be released in to the wild due to becoming too big for the tank. It is believed that her success was down to her young age. At only 1 years old, she was young enough to adapt to her new environment and not reject it completely [7].

There are many things to consider when keeping a Bull Shark captive, including the stress of captivity*, expressing different behaviours in captivity, parasites, costs of keeping them in an aquarium, the health of the

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shark*, violence (especially in Bull Sharks) and rejection of their new environment.

There are many things we need to consider when deciding to keep a shark in captivity in order to reduce their stress levels as much as possible including discovering ways to make the transportation of these sharks easier and by making their new home very similar to their natural environment [51]. Sharks need in saltwater aquariums with an enormous amount of space in order to roam and to make it as comfortable for them (bearing in mind many sharks migrate but to our knowledge this does not entirely include the Bull Shark which may be a positive aspect when keeping them in captivity). Along with this they eat an immense amount of food which can also be very costly [51].

There are many experts that feel that due to sharks being highly intelligent, living in a closed space (in comparison to their usual environment of the open ocean) can be very difficult for them [51] which can also cause them to become very aggressive. With a species like the Bull Shark aggressiveness is a massive possibility anyway and so it wouldn't be responsible to add any more reasons for this to occur [53].

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Sharks have been known to not continue to maintain their usual behaviours they would have had in the wild which means that by observing them in captivity in order to learn how they are in the wild isn't very successful or useful [51]. According to Sharks-World (n.d.) “We have learned some basics though about reproduction and even the recovery process”. Along with this, the sharks senses they would have used in the wild in order to pick up vibrations and electrical currents in the water have been known to become very confused when held in captivity [51].

Along with researching their biological functioning, sharks are also kept in captivity in order to be cared for before being returned back in to the wild [51] and because of the expense that occurs when keeping sharks, most locations will be more than willing to keep return them in to the wild as soon as they are well enough [51].

Following a conversation with sea world about Bull Sharks that they have and currently do keep, the following information was obtained: “Here at Sea World we have had a long history with Bull sharks as we have had on individual living with us since the 1980’s. This animal is a large female which came to

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us from Port Macquarie aquarium in New South Wales back in the 80s where she had lived for many years prior to coming to Sea World.

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This animal is very dominant in any exhibit that she has been in but maybe because she is very large and very dominant in nature. We have also housed a number (up to 10 at a time) of smaller bull sharks in an exhibit for about 12 months in 2009. These animals were between 1.2 and 1.8 m long and the larger animals became very food motivated and dominated the feeding times which in turn made them grow faster and become more dominant.

One of the main problems with bull sharks is the presence of the ectoparasitic monogenean flatworm parasites that are prevalent on these animals in the wild and also in captivity. With the single large female, she always has a small population of visible parasites that live on her dorsal surface between her 2 dorsal fins. She manages to keep these under control and the numbers fluctuate slightly over the course of the year depending on the season. The smaller animals that we held all together very quickly built up a heavy infestation of these parasites and we had to regularly dose the tank with Neguvon to kill the parasites. Unfortunately the

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eggs are resistant to almost everything so treatment had to be repeated to kill the new larvae that continued to hatch out of the eggs which are in the substrate. We have attempted freshwater treatments on these animals to remove the parasites but the length of time needed to kill the adult parasites is longer than the sharks can stand in full freshwater.

As far as feeding goes with this species, they will quickly assimilate to eating chopped thawed fish of many different sizes and species. We feed over 25 different species of food fish here at Sea World as well as squid and the bull sharks will eat all of them. Our large female will go off her food for about 3 months over winter when the water temperature is around 22 degrees celcius.

They donâ&#x20AC;&#x2122;t make very good tank mates for fish as they will regularly pick off fish even if you give them what is considered at adequate daily food intake. They will eat small sharks, large fish, small fish pretty much anything they can catch.

I donâ&#x20AC;&#x2122;t think they are a particularly good species for captive aquariums due to their predatory nature towards their tank mates and the persistent and potentially fatal monogenean flatworm parasites that live on almost

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100% of bull sharks here in local waterways and which get into aquariums via their incoming water supply.

They are impossible to get rid of and build up very quickly in a closed system with the appropriate host species in residence” Horton, M (2014) [53].

As you can see, it isn't only the amount of food needed, the expense that is incurred and the rejection of their environment that occurs but also parasites such as the ectoparasitic monogenean flatworm that are common among Bull Sharks. The ectoparasitic monogenean flatworms are highly regarded as a reason for fish diseases, especially among aquaculture [55]. According to Klaus, R., (2012) “The Monogenea is one of the largest groups of parasitic flatworms (Platyhelminthes) with many thousands of species described, and probably a larger number not yet described. The vast majority of species infects the gills, skin and fins of freshwater and marine fishes, some have secondarily adopted an endoparasitic way of life, most of these in the mouth cavity and urinary bladder of turtles and amphibians” “Effects on their hosts are usually insignificant, but occasionally large scale mortalities caused by monogeneans are reported, particularly but not exclusively in aquaculture” [55].

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Along with parasites, Bull Sharks can become extremely aggressive with other fish, including other sharks due to their extreme dominant behaviour [53] and as quoted by Horton, M. (2014) â&#x20AC;&#x153;they don't make very good tank matesâ&#x20AC;? [53].

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A Bull Shark tank should be designed in order to accommodate a Bull Sharks natural swim-glide swimming pattern and should ideally be 15 feet deep, containing around 700,000 gallons of water. The temperature of the tank needs to be constantly checked and kept at between 77-80°F [57]. The tank will need to be filtered at a rate of 5,700 gallons per minute, usually processing about 8.21 million gallons of water per day with the exhibit turnover rate being 1 hour and 45 minutes [57].

Along with the information Horton, M (2014) has provided about shark feeding, Sea World Florida has explained that the sharks should be fed twice a week, with the food items being fed during the major feeds ideally containing multivitamins. Some species may also have B1 and Vitamin C added to their food [57].

Breakout for the major feeds in Sea World Florida often have a combination of foods adding up to 90-125 pounds per feed (180-250 pounds per week) [57], working out with each individual receiving 3-5% of their individual body weights on a weekly basis. It is also suggested that

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the Bull Sharks are fed bonita, herring, salmon, blue runner, mackerel, capelin and squid [57]. The conversation with Sea World Florida can be found on the following page.

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Dear Louise Young, Thank you for your inquiry. We used to display Bull sharks at SeaWorld Orlando but that was over 10 years ago. Our Shark Encounter exhibit opened in 1980 and a few additional exhibits were added in 1991. The main shark exhibit is about 15 feet deep and contains around 700,000 gallons of water.

We keep the water temperature between 77 - 80°F. The exhibit was specifically designed to accommodate a sharkâ&#x20AC;&#x2122;s natural swim-glide swimming pattern. The water is filtered at a rate of 5,700 gallons per minute and the exhibit turnover rate is 1 hour and 45 minutes. The filtration system processes about 8.21 million gallons of water every day.

The sharks displayed in the main exhibit and shallows area are fed twice a week. All food items fed during the major feed have multivitamins in them. Some species also have B1 and Vitamin C added to their food.

Currently breakout for the major feed is a combination of food items adding up to about 90-125 pounds per feed (180 - 250 pounds per week). We feed them bonita, herring, salmon, blue runner, mackerel, capelin and squid. Each individual receives 3-5% of their individual body weight on a weekly basis.

As cold-blooded animals, sharks have incredibly slow metabolisms, and so their digestive processes are much slower.

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The process of maintaining a constant body temperature for mammalian species comes at great metabolic cost and so the amount of food required to maintain healthy body function is much higher.

If you would like more detailed information about the Bull sharkâ&#x20AC;&#x2122;s natural history, please click on the biological profile below. I hope this helps!

BULL SHARK

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Order - Carcharhiniformes Family - Carcharhinidae Genus - Carcharhinus Species â&#x20AC;&#x201C; leucas

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Glossary

[6] [7]

Abiotic Non-living

or organs !

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Anguilliform Having the shape or form of an eel

Anal Fin Fin on the lower rear underside of the body, in the midline, often near or behind the pelvic fins !

Anatomy Structure of a living thing, including the size and shape of tis internal parts

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Anterior Nearer head end

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Benthos Flora and fauna of sea or lake bottom from high water mark down to the deepest levels"

Biotic Life and living organisms

through the very thin walls to the surrounding tissues

Capillaries Microscopically narrow blood vessels where substances such as oxygen and nutrients can pass

Cartilage A lightweight, smooth, slightly soft and pliable but very strong material, sometimes called gristle. It

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makeup a sharks skeleton.

In our own bodies, cartilage forms the flexible inner parts of the nose and ears

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Caudal (1) of or pert. a tail e.g. caudal fin. (2) towards the tail end of the body

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Cartilaginous One of three basic fish groups. Sharks, rays, skates and ratfish are cartilaginous; the other types of fish are jawless and bony

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Ceratotrichia!

Thin rods of collagen which form sheets between rays of fins of elasmobranch fishes and stiffen them Cilia

Hair like structures present on the surface of body.

Motile hairlike outgrowth present on the surface of many eukaryotic cells, which makes whip-like beating movements

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Denticles Tiny, tooth-shaped scales.

Dermal denticles are the sharp scales on a sharks skin. Much larger, stronger denticles form its teeth

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Dorsal Fin fin on the upper side of the body in the midline. Many sharks have more than one dorsal fin, with the largest and foremost one â&#x20AC;&#x2DC;cuttingâ&#x20AC;&#x2122; the water in typical, seemingly menacing fashion

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Ectotherm Animal hat gets its warmth from the surroundings or environment, as do most sharks.

Endotherm Animals that â&#x20AC;&#x2DC;burnsâ&#x20AC;&#x2122; food in its body to generate heat and keep itself at a constant warm temperature

Elasmobranchii A subdivision of the cartilaginous fish, comprising sharks, skates and rays

Food Chain Series of feeding actions, when an animals eats a plant and is then eaten by another animal and so on.

Food chains are usually theoretical and link to form more realistic food webs

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Endangered IUCN definition - species or larger taxa whose numbers have become so low, or whose habitats have been so drastically reduced, that they are thought to be in immediate danger of extinction in the wild in the foreseeable future if there is no change in circumstances

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Food Webs!

Set of feeding relationships forming a weblike network, showing what eats what. It usually has plants at the bottom and top predators at the summit and its is a series of simpler food chains linked together

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Gill Slits Long, narrow openings in the side of the head in sharks, where water exits after flowing into the mouth and over the gill.

Most sharks have five gill slits on each side

Olfactory To do with scents and smells or the sense of smell

Heterocercal Design of tail (caudal fin) where the two lobes are unequal in size. In sharks, the vertebral column extends in to the upper lobe, which is larger.

Pathogen Any disease-causing organism

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Lamellae (1) any thin or plate like structure, (2) a layer of cells

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Nares Nostrils

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Oviduct Tube that carries eggs from tube to exterior

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Pectoral Fin Paired fins on the lower front sides of the body

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Pelvic Fin Paired fins on the lower rear of the body

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Taxonomy Scientific study of grouping or classifying living things according to their similar features and evolutionary relationships

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Thunniform In many cases the undulation in thunniform swimming is confined to the caudal fin. Thunniform swimming literally means to â&#x20AC;&#x2DC;swim like a tunaâ&#x20AC;&#x2122;

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Undulate Having wave-like undulations

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Ventricles Chamber or hollow part, for example, inside a sharks brain

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Viviparous An animal in which the embryo develops inside its mothers body

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Reference List for Biological Synopsis

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Books!

[1] Bone, Q., Marshall, N.B., & Blaxter, J.H.S. (1999).

Biology of Fishes. 2nd ed. Gloucestershire: Stanley Thornes (Publishers) Ltd. [2] Carrier, J.C., Musick, J.A., & Heithaus, M.R (2012).

Biology of Sharks and Their Relatives. Florida: CRC Press. 597.

[3] Castro, P., & Huber, M.E (2007). Marine Biology. 6th ed. New York: McGraw Hill Companies [4] Dent, M (2002). Eyewitness Shark. 2nd ed. London: Dorling Kindersley Ltd [5] Jorgensen, S (2013). Sharks: Ancient Predators in a Modern Sea. Ontario: Firefly Books Ltd [6] Lawrence, E (2000). Henderson's Dictionary of Biological Terms. 12th ed. Essex: Pearson Education Ltd. [7] Parker, S (2008). The Encyclopedia of Sharks.

London: A&C Black

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[8] Perrine, D (2002). Sharks. Minnesota: Voyageur Press [9] Perrine, D (2005). Sharks & Rays. Moray: Colin Baxter Photography Ltd [10] Ponsonby, D., & Dussart, G (2005). The Anatomy of the Sea.!

San Francisco: Chronicle Books

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Images!

[11] Briant, C.W., (n.d.), Bull Shark Hunting and Feeding, [Electronic Print], Available at: <http:// science.howstuffworks.com/zoology/marine-life/bullshark3.htm> Last accessed 3rd Feb 2014 [12] David, (2012), Bull Shark, [Electronic Print], Available at: <http://abyssdivecenter.wordpress.com/ 2011/11/11/what´s-so-cool-aboutâ&#x20AC;Śthe-bull-shark-dive/> Last accessed 2nd Feb 2014 [13] Jeon, J.S., (2012), Shark-internal, [Electronic Print], Av a i l a b l e a t : < h t t p : / / w w w. n v o . c o m / j i n / scrapbookanatomy/view.nhtml? profile=scrapbookanatomy&UID=10058> Last accessed 7th Feb 2014 Bull Shark, Page !103

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[14] Parker, S, (2008), A Sharks Brain, [Image], Found in: THE ENCYCLOPAEDIA OF SHARKS. London: A&C Black. Page 170 [15] Parker, S, (2008), Female Sharkâ&#x20AC;&#x2122;s Reproductive System, [Image], Found in: THE ENCYCLOPAEDIA OF SHARKS. London: A&C Black. Page 170 [16] Skerry, B.J., (2014), Bull Shark, [Electronic print], Available at: <http://animals.nationalgeographic.com/ animals/fish/bull-shark/> Last accessed 2nd Feb 2014 [17] Vector Templates, (2014), World Map, [Electronic Print], Available at: <http://www.vectortemplates.com/ raster/maps-world-map-02.png> Last accessed 25th Feb 2014 [18] Wet Set, (2012), Bull Shark, [Electronic Print], Available at: <http://wetset.com/products-page/scubadiving-tours-in-mayan-riviera-puerto-morelos-mexico/ coral-reef-scuba-diving-tours/advanced/2-tank-bullshark-dive/> Last accessed 2nd Feb 2014 [19] White, J, (2012), Bull Shark, [Electronic Print], Available at: <http://www.flickr.com/photos/wpages/ 6696493359/> Last accessed 2nd Feb 2014 [47] Flammang, B, (n.d.), Bull Shark Feeding, [ E l e c t r o n i c P r i n t ] , Av a i l a b l e a t : < h t t p : / / Bull Shark, Page !104

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www.flmnh.ufl.edu/fish/Gallery/Descript/bullshark/ bullshark.htm> Last accessed 2nd March 2014 [48] Curtis, T, (n.d.), The jaws of an 8-foot (245 cm) bull shark captured in the Gulf of Mexico, [Electronic Print], Available at: <http://www.flmnh.ufl.edu/fish/Gallery/ Descript/bullshark/bullshark.htm> Last accessed 2nd March 2014 [49] Ex, Garrick, (1982), Bull Shark teeth, [Electronic Print], Available at: <http://www.flmnh.ufl.edu/fish/ Gallery/Descript/bullshark/bullshark.htm> Last accessed 2nd March 2014 [51] SzNews, (2009), Bull Shark in Captivity, [Electronic Print], Available at: <http://english.cri.cn/ 6909/2009/03/02/195s459331.htm> Last accessed 2nd March 2014

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Grey Media!

[20] Anon. (n.d.). 450 Million Years of Sharks.

Available: <https://www.sharksavers.org/en/education/ biology/450-million-years-of-sharks1/>. Last accessed 2nd Feb 2014

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[21] Anon. (n.d.). Bull Shark . Available: http:// www.sharks-world.com/bull_shark/. Last accessed 25th Feb 2014.

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