( Blacktip Shark and Smalltooth Sawfish) James Gill

1. Phylum: ChordataSubphylum: Vertebrata Superclass: Gnathostomata Class: Chondrichthyes Subclass: ElasmobranchiiOrder : Carcharhiniformes & Pristiformes (Blacktip Shark and Smalltooth Sawfish) James Gill

2. Order Carcharhiniformes: • Largest Order of sharks containing 270 different species including catsharks, swellsharks, and the sandbar shark • Known as ground sharks • Nictitating membrane over each eye • Two dorsal fins • An anal fin • Five gill slits • Family Family Carcharhinidae: • Known as Requiem Sharks • Migratory • Live-bearing sharks (viviparous) • Responsible for most attacks on humas • Live in warm seas

3. Blacktip Shark (Carcharhinuslimbatus) Biological Facts: • Females are viviparous, usually bearing 4-7 pups • Usually grow to be about 4.9ft long • 90% of their diet is fish, the other 10% being crustaceans and cephalopods • Favored habitats are island lagoons, muddy bays coral reef drop-offs and mangrove swamps. • Most active at dawn and dusk • Usually live in sexually segregated schools until mating season • Most bites can be pinned on blacktip sharks but there has never been a recorded fatal incident. • Seasonal migration from North Carolina in the summer to Florida in the winter off the east coast of the US • Nearly threatened but not endangered Fun Facts: • Known to jump out of the water and spin in order to disorient schools of fish for feeding http://www.youtube.com/watch?v=Rzxob3G_3G0 • Known to utilize asexual reproduction when no males are present (automicticparthenogenesis) • Most timid of the large Requiem Sharks and will observe humans from a safe distance.

4. Blacktip VS Blacktip REEF sharks Blacktip: • Carcharhinuslimbatus • Timid but curious, will watch humans • Closer to reef drop-offs, sometimes mangrove swamps • Usually 4.9 feet Blacktip Reef: • Carcharhinusmelanopterus • Timid and skittish, very difficult to approach • Shallow inshore waters and sandy flats • Usually 5.3 feet

5. Order Pristiformes: Known as carpenter sharks Only 1 living family(Pristidae) and 7 species long, narrow, flattened rostrum Biological Facts: • Females are ovoviviparous • Little is known about the reproduction habits of the sawfish. They are estimated to mate once every two years, with an average litter of around eight. They mature very slowly (12 years) with low reproduction rates • Usually 7.6 meters in length • Small fish, crustaceans and mollusks • shallow tropical and subtropical waters in coastal parts of the Atlantic • All species are nocturnal • Rostrum is used for a multitude of purposes • All species are critically endangered

6. Differences between sawFISH and sawSHARKS Sawfish: • Gill openings on underside • No barbels • All teeth are the same size • Shallow, costal waters • Relatively large (up to 23feet) Sawsharks: • Gill openings on sides • Barbels • Alternating large and small saw teeth • Deep offshore waters • Relatively small (about 5feet)

7. Fun with Rostrums- a Multi Purpose tool • A sawfish’s saw is made up of thousands of sensory organs that allow them to monitor the movements of other organisms by measuring the electrical fields they emit. Because the sensory organs are more densely packed on the dorsal side of its saw, the fish can create an image of the three-dimensional area above it, even in waters of low-visibility, which helps explain its bottom-dwelling nature. Utilizing their saw as an extended sensing device, sawfish are able to “view” their entire surroundings by maintaining a position low to the sea floor. • Smalltooth sawfish have been observed to approach large shoals of fish while striking their saw rapidly from side to side. The sawfish has also been observed to attack larger prey by using their weapon to dislodge large pieces of meat from victims. They then use their serrated saw teeth to tear through flesh. • The rostrum’s “teeth” are called deticles. Because the fish can swing its body so quickly, it also acts as a defense mechanism to scare predators away. • The pups’ rostral blades are enclosed by a sheath – so as to protect the mother during the birthing process – which eventually disintegrates and falls off.