Sharks and RaysClass Chondrichythes

Common Rays in Hawaii

Fish vs. Sharks

Sharks are Fish!....ButDo not have bones5-7 external gill openingsNo gill coverNo swim bladderInternal fertilization with claspersPlacoid scales

Form and FunctionHeterocercal tail = upper lobe longer than the lowerStrengthen and support tail for forward thrust

Teeth in rowsTeeth lack roots and often breakEasily replaced

Placoid scalesReduce drag, protection

Paired Pectoral FinsAirplane wings, provide lift

Predominant dorsal finBalance

Sharks SEVEN SensesS SoundCan hear a fish 100 yards awayO OlfactionIn one nostril and out the otherL Lateral LineV VisionE ElectroreceptionT TouchT - Taste

ElectroreceptionSimilar to a metal detectorAmpullae of LorenziniDetects the magnetic field around living organismsOnly other animals with this sense: duck billed platypus and spiny anteater

Sharks in HawaiiAggressive Species

Tiger 18 ftGalapagos 10-12 ftHammerhead - 12-15 ftGreat White

Other SpeciesBlacktip 8 ftReef Black Tip 6 ftReef White Tip 6 ftSandbar - 5-6 ft

Shark Attacksnever swim alonedon't swim with open wounds or speared fishdon't swim erratically or make splashing noisesavoid the water at night - sharks hunt at nightavoid murky water - sharks may mistake you for a preydon't harass or provoke sharksif you witness fish behaving erratically, leave areaif you encounter a shark, remain calm and slowly leave area

Environmental ConcernsSharks are top predators

Keystone species that keep prey populations under control

Sharks extinct?Populations continue to decline

If fishing continues, could go extinct

18 species are threatened with extinction

Our Impact

Something to Think About~ 6 people killed by sharks a year~ 12 million sharks killed by humans

BycatchFisheries

Basic Fish Fin FunctionsDorsal fin - stability in swimming Pelvic fin - stability in swimmingCaudal fin - main propelling finAnal fin - stability in swimmingPectoral fins - Locomotion and side to side/ back forth movement.