sharks and rays class chondrichythes. common rays in hawaii
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Sharks and RaysSharks and Rays
Class Chondrichythes Class Chondrichythes
Common Rays in Common Rays in HawaiiHawaii
Fish vs. SharksFish vs. Sharks
Sharks are Fish!....ButSharks are Fish!....But
Do not have bonesDo not have bones 5-7 external gill 5-7 external gill
openingsopenings No gill coverNo gill cover No swim bladderNo swim bladder Internal fertilization Internal fertilization
with clasperswith claspers Placoid scalesPlacoid scales
Form and FunctionForm and Function
Heterocercal tail = upper lobe longer Heterocercal tail = upper lobe longer than the lowerthan the lower– Strengthen and support tail for forward Strengthen and support tail for forward
thrustthrust
Teeth in rowsTeeth in rows– Teeth lack roots and often breakTeeth lack roots and often break– Easily replacedEasily replaced
Placoid scalesPlacoid scales– Reduce drag, protectionReduce drag, protection
Paired Pectoral FinsPaired Pectoral Fins– Airplane wings, provide liftAirplane wings, provide lift
Predominant dorsal finPredominant dorsal fin– BalanceBalance
Shark’s SEVEN SensesShark’s SEVEN Senses S – SoundS – Sound
Can hear a fish 100 yards awayCan hear a fish 100 yards away
O – OlfactionO – Olfaction In one nostril and out the otherIn one nostril and out the other
L – Lateral LineL – Lateral Line V – VisionV – Vision E – ElectroreceptionE – Electroreception T – TouchT – Touch T - TasteT - Taste
ElectroreceptionElectroreception
Similar to a metal detectorSimilar to a metal detector Ampullae of LorenziniAmpullae of Lorenzini
– Detects the magnetic field around Detects the magnetic field around living organismsliving organisms
Only other animals with this Only other animals with this sense: duck billed platypus and sense: duck billed platypus and spiny anteaterspiny anteater
Sharks in HawaiiSharks in Hawaii
Aggressive SpeciesAggressive Species
Tiger – 18 ftTiger – 18 ft Galapagos – 10-12 ftGalapagos – 10-12 ft Hammerhead - 12-15 ftHammerhead - 12-15 ft Great WhiteGreat White
Other SpeciesOther Species Blacktip – 8 ftBlacktip – 8 ft Reef Black Tip – 6 ftReef Black Tip – 6 ft Reef White Tip – 6 ftReef White Tip – 6 ft Sandbar - 5-6 ftSandbar - 5-6 ft
Shark AttacksShark Attacks never swim alonenever swim alone don't swim with open wounds or speared fishdon't swim with open wounds or speared fish don't swim erratically or make splashing don't swim erratically or make splashing
noisesnoises avoid the water at night - sharks hunt at avoid the water at night - sharks hunt at
nightnight avoid murky water - sharks may mistake you avoid murky water - sharks may mistake you
for a preyfor a prey don't harass or provoke sharksdon't harass or provoke sharks if you witness fish behaving erratically, leave if you witness fish behaving erratically, leave
areaarea if you encounter a shark, remain calm and if you encounter a shark, remain calm and
slowly leave areaslowly leave area
Environmental Environmental ConcernsConcerns
Sharks are top Sharks are top predatorspredators
““Keystone Keystone species” that species” that keep prey keep prey populations populations under controlunder control
Sharks extinct?Sharks extinct? Populations Populations
continue to continue to declinedecline
If fishing If fishing continues, continues, could go could go extinctextinct
18 species are 18 species are threatened with threatened with extinctionextinction
Our Impact…Our Impact…
Something to Think Something to Think About…About…
~ 6 people killed ~ 6 people killed by sharks a yearby sharks a year
~ 12 million ~ 12 million sharks killed by sharks killed by humanshumans
– BycatchBycatch– FisheriesFisheries
Basic Fish Fin Basic Fish Fin FunctionsFunctions
Dorsal fin - stability in swimmingDorsal fin - stability in swimming Pelvic fin - stability in swimmingPelvic fin - stability in swimming Caudal fin - main propelling finCaudal fin - main propelling fin Anal fin - stability in swimmingAnal fin - stability in swimming Pectoral fins - Locomotion and side Pectoral fins - Locomotion and side
to side/ back forth movement.to side/ back forth movement.