Week 3:

B. Classes of Fishes

LampreyChondrichthyesOsteichthyes

Chondrichthyes~1000 species

sharks

rays

chimaeras

Holocephali

Elasmobranchii

shark

body shapepectoral fingill placementanal fin

ray

Elasmobranchs

Sharks~400 species

5th

superorder

Sharks

Galea (with anal fin) ~280 species

Squalea (mostly no anal fin) ~120 species

Phylum Chordata Class Chondrichthyes

Subclass Holocephali Order Chimaeriformes

Subclass Elasmobranchii

Division Selachii (text: Superorder Galea)

Order Orectolobiformes

Order Lamniformes

Order Carcharhiniformes

Division Batoidea (text: Superorder Squalea)

Order Rajiformes

Order Myliobatiformes

1.

Week 3 sharks...

Orectolobiformes~33 sp with terminal mouth

Lamniformes~ 15 sp. with subterminal mouth

Carcharhiniformes ~ 225 sp with subterminal mouth and nictitating eyelid

Carcharhiniformes

subterminal mouthnictitating membrane

nictitating membrane

cat sharks

NEAq 2010: coral, chain

Carcharhiniformes

Scyliorhinidae~160 sp.

oviparous

keratin egg case

1-2 m>20 y captivitylarge interspecific schools along Calif. coastovoviviparous ~30 pups/litter

Carcharhiniformes

Triakidae~40 sp.

hound sharks

Triakis semifasciataleopard shark

requiem sharks

Carcharhiniformes

Carcharhinidae Carcharhinus~30 sp.

~no spiracles~ram ventilators~viviparity

black-tip reefCarcharhinus melanopterus1.5 m

interspecific schoolingelaborate displayshierarchies

oceanic whitetipCarcharhinus longimanus

pelagic scavenger at ship and plane wrecks

silky shark Carcharhinus falciformeswith pilot jacks

aggressiveschools with tunabycatch

grey reef shark Carcharhinus amblyrhynchoides ~25 years

black tip reef shark Carcharhinus melanopterus

blacktip shark Carcharhinus tilsoni

inshore spinner

bull shark Carcharhinus leucas

freshwater spinner2-3 m length

also Mississippi, NAZambezi, AfricaLake Nicaragua, CA

Amazon River Valley

freshwater ~2000 mile migration

lemon sharkNegaprion brevirostris

color visionmature 24 ylife-span 30 yreplace teeth ~ 8 days3 m long

Carcharhinidae

low oxygen, salinity

fast-growingmatures 4-6 ylives~12 y

long labial furrows

nocturnalsolitaryonly ovoviviparous carcharhinid10-80 pups/litter

blue shark Prionace glauca

widest rangingmigratory > 6000 km/yr, 60 km/dayspeeds 30 km/h

Carcharhinidae

no spiracles

mating woundsfemale skin 3x thicker than male skin and teeth

segregated schools

aggressive

~13 ft~20 y

threatenedmost heavily fished~bycatchfinned, discarded

50,000/yroff Hawaii6 M/yr global

from Costa Rica

Traditional Chinese Medicine (TCM)

IUU illegal, unregulated, unreported

to Singapore

CarcharhiniformesSphyrnidae

hammerheads

stereoscopic detection

triangulation

manueverability

acute vision, chemical and electrical detection

~8 species

winghead

scoophead

scalloped

great hammerhead

mallethead

small eye

bonnethead

smooth

large schools near magnetic mounts

bycatchhigh mortality

viviparity

placental viviparity~4 month gestation

~parthenogenesis

Carcharhiniformes

subterminal mouthnictitating membrane

Week 3 sharks...

Orectolobiformes~33 sp with terminal mouth

Lamniformes~15 sp. with subterminal mouth

Carcharhiniformes ~ 225 sp with subterminal mouth and nictitating eyelid