Phylum
Chordata:
FISH
3 categories of marine
fish:
Jawless
Fish (Class Agnatha)
Cartilaginous Fish
Bony Fish
Class Agnatha
 Lack
jaws
 Body made of cartilage
 Eel-like body
 Unpaired fins
Class Agnatha: Hagfish
• Bottom dwellers
• Scavengers
• Often burrow into dead fish and
feed
Class Agnatha: Lamprey
• Fresh and salt water
• Parasitic and prey on
other fish
• Reproduce in fresh water
Lamprey preying on fish…..
Cartilaginous Fish
 Skeleton
made of cartilage
 Moveable jaws with well developed
teeth
 Mouth underneath head
 Sandpaper like scales
 Ex. sharks, rays, skates, and ratfish
Great White
Ray
Skate
Rat Fish
Sharks- Cartilaginous
 Adapted
for fast swimming
 Predators
 Called “living fossils”
 Changed little through time
 5-7 gill slits on each side
Respiration
• Sharks have uncovered gills used for respiration
• Extract oxygen as water passes over the gills
• Most species of shark
can pump water over
their gills for when
they are not moving
using the spiracle
• A small percentage of
sharks need to stay in
constant motion to
respire
Do Sharks Sleep??
• Scientists unsure!!
• Possible they sleep
in a similar manner
to Dolphins
– Half the brain
sleeps at a time
Teeth
• Sharks teeth are NOT attached to their
jaws
• Teeth range from needlelike to large flat
teeth
• Teeth are grown and replaced often
• Sharks have multiple rows of teeth
• Sharks can have about 25,000 to 30,000 teeth
in one lifetime
• Some replace teeth every
8-10 days, others every few
months
Smell/Vision
• Incredible sense of
smell
• Vision similar to
humans with
adaptations to see in
murky water
Locating Prey
Lateral lines
Sense organ used to
detect motion or
vibrations in the
water
Life Span
• Lifespan varies by species
• Most live about 20 – 30 years
• The spiny dogfish can live up to 100 years
• It is thought that the whale shark can live
over 100 years as well
Naming Sharks
 Name
is usually descriptive of a
characteristic of the shark, such
as appearance or demeanor
Black Tip Shark
Leo Shark
Hammerhead Shark
Lemon Shark
Species
 There
are over 360 species of sharks!
 They can range in size from small
enough to fit in your hand to up to ~50
feet!!
Species Size
 Smallest
Shark is the Pygmy Shark
 Largest Shark is the Whale Shark
 2nd largest shark- Basking shark
These are filter feeders, feeds on
plankton
Aggressiveness
 Great
white shark
 Bull shark- salt and freshwater
 Tiger shark
Bull Shark
Great White Shark
Tiger Shark
Bony Fish
 98%
of fish
 Skeleton is made partially of
bone
 Thin, overlapping scales
 Operculum protects the gills
Continued…………
 Mouth
located at end of body
 Teeth fused to jawbone
 Contain a swim bladder
Catfish
Tuna
Amberjack
Trout
Grouper
Moray Eel
Sunfish
Seahorse
Parrotfish
Porcupine Fish
Stonefish
Lionfish
Biology of Fish
ICTHYOLOGY- the
study of fish
Body Shape
 Shape
related to lifestyle
 Ex. bottom dwellers have an
irregular outline to resemble
rocks or seaweed
 Ex. eels can sometimes
resemble grass
Coloration
 Colored
pigments that allow for
camouflage is from cells known
as chromatophores.
Types of coloration
 Warning-
change color to warn
another fish; mood, poisonous,
taste bad, ready to mate
 Cryptic- blend with
environment to deceive
predators
Continued………..
 Disruptive-presence
of stripes,
bars, spots confuse predator
 Countershading
Locomotion
 Sharks
lack swim bladdercombination of large pectoral
fins and oil in liver
 Sharks cannot swim backwards
Continued…………..
 Fish
do have a swim bladder
 Fins allow great maneuverability
 Can swim in all directions
Behavior- Territories
 Establish
territories for feeding,
resting, and mating
 Will defend against intruders
 Fish like to “bluff ” by raising
fins, opening mouth, grinding
teeth/bones, or darting
Behavior- Schooling
 Herring,
sardines, and mackerels
school all their lives
 Some school only part-time
(feeding or reproduction)
 Most cartilaginous fish do not
school
Continued…………….
 Schools
tend to be similar in
size, keep constant distance,
turn, start, stop, etc. in perfect
unison
Possible reasons for schooling
 Protection
 Swimming
 Feeding
 Mating
efficiency
Reproduction
 Most
separate sexes
 Some fish are hermaphrodites
but can mate with others as
well; adaptation for deep sea
fish
 Some hermaphroditic fish can
also have a sex reversal
Reproductive Behavior
Courtship- series of behaviors to
attract a mate
 “dance”-posture change
 Color change
 Swimming upside down
Reproduction
 Bony
fish = external
fertilization
 Cartilaginous fish = internal
fertilization
Continued………
 Male
cartilaginous fish have
claspers
 Bite mate on back to show
interest
 Inserts claspers into cloaca