1. Chapt 10 Bony Fishes
Ichthyology
“the study of fish”

2. Phylum Chordata
• Class Actinopterygii
– “modern bony fish”
– 25,000 species or ½ of all vertebrate species
– So diverse no one characteristic can differentiate
them from sharks, skates, and rays (cartilaginous
fish)
• Taxonomy of fishes is concentrated on order or family
rather than phylum (b/c phylum is too broad)
– Taxonomy of fishes are still changing as new
technology and research reveal new characteristics

3. Phylum Chordata
• Characteristics
– Presence of swim bladder or lung
– Bones
– Bony scales
– Fin rays

4. Coelacanths “primitive fish”
• Historic fish that give rise to modern day amphibians
• Were thought to be extinct 65 million years ago until
living specimens were discovered in 1938 and as
time goes on finding more and more individuals
“living fossils”
• Live at depths 150-250 meters
• Bony skeleton but vertebrae is almost all cartilage
(like sharks)
• Maintain high amount of urea to maintain
homeostasis
• Reproduction: ovoviviparous

5. Ray-finned Fishes
• Most numerous and diverse of ALL
vertebrates in ocean
• Characteristic-fins attached to body by fin ray

6. 2 major groups
• Subclass Chondrostei • Subclass Neopterygii
– Heterocercal tail – Homocercal tails
– Skeleton made mostly of • Backbone does not
cartilage extend into tail
– Ganoid scales – Cycloid OR Ctenoid
• Armored appearance scales
• Florida Gar • Both are thinner and
more flexible than ganoid
scales

7. Body Shapes-determined by habitat
• Fusiform- streamlined
shape for active
swimmers
• Laterally compressed-
flattened so can
maneuver though corals
• Flattened: bottom-
dwellers
• snakelike: burrowing
fish

8. Respiration
• Gills: receive oxygen and remove CO2, and
maintain salt balance
– Made of gill filaments: blood flows in opposite
direction of incoming H2O
• Water must continuously pass over gills
– Meets with blood with lower O2 and higher CO2
• Diffusion moves from where to where?????
– Fish actually “pump” H2O over gills

10. Cardiovascular
• Close circulatory system: Heart, veins,
arteries
– Most complex we’ve seen so far!
– 4 chambered heart
• Draw diagram in your notes

12. Staying neutrally bouyant
• Buoyancy
– Swim bladder: gas filled sac; add and remove to
adjust buoyancy
• SCUBA divers must adjust air in BCD for same purpose
– To go down: let air/gas out
– To go up: add air/gas

13. Nervous System
• Brain, spinal cord, nerves
• Senses
– Olfaction: sense of smell: olfactory pits (nostrils)
– Taste: receptors on head, jaws, tongue, mouth
and barbels on some fish (catfish)
– Hearing: Eyes Lack eyelids
• Most set on sides of face: each eye see own
independent view.

14. http://i11.p
556ed59a
13352685
Reproduction
• Vast: depends on species
– Blue headed wrasse can change sex
• Perch: separate sexes
– Males and females spawn eggs
• FEMALES MUCH LARGER THAN MALES DURING
BREEDING-> FULL OF EGGS (female on bottom ↑)
– Early spring in sandy, shallow sediments
– Females lay more than 20,000 eggs at a time;
male comes afterward to fertilize
• No parental care for young

15. Perch Anatomy