This document discusses bony fish, including their: - Classification in the phylum Chordata and class Actinopterygii, with over 25,000 species. - Key characteristics like presence of swim bladders, bones, bony scales, and fin rays. - Two major subgroups based on tail type, skeleton composition, and scale features. - Diverse body shapes adapted for different habitats like streams, coral reefs, or burrowing. - Respiration via gills, circulation with a four-chambered heart, and buoyancy regulated by a swim bladder. - Varied coloration serving functions like camouflage, communication, and pred

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 are still
changing as new technology
and research reveal new
characteristics

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

4. 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

5. 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

6. Respiration and Circulation

7. 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

9. Cardiovascular
• Close circulatory system: Heart, veins, arteries
– Most complex we’ve seen so far!
– 4 chambered heart
• Draw diagram in your notes
• What does it mean to have
an open circulatory system?

11. Swimming and Movement

12. Muscle Contractions
• W shaped bands of muscle
• Movement occurs when
muscle contracts.
– Alternate from one side to
the other
– Starts at anterior and travels
to posterior end
• Contractions start at
different areas in the body
for different fish = different
swimming patterns.

13. 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

14. Fish Coloration
5 important types you need to know

15. Important to fish survival
• Help the fish to
– Find food
– Communicate
– Attract mates
– Defend itself from
predators
– Recognize species
– Conceal themselves
• Pigments: found in cells
called chromatophores

16. Different types
• 1. Structural colors
– Produced by light reflecting
from crystals located on
chromatophores
• 2. Obliterative
Countershading
– Found on fish living in
pelagic zone (open ocean)
– Dark on the top and white
on the bottom
– Why?

17. More types..
• 3. Disruptive Coloration
– Distract predator
– Lines, stripes, fake eyes
• Trying to aim predator in
the wrong direction
• Cryptic Coloration
– Sneaky
– Use colors to ambush prey
• Poster Colors
– Bright, showy colors that
advertise territorial
ownership or sexual
displays

18. Nervous System & Reproduction

19. 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: internal ears
– Sight: Eyes Lack eyelids
• Most set on sides of face: each eye see own
independent view.
• Lateral Line: Detect movement in water

20. • Vast: depends on
species
Reproduction
– Internal and external
sexual reproduction
– Some care and protect
young, others do not
• Perch: separate sexes
– Males and females
spawn eggs
– Early spring in sandy,
shallow sediments
– Females lay more than
20,000 eggs at a time;
male comes afterward to
fertilize

21. Perch Anatomy