Perch Dissection Pre-Lab
By Mrs. Shaw
• Anterior: situated before or at the front of
• Posterior: situated behind or at the rear of
• Ventral: situated on or toward the lower,
abdominal plane of the body; equivalent to the
front, or anterior, in humans.
• Dorsal: situated on or toward the upper side of
the body, equivalent to the back, or posterior, in
• Caudal: of, at, or near the tail or the posterior
end of the body.
External Perch Anatomy
Perch Classification in
• Kingdom: Animalia
– Phylum: Chordata
• Subphylum: Vertebrata
– Infraphylum: Gnathostomata
» Superclass: Osteichthyes – bony fish
• Class: Actinopterygii
• Order: Perciformes
• Family: Percidae
• Genus: Perca
• Species: Perca flavescens
Yellow perch (Perca flavescens) is a
species of perch found in the U.S.
and Canada in both fresh and salt
water lakes primarily.
Recognized by its dark vertical stripes
and gold or yellow body color.
Size: adults are usually between 4-
10 inches (10-25.5 cm) in length.
Lifespan: up to 11 years Spawning occurs at the end of April or
beginning of May, depositing 10,000 to
Diet: Adult perch dine primarily on 40,000 eggs upon weeds, or the
immature insects, larger branches of trees or shrubs that have
invertebrates, (crayfish, etc.) and the become immersed in the water. After
eggs and young of other fish, which fertilization the eggs hatch in 11 to 27
they take both from open water and days depending on temperature and
from the bottom. other weather conditions.
Perch Anatomy terms
• Operculum: a bony flap of skin over their gills that
protects the gills and which opens and closes to help bony
fish breathe when they are not swimming.
• Swim (air) Bladder: a gas filled sac that helps keep bony
• Gills: the organ by which gases are exchanged between
the fish and the surrounding water.
• Lateral Line: The lateral line is a sense organ in aquatic
organisms (chiefly fish), used to detect movement and
vibration in the surrounding water.
Internal Perch Anatomy
How do Gills work in respiration?
• The gill works by providing a
surface where the water (which
has dissolved oxygen) comes into
contact with the blood of the
• The blood circulation within the
gill is arranged in such a way that
it flows in opposite direction to
the flow of water
• Because oxygen will tend to flow
(diffuse) from the site of highest
concentration to the place of
lowest concentration, this
arrangement ensures that oxygen
will always flow from the water
into the blood.
Oxygen is not as abundant in water
as it is in the air, so for aquatic
animals, oxygen concentration is
a major limiting factor.
The best way to ensure that enough
water is "scanned" for oxygen at
the gills is providing a really large
surface area for gas exchange.
Thus, each gill is formed by filaments.
Each filament has secondary
lamellae that rise perpendicularly
to the surface of the filament. The
total surface area is extremely
large with respect to the volume
of the gills.
Gas exchange occurs at the
secondary lamellae, and it's here
where you can see the
How does the swim bladder help keep
the fish buoyant?
• When gas is added to the
swim bladder, the fish
becomes less dense.
• When gas is removed from
the swim bladder, the fish
becomes more dense.
• A swim bladder is filled
with air when the fish
wants to ascend, and it is
deflated when the fish
wants to descend.