Date: ________________________________
Oceans 11
Perch Dissection Lab
Specific Curriculum Outcomes:
FISH-8: describe and identify the external and internal anatomy of a major finfish or shellfish species
that is a part of the commercial fishery
35
Names of all group members:
BACKGROUND
Perch are members of the Osteichthyes group (bony fish).
Digestion
Food enters the fish’s mouth and passes through the stomach and into the intestine. Digestion is aided by bile
produced by the liver, which is attached to the intestine. Solid waste passes out through the anus. Wastes from
metabolism are processed by kidneys and pass out through the urogenital opening.
Circulation
Circulation is closed. They have a two-chambered heart; it includes an atrium and a ventricle. Blood leaves the
heart, goes to the gills, and then goes to various arteries, veins, and capillaries.
Respiration
Oxygen is obtained from the water as it passes over the gills. Waste carbon dioxide is passed into the water at
the same time.
Movement
Movement is achieved by the action of muscles attached to the bony skeleton of the fish and is guided by the
action of several types of fins. The fish has an air bladder in its body to help it stay afloat. The amount of gas in
the bladder is adjusted by gas exchange across the capillaries in the air bladder wall. The lateral line, found on
the outside of the body, allows the fish to sense differences in pressure and to sense low-frequency sounds.
EXTERNAL ANATOMY
1. Place the fish on the dissecting tray. Gather dissecting tools.
2. Locate the head region. Examine the eyes.
(a) Are there any eyelids present? (1 pt)
3. Locate the nostrils and mouth.
(a) Does the fish have teeth? (1 pt)
4. Examine the two flaps located on either side of the heads.
(a) What is the name of these flaps? (1 pt)
(b) What is their function? (1 pt)
Date: ________________________________
5. Examine the five types of fins.
(a) How many fins does the fish have? Complete the chart for each type. (5 pts)
Dorsal
Caudal
Anal
Pelvic
Pectoral
(b) What is the purpose of each of the fins? Complete the chart. (5 pts)
Dorsal
Caudal
Anal
Pelvic
Pectoral
6. Locate the lateral line.
7. Use tweezers to remove a scale from the fish. Observe the scale.
8. Now go to the microscope and observe the pre-made slide of a scale.
(a) Draw a sketch of the scale. (1 pt)
(b) Is the scale cteniod or cycloid? (1 pt)
9. Label the diagram of the external anatomy of the fish. (10 pts)
INTERNAL ANATOMY
Gills
1. Using your thumb, lift up the edge of the operculum and raise it
up as far as you can. Using scissors, cut the operculum off as
close to the eye as possible. You have exposed the gills. The
gills are layered one on top of another. Using your probe,
carefully lift each of these layers.
(a) How many layers did you find? (1 pt)
2. Remove one of the layers and examine the feathery structure.
Date: ________________________________
Internal Organs
Cutting Diagram
Anatomy Diagram
3. To expose the internal organs, you will cut away parts of the muscular wall. Refer to the cutting diagram
above.
4. Use the probe to locate and observe the following internal organs. Check off each one you see.
-
air (swim) bladder
stomach
intestine
liver
kidneys
-
gonads (ovaries or testes)
heart (atrium and ventricles)
muscles
ribs
vertebrae (backbone)
LAB QUESTIONS
1. What is the function of the air bladder? (1 pt)
2. What gonad was visible? Describe its appearance. (2 pts)
3. Do perch have an open or closed circulatory system? What does this mean? (2 pts)
4. Describe what the muscles look like. (1 pt)
5. What adaptations for life in the water did you observe in the perch? Describe what the adaptation does for
the fish. (2 pts)