Perch Dissection
By Elijah Durrett
Introduction
The purpose of this lab is to dissect the Perch. Other objectives
include identifying the following structures: all fins, lateral lines,
operculum, gills, maxila, mandible, nares, digestive system, reproductive
system, air bladder, excretory system, circulatory syrstem, and
nervous system.
The Perch scientific name is perca flavescens and comes from a
class of bony fish called osteichtheys. The perch is a fresh water fish,
which is very common.
Procedure and Materials
Refer to the lab manual, Nasco's Dissection for the Perch.
Notes
No notes were given for this lab.
Data
See "pictures" on the main page.
Questions
1. What is the function of the lateral line?
The lateral line is used for sensing water currents and vibrations in the water. It can help the fish tell if another fish is near or if there is a disturbance in the water.
2. Examine the growth rings on the scales under a microscope.
The set of two closely spaced rings equates to a fall/winter growth period. Count the winter growth rings and that should be equal to the number of years (or the numbers of winters) the fish has been around.
I think that our fish was around 5 or 6 years old. I would have known for sure if I drew my scale more detailed, I really didn't count the scales on it because they were so small and they were difficult to tell apart.
3. How did you determine the sex of your fish?
Female ovaries lie between the intestine and the swim bladder. Testes are white and lie just below the air bladder. Ours was a female. We could tell by the HUGE egg sack, it took up almost the whole body.
Conclusion
The first thing we saw when we cut open the fish is eggs. They took up most of the space in the body. I enjoyed this lab, but I'm not sure we identifyed all of the structures required. I'm not sure that we completed the objective.
