Fish Respiration Lab

Experiment: Determine how temperature affects the respiration of fish.

Materials:

• Mini-aquarium
• Large aquarium
• Water
• Ice
• Thermometer
• Killifish
• Timing Device

Parameters:

• Use only one fish per temperature.
• To count the gill beats you can count the times the fish opens its mouth or the times its operculum flaps.  Watch the fish and see which is easier for you, and notice how they go together. (Both motions are part of one breath)
• When you put the fish in the treatment let it sit for one minute, then count the gill beats for one minute and record the temperature.  Repeat this step two more times in the same treatment.  Be sure to record your results and averages in the data table.
• Never put the fish directly in the ice or hot water.

Experimental Method (Write up #1-7 before beginning the experiment):

Your report should include:

1. Problem
2. Hypothesis: be sure to mention both hot and cold water, and to give reasons for your predictions.
3. Experimental Plan: Create a Labeled Diagram/Sketch of the experimental set-up, including labeling each material used.  You need to talk over the plan with your group members but do not need to write out a procedure. (If you are a fast worker, you might challenge yourself to writing the procedure down, as it is a useful scientific skill to have.)
4. Independent & Dependent Variables
5. 5 control variables
6. Data Table and any other results (notes/observations you wrote down during the experiment)
7. Analysis (Based on Class Data)
8. Graph of Class Data
9. Conclusion (Based on Class Data)

• Your report should be written on notebook paper (not this handout).
• All parts that aren't diagrams, tables, or graphs need to be in complete sentences. 

Analysis Questions for Fish Stress Lab:

Answer in complete sentences.  Be sure to answer all parts of each question! You may add another paragraph if you have additional thoughts about your results that you didn't write while answering these questions.

1. What land uses (natural or manmade) might cause changes in the temperature of a body of water? How?
2. What natural events or weather might cause changes in the temperature of a body of water? How?
3. What conditions allow the temperature to change greatly in the Bay? What conditions help to moderate (or decrease the effect of) temperature changes in some areas of the Bay? How?
4. We can’t easily control temperature (HOT summer days are always HOT). What is the best action we can take to reduce the chance of D.O. levels getting too low in the summer? (Think about our other water tests & their connection to D.O.) How will this help even as the water warms?
5. What experiment would you perform to test another stress that fish are exposed to? Give your hypothesis for this experiment.

Conclusion:

Be sure your conclusion includes the following-

• Was your hypothesis accepted or rejected? Why or why not? (It's OK if it wasn't!)
• So, how do changes in temperature affect fish, according to this experiment?  Why?
• Be sure to include specific data (numbers) to support the trend you found between temperature and fish respiration.
• What is the connection between temperature and dissolved oxygen? How does this link to the experiment?
• Connect your findings to conditions in the Chesapeake Bay
• Include possible sources of error, or ways to improve the lab.
• Discusses the effects of the sources of error.

Re-read your conclusion to make sure it is organized and flows logically.