First Live Food Experiment!

Our young trout have grown to a size of about 2 or 3 centimeters in their "parr" stage. Are they ready to hunt and eat living prey? At this point in the year, classes are ready to conduct their first "live food" feeding experiments, using a common zooplankton, called "Daphnia". 

First, students have a chance to practice observation skills, as they get to know the "costar" of this experiment. Daphnia are about the size of a sesame seed. 

Then, student research teams prepare their hypotheses and perform an experiment to see how their trout will respond to an opportunity to try a new food... that just might try to escape! 

Finally, students evaluate their results and compare with other research teams. Here is a typical chart that depicts how many daphnia are eaten by trout during 20 second intervals over five minutes. Interesting... for more on this lesson and teaching materials, click on the "For Teachers" tab!