Trout Feeding Results!

We're almost done with live feeding experiments this year! Let's take a look at what we've found so far and some questions we might still have:

Based on the graph above we can see that we know our trout will eat daphnia, BUT each trout at each school behaves a little differently. These are cumulative (adding all together) numbers from each school, so we can see that there are particular times where trout find the daphnia and eat them right away. This is cool, but because the numbers are all together we miss how many trout didn't eat any at all or ate more than the number of daphnia we thought were introduced to that trout's beaker. 

Marina with South Hill trout experiments last week! 

At South Hill the other day: "My trout didn't eat anything at all!," proclaimed an upset 4th grader. She continued, "it didn't even move!" The other students at her table and the teacher agreed, the trout hadn't even moved. 

Following our classes it's not uncommon to see a complete lack of interest in the daphnia from at least one trout per classroom (South Hill that day had 5). Our students at South Seneca and Fall Creek came up with some ideas for changing the experiment to find out WHY some trout don't eat. 

"We could use a bigger container or put 2 or 3 trout together," suggest the 5th graders at South Seneca. Their observations led them to believe that perhaps the trout would eat more given a larger space or some companions to compete against. We tested this at Caroline, where the 4th graders poured their trout and any leftover daphnia back into the tank and observed with exclamations "Wow look how fast their eating!" and "That trout must've been really hungry!" 

Newfield trout feeding with DCL pre-COVID!

The 4th graders at Fall Creek had other ideas: "We could use a mirrored box," one student suggested, "that way the trout can't see us, but we can still observe the trout." This student thought maybe having everyone observe the trout made them eat less, no one likes eating with someone staring at them. Other suggestions included trying different food besides daphnia - things like smaller fish, ants, bugs, crushed crayfish, seaweed, or even fish lures - to see if perhaps daphnia just weren't motivating enough to make a good trout feeding experiment. 

All these great observations led to a complex scientific discussion. When we broke down watching the trout eat and how they behaved we came up with that we knew the trout would eat daphnia, but not WHY or WHEN or HOW QUICKLY. Through these observations we were able to conclude that our trout should be able to hunt and find food when released into a stream environment, but not all would survive the same and some might struggle to meet their basic needs after growing up in captivity.