The second graders at Cayuga Heights completed their first trout experiment today with the help of Trout in the Classroom instructors Bill, Michael, and Josh. (Big thank you to them!) Students had to make a hypothesis about whether or not the trout fry would eat the live food (daphnia) placed in a beaker with each fry. The students created a hypothesis based on their previous knowledge of the trout and their eating patterns. Then students tested their hypothesis with a group by feeding live daphnia to a trout and counting the number of daphnia eaten (out of about 10) over 5 minutes.
Most students predicted that their trout would instinctively know to eat the daphnia and the majority proved their hypothesis to be correct. One trout must not have been too hungry during the experiment and opted not to eat any daphnia. The majority of the trout ate all the daphnia presented to them during the experiment. Enjoy some photos below!
We also learned an important lesson from our trout this week... never bite off more than you can chew. This little guy didn't survive the week after he indulged on one of his tank-mates.
Monday, January 2, 2012
Our trout are now in their "parr" stage and are developing distinctive colors and patterns. We have been visiting classes with a slide presentation science-inquiry illustration activity to explore these color adaptations. Our Brown Trout, in particular, are able to change colors to blend in with habitat features, and several classes will be setting up experiments over the coming weeks to observe this phenomenon.
Trout are not the only fish that can change color. Flounders, like the one on the right, are masters of this skill.
How do they do it? They use special cells called chromatophores! For a quick intro to fish coloration. You can see chromatophores up-close here. Fascinating stuff!
Fish living in darker locations tend to take on darker colors, but did you know that blind fish turn dark colors, as well? Check out the links in "On-line Resources" if want to know more.