Thursday, October 11, 2012

TIC Supplement: Where Trout Live

Angler on the Paulinskill River
An angler on the Paulinskill River. 

Though our eggs didn't arrive as expected, we took time this Tuesday to learn about the trout we'll be hatching. This week we focused on how the tank and the stream were alike and different. First we reviewed the parts of the tank, looking at the chiller that keep the water at a steady 52 degrees Fahrenheit and the filter that keeps the water clean. Students noticed that the tank had cold water, gravel and bubbles for oxygen, just like the stream, but that it didn't have sand, silt, plants or other life in it. (Learn more about trout habitats.)

Those are really important observations. Right now, one of the most important things we need to do is build the bacteria colonies in our tank. That surprised the students! After all, aren't bacteria the things that make you sick?

Well, not all bacteria are bad. Our trout will need the bacteria to help them digest food, keep their scales and skin healthy and to decompose wastes, just like we do! So we've been adding special bacteria from a bottle to our tank for weeks, which helps the filter create a healthy colony. (Learn more about creating beneficial bacteria colonies in fish tanks.)

But we wanted to customize our bacteria. We want to create a tank environment that is as close to the environment that the fish will eventually live in when they are released into the Paulinskill River in May.

Rainbow trout swimming in a gravel-bottomed stream.

So we took a walk to Footbridge Park to visit the Paulinskill. The Paulinskill River is a  41.6-mile tributary of the Delaware River, formed when the Wisconsin Glacier melted 13,000 years ago. It begins just north of Newton, NJ and ends near Columbia, where it feeds into the Delaware. (Learn more about the Paulinskill.)

At the river we collected water samples and algae-covered rocks. By transporting them back to Kaleidoscope and adding them to our tank, we'll be able to transfer some of the microscopic life, including bacteria, to our artificial habitat!

When we got back to KLC, we poured some of our water onto white paper plates. There we used a digital microscope to look at the water. We saw lots of sediment, algae and even a few moving creatures, likely small bacteria, protists, insects or crustaceans. (Learn more about what lives in "pond scum.")

We can't wait until our eggs arrive next week on Tuesday, October 16 after 9:15 am!

Lesson extensions:
  • Have students draw the tank, labeling items like the chiller and filter. How much do they remember? What do the components do? What part of the stream environment do they mimic? They can check their drawings for accuracy next week! (Here are some examples that are similar to our tank.)
  • Go to a local river (or back to the Paulinskill) and do a scavenger hunt to explore the water and the surrounding Area. Use this worksheet to track your findings.
  • Describe a Dream Stream.
  • Watch "The Way of the Trout" and describe a trout habitat. What animals and plants are present? What are the trout’s prey? What are the predators?
  • Explore how glaciers form rivers like the Paulinskill. For a simple experiment fill an ice cube tray half full of water. To each cube, add various sediments like dirt, sand, gravel and rocks. (I would suggest two each with a single type of sediment, then several mixed samples.) Top off with more water as needed. Leave some cubes as just water. Freeze the cubes. In the morning, press out modeling clay into flat discs. Take each cube and drag it along the clay. Use different amounts of pressure. Go slowly, then quickly. Record your findings and draw or photograph examples of the results. Which looks like a river or valley to you?