Macroinvertebrates as Indicators of a Healthy Stream

In April, we will be bringing live stream samples into your classroom filled with insects our trout would eat in the wild. We will focus on aquatic invertebrates as indicators to assess stream health. 

We will start by reviewing the life-cycles and adaptive characteristics of these insects. Students will dig though a stream sample, isolating different types of insects they find in ice cube trays with their group. 

Using a dichotomous key, students will identify insect types using the live specimens they have collected. Once they have identified insects in their stream sample, students will "score the stream" using a tool that grants higher points to pollutant intolerant insects than tolerant ones. 

This lesson introduces the idea that we can infer much about the function of a system by making scientific observations of individual components. 

Finally, students will feed a few insect larvae to the trout and see how they react! This lesson is always a student favorite!

Cannibalism happening in tanks across the region

A bigger trout digesting a smaller trout in a tank at a Union Springs classroom in 2015

It seems every year, we hear of reports of cannibalism in trout tanks across the region. Sometimes there is a suspicion that cannibalism is happening, as trout seem to be "disappearing" from the tank, and one or two trout are abnormally larger than the rest. But sometimes, students actually see a larger trout eating a smaller one in action, as they will spot a fish tail hanging from a trout's mouth. 

Trout, like many fish are cannibalistic and will likely eat smaller members of their own species. This is an example of natural selection, as some trout are better at adapting to their environment. 

When visiting schools, I always ask students for an update about what's going on in their tank, especially since they are spending a lot more time interacting with their trout aquarium than I am. One of the first things I usually hear about is the possible cannibalism happening. I often ask students why they think this is happening. Then I'll ask them which kind of trout has a greater chance of surviving in the wild, the small trout or the bigger trout that is able to eat the smaller trout?

A trout that has moved beyond small, dried up fish food and is able to capture live, moving fish in their environment indicates smarter, faster, more agile behaviors. Wouldn't a fish displaying these behaviors have a better chance of fighting off future predators like bigger fish, otters and birds of prey?

An angler in Strawberry Reservoir in Utah found a partially digested fish in the mouth of a cutthroat trout. Brett Prettyman/Trout Unlimited 

 

March: A time to think about clean water and individual actions

Spring is just around the corner! Which has us thinking about the upcoming trout releases. And as we begin planning for the releases, one building block to the student's Trout in the Classroom experience is understanding the importance of caring for the trout's environment once they are swimming in local streams. Which is what this month's Watershed Pollution Prevention lesson is all about! 

During Visit #4: Watershed Pollution Prevention, we will present on topics including water cycle and watershed so students can gain an understanding of how pollutants can enter into a watershed. Then we will look at different types of pollutants and how they can eventually be harmful to trout, the food web, and the natural ecosystem once they make their way into the water. 

Students identify pollutant actions, with a particular focus on trash, pesticides, fertilizers and ways natural landscapes can increase or decrease run-off. Once they have a good grasp of harmful pollutants, how they make their way into a watershed, and the damage they can do to aquatic life, it's time for the class to conduct their own watershed pollution survey!

Groups of students use a pollution scavenger hunt worksheet to examine their school campus for signs of pollution hazards and pollution preventers. At the end of the hunt, students score their school and its process of eliminating or adding to watershed pollution. This has led to conversations about problems students noticed in their school, or awareness of positive school behaviors. It's great to see student's brain's working to come up with solutions, or goals to continue to prevent pollutants from entering waterways.

The pollution prevention lesson is happening during a convenient month for continued education on topics related to pollution prevention and watershed awareness. March 18th is Global Recycling Day, which brings awareness to recycling as a way of protecting natural resources. This year's theme is #RecyclingHeroes. Here are some great examples of rising youth stars who's bright ideas and initiatives have made a difference in local and global recycling efforts. 

As we visit 20+ schools in the region teaching pollution prevention, we often hear insightful ideas students have about protecting local streams from pollution. Students participating in the Trout in the Classroom program have a great opportunity to be environmental advocates in their community, as they learn trout's habitats needs and understand the importance of clean natural waterways for their trout to continue to live and thrive!

March 22 is World Water Day, which is a great time to ponder inequalities to clean and accessible water worldwide. Here are three activities put together by UN Water for school kids of all ages to learn about water conservation and peace building. Explore these concepts with your class through engaging and fun activities like art and even football! 

For a local way of engaging with conservation, students are invited to join Ithaca Fishing and Conservation Day is happening Saturday, March 23 at Boynton Middle School. The event is put on by Trout Unlimited and Discover Cayuga Lake will be there to do science activities with students. 

What would your trout would be doing in the wild right now?

We've been observing our trout hunting and eating zooplankton in captivity, but what about all the baby trout in the wild? Will they have the upper fin in hunting and competing for food when we release our captive trout? Is a winter stream environment a nurturing habitat for baby trout? Let's find out!

A baby wild trout has about 4 months of life in its stream habitat by this time in February and is known as a trout "fry" or "parr." Check out this cool video to see what a brook trout parr looks like at this time of year!

Here are some cool facts about wild trout parrs and how they grow up: 

1. A wild trout parr will be smaller than a trout parr raised in captivity. This is because growing up in the wild is typically colder than growing up in a tank, the water can even be a temperature that would normally cause water to freeze if the stream is running fast enough! The colder the water a trout grows up in, the slower the trout will grow. 
   

2. 

   Stonefly larvae in June 2020.

   A wild trout parr starts hunting almost right away as soon as it can swim, and sometimes even before it can swim! While our captive trout learn to come up to the surface of the tank and beg for food, a wild trout looks for its food at the BOTTOM of a stream. This is called BENTHIC feeding and means that trout grow up mostly eating stonefly, mayfly, and caddisfly larvae that can be found hiding among the rocks of healthy streams. 
   
3. A wild trout parr will hunt and eat zooplankton, just like we watched with our captive trout in our recent feeding experiments! Wild parrs don't typically eat Daphnia (the zooplankton we fed our trout), but they do eat a different species of zooplankton... known as copepods. In fact, a common copepod that trout like to eat is called a calanoid and might look like a Plankton you've seen before (hint: Spongebob).
   

   

   Calanoid, a microscopic zooplankton.

So what do you think? Who has the upper fin? A trout that has grown up hunting and spent its whole life in the wild, or a larger trout that doesn't have as much experience hunting or hiding among the rocks? 

-Originally posted by Marina Howard, March 17, 2021

Some Cool Facts About Daphnia!

Daphnia are a zooplankton, meaning that they are animals (zoo) that live at the water's surface, drifting with the currents (plankton). But daphnia are not just any zooplankton... they can live in incredible conditions! 

Studies show that daphnia can live in slightly salty water like you would find where a stream meets an ocean (estuary) and that they manage small levels of salt just as well as completely freshwater! This is incredible. If a human were stranded on a boat in even mildly salty water, they would not be able to survive drinking it because the salt would just make them thirstier - but daphnia can. 

A healthy daphnia (left) with a daphnia
producing hemoglobin (right). 

And here is something even more incredible: if the water source is not changed for the daphnia and they start to use up all their oxygen, they create the same chemical that we have in our blood (hemoglobin) to bind oxygen - making their oxygen intake much more efficient (and turning them slightly reddish colored). That's crazy! Think if you were trapped in your classroom without an air supply and everyone breathing up all the oxygen, pretty soon you would feel super lightheaded, but daphnia have a mechanism to be able to survive days longer in an environment without a lot of oxygen.

If you think that is cool, just wait until you get to watch a trout chase a daphnia around a glass in our feeding experiments. We will have videos and more results of our live feedings coming by the end of next week, stay tuned!

You can check out more about daphnia through our worksheet and a slideshow shared by our teacher program on the teachers' tab of this blog. 

-Originally posted January 29, 2021 by Marina Howarth

Daphnia heartbeat

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!

Trout Care Checklist