A fungus amongus?!
Three days ago, Bob Wible sent me two pictures of fungus that developed in one of the TIC tanks of the Central Vermont Chapter area. Here's one of those photos.
I sent the photos to some of our TIC supporters. Robb Cramer, Greater Upper Valley chapter TIC liaison and Dartmouth professor, sent an e-mail back to me saying, "Saprolegnia [the scientific name of the fungus]. Eggs probably won’t make it.
Our TU national TIC coordinator Tara Granke provided this response.
Here’s a post from the National Google Group with more information about Saprolegnia (aka water mold or common fungus):
It spreads very rapidly and is difficult to get rid of once it has spread to a majority of the eggs. It can be prevented by removing dead eggs daily or more often. It can also grow on gravel, plants, and live fish!
So what's the take-away? Make sure you remove those dead eggs ASAP!
BTW, that link that Tara provided also includes instructions on how to clean your tank if you're able to get a new batch of eggs or alevin. (You may need to join the national TIC Google Group to access that link.)
A leaky tank?
I got another e-mail from Bob Wible over the weekend. In it he said:
Had a teacher contact me last week concerned about her tank leaking. I tried to get a feeling of how much leakage a day. Maybe a quart to a gallon. (Of course, a gallon of water on the floor is quite a mess). I suspected it was more like a quart. Anyway, I visited last Thursday and found the insulation was not tight around the tank. The sides were connected to the back but neither sides nor back were connected to the base. This allowed a large gap between the tank and the back insulation. I believe this allowed an air flow and lots of condensation to be made. By the way, the tank is at 43 degrees. Today she said that water was no longer accumulating around the base. So, I assume this problem was solved by tightening up the insulation to reduce condensation build up.
As you've probably noticed, having a tank of cold water in a warm classroom invariably generates a lot of condensation on the glass of the tank. (This phenomenon, in itself, is an interesting "teachable moment" to address with your students. What NGSS would it address?) Fortunately, putting tight-fitting foam insulation around the tank greatly reduces the condensation, especially if there's minimal air circulation between the tank and the insulation board.
Lesson learned? Make sure there's no extra space between your tank and its insulation.
A new source of science-related YouTube videos
During a breakfast meeting this morning TIC volunteer and aquaculturist Lorena Schwarz told me about a great YouTube channel that she came across. Here's an example of the content you will find on it.
In this super series, host Sabrina Cruz addresses numerous basic and complex concepts of science, with categories for Earth Science, Engineering, Life Science, Physical Science, and Space Science. Most categories include 12 three- to six-minute long videos, with a total of 65 videos in all. They were designed for a 5th grade audience, but I learned a lot from and enjoyed them. Wonderfully, each video includes information on the NGSS that it addresses.
Here's a link to the channel. Please check them out and let me know what you think.
Temperature not holding constant
Recently I got a question from Michael Luzader, of Currier Memorial School.
Now that we have eggs in our tank and we are collecting data I notice that the temperature in the tank fluctuates by 2 degrees (42 - 44). Depending on the time of day, our temperature could be anywhere between these two numbers, and while I am trying to check at the same time of day, for record keeping, it could still be different; can you offer any guidance?
Here's how I responded.
Your chiller is performing the way it should. Like all heating and cooling device that utilize a thermostat, there’s always a regular fluctuation in the temperature, with it bouncing above and below the desired target. As I recall, your chiller has a setting for the number of degrees off the target that the water has to be before the chiller kicks back on (or off).
One of the reasons for this is to reduce the strain on the chiller that would result if, for example, the chiller kicked on at 42.5 and kicked off at 43.5.
Either recording the temperature at the same time each day, as you’re doing, or averaging the daily high and low is about the best you can do. BTW, it gets even more complicated when you consider what the in-tank temperature variations might be. I suspect that if you had ten thermometers scattered throughout the tank, you’d find even larger variations.
At this stage, when we’re using temperature measurements to predict swim-up and “first feed” behavior, the most important temperature is that of the water close to the breeder basket.
Joe Mark is Lead Facilitator of Vermont's Trout in the Classroom program.
In June 2012, I retired after 40 years in higher education, having spent the last 32 years of my career as dean at Castleton. One of the first things I volunteered to do in retirement was to work with a parent-friend to help the Dorset School, where his kids and my Vermont grandkids attend, start a TIC program. Gradually that commitment grew into my current role, which is both demanding and highly rewarding.