STOP ADDING BACTERIA--for now--unless your temperature is at or near 50 degrees F.
Some of the members of Vermont's TIC support team have been busy lately! On Monday I met with local professional aquaculturist Lorena Schwarz. On Tuesday, I had two telephone conversations totaling 40" with Doug Dent, head scientist at Ecological Labs, the company that makes both Special Blend and Nite-Out II. Then that evening, I spoke with Maryland/DC TIC coordinator Chuck Dinkel. Finally, on Wednesday, four of us, Lorena Schwarz, Central Vermont coordinator Bob Wible, GUV coordinator Robb Cramer, and I had a conference call. All of these conversations focused on how the two bacteria we add to our tanks work, especially in cold water.
Hatching too early or normal?
Here are some photos taken at Crossett Brook Middle School of early hatching eggs. In sending the pictures, Meg Ritter wrote:
We have two alevins and more on the way. Our intrepid photographer is a seventh grade student, taking the most recent pictures under the microscope (see attached). We even have a photo of an empty egg.
I've been getting a lot of inquiries from teachers regarding egg hatches--questions like:
Danielle Levine, of the Schoolhouse Learning Center, wrote this:
I keep having early hatchers. They are the ones the we put under the microscope; since they get warmed up, that makes sense. However, they seem to hatch and not make it. Any ideas on what I can do to help their survival? Are they just too small and victims of our need to study or is there something I can do?
Not sure. I assume that the “preemies” are biologically weaker than their normal-hatching peers. It may be that they are too weak to handle the additional stress of removal from the basket and exposure to the microscope light.
As long as you don’t have an epidemic of “early risers,” I think it’s okay. If you suspect it’s the warming of the microscope light, can you shorten the exposure time of use non-illuminated magnification?
Regardless, the educational benefits you’re providing your students are terrific and, IMHO, worth the casualties. If, however, alevin that haven’t been exposed to the microscope light keep dying, let us know.
Bob Wible offered this opinion:
I suspect two possibilities:
1. Light shock - strong UVA light, camera flashes, microscope light, etc. are detrimental.
2. Temperature change shock - great than 5 degrees. I assume you remove the egg from 52 degree water put it into a small container with a little tank water look at it for a while then return it to 52 degrees. While the egg is out of the tank its temp is rising well above 52. Can you ease it back into the tank 52 degrees so it doesn’t go from maybe 65 to 52 in one millisecond?? Maybe take 15 minutes or so.
Just some thoughts.
Both Bob and I both shared Danielle's question with Jeremy Whalen, Roxbury hatchery supervisor. On 1/25/18, he wrote back with this:
Teachers should start seeing some hatching at this point, your calculations are correct and the eggs should be around 53 DI. The DI chart says 90% hatched at 58 DI, so it’s not uncommon to see some early hatch’s. At 43 degrees teachers are gaining 0.69 DI daily, which puts 58 DI about 7 days away.
Then Poultney Elementary's Keith Harrington sent me this message today.
I was just wondering if anyone else was reporting preemies. We had two last week, neither of which survived. When I came in this morning, I had three more. Although they were swimming when I jiggled the breeder basket, I am concerned that they will suffer the same fate as the others. My tank has been kept at a steady 43 degrees since the eggs arrived. Thoughts?
So, a few conclusions from these exchanges:
Most important don't feed alevin at this stage. Unless you're running a high temperature, "the "swim-up" stage is still weeks away. As Jeremy said above, currently DI in most tanks should be in the mid-50s. Swim-up (for about 50% of the alevin) won't occur until the DI gets to about 85 or 90.
Photos from Schoolhouse Learning Center
Here are some great pictures of Danielle Levine's 4th grader as their share their TIC expertise with younger students. Here's what Danielle said in transmitting these great shots. Here are pictures of my 4th graders presenting the trout project to our preschoolers (4 year olds). They explained the tank, the lifecycle and then showed them the eggs under magnifying glasses and a microscope!
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.