Count before you release!! How do you catch those speedy fry? Dissection at Proctor. What do you transport fish in? Two takes on stream temperatures.

First trout
After publishing blog #21 last Thursday afternoon, I decided to hit one of the local streams for an hour or two of fly fishing. I caught (and released) my first trout of the year: a beautiful nine-inch native brown and a seven-inch brook trout that, by its colors, looked like it may have been stocked.

​The back of my right hand also served as a landing pad for a virtually black mayfly, which I believe is known as Hexagenia bilineata. See photo below.

Here are some artificial flies that are designed to imitate the nymph/larval and adult versions of the March Brown.

And when I went to the Castleton River on Friday and threw in my thermometer, I found that the water was 56 degrees. That means that it rose 12 degrees in a week. Pretty amazing! If you can, start taking the temperature of your release stream.
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Lisa Marks. of Ludlow Elementary School, netting out their fish last year

Count those fry!
In the past, some schools have neglected to count their fish before releasing them. If you don't count them, you will probably never know how many you released. Why is that? Some teachers use what I call the "subtraction method." They make an assumption about how many eggs they started with and then subtract the eggs and fish they know they lost. But this approach, for reasons identified below, is never accurate. Indeed, some teachers I've worked with have discovered that their actual total number of fish is two or more dozen more that they thought they had. Sometimes it's fewer. Here are some explanations.

• You almost certainly didn't get the number of eggs you asked for. Staff at the hatchery use a way to count eggs called the Von Boyer method. This approach utilizes a 12" angle-iron trough and is an estimation system that works only if the size of each and every egg is exactly the same as the staff assumed it is. They all most certainly won't be! Guy Merolle, of Castleton Village School, uses a very interesting and I think effective method to count the eggs. When he first receives the eggs, he arranges them in a single layer on the bottom of the breeder basket(s), making sure that none are stacked on top of other eggs. Then he takes a digital photograph of the eggs, shooting straight down at them. He projects this photo on the classroom screen and divides it into different quadrants. Students work in several groups with the task of counting the eggs. Once each group reports on the number of eggs they have counted, the class discusses the results and decides how many are there. He has found that in some years the number of eggs expected and the number actually received can vary by as much as 50%.
• Some teachers do their best to keep good records of eggs and fry lost, but this too is a challenging and almost certainly imperfect process. No matter how hard you try, you probably will not be able to record all the eggs and fish you lose. Why is that?
  • fish can get sucked into the filter;
  • they die and decompose in the gravel;
  • they get stuck behind some of the equipment;
  • they jump out of the tank while no one's looking; and, of course,
  • they get eaten by their bigger brothers and sisters.
• ​Once the fry are loose in the tank, it borders on impossible to get an accurate count, and unless you've got just a handful or two, whatever number you come up with is almost certainly an underestimation.

So, what's the best way to count them?
I know at least one teacher who builds counting the fry into the Release Day process. He sets up a recording station staffed by a couple of students. Then each team that has been given fry and released them goes to the recording station to report the number they released.

Most teachers, however, count fry as they remove them from the tank and transfer them to whatever container (more on containers later) they are going to use to transport the fry to the stream.

Two nets, one 7.75" wide, the other 4.75" wide, are handy when you're trying to capture your fish.

​Here's what I recommend.

1. Decide how you want to do it. Many teachers get students directly involved in the process, e.g., taking turns netting a few; others do the transfer themselves or working with, say, a community volunteer. However you decide to approach it, make sure it's clear who is responsible for recording totals. If you're going to do this with or in front of the whole class, take steps to avoid chaos; it tends to be an exciting process. 
2. Get a mid-size container to use (something six to eight inches square or in diameter would be perfect) and put some tank water in it. The idea is that, after you net a few fish, you don't put them directly into your transport container but put them instead into the mid-size container. That's where you count them, and only after you're certain that you got a good count do you dump that group of fish into the transport container. If your mid-size container is transparent, set it on top of a white or light-colored background when you're trying to count the fry.
3. Don't net too many fry at a time. If you have more than, say, six or seven fry in your mid-size container, it might be hard to get an accurate count. (The fry will seem agitated after you've netted them and will be swimming fast and frantically around the container.)
4. You'll probably find it helpful to have both a small and a large net.
5. Netting the first group of fry is pretty easy, but it gets progressively more difficult to get the rest. The last few can be a great challenge. For this reason, allow enough time--at least half an hour--for the process. Here are some suggestions for getting those fry that are especially good at evading your nets:
   1. ​Turn off and remove the chiller, filter, and aerator.
   2. Use a straight-edge to push the gravel to one end.
   3. You may discover that some students are more successful at netting the remaining fry. Get two or more of those to work together with their nets, one "driving" reluctant fry towards the net of the other student.
   4. Consider lowering the water level by using your siphon to partially drain the tank.
   5. Even after you think you think you got them all, have a couple of students scan the bottom of the tank carefully for some minutes, looking for any fry left behind. There's usually at least one. It might help to use a net or other devise to disturb the gravel to see if you can "put up" a hunkered down fry.​​

A whiteboard pressed into service to record the fish total.

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Dissection at Proctor Elementary School
On Friday, Danielle Fagan, at Proctor Elementary School, sent me a report and some photos of a dissection activity conducted by community volunteer Trip Westcott.  Here's what Danielle had to say after the activity.

Trip,

Thanks so much for teaching us about the anatomy of a trout. Everyone--the students, principal, and teachers present--thought it was very cool, especially the stomach contents. Later, we took a closer look at the scales, fin, and eyeball under the microscope. 
Thanks again,

​Danielle 

Danielle sent these photos. As you can see, Danielle used the classroom's digital camera to project onto the screen an image of Trip's dissection work.

So how do you transport fish on Release Day?
You've been working very hard since January to keep your fish healthy. That has included ensuring the tank water was cool and well aerated. On Release Day you'll have to worry about these issues too.

Back on March 13, I wrote a blog post that included a section on adapting a traditional 48-quart picnic cooler so that it is aerated, using an inexpensive battery-powered bubbler, and so that you can easily monitor the temperature of the water. (This also assumed that you froze dechlorinated water in plastic bottles and had them on hand in case you needed to use them to keep the temperature cool.)

If you can put together something similar, it will give you lots of options for Release Day scheduling. If you can't, you need to think about how long your fish can manage without aeration. Here's a photo of happy fry in an aerated cooler.

Shawn Nailor, TIC liaison for the Mad Dog chapter of Trout Unlimited, wrote me with this question:

Hi Joe,

Question for you; any idea on how long the fish could stay in water without aeration and chilling? I'm trying to get a sense if a release spot is near a school if just a cooler with water could work for an hour.

Shawn

I didn't have a good answer for Shawn, so I turned to the person I depend on most in these circumstances.

Here is his response.

Joe, 

When I transport fish to a release site, I aerate my cooler because I arrive early to collect the fish and get to the release site before the school buses.  Generally when we're ready to start the release of fish I have someone help me carry the cooler to the stream. At that time I remove the aerator.  I have never had fish die during the next hour and half to two hours during which kids rotate to the various stations of the release.  I keep the cooler in the shade and will add water from the stream to replace that which the kids use up filling their cups.  This helps keep the water in the cooler cool and aerated.  I carry a battery operated aerator just in case it is a very warm day and feel the fish need the extra O2.  I have probably used it once or twice.  I think Shawn should be OK if he adds some stream water to the cooler as the release progresses. 

Chuck Dinkel, MD TIC Coordinator

Here are two more ideas:

1. Another approach is what Mary Hogan's Steve Flint does. He created a five-sided almost-cube of netting and attached it inside a plastic milk crate, securing its corners to the corners of the crate. After adding a rock or two to weight the crate down, Steve positioned it in a shady, shallow area of his release stream. Then he transfered his fish from their un-aerated transport cooler. The fish can swim happily inside the crate for hours, surrounded by the water of their new home, while groups of students work their way through the several hands-on educational stations Steve and his volunteers staff for their benefit.
2. Manchester Elementary and Middle School community volunteer Gary Saunders will attend the first portion of the MEMS release, but then towards the end of the morning, Gary (and I) will go the school, get the fish, and bring them back to the release site. The only tricky part of this plan is that we need to allow enough time to net the fish out of the tank. I'm allowing 45" for that process. [And, after I posted this blog last night, I got this comment, and third suggestion, from Trip Westcott.] 
3. Hi Joe et al. For 25 years, I used this method at release: Visit the stream a few days or a week before the release. Take the temp; then compare it to a stream near your school. Note the difference. Use this as a guide. The difference will be the same. Change the temp in tank to match (gradually).Net the fish into a cooler. Have a kid constantly pour water with a solo cup from a 2ft height to make bubbles all through transport. Mix and match water at streamside. Give each kid a white paper cup with 2 to 4 netted fish to release. With a clip board, keep a count. I never lost one salmon fry using this method. Trip Westcott

What temperatures are the streams?
Earlier in this post I mentioned that the Castleton River was all the way up to 56 degrees. Well, not all streams are that warm.

On Monday I spent an hour fishing Mad Tom Brook, which drains Bromley Mountain and hits Batten Kill in the town of East Dorset.

On a beautiful, sunny day (as you can see from the photo), MTB was 50 degrees. This means that you can't rely on my reports of stream conditions, especially if you live and work in a fairly different part of the state. Instead, it would be best if, within four or five days of your release date, you could plunk a thermometer into your stream (or an appropriate local surrogate) and take its temp.

These next few weeks will be very busy!

Have a great Release Day!