Raisin' Fish: Not so cold anymore

I haven't posted in a couple of weeks for a number of reasons. The primary one is that my trusty home computer started acting very flakey. It has two internal hard drives and the secondary one died on me. That caused the entire system to slow down to a painful crawl. I didn't get around to fixing that until this afternoon. All is well now and all the pictures taken over the past few weeks have been transferred and the system is working much better. Now I can post easily again.

Well, we sure went through a cold spell in the Puget Sound region between Christmas and New Years in 2008. We had snow on the ground and on the streets for most of that time. I was pretty worried about the incubator for a while there. After the first day or so of snow the scene down by the creek looked like this:



We ended up with quite a bit more snow than that, but that's one of the only pictures I took of the incubator in the snow this year.

Once the temp started to come up during this past week, all of the snow started to melt and the creek level rose quite a bit. It got high enough to cover the outlet tube of the incubator, which always worries me. Several years ago, we had some flooding in the creek and the water level was above the outlet tube. Unfortunately, at about the same time a good-sized tree branch floating down creek got wedged under the inlet pipe and lifted it up out of the water. By the time the creek level went down enough for me to notice the lack of outflow, all of the salmon in the incubator had died. I felt sick about that for about a week. That's why I get nervous whenever the outlet tube gets covered.

One difference now, though is we are using a much bigger inlet pipe. It is larger (6" vs 3", before), quite a bit heavier (and so more resistant to getting jacked up by a passing tree branch), and we have hammered a couple pieces of rebar into the creek bed and wired the end of the outlet tube down so it won't come up easily.

As I think I mentioned before, the flow rate in the incubator system should ideally be at least 10 gallons/minute. The flow has been considerable less than that lately, but with all of the stuff going on around here (we had 4 fairly large trees come down on the property due to snow. Luckily, none of them did any major property damage, though Francis & Abby's Odyssey minivan does have a dent in the hood that it didn't have before Christmas and the cap on Francis' pickup truck was destroyed when a large branch broke off a second-growth Douglas fir in the upper lot.) I had not had time to check the water line.

The day before yesterday, I spent the afternoon in the creek, starting at the upper end and working my way down to the incubator. First I made sure that there was plenty of water flowing into the inlet pipe (there was). Once that was assured, I started moving down creek and stopping at ever pipe junction. The pipe is 3" ABS plastic pipe, just like the stuff you'd use for a plumbing project in your house. It's mostly 10' lengths that are held together by collars. Those collars have two stainless steel screws on the upward facing side that hold everything together. The pipe is not completely air or water tight, so occasionally there are pockets of air trapped in the system. These pockets have to be bled out so that the pipe can carry as much water as possible. To bleed the system, all I have to do is go to each pipe junction and back one of the screws all the way out. If there is air trapped in that section, the pressure of the water forces it out. It's kinda cool to pull out one of the screws and hear it hissing away. It means things will be getting better in the system. Once all the air bleeds out, water will start to spurt out the hole. At that point you put the screw back in and move downstream to the next junction.

By the time I bled the whole system, a couple of hours had passed and I had improved the water flow significantly. Just from looking at it, I figured it was much more than the needed 10 gpm. To test it, I emptied all of the water from the clarifier and timed how long it took to refill. It's got about 55 gallons capacity and refilled in 3 minutes 20 seconds. That works out to just over 16 gallons per minute! (Imagine the voice of Marv Alpert, veteran broadcaster for the New Your Knicks) Yessss!

That was Tuesday. Since then the waterflow has continued to be strong.

While I was fooling around with the clarifier and incubator, I dropped the water level in the incubator to look at the first tray of eggs. I was very surprised to see that most of the eggs have not yet hatched. I expect that a few have, but the majority have not. Usually by the time they have spent 20 days in the incubator, most of them are hatched. Guess the cold water and air temps are retarding their growth. Nothing I can do about that, really. Just watch and see what happens.

As long as I keep water flowing, they will be fine.

I've done a bunch of reading and will chronicle some of that in the next post or two. I don't feel like writing any more this evening.

Raisin' Fish: Dang it's cold

Seattle is in the grip of a major cold wave along with most of the northern half of the US. Normally we are sheilded from that by the Japanese current and being at sea level more or less, but not this time. It has been below freezing for several days now.

Water flow through my icubator is stll moving, but not at the rate it was before the cold set in. I hope that I don't end up with any frozen pipes. I shouldn't as long as the water keeps moving. One thing this will do is slow down the maturation process of the eggs/alevin.

The timetable for salmon maturation from egg fertilization through release is fairly well documented and based on what are call "thermal units." One thermal unit is equal to 1 degree above 32 Farenheit for 24 hours. From fertilization to hatch is 750 thermal units; from hatch to release is 1,000 thermal units. I got my eggs early because of two factors; the fall run of coho salmon at Issaquah Creek hatchery was earlier than usual, and the water temperatures there were a bit higher than normal (causing the eggs to reach the 'eyed' stage earlier).

Water is not all that quick to respond to air temperature changes; it generally varies much more slowly than the air above it. I haven't ever measured the water temp in McAleer Creek, but have guessed it to be about 42 degrees (more or less). That gives me about 100-105 days from the time I get eggs in the incubator until I release them. The water going down a degree or even two would only slow that rate by a couple of days at most, so I'm guessing that fish release will still be some time around the end of March 2009.

I watch the outflow from the incubator a couple of times a day. As long as it is still flowing, my babies are going to be happy. So far, they are happy.

Raisin' Fish: Getting Ready to Receive

I just got off the phone with Darren at the Issaquah Hatchery, one of the many fish hatcheries run by the Washington State Department of Fish and Wildlife. In cooperation with WSDFW and the Mid-Sound Fisheries Enhancement group I have been raising coho salmon in my front yard for the past 10 years. During that time I have incubated 630,000 coho salmon eggs.

I suppose a bit of explanation is in order.

I live on about 1.4 acres of land about a mile from Lake Washington in Lake Forest Park, Washington. McAleer Creek, which runs from Lake Ballinger to Lake Washington (perhaps 5 miles in all), runs right through my front yard. Back when my oldest daughter was in 6th grade, I met a local oncologist (father of one of Claire's classmates) who incubated wild salmon at his vacation house over in Hood Canal. He got me set up with the Mid-Sound folks who bought me the incubator once they saw the water supply I have all year round. Since that time I have been raising about 70,000 fish per year and releasing them into McAleer Creek. During that 10 years, there was only one year when I did not raise fish. That was the year I spent living and working in Mississippi (and that's a whole different story).

I have always liked raising fish and have had an acquarium whenever I could. While I was teaching school in Astoria, Oregon (1975-1988), I always dreamed of raising salmon in the classroom. Many of my students' parents where involved in fishing, so I wanted them to have an appreciation for the beauty and complexity of the whole process. I was never able to get anything set up during that time for a whole variety of reasons. A couple of years after we moved to Seattle, I stumbled on this opportunity and have been doing it ever since. Frankly, I love playing around in the water and this gives me a chance to do that and perhaps do my bit to enhance the viability of salmon in the Puget Sound basin.

So what's a fish incubator look like? It looks like a black plastic 55-gallon drum with some piping sticking into and out of it. Inside it there is space for trays to hold fish eggs and some plastic media that the young alevin can hide in (no worries, you are likely to read more about fish biology as we go along). I have a schematic drawing of one on one of my computers. I'll try to post it one of these days or draw a new one if I can't find it. Standing next to the incubator is another plastic drum (a bright blue one) that I use as a clarifier. The water flows into the clarifier at the bottom and then I take it out of the top of the clarifier and feed it into the bottom of the incubator. It flows up through the incubator and out the top via a pipe and screen arrangement. The water is fed into the clarifier via about 500 ft of 3" plastic pipe. The pipe leads far enough upstream that gravity makes sure that the water flows all year long.

With a setup like this, simplest is best. The fewer things there are to go wrong, the more likely it is that the fish will survive. If I were to use an electric pump to take water out of McAleer Creek, then I'd have to be sure that the pump would operate 24/7 for about 3 1/2 months during the winter. Unfortunately, that is the time when we have our most violent storms, and, because we live in a heavily wooded ravine, the power sometimes goes out when a tree falls across the lines. If I used a gas powered pump, in addition to the obnoxious noise, I'd also have to make sure that it never ran out of fuel for the entire time and that the motor would stand that kind of long term duty. So, I use a bunch more pipe, but gravity is fairly reliable (and significantly cheaper than electricity or gasoline to boot).

Because I will be playing host to 70,000 coho salmon eggs starting on Wednesday, December 10, I have to get the incubator up and running this weekend. Sometime during the summer the stream changed course slightly and left my inlet tube 500 feet upcreek dry. I'm going to have to get that fixed this weekend. While I'm at it, I'll take a bunch of pictures so that you can see what this is all about. I'll post them when I write up the maintenance/repair of the incubator sometime this weekend.