Tuesday, December 24, 2013

The Weather Outside Was Frightful!

There is an unwritten law that things will break during terrible weather, when you are short staffed, or on a Friday at 3:25.

Such was the case last Saturday when our weekend crew, Jeff and Nate, arrived to six inches of heavy snow. Now six inches of snow really doesn’t seem like a whole lot, but when you have 4 acres of overhead bird netting that needs to be shaken and far more snow to plow- in addition to taking care of 6 million fish- well, let’s just say the troops were called in. Good thing too. The problems didn’t end there.

Rob and Joe arrived and started on the snow while Jeff and Nate got on with their fish culture duties. While feeding the Chinook, Nate noticed the flow had almost stopped in one of the raceways. It was lucky raceway 13. Coincidence? I don’t think so….

This is not what you want to see...
This IS what you want to see
The flow had dropped from the usual 750 gpm (gallons per minute) to mere 100 gpm. Fortunately, the fish were doing okay. It was suspected that some of our water filtering media had broken up and gotten jammed in the valve. Usually you can break this media loose by opening and closing the valve. But this time that didn’t work.

The guys were able to install a backup pump to supply water from the adjacent raceway, pumping water from A14 to supplement the flow in A13. Both raceways had around 350 gpm each. Because of the low flows, both of these raceways off feed for the weekend. We would have to wait until Monday to take off the vacuum degasser and clear the blockage.
Help is on the way!

Alright, I know most of you can't sleep without knowing what happened on lucky raceway 13. The great news is that we got the valve cleared! It took some wrestling by our fantastic maintenance guys, Terry and Adam, to get the de-gasser off, but once that was removed, the plugged Koch rings were easy to pull out.
The culprits, plastic filter media, called Koch rings.

Surprisingly, there were only parts and pieces from about 3 Koch rings, which goes to show that it doesn't take much of a blockage to significantly restrict flows. Of course, a fair amount of moss also came out, which was likely packing the remaining space.

Great Work Team Dworshak!

Text by Angela Feldmann and Nate Wiese
Photos by Nate Wiese

Thursday, December 5, 2013

The next generation of Clearwater Chinook

The next generation of Chinook are on their way!!!!

In August we spawned adult Chinook. Their progeny have been quietly incubating in the dark, cold heath stacks here at Dworshak Fish Hatchery. Dark? Cold? I know, it doesn't sound all that pleasant, but if you are a salmon egg a nice 37 degree heath tray is a wonderful place to call home. You have oxygen rich water flowing around you at just the right volume, light is limited so eggs can develop properly, and there are NO PREDATORS! Easy living.

Our egg sorters count and separate live and dead eggs. 

After our initial egg counting, called enumeration, we hand pick any dead eggs from the incubation trays. This job is labor intensive, but it keeps fungus growth down and our eggs and rearing environment healthy. In a few short years, these tiny embryos will grow to be 10-20 pound adults.

Jeff is removing dead eggs from a heath tray. There are 5000 eggs in each tray! This year we have about 2.15 million Chinook eggs in incubation at Dworshak. The eggs are incubated in 37 degree water (F). It is chilly in the incubation room!

A tray full of healthy eggs is a beautiful sight!!!

Twins! The center egg has two embryos inside. They are probably conjoined at the yolk sack, and unfortunately they will not survive. The egg on the left is a healthy embryo. The egg on the right is an embryo that is not forming correctly; notice how tiny the eye spots are. The top egg is dead.

With good rearing and a little luck most of these tiny eggs will be released as smolts in the spring of 2015. After that they will have to fend for themselves, but some, hopefully many, will return as adults and we will start the process again. 

Photos and Text by Angela Feldmann