Tuesday, February 5, 2013

"You do WHAT to the fish?????"!

Finally!! Back from that field trip and what a doozy it was!! Remember I was telling you about that " been there done that " feeling?  Well we recently took a field trip to the Feather River Fish Hatchery (yes still here in Oroville, CA.)  We've been to the fish hatchery before, a few years back in the Fall when the Salmon were running, but this time was very different. 

The populations of Chinook returning up the Feather River to spawn in the Fall are phenomenal and the season lasts from September through November.  During that time the hatchery maintains spawning facilities for somewhere between 9,000 to 18,000 Salmon -- this process produces, on average 18 to 20 million eggs -- Yes I said MILLION!! Can you imagine??  This hatchery is an essential part of maintaining the sport fishing for the Feather and Sacramento Rivers, AND even contributes to the commercial and sport fishing in the Pacific Ocean.

This time of year Steelhead are running!! So our visit to the fish hatchery was quite a bit calmer than the last time we visited.  Steelhead populations are quite a bit smaller and the run is a shorter period of time, typically December through January.  We had a great "tour" guide, Jana, from the State of California Department of Resources (DWR).  (The DWR was where I called to inquire about tours/field trips, by the way -- a tidbit that might be noteworthy for your 'resource list' -- just sayin'!...) 

As we stood at the viewing window above the spawning area we learned that Steelhead don't die when they spawn, as the Chinook do.  Thus the spawning process involved is much different.  Some of you may know that since the Chinook spawn at the end of their life cycle, the hatchery will anesthetize prior to, then humanely euthanize the fish following collection of, the eggs and milt needed for spawning. 

[SPECIAL NOTE:  Jana shared with us that the meat of the Chinook is not wasted.  It is used through a local program to feed homeless and low income in Butte County.  We thought this was a great community service, and were glad that she shared that tidbit. -- I don't remember that being shared on our previous trip here.  Ahh... another perk of a personal family tour.]

So, back to the Steelhead -- the hatchery worker will introduce the fish into water with higher carbon dioxide to slow down their movement.  The females are then injected with air in order to release the eggs into a tub -- she is then released back into a holding tank until her movement is normal and then released through a shoot back into the river.  As soon as the eggs are expressed from the female, the milt is released from the male into the same bucket and the male is released through the same shoot.

Jana noted that the eggs and milt are mixed quickly and then put into trays and taken to a specially equipped room to be diligently cared for until hatching.  The "nursery" for caring for these fish is amazing!  The record keeping alone is a quite a task, not to mention maintaining water temperatures and tracking each tray for growth, including removal of eggs that fail to thrive. 

Even though the Steelhead population is smaller, they still spawn approximately 2,000 fish each year.  Then the eggs are cared for at the various stages of development, including spending a time in "raceways" as they progress through the stages of "Fry" -- "Fingerlings" -- then "Yearlings" --  It takes many months until they are large enough to be transported via special fish tanker trucks to the San Francisco Bay Delta.

If you'd like to see some video about this I encourage you to visit YouTube and search "Feather River Fish Hatchery" -- You'll see some great video of the fish ladders and get a feel for the numbers and sizes of fish that travel back up the Feather River each year.  It is really amazing to think that the Chinook make the trip from Oroville, at the Feather River Hatchery, down to the San Francisco Bay (and beyond -- some reports as far as Alaska and even Japan!! -- ) and then back again in their life cycle, which averages three to four years. 

It is absolutely ASTOUNDING to think that the Steelhead may make a similar journey several times in their life span of six to nine years; during their life they may spawn between two to four times, on average.  That may not sound like much, but if you take time to look at a map and find Oroville, CA (north of Sacramento and just SE of Chico) then find and follow the Feather River down through the Sacramento River and on to the San Francisco Bay -- Wow!!  And then... think about their ocean travels?? An amazing feat for a fish less than two feet long, don't you think?

One more side note -- I mentioned earlier about searching YouTube for the Feather River Fish Hatchery, and that one of them shows the "fish ladders".  Now there's a term that conjures up mental images akin to a Dr. Seuss drawing, huh? Well, they're not what you think... the fish don't get out of the water and go vertical!  Geesh! Some people... tee hee hee...

The fish ladders were built as a means for the fish to traverse the river that has been impacted by the Oroville Dam (more about the Dam will be in a later blog -- perhaps the next one...?? ) You see, fish in the Salmon family carry genetic markers for where they were born... that is how they navigate their way back to their birthplace for spawning.  Since the placement of the Oroville Dam in the late 1960's has made that rather challenging, the State Water Project incorporated the fish ladders to aid this natural process.

While we didn't take any pictures of the eggs and milt being expressed I did see quite a few cool videos on YouTube, but not sure if I can post without permission -- So I hope you will take time to look up the Feather River Fish Hatchery, Oroville, CA and enjoy the videos.  Until next time...

Enjoy the journey...



  1. Wow! I had no idea so much went into that! On one hand it is really cool that you got to see how the eggs and milt are expressed, but on the other it is sad that we have to have a human intervention into this process. There are so many aspects of nature that I feel should left to nature and it is sad that we can't always allow it to happen without human interference ~ Victoria

  2. Well you learn something new everyday. But I have to say I agree with "Victoria's" comment about the human intervention, but if it works then it works!

  3. I totally agree, that not interfering with mother nature is best. However the hatchery was created as part of the Oroville Dam water project. The dam creates a huge reservoir that provides water, not only for recreation but for residential, commercial and agricultural use. Additionally it provides flood control for the Upper Sacramento Valley.

    You'll be happy to know that there is still a significant number of fish that spawn in the river each year, but the hatchery increases the population to a level that is more near to or beyond what it would be if the dam were not there. The hatchery also increases the overall survival rate as the eggs of the salmon, as well as in the fry and fingerling stages, are especially vulnerable to predators.

    Your comments are very much appreciated... stay tuned, we'll be sharing more about Oroville Dam and our field trip there! :)