Red spring vs white spring

[ericl]

I find where you catch them makes a big difference - whether or not they are still silver - or have adjusted to the freshwater...

That's why we call them "boots" - no comparison between an ocean fish caught 100+ miles from the river & a boot. The small immature's can taste pretty nasty as well. When I buy Chinook (cheapest way to get it IMO) I ALWAYS look at the skin to make sure it isn't starting to turn & also it has to have a thick belly or else I pass. All the white's Iv'e caught WCVI have been great as have been those Iv'e bought outta Sitka.

 

[agentaqua]

...At the cleaning station we were talking about it and a guy says you can tell through the gill plate. He looked and said nope it’s red.
I opened it up and sure enough it was white. Although it was a bit marbled. ...

Interesting post, TU. I am convinced that the red or white colour has to do with what they feed on.

I am assuming that the red colour comes from feed (esp. krill) that contain a carotenoid called astaxanthin that causes the red color. Fish farms use feed formulas that contain astaxanthin to finish-off their feeding of Atlantics before harvest - in order to produce the red colour in their product before harvest.

As far as Chinooks go - I believe what they feed on is related to their life history - which has a genetic component.

So, red Chinook somehow feed at the depths krill are found; while white chinook feed more on herring and other forage fishes, IMHO. That also explains the taste and oil differences between red and white Chinook - as herring are more oily.

I think it might also explain differences in gill rakers - as plankton-feeding fish have finer and more numerous rakers than fish-eating fish - altho krill are the some of the largest "plankton" going. Would be an interesting study to compare white and red spring rakers.

 

[SpringVelocity]

Interesting post, TU. I am convinced that the red or white colour has to do with what they feed on.

I am assuming that the red colour comes from feed (esp. krill) that contain a carotenoid called astaxanthin that causes the red color. Fish farms use feed formulas that contain astaxanthin to finish-off their feeding of Atlantics before harvest - in order to produce the red colour in their product before harvest.

As far as Chinooks go - I believe what they feed on is related to their life history - which has a genetic component.

So, red Chinook somehow feed at the depths krill are found; while white chinook feed more on herring and other forage fishes, IMHO. That also explains the taste and oil differences between red and white Chinook - as herring are more oily.

I think it might also explain differences in gill rakers - as plankton-feeding fish have finer and more numerous rakers than fish-eating fish - altho krill are the some of the largest "plankton" going. Would be an interesting study to compare white and red spring rakers.

No they feed on same thing. The whites genetically can't retain the Carotinoids when they break down food. Marble are just fish that are able to break it down but not as effectively. Been studies before.

https://www.adfg.alaska.gov/index.cfm?adfg=wildlifenews.view_article&articles_id=738

 

[agentaqua]

Thanks for your post SV - adds depth to that conversation. The 2 theories do not have to be mutually exclusive, however: In order to metabolize carotenoids in ones diet - they have to be there to begin with. It is possible that Chinook who can metabolize carotenoids preferentially eat non-astaxanthin containing feed like herring - and it is interesting that farmed Atlantics seem to be able to metabolize astaxanthin in their diet. So, it seems to me to be the start of answering the question - not necessarily the end...

 

[Birdman]

They've done tank tests that show in some fish that have the genetic defect they could eat buckets of krill and the meat would be white as snow.

Anecdotally I know I've caught lots of white and marbled springs filled with krill.