Wednesday, May 23, 2007

Have you heard of white-fleshed Chinook salmon?

“Hi”

I have several questions that quite possibly you maybe able to help me with.

  • Do you have any information on the white fleshed king salmon?
  • Why white meat?
  • What rivers do these white-fleshed king salmon spawn in?
  • Do you have any information on the numbers of king salmon released by Canadian hatcheries?

Thank you very much
Bill

===

Hi Bill

In Canada we refer to this as white-flesh Chinook, not to be confused with the “spirit salmon” a rare occurrence where the salmon’s exterior and internal flesh are almost colourless, but not albino. The “spirit salmon” result from a recessive gene similar to the spirit bear.

White Chinook salmon are called the spirit salmon.

White Chinook salmon are called the spirit salmon. Photo: Vancouver Aquarium

Flesh

White-flesh Chinook salmon are a natural form of Chinook salmon and more common in some stocks than in others. 
 
Salmon traits are inherited through their genes and colouration is one of those traits. Some traits are recessive and some dominant; however, colouration is a blended gene similar to height in humans. Human offspring are not exactly the height of one or the other of the DNA contributor, but rather a combination. 
 
The colouration in salmon flesh is produced by carotenoids, a photosynthetic natural pigment produced only by phytoplankton, algae, plants, and a limited number of fungi and bacteria. It’s bio-accumulated up the food chain to produce the familiar pink, orange and red colours flesh colours in salmon.

White-fleshed Chinook salmon taste like salmon but look more like tuna.

White-fleshed Chinook salmon looks just like other Chinooks on the outside. Photo: Salmongram

Salmon aren’t alone in showing their carotenoids. Numerous species of birds (flamingos especially) crustaceans, fish and insects are also pigmented with carotenoids obtained from their diet. The distribution and storage of the colouration is determined by each animal’s genes. White flesh still has significant quantities of carotenoids even if we cannot see it with our naked eye.

Carotenoids

This fat-soluble pigmentation molecule has many important roles to play in salmon, humans and other wildlife. Two important ones for salmon are during the development of secondary sex characteristics (in the egg) and sexual maturation of the adult fish (when they spawn).

In salmon eggs carotenoids offer important protection from UV rays and other harmful occurrences. When salmon spawn, carotenoids are redistributed from the flesh to the skin to produce spawning colours.

Salmon accumulate carotenoid from their diet and then deposit it in their muscle tissue. This accounts for 65 percent of a salmon’s body mass! In the muscle tissue carotenoids protects the salmon’s fatty acids and other sensitive cellular components from oxidative stress during their extremely taxing migration hundreds of kilometres to spawn in their natal streams.   
 
Research showed the following average concentrations of carotenoids in wild salmon.

  • Sockeye salmon range: 30—58 mg/kg, average: 40.4 mg/kg
  • Coho salmon range: 9—28 mg/kg, average: 13.8 mg/kg
  • Pink salmon range: 3—7 mg/kg, average: 5.4 mg/kg
  • Chum salmon range: 1—8 mg/kg, average: 5.6 mg/kg
  • Chinook salmon range: 1—22 mg/kg, average: 8.9 mg/kg (it has the lowest and therefore displays the white flesh we are familiar with)
Spirit bear sow with 2 black bear cubs.

Spirit bear sow with 2 black bear cubs. Photo: Bear Matters

So what’s similar to carotenoids? Beta-carotene found in carrots is the most familiar to us. Humans convert beta-carotene to vitamin A for use in the macula region of the eye to reduce UV light damage, the same as the salmon uses carotenoids to reduce UV light in the egg.

Where can you find white-fleshed Chinook salmon? The Harrison River late run (fall), the Upper Pitt River summer run and the Chilliwack River fall run are all predominately white flesh. Many other systems also have white-flesh Chinook. Your best bet to find other runs of white-flesh Chinook is to ask locals.

Hatcheries
 
In BC we have 3 main types of hatcheries (or hybrids of the following):
 

  1. Major facilities producing fish in areas where the Federal government (Department of Fisheries and Oceans) is the main steward, and in watersheds where the stocks or habitat has been compromised or degrader. These facilities generally produce commercially, recreationally and First Nations (FN) fishable abundance.
  2. CEDP (Community Economic Development Program) facilities producing large enough numbers of fish in degraded watersheds. These facilites focus on support recreational and FN fisheries and are generally managed by the Federal government in partnership with FN or a local stewardship organization.
  3. Public Involvement Hatcheries that are very small and work to conserve and rebuild degraded runs. These facilities are conservation based and salmon returns are not targeted for fishing. They are generally run by the Federal government in partnership with volunteer aquatic stewards such as Fish and Game protection associations, Streamkeepers and Enhancement Societies.

Chinook enhancement and conservation is very important as it is a species of fisheries management concern for its environmental (ecosystem), cultural, spiritual, economic, educational and social value. These fish matter to us all!

The numbers of juveniles released from hatcheries of all three types provide food for the entire food web. Hatchery salmon are eaten by everything from birds to whales.

The biggest threat hatchery salmon face is loss of productive habitat, including their ocean habitat. Global warming may be their biggest threat as it changes ocean productivity, ocean currents, predator / prey timing and freshwater habitat by increasing water temperature and reducing flows in the rivers. 
 
Unfortunately, much of the historic and alternate habitat that saved salmon during the most recent 5 climate changes is no longer accessible. It’s now behind dams and dykes.
 
Fisheries and Oceans Canada is working with many community partners, including the Pacific Salmon Foundation to conserve and enhance our Pacific salmon legacy.  We invite you to contact/visit a stewardship group any time you come to Canada.
 
More information:

 
Hope this answers your questions. Thank you for asking!

Fin,
Professor Salmon 

Posted by Professor Salmon on 5/23
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