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Wednesday, May 23, 2007
I have several questions that quite possibly you maybe able to help me with.
Thank you very much
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. Photo: Vancouver Aquarium
White-flesh Chinook salmon are a natural form of Chinook salmon and more common in some stocks than in others.
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.
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.
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.
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.
Posted by Professor Salmon on 5/23
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