Why is Albacore tuna meat white in colour and not red like the other kinds of tuna?

The information on http://www.goodeatsfanpage.com/Season6/Tuna/TunaTranscript.htm
explains why tuna meat is red as follows:

"...like sharks, tuna never stops swimming, ever."
"You see, since they never stop moving, the tuna's muscles require a
lot of oxygen. But to burn oxygen you've got to have myoglobin in the
muscle. Now myoglobin is red."

On the other hand, the information on
http://www.bcseafoodonline.com/files/albacore_tuna.html about albacore
tuna indicates:

"Due to its white meat colour, albacore tuna is sometimes referred to
as the 'Chicken of the Sea'. In fact, it is the only species allowed
to be labeled as 'white meat' tuna."

I assume that albacore tunas never stop swimming either, if so, why is
their meat white and not red?

I'm looking for a scientific answer that is easy to understand and yet
thorough. I also need your source of information for bibliographical
purpose too.

Howdy noguchihideyo-ga,

I reckon it is a combination of two factors.  Albacore (1) is a smaller fish
than other tuna species.  The younger albacore's diet is lots of (2) krill,
and the food the albacore eat, determines to a certain extent, the coloration
of their flesh.

Perhaps the fact that large amounts of fishing has made the average albacore
that is most prevalently caught younger has made a difference.

Here is a fun animated slide show on albacore.  Warning, though, as it
contains animated violence.  It does give you the chance to skip that part.
www.albatuna.com/Movies/ALBACORE.SWF

"Meet the Pacific Albacore Tuna" - sponsored by the American Fishermen's
Research Foundation

Looking Forward, denco-ga - Google Answers Researcher