Blue whale vocalization

["oryoki2000" oryoki2000]

Here's an interesting report of Blue Whale vocalizations, observed as
the whale circulated close to shore in Baja California, Mexico.
(Sorry, just a text description, no recording!)

http://michelszulckrzyzanowski.blogspot.com/2009/02/whale-called-louis-arms=
trong.html

I thought Blue Whales vocalized at very low frequencies.  Could the
sounds reported be harmonics of the fundamental call?

--oryoki