amazon catfish migration ?

heard about yer man Heiko Bleher seeing huge catfish migrations on an amazon tributary ,he estimates several billion catfish of different species moving up river to spawn (that many cats that freshwater rays and other fish were floating to the surface from lack of oxygen ).could only find some writing bout this,has anyone else come across any other info bout these huge catfish migrations,would b very interested

Brian, my brother in law is on good terms with Heiko, spent 2 weeks with him on the Amazon last year (and never stops talking about it ). I'll ask him to get some info, he's meeting up with him at the aquatics live show.

excellent 2poc any info vids etc would be very welcome.
thanx