@aerobat77:
that due to my understanding cannot be and one statement ( pings are from an ulb ) excludes the other . ( bluefind scanned the bottom around the ping and nothing was found )
Yes but the area searched was centred around the 4th ping detection location to the south east. It appears that the pings detected on April 8th were intermittent and at an even lower frequency of 27kHz and have been recently disregarded as potentially coming from a ULB.
The area of the first, consistent 2h 20m long detection to the north west on April 5th has NOT been searched via Bluefin-21. Potentially because the depth there approaches 5000m, beyond the depth rating of the submersible.